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Cardiorespiratory and metabolic responses to treadmill versus water immersion to the neck exercise in.. Frangolias, Despina Daisy 1993-12-31

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CARDIORESPIRATORYAND METABOLICRESPONSES TO TREADMILLVERSUS WATERIMMERSION TO THENECK EXERCISEIN ELITE DISTANCERUNNERSbyDespina Daisy FrangoliasB.P.E., The Universityof British Columbia,1985A THESIS SUBMITTEDIN PARTIAL FULFILLMENTOF THE REQUIREMENTSFOR THEDEGREE OF MASTEROF PHYSICAL EDUCATIONinTHE FACULTYOF GRADUATE STUDIES(School ofPhysical Education)We accept thisthesis as conformingto the requiredstandardTHE UNIVERSITYOF BRITISH COLUMBIASeptember 1993Despina Daisy Frangolias,1993In presentingthis thesis inpartial fulfilment ofthe requirements foran advanceddegree at theUniversity of BritishColumbia, I agreethat the Library shallmake itfreely available forreference andstudy. I further agreethat permission forextensivecopying of thisthesis for scholarlypurposes maybe granted by thehead of mydepartment or byhis or her representatives.It is understoodthat copyingorpublication ofthis thesis for financialgain shall not be allowedwithout my writtenpermission.Department of\k\c\ &\c\:—\ csThe Universityof British ColumbiaVancouver, CanadaDate(Signature)DE.6 (2/88)ABSTRACTThe purpose of this study was tocompare the following: a) thecardiorespiratory responses, in eliteendurance runners familiar withwater immersion to the necknon—weight bearing (WI) running, atventilatory threshold (Tvent)and at maximal effort (ie. VO2m) fortreadmill and WI running performanceto exhaustion and b) thecardiorespiratory and metabolic responsesto prolonged performance (42mm.) at exercise intensities reflectingthe treadmill and WI Tvent.Thirteen endurance trained runnersfamiliar with water running completedcomparable treadmill and WI VO2maxtests. Oxygen consumption(V02),ventilation (ye), heart-rate (HR),respiratory exchange ratio (RER),ratings of perceived exertion(RPE) and stride frequency (SF)weremeasured at Tvent and VO2max.Blood lactate [BLa] samples were obtained30 seconds and 5 minutes post—test.Correlated t—tests revealedsignificantly (p<O.05) higher VO2max(59.7 vs 54.6 mlkgmin), HRmax(190 vs 175 bpm), RERmax (1.20 vs1.10), V02 at Tvent (46.3 vs42.8mlkgmin1),HR at Tvent (165vs 152 bpm) for the treadmill vs WI,respectively. Similar values wererecorded for Vemax (109.0 vs 105.8lmin), Ve at Tvent(66.4 vs 65.7 lmin), RER at Tvent (0.99vs0.89) and post—test [BLaJ at 30sec (10.4 vs 9.8 mmoll) and5 mmpost—test (9.7 vs 9.2 mmoll1)for the two conditions. Wilcoxonsmatched pairs signed—ranks testrevealed no differences in RPE atTventandVO2maxlevel for the two conditions.Significantly higher SF valuesover time were recorded (88 vs 54stridesmin, averaged over time) oniithe treadmill. The lower WI VO2maxwith similar peak [BLa) and lower SFsuggests that the active musculatureand muscle recruitment patternsdiffer in WI running due to the high viscocityfriction of water, andthe non—weight bearing nature ofWI running.During steady state exercise attreadmill and WI Tvent nodifferences in Ve response toexercise were noted in the treadmill andWI conditions. [BLa] response exhibited adecreasing trend over time inthe WI condition both during thetreadmill and WI Tvent intensity tests.Similar HR values were exhibitedfor exercise at WI Tvent in bothconditions, confirming that the lower HR exhibitedat Tvent from the WIVO2maxtest was related to the lower V02 atWI Tvent and not the WIcondition. Significantly lower HRvalues were exhibited for exercise attreadmill Tvent in the WI versusthe treadmill condition suggesting thatHR is lower only at workloadscorresponding to and above 84.8 % of WIVO2max.Results suggest that exercise in thewater immersion to theneck condition affects (reduces) HRand [BLa) response over time, withthe intensity of exercise beinga factor. The WI condition,howeverdoes not affect Ve and RPE responses.iiiTABLE OF CONTENTSAbstract__________iiList of Tables____viii.List of Figures--AcknowledgementxiiChapter 1.1.0________1.1_____________________________________1.2______________________________________1.3________________________________________________2.0 Review of Literature202.1 Cardiovascularresponses to water immersiontothe neck________________________________________________2.1.1 Heart—rate_______________________________________2.1.2 Preload, Contractilityand Afterload________________2.1.3 Cardiac outputand Stroke volume_____________________2.2 Respiratoryresponses to water immersionto theneck2.2.1 Static Lungvolumes_______________________________2.2.2 Exercise Respiratoryresponses2.3 Water immersionexercise studies________________________2.3.1VO2maxand short durationsubmaximal effort__________Introduction__________Definition of Terms_Statement of Problem1.41.5157Hypotheses8Delimitations15Assumptions151.6 Limitations_1.7 Significance_Chapter 2.16•2 02125262828_3 03 131iv2.3.2 Submaximal prolonged duration exercise in waterimmersion402.3.3 Comparison of the specificity of training: WIversus land—based training 402.4 Ventilatory threshold (Tvent) performance42Chapter 3.3.0 Methods and Procedures 443.1.0 Sample443.2.0 Physiological test equipment483.3.0 Underwater film assessment apparatus andprocedures_523.4.0 Treadmill and WIVO2maxand Tvent performance testprotocols and procedures 533.4.1 Treadmill andVO2maxcommon procedures 533.4.2 TreadmillVO2maxtest protocol and procedures 543.4.3 WIVO2maxtest protocol, procedures and equipment 553.4.4 Ventilatory thresholddetermination 613.4.5 Tvent performance tests613.5.0 Experimental design633.6.0 Statistical analysis65Chapter 4.664.0 Results4.1.0 Physical characteristics of the sample664.2.0 Maximal oxygen consumption (VO2max)test results 674.2.1 Maximal responses674.2.2 Ventilatory threshold (Tvent)responses 694.3.0 Tvent steady state performance test results764.3.1 Heart-rate76V4.3.2 Oxygen consumption824.3.3 Ventilation874.3.4 Blood lactate concentration934.4 Hypothesis verification984.4.1 Test of hypothesis 1984.4.2 Test of hypothesis 2984.4.3 Test of hypothesis 3994.4.4 Test of hypothesis 4994.4.5 Test of hypothesis 51004.4.6 Test of hypothesis 61004.5 Summary of hypothesis results102Chapter 55.0 Discussion1035.1 Maximal and Tvent responsesfromVO2maxtest results 1045.2 Comparison of thetreadmill and WI steady stateTvent performance tests1125.2.1 Heart-rate1155.2.2 Ventilation1165.2.3 Blood lactate concentration1175.2.4 Respiratory exchange ratio1195.2.5 Ratings of perceived exertion120Chapter 66.0 Conclusions1236.1 Recommendations for futureresearch 1246.2 Training implications1266.3 Bibliography130AppendicesviSubjects Raw Data136Repeated measures analysis for HR, V02, yeand [BLa]162Stride frequency172Repeated measures analysis for RER and RPE175Quality of workouts190Laboratory temperature and barometric pressureover test sessions192Determination of Tvent from Ventilatoryparameters194Appendix H: Subject Informed Consentform 196Appendix A:Appendix B:Appendix C:Appendix D:Appendix E:Appendix F:Appendix G:viiLIST OF TABLESTable 1.0. Physical Characteristics and TreadmillMaximalOxygen Consumption of the Sample66Table 2.0VO2maxResults : Maximal ResponsesTable 3.0VO2maxResults : Results at Tvent70Table 4.0 2 X 2 X 7 Repeated Measures analysisResults forHeart—rate163Table 4.1 2 X 2 X 7 Repeated Measuresanalysis ResultsTrTrTVentVSWlTrTventfor Heart-rate 164Table 4.2 2 X 2 X 7 Repeated Measuresanalysis ResultsTrwITVefltV5WIWITventfor Heart—rate 164Table 5.0 2 X 2 X 7 Repeated Measures analysisResults forOxygen Consumption165Table 5.1 2 X 2 X 7 Repeated Measures analysisResultsTrTrTVent‘sWITrTventfor Oxygen Consumption 166Table 5.2 2 X 2 X 7 Repeated Measuresanalysis ResultsTrWITVefltV5WIwITventfor Oxygen Consumption 166Table 6.0 2 X 2 X 7 Repeated Measuresanalysis Results forVentilation167Table 6.1 2 X 2 X 7 Repeated Measuresanalysis ResultsTrTrTVentV5WITrTventfor Ventilation 168Table 6.2 2 X 2 X 7 Repeated Measures analysisResultsTrwITVefltVSWIWITventfor Ventilation 168Table 7.0 2 X 2 X 7 Repeated Measuresanalysis Results forBlood Lactate Concentration169Table 7.1 2 X 2 X 7 RepeatedMeasures analysis ResultsTrTrTVentVSWlTrTventfor Blood LactateConcentration170Table 7.2 2 X 2 X 7 RepeatedMeasures analysis ResultsTrwITVefltVSWIwITventfor Blood LactateConcentration170Table D1.0 2 X 2 X 7 RepeatedMeasures analysis Results forRespiratory Exchange Ratio181Table D1.1 2 X 2 X 7 Repeated Measuresanalysis ResultsTrTrTVentvsWITrTVentfor Respiratory ExchangeviiiRatio 182Table Dl.2 2 X 2 X 7 Repeated Measures analysis ResultsTrwlTvefltVSWIWITventfor Respiratory ExchangeRatio 182Table D2.O 2 X 2 X 7 Repeated Measures analysis Results forRatings of Perceived Exertion 188Table D2.1 2 X 2 X 7 Repeated Measures analysis ResultsTrTrTVentVSWlTrTventfor Ratings of PerceivedExertion 189Table D2.2 2 X 2 X 7 Repeated Measures analysis ResultsTrWITVentVSWIwITventfor Ratings of PerceivedExertion 189ixLIST OF FIGURESFigure 1.0. Hypotheses Summary Chart14Figure 2.0. Underwater photograph of asubject WI running 47Figure 3.0. WI running; an above andbelow surface picture 50Figure 4.0 WI running set-up51Figure 5.0 Treadmill and WIVO2maxProtocol description 59Figure 6.0VO2maxand Tvent tests schematic representationof procedures60Figure 7.0 Diagram of thefactors and levels of the experimentaldesign64Figure 8.0. Mean V02 (+1 std) atmaximal effort and Tvent fromthe treadmill and WIVO2maxtests 71Figure 8.1. Mean HR and ye(+1 std) at maximal effort and Tventlevel from the treadmill and WItests 72Figure 8.2. Mean RER and RPE (+1std) at maximal effort andTvent level from the treadmill andWIVO2maxtests 73Figure 8.3. Mean post-test [BLa)andVO2maxtest duration atmaximal effort and at Tvent levelfrom the treadmilland WIVO2maxtests74Figure 8.4. Comparison of the treadmilland WIVO2maxand Tventresponses and the %age of the respective VO2maxthateach Tvent represents, comparedto their respectiveVO2maxresponses76Figure 9.0. Mean HR response forcondition and Tvent main effectsand Condition X Tvent interaction79Figure 9.1. Mean HR response overthe steady state performancetests over time80Figure 9.2. Mean HR response forCondition X Time and Tvent XTime interactions81Figure 10.0 Mean V02 (in mlkgmin) response for Conditionand Tvent main effects and ConditionX Tventinteraction84Figure 10.1 Mean V02 (in mlkgmin) response over thesteady state performance testsover time 85xFigure 10.2 Mean V02 (in mlkg1min)response forCondition X Time and Tvent XTime interactions 86Figure 11.0 Mean ye response forCondition and Tvent maineffects and Condition XTvent interaction 90Figure 11.1 Mean ye response overthe steady state performancetests over time91Figure 11.2 Mean ye responsefor Condition X Time and Tvent XTime interactions92Figure 12.0 Mean (BLa] responsefor Condition and Tvent maineffects and Condition X Tvent interaction95Figure 12.1 Mean BLa) responseover the steady stateperformance tests over time96Figure 12.2 Mean [BLa] responsefor Condition X Time and TventX Time interactions97Figure C1.0 Comparisonof stride frequency (strides/mm)duringthe treadmill vs the WI VO2maXtests174Figure 01.0 Mean RER responsefor Condition and Tvent maineffects and Condition X Tventinteraction 179Figure 01.1 Mean RER responseover the steady state performancetests over time180Figure D2.0 Mean RPE responsefor Condition and Tvent maineffects and Condition X Tventinteraction 186Figure 02.1 Mean RPE responseover the steady state performancetests over time187Figure E1.0 Comparisonof the quality of the subjects’WIrunning workouts compared tothe magnitude of thedifference in WI and treadmill VO2max(in mlkg1min1)190Figure F1.0 Laboratory temperatureand barometric pressureoverthe test sessions192Figure G1.0 Determinationof Tvent from ventilatoryparameters(ExCO2 and Ve/V02)194xiAcknowledgementsTo Mr. and Mrs.Steve Frangolias:Dear Mom and Dad,For the person youcreated,For the person 1 havebecome,I dedicate thisto you.I would liketo express mysincere gratitudeand appreciationto mysubjects who volunteeredtheir precioustime and gavetheir personalbest to makethis investigationpossible, and to myfellowcolleagues, friends,workstudy studentsand family whoassisted inthe data collectionand were simplythere for me.I extend mysincere appreciationto my committeemembers: Drs. AngeloBelcastro, Ken Coutts,Igor Mekjavic,Jack Taunton andthesis advisorDr. Ted Rhodes,for theirguidance, patience andsupport.I am indebtedto Dr. J.R. Ledsomeand Mr. JimPotts (Ph.D student)and his father fortheir technicalsupport in this investigation.xiiCHAPTER 11.0 INTRODUCTIONWater immersion to the neck(WI) has been used as a method ofsimulating various aspects ofthe aerospace environment. Theapplication of knowledge attainedfrom this area of research hasexpanded beyond the aeronauticalsciences (Epstein, 1976). Thenon—weight bearing nature of waterimmersion exercise has made thisform ofexercise popular among populationsof low fitness levels andthoseexperiencing muscle and jointproblems (Vickery et al, 1983; Evansetal, 1978). It has also become popularamong special needs populations,such as during pregnancy among women(McMurray et al, 1988) and withindividuals affected by chronicsoft tissue degeneration andneurological disease (eg. rheumatoidarthritis, multiple sclerosis)(Danneskiolt-SamSoe et al, 1987;Compton et al, 1989).WI running has gained popularityamong runners. WI runninghas beenused by runners and has beenprescribed by athletes’ doctors andcoachesas an alternative toland based running. Itis currently being usedboth as a rehabilitativetreatment for lower trunk injury(Koszulta,1986), and as a supplementto the runners’ land based trainingregimen(Town and Bradley, 1991;Richie and Hopkins, 1991; Yaxnajiet al, 1990;Bishop et al, 1989). Thenon-weight bearing nature of WI runningmakesthis form of exercisepopular among runners experiencingmuscle andjoint problems, or tryingto avoid such injuries by proportioningtheirweekly ‘mileage’ betweenland and WI running.1The non—weight bearing nature of WI running and the viscosityfriction experienced in WI, however, also raises the question of howsimilar these two activities are. Johnson et al (1977) noted a higheroxygen consumption for similar leg exercise in WI versus land. Theynoted that, whereas, more energy is required on land to lift a greatermass, a similar effect is present in the WI condition related to thefrictional resistance and turbulence of the water. The longer thelever, the larger the girth of the legs and the greater the speed of themovement, the greater will be the frictional resistance and turbulenceexperienced during WI exercise.The goal with WI running is to simulate land—based running motionwhile immersed to the neck in water and non—weight bearing. Theassumption is made that the same muscle groups and recruitment patternsare involved in WI running as are with land—based running. Studiescomparing land and WI cycling have found no differences inVO2maX(Christie et al, 1990; Connelly et al, 1990; Shedahi et al, 1987;Dressendorfer et al, 1976), however, studies which have comparedtreadmill and WI running have reported lowerVO2maxresponses in WIcompared to treadmill running (Svedenhag and Seger, 1992; Town andBradley, 1991; Butts et al, 1991; Welsh, 1988). WI running style andfamiliarity with WI running may be factors responsible for the lower WIVO2maxreported by WI running studies.Responses during submaximal exercise on the treadmill and WI runninghave also been investigated recently (Svedenhag and Seger, 1992; Richie2and Hopkins, 1991; Yamaji et al, 1990; Bishop et al, 1989). Theauthors comment that although their subjects were familiarized with WIrunning, they were ‘less conditioned’ in the WI compared to the land(treadmill) condition. These studies have compared the physiologicalresponses of WI and treadmill running among runners with limited WIrunning familiarity and at absolute workloads, which most likelyrepresent in the WI condition a higher metabolic requirement. This hasbeen demonstrated by the WI running studies comparing treadmill and WIVO2max,which have found lower WI responses.Static lung volumes have been reported to be reduced in WI (Withersand Hamdorf, 1989; Hong et al, 1969; Agostoni et al, 1966). Exerciseminute ventilation (ye) (in relation to V02) has been reported to remainunaffected (Svedenhag and Seger, 1992; Sheldahl et al, 1987; and Welsh,1988), or reduced (Butts et al, 1991; Dressendorfer et al, 1976) in theWI condition.Lower maximal HR has been reported for WI running and ergometercycling (Svedenhag and Seger, 1992; Butts et al, 1991; Town andBradely, 1991; Connelly et al, 1990; Christie et al, 1990; Welsh, 1988;Sheldahl et al, 1987; Dressendorfer et al, 1977). However, there is noclear consensus on resting and submaximal HR responses. Resting HR inupright WI compared to land has been reported to remain unchanged(Connelly et al, 1990; Christie et al, 1990; Arborelius et al, 1972) orto decrease (Risch et al, 1978; Fahri and Linnarsson, 1977; Lollgen etal, 1976). Similarly, submaximal exercise HR response (matched for V02)has been reported to remain unchanged (Christie et al, 1990; Sheldahl et3al, 1987; Evans et al, 1978; McArdle et al, 1976)or to decrease(Conrielly et al, 1990; Christie et al, 1990; Welsh, 1988; Johnson et al,1977; Rennie et al, 1971) in WI compared to land exercise.Cardiorespiratory mechanics are altered by WI at rest andpossiblyin exercise. It is therefore important todistinguish thephysiological differences which can be attributed tothe WI conditionversus differences which are attributed to limitations of these studies.Studies comparing treadmill and WI running have predominately usedrunners untrained in WI running (who are not incorporating WI runningintheir training regimen) and have compared physiological responsestoexercise at dissimilar workloads in the two conditions. Ventilatorythreshold (Tvent) is representative of one’s aerobic capacity (Andersonand Rhodes, 1991; Loat and Rhodes, 1991; Andersonand Rhodes, 1989;Wiley and Rhodes, 1986; Caiozzo et al, 1982; Rusko et al, 1980;Volkovet al, 1975) and is highly correlated with long distance performance(Coen at al, 1991; Maffulli et al, 1991; Rhodes andMcKenzie, 1984).The purpose of this study was twofold: a) to compare thephysiologicaland metabolic responses to treadmill and WI runningat ventilatorythreshold (Tvent) and at maximal effort among a groupof elite distancerunners familiar with WI running, and b) to comparethe physiologicaland metabolic responses to treadmill and WI runningduring prolongedexercise at Tvent (WI and treadmillTvent). It was postulated thatstudies to date had not controlled adequately for WI running styleandthe extent of the runners’ familiarity with WI running.41.1 DEFINITION OF TERMSExcess CO2. The non-metabolic CO2 has beencalculated by Issekutz andRodahl (1961) by the following formula: Excess CO2 = — (RQrest*V02), withRQrest= 0.70—0.80). It is the non-metabolic CO2 (and water)generated by the bicarbonate buffering system of the hydrogenionsproduced within exercising muscle from the dissociationof lactic acid.The chemical reactions are as follows HLa+ NaHCO3 = NaLa + H2C03 =CO2 + H20 (Wasserman et al, 1973).Lactate. Also referred to as lactic acid orblood lactate. It is themetabolic by—product of anaerobic energy production (Brooksand Fahey,1985).Respiratory Exchange Ratio (RER). Different amountsof oxygen (V02) arerequired for the catabolism (oxidation) of carbohydrate,fat and proteinto carbon dioxide (C02), water and energy. Theratio of CO2produced/V02 consumed is defined as the RER and variesdepending uponthe substrate metabolized (Brooks andFahey, 1985).Runner Trained in WI Running. A runner trainedin WI running is definedby this study as the runner who utilizesWI running on a regular basisin their training regimen. It isthe runner who performs a minumum 6sessions of WI running per month, of at least 45minute duration persession, for the previous 6 months prior to participationin the presentstudy.5Steady State Exercise. The intensity of exercise that can be performedfor a prolonged period of time without appreciable elevationsin V02,HR, Ve, RER, (BLa] etc.Ventilatory Threshold (Tvent). Characterized by the non—linearincreasein excess CO2. It is the intensity of exercise just below thepoint ofthe abrupt increase in excess CO2. The abrupt increase in excess CO2 isrelated to increased reliance on anaerobic processes for energy becauseaerobic energy sources are unable to meet tissue requirements (Loat,1991; Anderson and Rhodes, 1991; Anderson and Rhodes, 1989).Maximal Oxygen consumption(VO2max).Defined as the point where V02plateaus and exhibits no further increase (or increases only slightly)with additional workiads (Brooks and Fahey, 1985).Water Immersion to the Neck Running (WI Running). The simulationofland-based running motion in deep (non-weight bearing) water. The WIrunner is immersed in water to the neck and propels herselfin the waterby simulating land-based running motion. There is no weightbearing,consequently no push—off phase on a stable immoveable surface.Theindividual propels herself through the water workingagainst theresistance of the water. A flotation devise may be worn toprovideminimum boyancy and facilitate the simulation of land—basedrunningmotion.61.2 STATEMENT OF PROBLEMThe purpose of this study was to investigate the cardiorespiratoryandmetabolic responses during maximal effort and duringprolongedperformance at the ventilatory threshold (Tvent) during treadmillandwater immersion to the neck (WI) running in a group of elite endurancerunners familiar with WI running.1.2.1 SubproblemsThe subproblems were:1) To utilize elite endurance runners who regularly include WI runningin their training regimen.2) To compare the cardiorespiratory andmetabolic responses totreadmill and WI running at Tvent and maximal effort (ie. VO2max)amonga group of elite endurance runners familiarwith WI running.3) To compare the cardiorespiratoryand metabolic responses totreadmill and WI running during prolongedexercise at Tvent (WI andtreadmill Tvent) among a group of elite endurance runnersfamiliar withWI running. That is the subjects would beasked to performed four Tventprolonged performance (42 minute) tests and they were thefollowing:TrTrTVent(treadmill Tvent intensity performed on the treadmill).TrwlTvent(WI Tvent intensity performed on the treadmill).WlTrTvent(treadmill Tvent performed in the WI condition).7WIWITvent(WI Tvent performed in the WI condition).1.3 HYPOTHESES1. TheVO2maxvalues determined during the treadmill versus the WIrunningVO2maxtest for WI running trained endurance runners would besimilar at the 0.05 level of significance.Specific hypothesis was:TrvO2max = WIVO2maxat >O.O5.RATIONALE: The runners would be simulating land—based running mechanicsin an aqueous environment and sinceVO2maxis unaffected by this medium,performance in both environmental conditions should be similar asexhibited with land versus WI ergometer cycling studies (Connelly et al,1990, Christie et al, 1990, Sheldahi et al, 1986, Avellini et al, 1983,Dressendorfer et al, 1976). Welsh (1988) reported lower treadmillversus WIVO2maxvalues. He attributed these findings to increasedblood flow to the upper body musculature, a greater proportion of workperformed by the upper body and a reduced ability of the upperbodymusculature to extract oxygen as possible factors. Lower VO2max valuesfor WI versus treadmill running have been reported by Svedenhag andSeger (1992), Butts et al (1991) and Town and Bradley (1991). These WIrunning studies utilized runners unexperienced to WI running. Therunners were given one to two sessions of instruction and thenclassified as runners trained in WI running. The authors suggest intheir discussions that less familiarity with WI running may have beenafactor for the lower WIVO2maxvalues (Svedenhag and Seger, 1992; Butts8et al, 1991; Town and Bradley, 1991). If the uppertorso is utilized toa greater extent in WI versus treadmill running,in an attempt to remainafloat, then WIVO2maxvalues will be lower than treadmill values. Itis postulated that the control measures set in thisstudy, regarding WIrunning experience and acceptable WI runningstyle will prevent thistrend.2. The treadmill Tvent will be significantlyhigher than the WI Tvent,at the 0.05 level of significance.Specific hypothesis is:TrTveflt>WlTventat pO.O5.RATIONALE: The assumption was made herethat there would be nosignificant differences in treadmill and WI VO2maxvalues. It washypothesized that the absolute and relativetreadmill and WI Tventvalues would be different. The upperbody musculature would beperforming a proportionately greaterquantity of work in WI versustreadmill running. Arm crank versuscycle exercise elicits a loweranaerobic threshold due to the smaller musclemass available forrecruitment (Sawka, 1986) and a proportionatelyhigher ratio ofglycolytic to oxidative muscle fibers, andso increasing lactateproduction and facilitating exhaustion. It waspostulated that WIrunning motion would simulate treadmill(or land—based) running motion,however, the resistance of thewater would result in increased workperformed by the back and shoulder musclesas the arms swing back duringthe running cycle. This wouldresult in a lower WI versus treadmillTvent value.93. Cardiorespiratoryand metabolic (HR, vo2,ye, and BLa])responsesduring prolongedexercise at Tvent (determinedfrom the WI andtreadmillVO2maxprotocols, ie. WITventandTrTventrespectively) woulddiffersignificantly for the(WI running trained)runners during treadmillversus WI runningtests at treadmilland WI Tvent at the0.05 level ofsignificance.i) Heart—rate (HR)response duringprolonged performanceat treadmilland WI Tventwould differ significantlyduring treadmillversus WIrunning. The specifichypotheses were:TrHRWITVent> WIHRw,y andTrHkTrTvent> orTrHRTVent> WIHR( WlTventTrTvent)at pO.O5.RATIONALE :Lower WI HR valueshave been reportedat maximal effort(Svedenhag andSeger, 1992; Christieet al, 1991; Connellyet al, 1991;Welsh, 1988; Sheldahlet al, 1987;Dressendorfer et al,1977; Arboreliuset al, 1972), andat Tvent (Welsh,1988). Lower WIrunning HR valueshave been reportedduring 5 minuteexercise intervalsat 65 %VO2maxandabove (Svedenhagand Seger, 1992).Lower submaximal WIHR values havealso been noted bystudies comparing WIversus land ergometercyclingexercise (5 minuteintervals) at 60%,80% and 75% VO2maxand above,respectively (Connellyet al, 1991; Christieet al, 1991; Sheldahletal, 1987). SimilarWI HR values werereported duringexercise, by thesefour studiesbelow these exerciselevels (Svedenhagand Seger, 1992;10Connelly et al, 1991; Christie et al, 1991; Sheldahl et al, 1987).Middle distance runners commonly reach Tvent at approximately 80%(Davis et al, 1984), thus lower WI HR values would be expected for theWI tests atTrTventandWlTvent.The hydrostatic pressure gradient andconsequent cephalad redistribution of blood volume are suggested to beresponsible for the lower WI HR values (Svedenhag and Seger, 1992;Christie et al, 1991; Connelly et al, 1991; Sheldahi et al, 1987; Lin,1984).ii) Oxygen consumption (V02) during the Tvent prolonged performancetests would be significantly greater in WI versus treadmill running.The specific hypotheses were:WIVO2WITvent>TrVO2WITventandWIVOTrTvent>TrVO2TrTVentorWIVO2Tvent >TrVO2,1 (ifWlTventTrTvent)atp<O.O5.RATIONALE: WI running would utilize a larger muscle mass than treadmillrunning and therefore would require a higher V02 for the activity overtime. WI work would result in a greater energy expenditure, andtherefore, V02 compared to the same work performed on land. This wouldbe related to the viscocity friction and turbulance of the aqueousenvironment (Evans et al, 1978, Johnson et al, 1977, Costill, 1971). IfTvent was not affected by the condition (ie. treadmill vs WI), the V02would still be expected to be higher during the WI versus treadmillprolonged performance tests, due to these properties of the aqueousenvironment.11iii) Ve during theTvent prolonged performancetests would besignificantly greaterin WI versus treadmillrunning. Specifichypotheses were:WIVeITvent>TrveWlTventandWIVeTrTVent> orWIVeTVent <TrVe (ifWlTvent=TrTvent)at p<OO5.RATIONALE: Similar maximalye values have been reportedby WI runningstudies (Svedenhag and Seger,1992; Town and Bradley, 1991,Butts et al,1991; Welsh, 1988) andby Sheldahl et al (1987)for WI cycling.Dressendorfer et al (1977)noted lower maximal Vereponse in WI cycling.Similar Ve and ventilatoryequivalent for V02 has been reportedat Tventfor WI versus treadmill running(Welsh, 1988). Svedenhagand Seger(1992) reported similarVe responses during 5minutes of WI versustreadmill running atsubmaximal exerciseintensities. Similarsubmaximal Ve have alsobeen reported for five minuteexercise intervalsin WI versus land cycling(Sheldahi et al, 1987; Sheldahiet al, 1984).This study hypothesizedthat ye during theTvent prolonged performancetests would be higherin the WI condition. Thiswould be related tothehigher relative intensityof the exercise in the WIversus the treadmillcondition. Thishypothesis was based on theassumption thatWlTvent<TrTvent.If WI and treadmillTvent are similar, then no differencesinVe would be expected for theprolonged performance testsat Tvent in the2 conditions.12iv) Blood lactateconcentration BLa] duringthe Tvent prolongedperformance tests wouldbe significantly higherin the WI versustreadmill running.Specific hypotheses were:WI[BLa]WITVent>Tr[BLajWITvefltandWI[BLa)TrTveflt>Tr[BLa]TrTventorWI[BLa]Tveflt = Tr[BLaITveflt(ifWlTventTrTvent)at pO.O5.RATIONALE: The greatermetabolic demands of WIrunning, due to thehigher relative intensityof the WI prolonged performancetests comparedto the same absoluteintensity performed on thetreadmill would resultin higher bloodlactate accumulation inthe WI (ie.WlTrTventandWIWITvent)versus the treadmill(ie.TrTrTVentandTrWITveflt)prolongedperformance tests. Ifthe Tvent did not differ inthe two conditions(ie.WlTventTrTvent),then no differencesin blood lactateconcentration wouldhave been expected.See figure 1 for a summaryhypotheses diagram.13LuiiwTv.nt>Tro2wTventjjWITvent>TrVeWITveJFigure 1. Hypotheses Summary Chart.TventjjWITventErTVentTrTv.ntLiiTrTvent>T02TrTveJvent>jrvJbvent<TrvejjjrTvent>TTrTventEa1TtTrtBLa1w1TvJaTvent=BLaITvJjaTrTvent>TrcBLaTrTveJ141.4 DELIMITATIONS1) The study wasdelimited to maleand female distancerunners, 20-35years—old, who weretrained on land, treadmilland WI running,and whocould demonstrate WIrunning style duringhigh intensityexercise as setby this study(see sampling section).2) The samplesize was restrictedto 13 elite runnerstrained in WIrunning.3) The studywas delimited tosubjects with a minimumtreadmillVO2maxof 50 and 60mlkg 1min, for femaleand male runnersrespectively.This was to ensurethat the subjectshad enhanced cardiorespiratoryandmetabolic abilitiescomparable in levelto top—levelvarsity andnational caliber distancerunners.4) Thestudy was delimitedto examine onlyone intensity ofexercise(Tvent intensity),with WI and treadmillTvent performedand compared onthe treadmill andWI condition.1.5 ASSUMPTIONS1) The subjects’measuredVO2maxvalues were a truereflection of theiraerobic capacity.2) The subjectswould be able torun on the treadmilland simulate landrunning motionwith WI running.153) The trial sessionsfor familiarizationto the equipment andenvironmental test conditionswould be adequate.4) Running in thewater immersed to the neckrequires activation ofpredominantly similarskeletal muscle groups whichare activated duringland—based running.Land—based running motionis simulated duringWIrunning motion.5) Subjects wouldperform maximally toexhaustion in bothconditions(ie treadmilland WI running). Use ofthe Borg scale for ratingsofperceived exertion duringtheVO2m8Xtests and post—test [BLa]measureswould provide additionalevidence thatVO2maxwas achieved.6) Hydration and coolingprovided for the laboratorytreadmill testswould be adequate forthe subjects.1.6 LIMITATIONS1) The investigationwas limited by the WI runningergometer and WIrunningVO2maxprotocol used to assess VO2maxand Tvent in WI running.2) The investigationwas limited by the WI runningergometer which withincreasing load facilitateda foward lean due tothe harness pulling thesubjects’ trunk in abackward direction.163) The investigationwas limited bythe functioningof the Beckmanmetabolic cartand the accuracy ofits readings.4) The study waslimited by the laboratoryenvironmental conditionsandthe inabilityto control laboratorytemperature andhumidity for thecomfort of thesubjects during testing.Attempts were madeto maintaina comfortableenvironment for thesubjects by providingthem with waterto maintain adequatehydration and somecooling by use ofan electricfan.5) The investigationwas limited bythe subjects’ability andmotivation to performmaximally to exhaustionon the WIand treadmillVO2maxtests.6) The studywas limited by thewater turbulence inthe pooi caused byactivities ongoingduring WI testtimes. This increasedturbulence ofthe water, wouldwork to reduce or increasethe subject’s workload.7) The investigationwas limited by thesubjects’ abilityto correctlyand consistantlysimulate WI runningmotion. Subjectswere to remainalmost verticalin the pooi immersedto the neck withthe arms followingnormal runningmotion; the handswould not ‘cup’the water.Normalrunning motionof the lower trunkwould include flexionof the hipfollowed by hipand leg extension.8) The study waslimited bythe ability of theinvestigator toobjectively evaluatethe subjects’running styleduring testingfrom17videotape of the sagital view of the subjects’ performance against thescaling grid.9) The investigation was limited by the minimum requirements set for arunner to be trained in WI running, which were neccesary for inclusionin this study. That is the regular WI running training sessions and thequality of the work-outs completed by the subjects during the six monthsprior to participation in the present study.10) The investigation was limited by the ability of the unbiasedreseachers to extrapolate the Tvent levels from the ExCO2 over timecurve (and Ve/V02 over time curve and RER around 1.00).1.7 SIGNIFICANCENumerous studies have examined the cardiorespiratory responses ofexercise in WI compared to exercise on land. These studies, however,have been limited to the investigation of maximal responses and shortduration submaximal exercise at similar absolute intensities. Morerecently WI running at submaximal intensities of a prolonged nature havebeen examined and compared with treadmill responses, however, theexercise intensity has not been objectively controlled. Studiescomparing treadmill and WI running have utilized predominately runnersuntrained in WI running, as their subjects. Could differences inphysiological responses reported for WI and treadmill running be relatedto the subjects’ unfamiliarity with WI running? Since WIVO2maXvalueshave been reported to be lower than treadmill values, could the18responses then, exhibited during submaximal exercise be relatedto thehigher relative intensity of the exercise in the WI condition.HR response during submaximal exercisehas been reported to besimilar, or lower in the WI versus land (treadmill) condition.WI HRresponse seems to be exercise intensity dependent, butthere is noagreement as to what intensity of exercise (% of VO2max) resultsinlower WI HR values. Determination of Tvent and comparison ofexerciseat similar relative exercise intensities (at andabove WI Tvent) wouldprovide new information on HR response in WI.WI running is often used by runners.The incorporation of WIrunning in the training regimens of elite runners isjustified as eithera preventative measure to avoid the occurrenceof sports—relatedinjuries, or as a form of maintenance training following injury.Thetraining regimens of runners incorporate theprinciple of specificity oftraining, which requires that one’s trainingregimen overload themetabolic system and muscles which support his activity (BrooksandFahey, 1985). If WI running requires a very similarmuscle recruitmentpattern, then one should expect the runner to beable to sustain theactivity at a specific intensity (ie. Tvent) elicitingsimilarcardiovascular and metabolic responses as during running onland. Ifthis is the case then WI running can alsoprovide training benefitswhich can be transfered to land—based running and can serve to enhancearunner’s training regimen.19CHAPTER 22.0 REVIEW OF THE LITERATUREDuring the last 30-35 years waterimmersion to the neck (WI) hasbeen used to simulate weightlessness.Recently, exercise in WI hasgained popularity due to its non-weightbearing nature. Running isbecoming a common activityin the WI condition. It is beingusedextensively by competitive runnersand other athletes not only duringrehabilitation but also to complementtheir regular training. Thisliterature review will present researchpertaining to cardiovascular andrespiratory responses to the WIcondition, WI exercise studiesand theventilatory threshold concept withrespect to steady state exercise.2.1.0 CARDIOVASCULAR RESPONSES TO WATERIMMERSION TO THE NECKThe four major determinants of cardiac performanceare heart—rate(HR), preload, contractility and afterload. Preloadis defined as theextent of ventricular filling before contraction.Preload is determinedby the venous return of blood to theheart, and venous return isdirectly affected by cardiac output(CO) (Brooks and Fahey, 1985).Afterload is defined as the resistanceto ventricular emptying, that isthe force against which the heart musclemust contract during theejection phase of systole. Increasedafterload increases the workloadfor the heart. Increased afterloadis characterized by reducedventricular—ejection fraction, shorteningvelocity and increased20ventricular end—diastolicand end—systolic volumes(Brooks and Fahey,1985). Contractilityis described as the qualityof ventricularperformance. Enhancedcontractility enablesthe heart to increasestroke volume (Brooks andFahey, 1985). HR isdescribed as the majordeterminant of CO,especially during moderateto maximal exercise(Brooks and Fahey, 1985).During upright water immersionto the neck (WI) a mean hydrostaticpressure of 20 cm water isexerted on the thoracic cavityand abdominalarea. Atmospheric air pressureof 1 atm is exertedon the unimmersedhead and neck and is transmittedthrough the airwaysinto the alveoli.An imbalance is created betweenthe air pressure in the alveaolarspacesand the greater pressure exertedon the thoracic cavity (Epstein,1976).A redistribution of blood volumeto the central circulationby 700 ml isinduced. The heart acceptsapproximately 200ml of this blood volume(Arborelius et al, 1972).2.1.1 Heart-rateResting and submaximal HR responseshave been reportedto remainunchanged or to decreasein WI. Although thereis agreement thatmaximal HR is lower in WI (Svedenhagand Seger, 1992; Town andBradley,1991; Butts et al, 1991;Connelly et al, 1991;Christie et al, 1991;Welsh, 1988; Sheldahl etal, 1987; Sheldahlet al, 1984; Dressendorferet al, 1976), there isno clear consensus on the mechanismsresponsiblefor the lower HR responsesin WI at higher exercise intensities.Thecephalad shift in blood volumewhich causes the redistributionof 700 ml21of blood from the lower extremitiesand abdomen to the centralcirculation is implicated (Lin,1984; Fahri and Linnarsson, 1977;Arborelius et al, 1972). The heartaccepts 200 ml of this blood (Fahriand Linnarsson, 1977; Arborelius etal, 1972). It is suggested that theincrease in atrial blood volumewith WI could result in a reflexincrease in HR at rest and up to moderateexercise, offsetting a cardiacdecelerating reflex (Christie etal, 1991; Sheldahl et al, 1987;Sheldahi et al, 1984). Thisis suggested to occur throughtheBainbridge reflex (Sheldahl et al,1987; Lin, 1984).Bainbridge reported HR to increasewith infusions of blood orsaline. This was observed when centralvenous pressure increased to theextent to distend the right sideof the heart. In this case cardiacfilling rose resulting in increasesin HR (Berne and Levy, 1988).It has also been postulatedthat CO may be regulated at a higherlevel in WI in order to maintain an‘appropriate’ arterial bloodpressure response (Christie et al,1991; Sheldahl et al, 1987; Lin,1984). Sheldahi et al (1987) proposes that sincesimilar systolic bloodpressure responses are exhibited duringWI and land exercise (Sheldahiet al, 1987; Arborelius et al, 1972) andif systemic vascular resistanceremains lower during exercise inWI, a greater CO would be neccessary tomaintain the same blood pressureresponse as exhibited on land.Arborelius et al (1972)has noted lower (by 30%) systemic vascularresistance in resting WI.22Lower sympathetic neuraloutflow in WI has alsobeen suggested toexplain the lowerHR response to heavy exercise(Christie et al, 1991;Connelly et al 1991;Sheldahi et al, 1987).Lower plasma norepineprineand epineprine concentrationshave been noted during heavyand maximalexercise in WI comparedto land responses (Connellyet al, 1991). Anexercise intensity dependentresponse of plasma catecholaminelevels inWI is suggested (Connellyet al, 1991; Christieet al, 1991).HR response in WI is alsoaffected by temperature.Similar HRvalues have been reportedduring rest and submaximalexercise inthermoneutral WI(29°-35° C) compared to land values(Sheldahl et al,1987; Fahri and Linnarsson,1977; McArdle et al, 1976;Arborelius et al,1972; Craig and Dvorak,1966). Lower HR valueshave been reportedduring rest and exercisein WI at250C compared to thermoneutralwater(Craig and Dvorak, 1966).McArdle et al (1972) notedlower HR valuesfor exercise at oxygen consumption(V02) values of 1.5and 2.8 lminin WI at 18—25° C. ConsequentlyV02 was higher (by 250-700mlmin) inWI at 18-25° C comparedto V02 values on landand WI at 33° C (McArdleet al, 1972). Lower maximalHR(HRmax)values, however, werereportedfor similarVO2maxvalues for WI exerciseat18_250C compared tothermoneutral WI exercise(Dressendorfer et al,1976; McArdle etal,1972).Rennie et al (1971) reportedlower restingHR values, (a-v02)difference (15%) and COin WI at 28-32° C. During exercise,however, nodifferences in CO—V02 relationshipwere noted, although HR andstrokevolume (SV) were lower and higherrespectively from land values.The23authors concluded that thedecline in skin bloodflow, CO, HR at restinWI were related to watertemperature. Anydifferences, however,in COduring WI exercise wereminimized by the higherperfusion of muscleinexercise. They postulatedthat the reducedHR and increased SV duringexercise were theresult of negativefeedback controlfrombaroreceptors.Resting heart—rate (HR)has been reportedto remain unchanged(Connelly et al, 1990;Christie et al, 1990;Arborelius et al, 1972)orto decrease in waterimmersion to the neck(WI) in water temperaturesranging from27_310C compared toresting HR values reportedon land(Risch et al, 1978; Farhiand Linnarsson, 1977;Loilgen et al, 1976).Similarily submaximalexercise HR responses(matched for oxygenconsumption) have been reportedto remain unchanged(Christie et al,1990; Sheldahl et al, 1987;Evans et al, 1978;McArdle et al, 1976)orto decrease (Connelly etal, 1990; Christie et al,1990; Johnson et al,1977; Rennie et al, 1971)with upright exercisein WI compared to onland.Connelly et al (1990)and Christie et al(1990) reportedsignificantly lower WI HRresponses at exerciseintensities (on cycleergometer) correspondingto 60 %VO2maxor above and 80%VO2maxrespectively. Svedenhagand Seger (1992) reportedsignificantly lowerHR responses elicitedin WI running at intensitiesover 80 %VO2maxcompared to treadmillrunning. Welsh (1988) reportedsignificantlylower WI HR responses at ventilatorythreshold (Tvent) comparedto TventHR determined from thetreadmillVO2maxprotocol, among endurance24trained runners. The HRresponses at Tventin the WI and treadmillcondition corresponded to83 and 86 percent oftheir respectiveVO2max.Sheldahi et al (1987) comparedWI and land stationaryergometer cyclingand reported lower exerciseHR responses at 80 %VO2maxin WI. Inanother study Sheldahiet al (1984) notedlower HR values duringWIexercise at 76 %VO2maxand above.Although differencesin WI and land-basedHR’s at rest andatsubmaximal exercise intensitiesare still being debated,there isagreement that HR responseto maximal exercise is lowerin WI comparedto maximal exercise onland. LowerHRmaxvalues have been reportedbystudies comparingWI and land stationary ergometercycling (Connellyet,1990; Christie etal, 1990; Sheldahl etal, 1987; Sheldahi etal, 1984;Dressendorfer et al, 1977)and by studies comparingWI and treadmillrunning (Svedenhag etal, 1992; Butts et al,1991; Town and Bradley,1991; Welsh, 1988).2.1.2 Preload, Contractilityand AfterloadSheldahl et al (1984) notedincreases in ventricularend-diastolicvolume and end—systolicdiameter during exerciseat 37% and 47%VO2maxin WI versus land cycleexercise. The authorsconcluded that preloadmay be enhanced inWI and suggest that preloadmay be under—utilizedduring exercise onland. The decline in theratio of systolic bloodpressure and end—systolicdiameter during WI exercisemay indicate lowermyocardial contractilityin the WI condition.The greater leftventricular end—diastolicvolume during WI exercisesuggests that the25left ventricularwall tension isgreater ata given left ventricularpressure. Thisis suggested to resultin increased afterload(Sheldahiet al, 1984).Christie et al(1991) also notedhigher left ventricularend—diastolicvolume duringWI exercise, coupledwith similar systolicblood pressureand concluded thatafterload is increasedin WI, but thatcontractility,most likely,is reduced.2.2.3 Cardiac Outputand Stroke VolumeCardiac output(CO) has been reportedto increaseduring restingWI(Christie et al,1991; Farhi andLinnarsson, 1977;Begin et al,1976;Arborelius etal, 1972;). Declinein CO has also beenreported (McArdleet al, 1976; Rennieet al, 1971; Hoodet al, 1968),but this declinehasbeen attributedto water temperature(below thermoneutrality)(Farhi andLinnarsson,1977; Rennie et al,1971).Farhi and Linnarsson(1977) noted a progressiveincrease in COfromland (5.1 lmin1)to water immersionto the hip (5.7lmin1), xiphoid(7.4 lmin1)andneck level (8.3lmin1). HRdecreased duringhip andxiphoid level waterimmersion, butincreased duringimmersion totheneck (WI). Strokevolume (SV), onthe other hand,increased at eachwater immersionstage. The authorsconcluded thatin the first twowater immersion stagesatrial baroreceptorsplayed the dominantrole andnoted that as COincreases and bloodpressure rises,HR is reflexlylowered. During neckimmersion atrialstretch receptorsare responsiblefor the increasein HR (Farhi andLinnarsson, 1977).Increase in26resting SV during the WI comparedto land condition havebeen noted byChristie et al (1991) and Sheldahiet al (1987).The 30-35% increase in CO duringresting WI has beenattributed tothe increase in SV (upto 77% increase)(Lin, 1984; FarhiandLinnarsson, 1977) relatedto enhanced diastolicfilling (enhancedpreload) (Farhi and Linnarsson,1977; Begin et al, 1976; Arboreliusetal, 1972).Higher SV has been reportedduring graded intensitiesof exercise inthe WI versus land condition(Christie et al, 1991;Sheldahi et al,1987; Arborelius et al,1972; Rennie et al, 1971).Higher CO at a givenV02 has been noted duringsubmaximal exercise(Christie et al, 1991;Sheldahi et al, 1987; Bonde-Petersonet al, 1980), although thepatternof increase was similar inthe WI and land condition(Christie et al,1991).Submaximal (above 40%VO2max)to maximal exercisedoes not result infurther increases in SV, althoughSV has been reportedto be higher atany given submaximaland maximal exercise intensitywhen compared toland values (Christieet al, 1991). Possible explanationsfor the lackof further increasein SV with WI exercise isattributed to: a) thecephalad shift of bloodvolume during resting WIhas reduced the amountof blood available tobe centrally shifted with exercise,or b) theleft—ventricular diastolicvolume during restingWI is near maximal,consequently thereis limited ability to increaseSV further withexercise (Christie et al, 1991;Farhi and Linnarsson,1977).27Cold stress in WI alsoaffects CO and SV.McArdle et al (1976)reported SV values toincrease in cold WI, withSV greater at 18°Cversus250C and versus thermoneutralwater. When SVand HR wereplotted over V02, the increasein SV observed parallelledthe decreasesin HR in cold stress.In summary CO and SV increasewith WI. The majorityof the increasein CO and SV occurswith initial WI inrest. SV does notexhibitfurther increases withexercise beyondthe increase exhibitedwithresting WI, but comparedto land exercise valuesWI SV values are stillhigher. CO increases by30-35% with resting WIand during gradedexercise a similarin magnitude increase occursas during similar landexercise (similar CO—V02slope). HR response duringresting WI remainsmost likely similarto land—based values,as a consequence of atrialstretch receptor activity whichincreases HR to landresting values.There is no clear consensuson HR response during submaximalexercise,although there is agreementthat maximal HR is lowerin the WI versusland condition.2.2.0 RESPIRATORY RESPONSESTO WATER IMMERSION TOTHE NECK2.2.1 Static Lung VolumesVital capacity is reduced(3-9%) with WI (Withers and Hamdorf,1989;Hong et al, 1969, Agostoniet al, 1966). The reductionin vitalcapacity is attributed tothe rise of the diaphragmand the increase in28intrapulmonary blood volume (Rischet al, 1978; Hong et al, 1969).Dalback (1975) attributes the reductionin VC solely due tointrathoracic blood accumulation.Tidal volume during resting WIis unaltered (Withers and Hamdorf,1989; Sheldahl et al, 1987; Honget al, 1969). Breathing frequencyalsoremains unaltered during restingWI (Withers and Hamdorf, 1989; Sheldahiet al, 1987; Dressendorfer et al,1976; Hood et al, 1968). Reductioninmaximal voluntary ventilation (MW)(12%) with no change in breathingfrequency during WI compared toair was reported by Dressendorferet al(1976).Decreases have also been reported duringWI for expiratory reservevolume (ERV) (62—70%) (Withers and Hamdorf,1989; Hong et al, 1969;,Agostoni et al, 1966), functional residualcapacity (FRC) (30—54%)(Withers and Hamdorf, 1989; Fahri and Linnarson,1977; Hong et al, 1969;Agostoni et al, 1966), residual volume (RV)(16%) (Withers and Hamdorf,1989; Hong et al, 1969;, Agostoni et al,1966). The preceeding lungfunction reductions are attributedto the hydrostatic pressure of thewater counteracting the forces of the inspiratorymuscles, therebycompressing the abdomen and raisingthe diaphragm to a positionapproaching full expiration (whenthe respiratory muscles are relaxed)(Agostoni et al, 1966). This results ina restriction of the forcerequired for inspiration by reducing totallung capacity (TLC) and VC(Withers and Ha.mdorf, 1989; Dahiback etal, 1978a; Dahlback et al,1978b).29The hydrostatic pressure ofthe water also causesa redistributionof blood volume from thelower extremitiesto the thoracic cavity(Honget al, 1969;, Agostoniet al, 1966). Thisincrease in thoracic bloodvolume results ina reduction in lungcompliance, and to spacecompetition between thoracicair and redistributedthoracic blood(Dahiback et al, 1978a;Dahlback et al, 1978b; Arboreliuset al, 1972;Agostoni et al, 1966).These events arealso responsible forthereduction in lung compliance(Dahlback et al, 1978b).The reduction inlung compliance resultsin an increase in RV, howeverthe net effect ofthe hydrostatic chestcompression and centrallyredistributed bloodvolume produces a net reductionin RV (Withers and Hamdorf,1989).Hong et al (1969) calculatedthe work of breathingat resting WI andreported an increase withWI by 39 %, of which29 % was ascribed to anincrease in elastic workand 10 % to an increasein dynamic work. Theincrease in dynamic workwas attributed to increasedflow resistance ofthe airways functioningat reduced lung volumes(reduced ERV).2.2.2 Exercise Respiratory Responses.Exercise ye is notaffected by the WI condition.Similar Ve(matched for V02) responseshave been noted by Sheldahlet al (1987) atrest and during exerciseat 44%, 60% and 80%VO2max.Greater increasesin Bf and lower TV valueswere noted during WIversus land exercise(Sheldahi et al, 1987).This is in agreement with thefindings of Welsh(1988) for Ve at Tvent andVO2maxfor treadmill and WI running.Welsh30(1988) also noted higher Bf and lower TV atTvent andVO2maxduring WIversus treadmill running.In summary respiratory mechanics are altered bythe externalapplication of hydrostatic pressure. The cephaladshift in blood volume(700 ml) is partly accomodated by the heart(which accepts 200 ml) andthe remainder is accomodated by the pulmonarycirculation. WI resultsin changes in static lung volumes, but doesnot seem to affect Ve.2.3.0 WATER IMMERSION EXERCISE STUDIESThis section will review literature froman exercise scienceperspective.2.3.1VO2maxand Short Duration SubKaximal Effort.Svedenhag and Seger (1992) compared treadmilland WI runningVO2maxandshort duration (5 minute bout) submaximalexercise responses in a groupof middle and long distance runners (N=9). Seven ofthe subjects hadprevious WI running experience and the tworemaining were familiarizedwith WI running once before testing. A wetvest was worn during WIrunning testing. Four minute submaximal exercise bouts(with one minutepause) of progressive intensity were performedat exercise intensitieseliciting HRs of 115, 130, 145 and 155—160bpm. The subjects WI ranlengths alongside the pool deck and expired air was collectedin Douglasbags during the last 1-1.5 minutes of each exercise bout. At theend of31each exercise bout bloodlactate sample (from theearlobe) and RPE wereobtained.Following completion ofthe fourth exercise bout,the subjects wereasked to increase theirexercise intensityto maximal effort within1—2minutes and to maintainthis intensity for aslong as possible (2minutes). HR and expiredair were collected duringthe last minuteofexercise(3_4thminute) at maximal effortand blood lactate obtained30seconds post—test. Thetreadmill protocolsfor the submaximal exercisetests were matched tothe V02’s determinedfrom the WI tests. Thetreadmill protocol fordetermination ofVO2mdid not match the WIVO2maxprotocol. A treadmillVO2maxprotocol of set velocityandincreasing grade over timewas utilized.LowerVO2maxvalues were reported forWI compared to treadmillrunning (4.03 vs 4.60 lmin).Significantly lowerHR8 were reportedat a V02 of 3.5 l’min(155 vs 165 bpm) and maximaleffort (172 vs 188bpm) for the WI comparedto the treadmill condition.Submaximal andmaximal Ve responses weresimilar for the two conditions.[BLa] valueswere higher in the WI conditionat a V02 of 3.5 lmin’(5.01 vs 1.33mmo11) and 70 %VO2maX(4.6 vs 1.5 mmol11).Peak [BLa] values(12.4 vs 10.0 mmo11) werealso higher in the WIcondition compared totreadmill values. HigherRER values were notedfor WI versus treadmillrunning at a V02 3.5 lmin’(0.98 vs 0.95).RERmaxwas lower for WIversus treadmill running(1.10 vs 1.20). SimilarRPE values werereported for breathing andlegs separately for treadmilland WI running.Higher RPE values were reportedduring exercise ata V02 of 3.5 lmin32(14.6 vs 12.6) and fora HR of 150 bpm(14.2 vs 10.4) inthe WI versusthe treadmill condition.The authors concludedthat the higheranaerobic metabolismassociated with WIrunning is likelyrelated to the reducedperfusionpressure in the legs witha consequent reductionor maldistributionintotal muscle bloodflow. The authorsalso noted thatalthough thesubjects were familiarizedwith WI running,they were less conditionedto WI running (Svedenhagand Seger, 1992).Consequently the lowerWIrunning conditioningmay be directly responsiblefor the RPE, [BLa]andRER behaviour exhibitedduring submaximaland maximal exercise andnotthe WI condition.Butts et al (1991)compared treadmill andWI running responses(N=24). A wet vest wasworn for WI running.For WI testingthesubjects were tetheredto the side of thepool. Stride frequencywasused to producea progressive incrementaltest to exhaustionfor WIrunning. The subjectsWI ran initially at100 strides per minuteandwere told to increasetheir stride frequencyevery two minutesby 20strides per minute. Thesubjects were encouragedto ‘go all out’ whenthey were unableto maintain thespecific stride frequencyfor anadditional minute.Lower WI valuesforVO2max, ye, HR and RER werenoted. The lowerWIVO2maxvalues were attributedto the hydrostaticpressure and mechanicalconstraints imposed onWI running related tothewater resistance.Restrictions to maximallimb movement anda decreasein active muscle massin WI running were alsosuggested as possibleexplainations. Theauthors note that antigravitymuscles active during33land—based running are notneccessary in WI running,consequently themetabolic cost of WI runningmay be reduced.Town and Bradley (1991) comparedVO2maxvalues from distance runners(N=9) familiarized with water runningin WI running, shallow water(SW)running (1.3 meters indepth and arms above thewater level) andtreadmill running.VO2maXtests for water running (SWand WI) were 4minute duration tests andthe subjects were askedto increase theireffort each minute resultingin exhaustion by the fourth minute.Thetreadmill test producedhigherVO2maxvalues compared to SWrunning(representing 90 % of the meantreadmillVO2maXvalue). Both modesproduced higherVO2maXvalues than WI running(representing 73.5 % ofthe treadmillVO2maX).HR was lower in the WI runningtest. Similaroxygen pulse (HR/V02)valueswere noted for treadmill (2.66beatsml)and SW (2.63 beats ml1) running.Lower HR/V02 was reportedfor WIrunning (3.40 beatsml)and the authors attribute thisrelationship togreater left ventricularend—diastolic and end—systolicdimensionsobserved during WI. RERand [BLa] were similar in all threeprotocols,but treadmill running showeda trend toward higher (ie.19 %) [BLa)levels than the WI and SWrunning tests.Welsh (1988) comparedtreadmill and WI running TventandVO2maXresponses in middle distance runners(t4=16) who regularly performedWIrunning workouts. LowerV02, and HR values were exhibitedat Tvent andVO2maxin WI compared to treadmill running.Similar Ve values werenoted at Tvent andVO2maxin the two conditions, but higherventilatoryequivalent for V02 (Ve/V02)values were noted in WI versustreadmill34running. Tidal volume(TV) and breathing frequency(Bf) were measuredat Tvent and maximal efforton a subsample (N=4).Bf at Tvent values(37.9 vs 37.1 breathsper minute (brpm)) weresimilar and slightlyhigher at maximal effort(54.6 vs 48.7 brpm) inWI versus treadmillrunning. TV values were lowerat Tvent (2.17 vs 2.28liters) andmaximal effort (2.32 vs2.56 liters) inWI versus treadmill running.TC-99 2—methyloxy isobutylisonitrile was injectedin two subjects tomonitor blood flow distributionin the lower trunkduring WI andtreadmill running at Tvent.Although leg blood flowdecreased in onesubject, it increasedin the other subject duringWI running. Theintersubject differencesin blood flow distributionswere suggested tobe related to WI runningstyles.Dressendorfer et al (1976)reported similarVO2maxvalues for WI andland (3.18 vs 3.92 1min)ergometer cycling(N=7). Similar RER (1.08vs 1.12) and lower HR(169 vs 130 bpm) and Ve(130.2 vs 145.9 lmin)values were also reportedfor WI compared to landcycling at maximaleffort.Sheldahl et al (1987) comparedWI and land ergometercycling HR,V02, CO, SV, Ve, TV and Bf responses(N=19). SimilarVO2maxvalues werenoted in both conditions. Exerciseresponses were comparedduring 5minute exercise boutsat 40, 60, 80 %VO2max.In both conditionsworkloads were matched forV02. Lower HR valueswere noted only duringexercise at 80 %VO2max.SV values were greaterin WI at rest andexercise at 40 %VO2max.A linear increase in COvalues with V02 werereported for both conditions,however CO was higherat rest and during35exercise at 40 and 60 %VO2maxin the WI condition.The authorsobserved, however, somevariability (lower)in Co with WI exercise,ye,TV and Bf were not alteredat rest by the WI condition.Ve responseswere similar during exercisein both the WI and landconditions. HigherBf values were reportedduring WI exerciseat 40 and 80 %VO2max.Decline in TV responsewere noted in the WIcondition during exerciseat80 %VO2max.Connelly et al (1991)compared V02, HR,RER, blood lactate andplasma catecholamine responsesto upright graded WIand land cycleergometer exercise (N=9).SimilarVO2maxvalues were reportedfor WIand land cycling. Fiveminute exercise bouts wereperformed at 43,61,78-82, and 100 %VO2max.Similar RER and bloodglucose values werenoted at each exerciseintensity and atmaximal effort. V02 valuesateach exercise intensitywere similar.HR values were lowerduringexercise at and above61 %VO2max.[BLa] values were lowerin the WIcondition onlyat maximal effort. Plasma norepinephrinevalues werelower at and above 78—82%VO2max,whereas plasmaepinephrine valueswere lower only at maximaleffort in the WI condition.Connelly et al(1991) concluded that plasma catecholamineresponsesare altered by WI. Itwas, however, unclearwhether the decrease innorepinephrine wasthe result of reduced sympathoadrenalactivity, ordue to an increase inthe clearance of epinephrine,or to an alterationin metabolic responseto exercise. The lowerplasma epinephrineexhibited during maximaleffort was suggested thatit may have served toreduce muscle glycogenolysisand thus [BLa]. It wasalso suggested that36there may be an increasein muscle blood flowin WI, which may increaseaerobic metabolism andreduce [BLa] resultingin a lower increaseinplasma epinephrine.It was also suggestedthat plasma epinephrineandlactate clearancemay be increased duringmaximal exercise.The effect of theredistribution of bloodvolume in WI wasinvestigated by Christieet al (1991).Land and WIVO2maxtests werecompleted on cycleergometers (N=l0).Five minute exercisebouts(matched for V02) werecompleted in the two conditionsat 40, 60, 80 and100 %VO2max.No differencesin resting HR, systolicblood pressure,V02 andVO2max(43.5 vs 42.5 mlkg1min)were noted on landand WI.Similar V02 valueswere reported foreach exercisebout in bothconditions. LowerHR values were notedfor exercise at 80and 100 %VO2max.Christie et al(1991) reported cardiacindex to be higherin WI andto increase ina linear fashionwith increasing V02.Centralhypervolemia was suggestedto alter the cardiacoutput-V02 relationshipwith upright WIexercise. The authorsbelieve that the additionaloxygen delivered bythe heart may notbe utilized by theexercisingmuscles. Stroke indexincreased during restingWI, with no furtherincreases noted withWI exercise. Theincrease in strokeindex wasattributed to enhancedpreload. Thelower WI HR’s at higherintensityworkloads were suggestedto be the result ofreduced sympatheticneuraloutflow. It was suggestedthat reduced sympatheticneural outflow couldbe the result of alteredbaroreceptor activitycaused by increasedcentral blood volume,or increased muscle bloodflow. Similar resting37and submaximal HR’S weresuggested to beindicative of cardiopulmonarymediated vascular dilation.In summary it appearsthat differencesin WI and treadmillVO2maXand Tvent may be attributedto less familiarity of therunners to WIrunning and possiblynot to the WI condition.HR is lower at maximaleffort in WI, however,there is no clear consensusregarding submaximalHR response in WI versusland exercise. yeis not affected by theWIcondition, however Bfis higher and TV reducedduring WI exercise.There is no consensuson [BLa] and RERresponse to WI versuslandexercise, however, couldfamiliarity to theactivity soley have dictatedthe patterns exhibited.2.3.2 Submaximal ProlongedDuration Exercisein Water IRmersion.Responses during submaximalexercise on the treadmilland WI runninghave also been investigatedrecently. Bishop etal (1989) compared V02,HR, Ve, RER, and RPE duringa 45 minute subject selectedpace on thetreadmill and WI running(utilizing a bouyancyvest). The runners wereasked to select a runningpace which they couldcomfortably sustainfor45 minutes. The authorsstate that the runnerswere ‘familiarized’ withWI running and they concurrentlydetermined their 45minute WI runningpace following onlytwo practice trials.V02 in the WI run was36percent lower thantreadmill values(ie.W1v02=29 mlkgmin vsTrVO2=4O.6mlkg1min) forsimilar RPE responses(WIRpE=l2.4vsTrRpE=ll.7).Lower Ve andRER were also noted for WIversus treadmillrunning (ie.WIv5=58.l1’min andWIRER=O.92vsTrve=79lmin andTrRER=O.9S). It was concluded that the metabolic cost forWI running at38a preferred intensity wasless than for treadmillrunning at a preferredintensity (Bishop et al, 1989).Richie and Hopkins(1991) suggest that thebouyancy vest Bishopetal (1989) utilized may itselfhave been a limitationto simulatinglandrunning style in theWI condition, but mayalso have reduced theneedfor the runners to exercisemaximally to remainafloat. However, themain contributing factorsfor the differencesmay be related to theunfamiliarity of the runnersto WI running and thebouyancy vest.Richie and Hopkins(1991) compared WI runningto treadmill androadrunning at a hard andnormal training pacein distance runnerswho weretrained’ in WI runningtechnique. WI runningtraining consistedof twosessions with instructionin WI running technique.The subjects werethen asked to completea 30 minute WI running sessionwith V02, RER,HRand RPE measured and comparedto 30 minutesof subject determined normaltraining pace and30 minutes at a hard trainingpace on the treadmilland to 30 minutes of roadrunning at their normal trainingpace. HigherV02, RER, and RPEwere reported for WI runningcompared to normaltraining pace runningon the treadmill. SimilarHR responses werereported by the authorsfor WI running andnormal training pacetreadmill and road running.However examinationof the V02 during thesesessions reveals ahigher V02 and RER forthe WI compared to the normaltraining pace treadmillrun, therefore HR was lowerin WI relative tov02.Yamaji et al (1990) comparedthe HR-V02 relationshipfor WI andtreadmill running in a groupof runners (N=10) withvarying WI runningabilities. Althoughthey found no differencesbetween the twoconditions, they suggestthat the (low) WI runningskill level of the39runners may have producedthe higher HR forsimilar V02 in theWIcompared to the treadmillcondition. They notedthat runners whohadutilized WI runningextensively did demonstratelower HR values thanthose runners lessfamiliar with the activity.It was noted thatrunners less familiarwith WI running tendedto utilize their uppertorso to a greater degreeto remain afloat.Commonality in all threeof these studies (ie.Richie and Hopkins,1991; Yamaji et al 1990;Bishop et al. 1989),is the use of runnerswhowere untrained in WIrunning. Comparisonsof the physiologicalresponses to WI andtreadmill runningwere made at dissimilarintensities of exercisein the two activities.Consequently itisunclear from these studieswhether the responsesexhibited were relatedto the WI conditionor to the samples utilized.In summary it appearsthat WI running studieshave compared thephysiological responsesof WI and treadmillrunning among runnerswithlimited WI running familiarityand at absolute workloads,which mostlikely represent inthe WI condition a highermetabolic requirement,ashas been demonstrated bythe WI running studiescomparing treadmillandWIVO2max.2.3.3 Comparison of thespecificity of training:WI versus land-basedtraining.Avellini et al (1983)and Sheldahi etal (1986) investigatedthecardiorespiratoryadaptations in malesto ergometer cycling whileimmersed in water at shoulderand neck level respectivelyversus landcycling. Subjects were assignedto either the WI cyclingor the land40based cycling training group.In Avellini et al (1983)the subjectstrained for one hourper day, 3 times perweek for 12 weeks.InSheldahi et al (1986) thesubjects trainedfor one hour per day,5 daysper week for 4 weeks.The intensity of trainingin both studies was setbetween 60—80%and controlled for the dampenedHR responses withWI (trained at a 10 bpmlower HR in WI).Training resulted in increasedVO2max of the same magnitudein both the WI and landtraining groupsinboth studies. Pre andpost testingVO2maXtests were completedon thetreadmill. SubmaximalHR, systolic and diastolicBP were lower andsubmaximal SV higherat the same exerciseV02 following training,inboth the WI and land traininggroups.The authors concludedthat differences in physiologicalresponses toWI versus land exercise donot alter cardiovascularadaption to exercise(Sheldahl et al, 1986;Avellini et al, 1983).The ability to stabilizethe body on a cycle ergometertherefore permits centraland possiblyperipheral adaptationswhich may facilitateland-based cyclingperformance.In summary it appears thatthe WI condition used asthe trainingenvironment for cyclingtraining does not hindercardiovascularadaptations. Targettraining HR for WI exerciseof 10 bpm lower thanland training HR appearsto have produced equivalentWI and landtraining programs.Consequently, it appearsthat submaximal HR responseis lower in the WI versusland condition.412.4 VENTILATORY THRESHOLD(Tvent) PERFORMANCETvent during incrementalexercise to exhaustionprovides anindication of lactatesteady-state (Yamamotoet al, 1991).Tvent hasbeen identified as thepoint where there isa non—linear increaseinexcess CO2 (Anderson andRhodes, 1991; Loat, 1991;Rhodes and McKenzie,1984). Ve (Davis etal, 1976), RER (Wassermanet al, 1973) and Ve/V02(Ciaozzo et al, 1982;Davis et al, 1979) havealso been used to identifyTvent. The use of excessCO2 to identify Tventhas been suggested asabetter indicatorof metabolic acidosisin the exercisingmuscles,because excess CO2 isthe direct result ofmetabolic buffering(Loat,1991; Anderson and Rhodes,1991; Rhodes and McKenzie,1984).Tvent intensity levelhas been used to predictdistance runningperformances. Rhodesand McKenzie (1984)reported a high correlation(r=O.94, p<O.O1) betweenpredicted and actualmarathon times.They usedthe excess CO2 curves fromprogressive incrementalVO2maxtests toidentify the velocityat Tvent. The runnersthen completed aninternational marathonand their completiontimes were comparedto thepredicted time from Tventvelocity. It was concludedthat the velocityat Tvent representedthe optimal pace tocomplete a marathon fortrainedmarathoners.Other studies havealso used Tvent velocityto predict runningperformance for 3.2km to 42.2 km runs (Hearst,1982; LaFontane etal,1981; Farrell et al,1979). Tvent has alsobeen used to predict steady—state cycling velocity (Loat,1991) and Ironman triathlonperformance by42predicting swim, cycleand run time fromTvent pace (Langill andRhodes,1993).Loat (1991) determined individualTvent workload levelsfrom excessCO2 curves and thenhad the cyclists cycleat their determinedTventworkload for 60 minutesin the laboratory.The cyclists completedthetest without significantelevations in ye, V02,HR and [BLa). Hearst(1982) noted low [BLa]maintained over timeduring exerciseat Tvent,but elevated [BLa)(and HR, vo2,ye, excess C02) levelsnoted whenexercising one kilometer(and 2 km) above Tvent.In summary Tvent determinedfrom the excess CO2 curverepresentsthe maximal steadystate exercise intensity.Exercising at Tventintensity appearsto allow prolonged exercisewithout elevationsin[BLa], V02, ye andHR.43CHAPTER 33.0 METHODS AND PROCEDURESThis study examined and compared maximaloxygen consumption(VO2max)and ventilatory threshold (Tvent) responseson treadmill and waterimmersion to the neck (WI) runningin a group of elite distance runners,trained in deep water running. Fortytwo minute performance testsateach runner’s treadmill andWI Tvent values were thereafter completedand minute ventilation (ye), oxygenconsumption (V02), heart—rate(HR)and blood lactate concentration ([BLa))values were measured. Subjectscompleted all testing within a2.5-4 week period with02maxtestsseparated by at least 5 days.Tvent performance testswere completedwith a minimum one day rest period.3.1.0 SAMPLEThirteen elite distance runners‘trained in WI running’ withaminimumVO2maxof 50 mlkgmin and 60mlkgmin for the female(5) and male (8) runners, respectivelyparticipated in the study.Tenof thirteen elite distance runners20 to 35 years of age who volunteeredcompleted all testing required forthe study. This sample consistedof4 female and 6 male runners. Completeresults for only the treadmilland WIVO2maxtests are available on the threeremaining subjects (N=3)and they have been included fortheVO2maxsection of the studyanalysis. The subjects ranged inage from 21 to 35 years of age.Theycompeted in distance events whichranged from 800 meters tomarathon and44ultramarathon distancesand were trainedin WI running.The goal ofthis study wasto utilize runnerswho regularlyincorporated WIrunningin their trainingregimens andsimulatedin their WI runningstylecertain key land—basedrunning motions.This study definedan elite distancerunner trainedin WI running asone who incorporatesin their trainingregimen a minimumof 6 sessions(approximately45—60 minutes persession) per monthof WI runningforthe former 6 monthsprior to theirparticipationin this study. Onlyrunners who practicednon—weight bearingWI running wereaccepted in thestudy. WI runningstyle was assessedduring a WI runningsession withthe investigatorand duringthe WIVO2maxtest. An underwatervideocamera was used tovideotapeeach subject’sWI running style,initiallyunattachedto the pulley systemand then duringthe WIVO2maxtest. Thevideotaped WIrunning performanceswere assessedfor comparabilitytoland—based runningmotion. Subjectswho met WI runningstyle andtraining criteriawere kept in thestudy. Itwas not the intentionofthis study to doa biomechanicalanalysis, but onlyto maintain similarbasic running stylesin WI as on thetreadmill.Three criteria wereset to evaluateWI running stylewhich had to bemet by each subjectto participatein the study.If the criteria werenot met the runnerwas excluded. The3 criteria werethe following:i) The trunk remainedupright with respectto the scalinggrid. Afoward lean ofup to 45 degreeswas deemed acceptable.45ii) Unilateral fowardmotion of thearms andlegs was followed,specifically:a) The lower rightknee was broughtfoward and upward,in the recoveryphase of the rightleg cycle. Whenthe thigh reacheda horizontal ornear horizontal positionthe lower legswung forward.The right legbegan to descendand the left legbegan to move forward.b) The arms wereflexed at approximatelyright angleswith the elbows.The left armwas swung fowardas the rightknee swung fowardandbackward and theright leg descended.iii) The hands werenot used to significantlypropel the runner.Toprevent cupping ofthe water andthus excessiveuse of the upperbodymusculature and excessivefoward lean, thesubjects were instructedtohold small spongesin either handduring the water tests.46Figure 2. Underwater photograph of a subject WI running. The subjectruns in deep waterand there is no weight bearing involved. The subject is instructed to simulateland-basedrunning motion and remain in an upright posture, while WI running. Thegrid board, situatedbehind the runner serves to assess his forward lean. A maximum leanof 45 degrees isdeemed acceptable and is depicted by the diagonal lines on the board.The water ski beltcan be seen worn by the subject around his waist. Worn underneath the waterski belt isthe waist harness. The attachment ropes connect to the waist harnessand lead to thepulley system of the WI ergometer.473.2.0 PHYSIOLOGICALTEST EQUIPMENTThe followingequipment wereused for physiologicaltesting:1) Beckman MetabolicCart was utilizedto measureexpiratory gasesandvolumes (V02,VCO2, Ve, tidalvolume (TV),breathing frequency(Bf)).The Hewlett Packard3052 A DataAquisition systemwas used toprocessthe metabolicdata collectedand obtainVe (in STPD),ExCO2 andVe/V02calculations.Expired gaseswere sampledat 30 second intervalsby themetabolic cart.2) Two HR monitormodels were utilizedfor HR sampling.The POLARACCUREX andthe POLAR FAVORHR monitors wereutilized. ThePOLARACCUREX was utilizedfor all treadmilltests. ThePOLAR ACCUREXwasused in conjuctionwith the POLARFAVOR for WItests, when possible(the2 HR monitors transmittedat differentfrequencies).The POLAR ACCUREXHR monitor wasworn at thelevel of thesternoxiphoidjunction (fortreadmill andWI testing) andthe POLARFAVOR was wornat the levelofthe third rib(for WI testing)(see Figure3 for HR monitorplacementfor WI testing.A nylon spandexsports top wasworn by the malesubjects duringWItesting. These lattertwo stepswere taken primarilyto avoid loosingHR values during WItesting. Thisoccurred oftenwith the malesubjectsand was due towater moving freelybetween the subjects’sternum and theHR monitor belts.This inhibitedcontinuous contactof the HR monitorbelt with thesubjects’ chest andtherefore theHR signal wouldbe lost.483) Water ski belt was worn by the subjects around thewaist for the WIrunning tests. This was a limited buoyancy devise providingenoughbuoyancy to limit upper body musculature involvementduring WI runningfor the purpose of remaining afloat. The buoyancysection was worn inthe front (on the abdominal region) versusthe back, which caused thesubjects to lean foward excessively due tothe belt rising up their back(see Figure 2 and 3).3) Kontron Medical LA640 Blood Lactate Analyzerwas used to analyze[BLa] samples. Twenty microliter blood samples were drawn fromthefingertip and immediately haemolyzed. The bloodsamples were thenplaced in the refrigerator and later analyzed for lactatecontent (inmmol/l blood) with the lactate analyzer.4) Quinton 24-72 treadmill was used for treadmill tests.5) A modified tethered swimming apparatus (ie. WI ergometer)was usedfor the WI tests (see section 3.4.3 for descriptionand Figure 4 forpicture).6) Underwater film assessment recorder was used forunderwatervideotaping of WI running.49Figure 3. WI running;an above and belowsurface picture. A. Underwaterpicture of asubject WI running. The waistharness is shown in thispicture. During testingthe waterski belt would be wornon top of this harness(see Figure 2). Also shown arethe positionsof the 2 HR monitors wornfor WI running testing.B. Mouthpiece apparatusassembly forWI running testing is shown.The mouthpiece is securedon the subject withhead supportforVO,ak. testing.050_:-.iFigure 4. WI running set-up. A. Picture of the WI running set-up from behind the WIergometer. The WI ergometer is a simple frame equipped with 2 pulley systems and ispositioned at the edge of the pool. The rope which attaches to the waist harness runsthrough the lower and upper pulley systems of the WI ergometer and finally attaches to theloading bucket. The position of the subject and metabolic equipment are visible in the fardistance. The position of the video operator relative to the subject is also shown in thispicture. B. This picture provides a forward view of the WI set-up. In this picture theinvestigator can be seen obtaining the final blood lactate sample from a subject following asteady state test. The mouthpiece apparatus and metabolic measurement equipment arevisible. The WI ergometer position is also visible in the background. Note the differentorientation of the mouthpiece for the steady state Tvent tests versus theVO2maxtests (seeFigure 2 B). This was to allow for ease of insertion and removal during these tests.Rope to PulleyI513.3.0 UNDERWATER FILM ASSESSMENTAPPARATUS AND PROCEDURESA grid board and an underwatervideo recorder were utilized tomonitor WI running motion. Thegrid board measured 1.2 X 2.4 metersandwas immersed, longest side across,along the pool wall.Vertical andhorizontal lines (2.5 cm in width,vertical lines were spaced 15 cmapart, and horizontal lines werespaced 30 cm apart) were painted ontheboard. A 2.5 cm tape in bold colourswas placed along the gridboard at45 degree angles with theirpoint of initiation 0.76 meters fromthe topof the grid board. Thislevel was determined to approximate on averagethe location of the pelvis area.Hooks attached the grid board to thepool deck and weights attached tothe lower end of the board preventedexcessive movement of the immersedgrid board due to water turbulence(see Figure 2 and 3 for a schematicpresentation).The underwater videocamera was used to tape the WI VO2maxtests.The subject was positioned at thecenter of the grid board and therewasrelatively little motionof the subject in relation to thegrid boardduring the WI VO2maxtest. The video operator videotapedfrom astationary position 6 feet infront of the grid board (ie. thesagitalview was videotaped) (see Figure4). The video operatorwas instructedto videotape the whole grid board andthe limbs of the subject. Thevideo operator was thus filming a 2.4X 1.7 meter area. Filmingbegan30 seconds prior to test initiation.Test initiation was signalled onthe videotape by the investigatorwaving her arm or a small board acrossthe grid board under the water.523.4.0 TREADMILL AND WIVO2maxAND Tvent PERFORMANCETEST PROTOCOLS ANDPROCEDURES3.4.1 Treadmill andWIVO2mCommon ProceduresSubjects were askedto refrain from eating2 hours prior to testtime and from heavytraining on testday. Subjects reportedto thelaboratory andfollowing the subjects’self selected warm—up(withrespect to paceand duration),height and weight measurementsweretaken. Expired gaseswere sampled bya Beckman Metabolic CartduringtheVO2maxtests every 30 seconds.Heart—rates were recordedduring thelast 5 seconds of eachminute utilizing theHR monitors. Subjects wereinstructed to pointto their percieved exertionrating (Borg scale fromBorg, 1970) every 2 minutes45 seconds into the workload.At test terminationa blood lactate sample wasobtained within thefirst minute post—test(within 30 seconds post-test).At 5 minutespost—test an additionalblood lactate samplewas obtained. Thesameprocedures were followedfor the treadmill andWI tests. In the caseofthe WIVO2maxtest the subject was instructedto come out ofthe poolafter the first lactatesample was obtained andthe second [BLaJ samplewas obtained on the pooldeck (see Figure6 for a schematic diagramofVO2maxtest procedures).533.4.2 TreadmillVO2maxTest Protocoland ProceduresThe treadmillVO2max protocol followed a continuousprogressiveregimen. Thetreadmill speedcommenced at5 mph and was increasedevery60 secondsby 0.5 mph.If the treadmillspeed reached12 mph at minute15 of the test,the speed wasno longer increasedinstead thetreadmillgrade was increasedevery followingminute by 2percent untilphysiologicalor volitional fatigue(see Figure 5).The increaseinpercent grade wasintroduced to ensurethat a true maximumwas achievedand to preventthe treadmill speedexceeding therunner’s runningskillor capabilitiesbefore achievinga trueVO2fflaX.The durationof theprotocol rangedfrom 12 to19 minutes (meantest durationwas 14.5minutes, Table2).A 5-25 minutewarm-up preceededthe test andthe intensity ofthewarm—up was subjectselected.Height and weightwere then assessedandthe HR monitor,nose clip andmouthpiece securedon the subject.Thesubject was theninstructed torun on the treadmill(treadmill speed=5mph) and the testcommenced within2 to 3 minutesfollowing finaladjustments tomouthpiece position(see Figure 6forVO2maxprocedures).Termination ofthe test wasdefined by exhaustioncharacterized bythe point whenthe subject experiencedat least two ofthe followingcriteria: 1) volitionalfatigue, 2) a plateauin V02, 3) an RER1.10.543.4.3 WIVO2maxTest Protocol, Proceduresand EquipmentThe WIVO2maxprotocol followeda continuous progressive modelandwas designed to resemblethe treadmill protocol inloading progressionand duration. The goalwas to produce a linear progressionof Ve, V02with a distinct ‘breakaway’point in order to establishthe Tvent, butalso to ensure that the durationof the test was similarto thetreadmill protocol (thatis 12 to 19 minutes). Thodenet al (1987)suggest that measurementof cardiorespiratory parametersbegin frompower outputs which represent 20% of a subject’sVO2m8X.The protocolwhich was originally proposed tobe utilized for theWIVO2maXtest wasby Welsh (1988). This protocol,however, produced initialpower outputswhich would represent 45 to52 % of the present study’s subjects’VO2maxvalues. The protocol was revisedto meet this study’s goals andtoaccount for sex differencesin size, muscle mass and possiblythe lowerfitness level of this study’spopulation of runners fromwhich thesample was drawn.The water immersion running ergometer(IRE) utilized by Welsh (1988)was used in this study withslight modifications.The IRE was amodified tethered swimming apparatus.It was a rectangularshaped 2.5meter high frame whichsat at the edge of the pool.At the topextension rod a pulley system of lowresistance was attached andmarinerope of 1.5 cm diameter passed through.Another pulley system (this onewas a double pulley system)was secured on the bottom rod, whichwas 1 min front of the top rod,and the marine rope was passedthrough thissystem. The rope finally attachedto a 6 cm flat waist harness which55was worn by the subject(see figure 2 to4) and reached thecenter ofthe grid board. Therope at the otherend of the pulleysystem wasattached to a bucket, whichwas loaded with weightsfor the WI tests.For all WI tests the subjectswere immersed to the neckand wore awater ski belt aroundtheir waist (with theflotation segment situatedaround the abdominalarea, see Figure2 and 3). This beltwas wornabove the waist harness.The IRE was placed by theend of the poolwiththe lower pulley rod extendingover and into the pooisurface. Fourmeters of ropewas passed throughthe pulley system,in order toposition the subjectin the middle ofthe grid board. The subjectswererequired by correctrunning motion to maintainthe bucket 6 cm fromthetop pulley systemfor the duration ofthe test. A±4 cm variation inthe position of the bucketwas allowed.The WIVO2mtest required the subjectto maintain his/her positionin the water (and thusthe bucket positionstationary) with progressiveincreased loading. A pointof reference was placed1 m in front of thesubject as a point ofreference for the subject.With increasing loadper minute the subjectwould be forced torun faster and faster(ie.increase their cadence,length and power)to displace more waterinorder to maintain his/herposition. The protocoland subject would thusbe simulating treadmillperformance whichforces the subject torunfaster and faster withincreasing velocityuntil fatigue.The bucket on the IRE was initiallyloaded with 500 gram(g) and 750g weights, respectively, for the femalesand males. Afterminute 1 the56load was increasedby 400 g/min forboth femalesand males until minute15. On minute15 and until exhaustionthe load was increasedby 500 and750 g/min respectivelyfor the femalesand males, withthe goal beingtosimulate the changeto increasing gradeon the treadmillprotocol (seefigure 5 for comparisonof the treadmilland WIVO2maxprotocols).Termination of thetest was definedas the point ofexhaustioncharacterized bythe following:1) the subject wasno longer capableofmaintaining his position,and thus the positionof the bucket relativeto the top pulleysystem was greaterthan 11 cm,2) volitional fatigue,3) a plateau in V02for more than1.5 minutes, 4)RER > 1.10.Meetingthe first criterionand at least twoof the other criteriawereneccessary to establishVO2max.Post—test evaluationof maximaleffortincluded thecomparison of post—testpeak BLaJ valuesto treadmillvalues. The testprotocol was approximately12 to 19 minutesinduration (meantest duration was15.0 minutes, seeTable 2).WI running motion wasalso subjectivelymonitored duringthe test bythe investigatorto ensure acceptablerunning motion(discussed insection 3.1) in additionto underwatervideotaping.A foward leangreater than 45degrees relativeto the grid boardand excessive useofthe upper body musculaturealso resultedin early terminationof thetest. Underwatervideotaping was usedto assess WI runningmotion post—test and if the subject’srunning motion deviatedfrom the study’ssetcriteria, the testand subject werenot used in thestudy’s results.57Deviation of WI runningmotion from the setcriteria duringthe last2 to 3 minutes of the testwith an RER between1.10-1.20, resultedinconsideration thatVO2maxwas reached prior todeviation in acceptableWI running style. TheV02 prior to runningstyle deviation was acceptedas the subject’sVO2max.The rationale forthis exception wasbased onthe premise thatwhen on thetreadmill and thesubject reachesexhaustionhe/she can no longermaintain the treadmillpace and musteither step off orrisk falling onthe treadmill.The subject,however, does not580.5 mph/mm400 g/mmn750 g/minFigure 5. Treadmill and WI VO2maxProtocol description. WI VO2mtest loadingdiffered by gender.The loadings were higher for malerunners.Initial Load 5 mphMinute 15grade by 2%Immn750g 500g500 g/minUntil Volitional Fatigue59VO2maxPROCEDURESTventPROCEDURESSUBJECTSELECTEDWARM-UP(5-25MIN)TIME (MIN)HGTANDWGTDETERMINATIONEQUIPMENT HOOK-UP-13TESTSTARTWARM-UPTEST-8-30TEST COMPLETION[BLa]SAMPLING+0.5+5SUBJECTSELECTEDWARM-UP(5-25MIN)WGTEQUIPMENT HOOK-UPTIME(MIN)TEST WARM-UP-16-11-8START TESTMOUTHPIECE ONIAI0AAIITEST TERMINATIONII——******42TiT2T3T4T5T6T7*-Expiredgasesand—-[BLa]collection.HRcollection.Figure6.VO2maxandTventtestsschematicrepresentationofprocedures.experience the samefear with WI running.When the subject can nolonger maintain his/herposition in the water,the subject is eitherpulled back as thebucket goes down or beginsutilizing non—fatiguedmusculature to remainafloat and maintain theirposition. In the lattercase the subject increasesarm and shoulder contribution.The elbowsare pushed out tothe sides, in line withthe shoulders and thehandsused to cup the water.This action also resultsin increasing fowardlean of the subjectbeyond 45 degrees.3.4.4 VentilatoryThreshold DeterminationExcess CO2 (ExCO2) was plottedagainst time for the treadmilland WIVO2maxtest for each subject.Tvent was determined asthe point wherethe slope of ExCO2increased disproportionately(Anderson and Rhodes,1991; Loat andRhodes, 1991; Andersonand Rhodes, 1989; RhodesandMcKenzie, 1984; Volkovet al, 1975) andwas established independentlybytwo to three reseachers.The correspondingminute V02 values werecalculated at Tvent. Thetreadmill velocity and WIloading at the Tventlevels were used toapproximate the woakloadsfor the Tvent performancetests. The Ve/V02 plottedover time (to locate thebreak—away’ point)and an RER near 1.00were also used to substantiateTvent (see AppendixG).3.4.5 Tvent PerformanceTestsFour Tvent performancetests were completedby each subject andthese were:61TrTrTVent(treadmill Tvent performed on thetreadmill)TrWITveflt(WI Tvent performed on thetreadmill)WIWITvent(WI Tvent performed in WI)WlTrTvent(treadmill Tvent performed in WI)The minute V02 (in mlkgmin)values from the treadmilland WITvent extrapolations wereused to determine the testworkloads for alltest conditions. Similarily totheVO2maxtests, the subjects completedtheir self selected warm-up (5-25minute duration) and then hadtheirbody weight measured andequipment fitted, except forthe mouthpiece.During the Tvent test warm—upthe subjects were progressivelyloaded, orthe treadmill velocity increasedwith HR monitored. Once a HRwasachieved just below the anticipatedHR at Tvent the subject wasasked toput the mouthpiece on(with assistance). Whilecontinuing to run,expired V02 was monitoredand treadmill velocity(or WI loading)manipulated until the desiredminute V02 at Tvent was obtained.Oncethe workload at the respectiveTvent was obtained expiredgases weremonitored for 2—3 more minutesto ensure that the minute VO2wasmaintained within the acceptablerange. Minute VO2 values ±0.5ml/kg/min of the V02 atTvent were deemed acceptableand data collectedduring this period signaledcommencement the of the Tventtest and wasidentified as collectioninterval Ti. The totalprocess for reachingTvent workload was establishedwithin 4-5 minutes.HR, V02, Ve were monitoredand collected for 1.5 minutes attestinitiation (Ti) and at 6.5—8.0mm (T2), 13.5—15.0 mm (T3),20.5—22.0mm (T4), 27.5—29.0 mm (T5),34.5—36.0 mm (T6) and40.5—42.0 mm (T7).62Blood lactate sampleswere drawn during collectionperiods T2 throughT7. Blood lactatesamples were obtained followingthe last expired gascollection for the intervalby the metabolic cart.Expired gases (andHR) were continouslysampled every 30 secondsduring the stated timeintervals for the treadmilland WI Tvent performancetests (see figure 6for schematicdiagram of Tvent steady stateprolonged performancetestprocedures).3.5.0 EXPERIMENTAL DESIGNThe independent variablesin this study wereCondition(environmental) (factor 1)and Tvent (factor 2),with 2 levels each.The two levels of factor1 were the treadmill andWI (to the neck)conditions. The two levelsof factor 2 were treadmillTvent(TrTveflt)and WI Tvent (WlTveflt),determined from the treadmilland WIVO2maxtests, respectively.The experimental designfor theVO2maxtest data for hypotheses1and 2 can be treatedas a one way withinsubject comparison (of VO2maxand Tvent) undertwo different conditions(treadmill versus WI). VO2m&xand Tvent were treatedas the main dependentvariables.The dependent variablesfor the Tvent steadystate prolongedperformance tests wereexercise HR, V02, Veand [BLa]. The experimentaldesign for the Tventtest data, for hypotheses3, 4 and 5 (ie. HR,V02and ye), were treatedas a 2 X 2 X 7 withinsubject design with repeatedmeasures on all 3 factors(ie. Condition, Tvent,and Time).63The experimentaldesign for the Tvent test datafor hypothesis 6(ie. [BLa)), were treatedas a 2 X 2 X 6 within subject design withrepeated measures on all 3 factors(see Figure 7).A counterbalancedsingle factor design with4 treatments wasemployed. The treatments werethe 4 Tvent intensity steady stateprolonged performance tests,that isTrTrTvent, TrwITvent, WlTrTventandWIWITvent.TRT_,.Figure 7. Diagramof the factors and levelsof the experimentaldesign. Thestudy examined whetherthe Condition (WI vs treadmill),Tvent (WI vstreadmill) and Time(over the 42minute tests) factors,were responsible forthedifferences in physiologicaland metabolic function.The contributionof eachfactor separately andin combinationwith the other two factorswere exploredwith repeated measuresanalysis of varianceand trend analysis(see section3.6.0).-6 levels for [BLaJ,starting at T2.FACTOR 1Levels=2 ICONDITIONTRPDM ILLIwilFACTOR 2:LeIs=2FACTOR 3:LeveI=7TIME___I I___ ___I IT1T2T3jIT4T5JIT6IT71643.6.0 STATISTICAL ANALYSISThe data collected wasanalyzed as follows:1) Correlated T—Testswere conducted totest Hypotheses 1 and 2regarding the comparisonof treadmill versusWIVO2maxand treadmillversus WI Tvent (V02 atTr and WI Tvent). Differencesin HR, Ve, RER,RPE, test duration at VO2maxand Tvent and post—test [BLa)at 30 secondsand 5 minutes fromtheVO2maxtests were also analyzedin the twoconditions using correlatedT—Tests.2) 2 X 2 X 7 withinsubject repeated measuresanalysis of variancewithtrend analyses wereutilized to test hypotheses3 to 5 regardingdifferences in V02, HR,and ye over Condition, Tventand Time. Two 2 X7 withinsubject repeated measuresanalysis of variance withtrendanalysis were usedto specifically compare TrTrTventV5WlTrTventandTrWITvefltvsWIWITvent.3) 2 X 2 X 6 withinsubject repeated measuresanalysis of variance andtrend analysis wasused to test hypothesis6 regarding differences in[BLa] over Condition,Tvent and Time. Two 2 X6 within subject repeatedmeasures analysisof variance withtrend analysis wereused tospecifically compare TrTrTventVSWlTrTventandTrwlTvefltvsWIWITvent.65CHAPTER 44.0 RESULTS4.1.0 Physical Characteristics of the SampleThe sample consisting of five (5) female and eight (8) maleendurance runners trained in water immersion running to the neck (WI)(ie. simulating land—based running style andwith minimum WI runningexperience of 6 months) were selected for this study. Three subjects(one female and two males) have complete dataon only the two maximaloxygen consumption tests(VO2max)(ie the treadmill and the WIVO2maxtests) due to technical difficulties in completing theremaining steadystate performance tests and have only been used for the VO2max resultsanalysis. The female and male subjects hadto demonstrate a minimumtreadmillVO2maxof 50 and 60 mlkg min respectively forinductioninto the study. Table 1 contains the mean physicalcharacteristics ofthe subjects and mean treadmill VO2max by gender.Table 1.0. Physical Characteristics and Treadmill Maximal Oxygen Consumptionof the Sample.; VARIABLE FEMALE (N=5) MALE (N=8).,Mean (std) Range Mean (std) RangeAge (yrs) 242 (6 7) 18 0 35 0 273 (4 1) 22 0 340Height (cm) 1656 (43) 1597 1709 1825 (50) 1747 1910Weight (kg) 542 (4 9) 49 2 61 1 71 5 (4 6) 677 79 4VO2max (I/mm) 2.91 (0.29) 2.60 . 3.17 4.56 (0.36) 4.18. 5.03VO2max (mI/kg/mm) 53.7 (4.2) 50.5 - 61.0 63.4 (4.2) 60.0- 72.7664.2.0 MaximalOxygen Consumption (VO2max)Pest ResultsThe purposeof the firstpart of this studywas to comparemaximaland Tventresponses fromthe progressiveincremental loadingtoexhaustion(ie.VO2max)tests on thetreadmill and WI.The 3 maincriteria setto control subjectselection a prioriwere a) WI runningstyle, b) familiaritywith WI runningand c) minimumtreadmill VO2m(of 50 and60 mlkg min’for femaleand male runnersrespectively)for classificationas an ‘elitedistance runnerfamiliar withWIrunning’ (seeMethods and Procedureschapter). Thethirteen subjectsincluded in thepresent studymet the aboveset a prioricriteria.4.2.1 Maximal ResponsesThe treadmillrunning (Tr) VO2maxwas significantlyhigher, bothexpressed inlmin (p<O.O5)and in mlkg’min1(p<0.O5),whencompared to thewater immersionrunning (WI) VO2max(Figure 8.0 Aand B,respectively).The lower WIvo2maxwas accompaniedby significantlylower maximalheart-rate (p<O.O5)(Figure 8.1A) and RER (p<0.05)(Figure 8.2A) responses.However therewere similarminuteventilation(ye) responses(p>O.O5) (Figure8.1 B), ratingsof perceivedexertion (RPE)(p>O.OS)(Figure 8.2 B)and post-testblood lactateconcentrations((BLa]) (bothfor 30 sec.(p>0.O5) and 5mm. post-test(p>O.O5) values)(Figure 8.3 A)for both protocols.The durationof theWIvo2maxandTryo2maxtests were similar(p>0.OS) (Figure8.3 B). SeeTable 2 meanvalues (±std)for maximal responsesof V02, HR,Ve, RER,RPE, (BLa],and test duration.67Table 2.0. VO2m Results: Maximal Responses.CONDITIONTREADMILL WI(T-TEST)VARIABLEMean (std) Mean(std) p-valueV02 (I/mm)3 92 (0 89) 3 60 (078) 0 001V02 (mI/kg/mm)59.7 (6.4) 54.6(5.2) 0.001HR (bpm)190 (11) 175 (12)0.001Ve (1/mm)109.0 (22.7) 105.8 (19.1)0.73RER1.20 (0.08) 1.10 (0.06)0.003[BLa]-30 sec.-post10.4 (1.9) 9.8 (2.3)0.24[BLa] 5 mm post9 7 (2 0) 9 2 (25) 0 57Test Duration (mm)14 30 (2 00) 15 00(2 40) 0 37RPE20 (0) 20(0) 1.00684.2.2 VentilatoryThreshold(Tvent) ResponsesThe treadmillventilatorythreshold (TrTveflt)(ie. V02 atTvent) wassignificantlyhigher,expressed inlmin (p<O.O5)and in mlkg”min(p=O.03),when comparedto the waterimmersionventilatorythreshold(WlTvent)(Figure 8.0A andB). WhenTventwas expressedas apercentageof the respective VO2maxresults the TrTvefltand the WITvefltoccurredat approximately78 percent(p>O.O5)(Figure8.4).Asignificantlylower WlTvefltversus TrTvefltheart—rateresponsewasexhibited(p<O.05) (Figure8.1 A) andtheWlTventoccurredapproximately2 minutesearlier intheTrTyeflt(p<0.05)(Figure 8.3B). Therewere nosignificantdifferencesin Ve (p>O.O5)(Figure8.1 B),RER (p>0.O5)(Figure8.2 A) andRPE (p>O.O5)(Figure 8.2B) responsesatTrTvefltandWlTvent.See Table3 for meanvalues (±std)for Tventresponsesof V02,HR, Ve,RER, RPE,[BLa), testduration,and %VO2max.69Table 3.0. VO2m Results: Results at Tvent.‘:CONDITIONTREADMILL WI(T-TEST)VARIABLEMean (std) Mean (std)p-value? V02 (1/mm)3.03 (0.74) 2.81(0.69) 0.04V02 (mI/kg/mm)46 3 (6 4) 42 8(5 1) 0 03HR (bpm)165 (10 8) 152 (12)0 002‘ Ve (I/mm)66.4 (16.4) 65.7(16.0) 0.73RER0 99 (0 04) 0 98(0 04) 0 45% V02n,ax77 7 (6 8) 783 (4 7) 0 76Tvent Time (mm)8 10 (2 00) 6 20(2 00) 0 004£RPE13(2) 12(2)0.13‘70V02 (I/mm)V02 (mI/kg/mm)*Figure 8.0. Meanoxygen consumption(+1 std) at maximaleffort and Tvent levelfromthe treadmill (Tr)and water immersion(WI) VO2m tests. A.Absolute oxygenconsumption (lmin1)at VO2m and Tvent.B. Relative oxygenconsumption (mlkg’1min)at VO2m and Tvent.*Significant differencesat a=0.05.I*ITMaximalTventMaximalTvent71HR (bpm)Ve (I/mm)Figure 8.1. Meanheart-rate (HR) and minuteventilation (Ve) (+1std) at maximaleffort and Tvent levelfrom the treadmill (Tr)and the water immersion(WI) VO2mtests. A. Mean HR (bpm)response at VO2mand Tvent, significant differencesfoundat a=O.05(*).B. Mean Ve (Imint)response at maximal and Tvent,no differencesfound for Ve on the Trand WI conditions ata=O.05.MaximalTvent MaximalTvent72MaximalMaximalFigure 8.2.Mean RERand ratingsof perceivedexertion(RPE) (+1 std)at maximaland Tvent levelfrom the treadmill(Tr) and thewater immersion(WI)VOm tests. A.Mean RER responsesatVO2max and Tvent, significantdifferences(*)were foundatVO2m level only (a=O.05).B. Mean RPEresponsesatVO2m and Tvent, nodifferences werefound forRPE on theTr and WIatVO2m and Tvent at a=O.05.R ERRPETventTvent73[BLaJ (mmol/l) Duration (mm)Figure 8.3. Mean post-test blood lactate concentrations ([BLa]} andVO2ma,,testduration at maximal effort and at Tvent level from the treadmill (Tr) and the waterimmersion (WI)VO2ma,,tests. A. Mean [BLa] at 30 sec. and 5 mm. post-test on theTr and WI following maximal effort, no significant differences were found on theTr and in the WI conditions at a=0.05. B. MeanVO2mtest duration time andmean time at which Tvent occurred in the Tr and WIVO2mtests, significant(*)differences found only for Tvent time occurance (a=0.05).30 sec.-post 5 min.-postMaximal Tvent746055Figure 8.4.Comparisonof the treadmilland WI VO2m,, andTvent responsesandthe %ageof respective VO2maxthat eachTvent represents,comparedto theirrespective VO2mresponses.SignificantlylowerVO2maxand Tventresponseswere exhibitedwith WI running.No differenceswere found whenWI and TrTvent wereexpressedas a percentageof the respective VO2max.V02 (mlkg1m1n’)65%age80—I705045403560503040ETreacimillIwiVO2maxTvent % of VO2max753.3.0 Tvent SteadyState PerformanceTests Results4.3.1 Heart-rateHeart—rate responsesduring the steadystate performance testswereexamined inrelation to HR responseduring the performancetests in the2 Conditions(treadmill versus WI)and to Tvent (the TrTvefltversus theWlTventintensity) overTime and averaged overthe Time factor.There was a significantCondition main effectexhibited forHRaveraged over theTvent and the Timefactors (F1,9=19.35,p<O.O5). WhenHR responses wereaveraged acrossall the time intervalsand over thetwo Tvent’s (TrTvefltandWITveflt)mean HR was significantlydifferent inthe two conditions.Mean HR averagedover conditionand across time was9 bpm higheron the treadmill vsWI(TrHR=162bpm vsWIHR1SBbpm), andthe lower mean WIHRis directly attributableto the WI environment(Figure 9.0 B).There was a significantTvent main effect forHR, when HRwasaveraged overCondition and acrossthe Time factor (F1,9=6.48,p<0.05).Averaged overthe 2 conditionsand across thetime intervals mean HRresponse wassignificantlylower with the WlTvent (HRwITventl53bpm)versus the TrTveflt (HRTrTventl62bpm) tests (Figure9.0 A and B).There was a significantCondition by Tventinteraction (F19=6.88,p<O.O5). Averaged acrossall time intervalsmean HR responsewas 12 and7 bpm respectivelyhigher whenthe performancetest was performedon the76treadmill(HRTrTveflt=l6Sbpm andHRWITvent=i56bpm) versus WI(HRTrTvent=l5Gbpm andHRWITVent=l49bpm) (repeated measures(RM’s)analysis of mean HRaveraged over time for TrTrTVentVSWlTrTventandforTrWITventVSWIWITventidentified thatmeanHReswere significantlylower whenTrTvefltandWlTventwas completed inthe WI condition).Averaged acrossall, time intervalsmean HR responsewas 12 and 7 bpmhigher when TrTvent (TrHRTrTvent=l6Bbpm vs WIHRTrTvent=i56bpm,p<O.0002) versus WlTvent (TRwITventl5Gbpm vsWIHRWITVent=149bprn,p<0.05) intensitywas performed in thesame condition (Figure9.0 A andC). See Table5.0 for HR RN’s resultsand Tables 5.1 and5.2 for HRRN’s results for TrTrTVentVSWITrTventandTrWITvefltVSWIWITventrespectively.There was a significantTime main effect,and conclude thattherewas a significantdifference in meanHR responseover Time(F654=40.34, p<O.05).Ninety nine percentof the variabilityin Timewas accounted forby a significantlinear trend (F19=62.82,p<O.O5) asevidenced by thesteady linear increasein mean HR from 153bpm at Ti to162 bpm at T7(see Figure 9.1 A andB for mean HR responsesover Timefor individual tests).There was a significantCondition by Timeinteraction (F654=i0.96,p<O.O5) and concludethat the nature of theoverall change inmean HRresponses over the7 collection timeswas differentbetween the twoconditions. MeanHR responses overTime were consistantlylower in theWI versus thetreadmill condition.Ninety five percentof thevariability is accountedfor by a significantlinear trend(F1914.23,77p<O.O5), as evidencedby the steady linearincrease in mean HR inbothconditions (with WIHRat T1=151 bpm toT7155 bpm and TrHR at T1=].55bpmto T7=168 bpm) (Figure9.2 A and B).RM’s analysisof mean HR over timeforTrTrTVentVSWlTrTventandTrwipventVSWIWITventfound significant Timemain effects andConditionby Time interactions,in both comparisons.Lower mean HR responsesovertime were exhibitedin the WI comparedto the treadmill conditionatbothTrTvefltandWlTvent(p<O.O5 in both analyses)with significantincreasing lineartrend exhibited overtime (Figure 9.2 A andB).There was no significantTvent by Time interaction(F554=2.60,p>O.O5) (Figure9.2 A and C) and Conditionby Tvent by Time interaction(F654=O.26, p>O.O5).7811111TventTr WI TotalsTr 168 156162CONDITIONWI 156 149153Totals 162 153_______________________Figure 9.0. MeanHR response for Condition and Tvent maineffects, andCondition X Tvent interaction.A. Table of the mean HRresponse byCondition and byTvent. B. Comparison of mean HR responseover Condition(Tr vs WI) andover Tvent (TrTvent vs WlTvent)averaged over Time (Conditionand Tvent main effects).C. Comparison of mean HR responseaveraged overthe steady state tests performedon the treadmill (ie. at Tr and WITvent) versusthe steady state tests performedin WI (ie. at Tr and WI Tvent)(Condition XTvent interaction).HR (bpm)HR (Iprn)Condition TventTr—I—IR WI—HR79TimeTi T2 T3T4 T5 T6T7• TrTvent160 164 166168 172174 175TRWlTvent 149152 154 156159 160 161TrTvent 154 155155 156157 158 159:wiWlTvent 148 149148 148148 150151: Mean Test153 155 156157 159 161162Figure 9.1. MeanHR response overthe steady stateperformance testsover time.A. Table ofmean HR responseover time for the4 steady state testsand mean Tventtest. 8. Comparisonof mean HR responseover time for eachtest condition andTve nt.HR (bprn)1 80B155150-1451 40Ti T2 T3T4 T5 T6 T7TimTrTrTvent TrWITvent*WlTrTvent *-WIWITvent80TIMETi T2 T3 T4T5 T6 T7Tr 155 158 160 162166 167 168CONDITIONWI 151 152 152152 153 154 155Tr 157 160 161 162165 166 167‘ TventWI 149 151 151152 154 155 1561 80Tr WI170160150HFigure 9.2. Mean HR response for Condition XTime and Tvent X Timeinteractions. A. Table of mean HR responses forCondition X Time and Tvent XTime interactions. B. Comparison of mean HR responseover time for the meansteady state tests completed on the treadmill vsin WI (ie. mean HR at each timeinterval for Tr and WI Tvent combined)(Condition X Time). C. Comparison ofmean HR response over time for mean steady state testscompleted at Tr vs WITvent (ie. mean HR at each time interval for Tr and WI conditionscombined)(Tvent X Time).HR (bprn)1 40HR (bpm)180Tr WI170160 - -150 - -140Ti T2 T3 T4 T5 T6 T7TimeTi T2 T3 T4 T5 T6 T7Time814.3.2 Oxygen ConsumptionOxygen consumption(V02) was the variableused to set the Tventintensity of each42 minute performancetest. After the workloadproducing thespecific V02 was establishedand a steady V02 at thespecific Tvent(either theTrTvefltor theWITvent)intensity wasobtained, V02 was nolonger controlled. V02responses during thesteadystate tests were examinedin relation to V02response during theduration of theperformance tests inthe 2 Conditions(treadmill and WI)and to the 2 Tvent(theTrTventand theWlTvent)intensities over theperformance tests’stime intervals and averagedover the Timefactor.There was nosignificant Condition maineffect averaged overthe Tventand Time factors(F1,9=1.14, p>0.05)(Figure 10.0 Aand B).There was asignificant Tvent maineffect when averagedoverCondition and acrossthe Time factor (F1,g=7.27,p<O.O5). Averagedacross all time intervalsthe mean V02onTrTveflt(47.1 mlkg4min)was significantlygreater than the meanV02 onWITveflt(42.9 mlkg1min’) averagedover the two conditions,as hypothesized(Figure 10.0 Aand B).There was nosignificant Conditionby Tvent interaction(F1,90.68,p>O.O5) (see Table 5.0 foroxygen consumptionRM’s results).RN’sanalysis of meanV02 forTrTrTventVSWlTrTventand forTrwlTvefltVSWIWITventfound no significantdifferences inmean Va2 averagedovertime for TrTveflt(and no differenceforWlTvent)intensity test82completed inWI versuscompletedon the treadmill(see Table 9.1and 9.2for RM’sanalysisresults for TrTrTVentV5WlTrTventandTrWITVentVSWIWITvent).There wasa significantTime maineffect (F654=4.70,p<O.O5), withseventy twopercent ofthe variabilityaccountedfor by a significantlinear trendin mean V02over timefrom T1=44.4mlkgminto T7=45..3mlkgmin(see Figure10.1 Aand B formean V02 responsesover timeand individualtest V02 responsesover Time).There wasno significantCondition byTime interaction(F654=O.25,p>O.05) (Figure10.2 A andB). RMsanalysisof mean V02over timeforTrTrTVentvsWlTrTventandTrwlTvefltvsWIWITventfound nosignificantTime maineffectsand Conditionby Time interactions,in bothcomparisons(p>O.OS). Therewas a smallincreasein mean V02over timeexhibitedin the WITrTventandTrTrTVent(see Table6.0 for RM’sanalysisresults andTables 6.1 and6.2 for RMsanalysisofTrTrTventvsWlTrTventandTrwlTvefltVSWIWITventrespectivelyand Figure10.2 Aand B).There wasno significantTvent by Timeinteraction(F654=0.47,p>O.O5)(Figure 10.2A and C),and Conditionby Tventby Timeinteraction(F654=O.82,p>O.O5).83TventTr WITotals.Tr471 432452CONDITIONWI47.0 42.544.8Totals471 429V02 (mlkg1min)Figure 10.0.Mean V02 (inmIkg1min)response forConditionand Tvent maineffects , andCondition XTvent interaction.A. Tableof mean V02response bycondition andby Tvent. B.Comparison ofmean V02response overcondition(Tr vs WI)and over Tvent(TrTvent vsWlTvent)averaged overTime (Conditionand Tventmain effects).84TimeTi T2 T3 T4 T5 T6T7TrTvent 46 5 47 0 47 0 46 747 0 47 4 47 8TRWlTvent 42.5 43.0 43.0 43.143.3 43.8 43.6; TrTvent 46.1 47.2 47.2 47.0 46.9 47.7 47.2WIWlTverit 42 5 42 5 42 5 42 242 4 42 8 42 7Mean Test 44 4 44 944 9 44 8 44 9 45 4 45 3V02 (mIkg1min)40Ti T2 T3 T4 T5 T6 T7TIMETrTrTvent TrWITvent WITrTvent WIWITventFigure 10.1. Mean V02 (inmIkg1min)response over the steady stateperformance tests over time. A. Tableof mean V02 response over time for the 4steady state tests and mean test. B.Comparison of mean V02 response overtimefor each test condition and Tvent.85TIMETi T2 T3T4 T5 T6T7Tr 44 545 0 45 0 44 945 2 45 6 45 7CONDITION- WI44 3 44 9 449 44 6 44 745 3 45 0Tr 46 4 471 47 1 46 947 0 47 6 475TventWI 42 5 428 42 8 42 742 9 43 3 43 2;V02 (m[kg’1min)V02 (m[kg1minj::44 -444242-40Ti T2 T3T4 T5 To T7Ti T2 T3 T4 T5To T7TimeTimeFigure 10.2. MeanV02(mI’kg1min-)response for ConditionX Time andTvent XTime interactions.A. Table of meanV02 response forCondition X TimeandTvent X Timeinteractions. B.Comparison of meanV02 responseover time forthe mean steadystate tests completedon the treadmillvs WI (ie. mean V02 at eachtime intervalfor Tr and WI Tventcombined) (ConditionX Time). C.Comparisonof mean V02 responseover time for meansteady state tests completedat Tr vs WI(ie. mean V02at each time intervalfor Tr and WI conditionscombined) (Tvent XTime).864.3.3 VentilationMinute Ventilation (Ve) responses during the steady state tests wereexamined in relation to Ve response during the duration of theperformance tests in the 2 Conditions (treadmill and WI) and to the 2Tvent (theTrTvefltand theWlTvent)intensities over the performancetests’s time intervals and averaged over the Time factor.There was no significant Condition main effect averaged overtheTvent and Time factors (F1,g=3.87, p>O.O5). Averaged over thetwoTvent’s and across all time intervals, the mean ventilation response onthe Treadmill (Ve=68.0 l’mirz1) was similar to the mean response in WI(Ve=73.5 lmin) (Figure 11.0 A and B).There was a significant Tvent main effect when Ve was averaged overCondition and across the Time factor (F1,9=9.26, p<O.05). Averaged overthe two conditions and across all time intervals mean ventilationresponse atTrTveflt(Ve=76.2 lmin) was significantly higher than atWlTvent(Ve=65.3 lmin) (Figure 11.0 A and B).There was a significant Condition by Tvent interaction averagedover the Time factor (F19=5.33, p=O.O5). Averagedacross all timeintervals mean ventilation response was 8.8 and 2.2 lminrespectivelylower when Tvent intensity wasperformed on the treadmill(VeTrTveflt=7l.Blmin1 andVewlTvent=64.21min) versus WI(VeTrTveflt=BO.6lmin’ andvewlTvent=66.4lmin1). RM’s analysis ofmean ye forTrTrTventvsWlTrTventand forTrwlTvefltvsWIWITventfound87significantly highermean ye averaged overtime forTrTveflt(and nodifference for WITveflt)intensity testcompleted in WI versus completedon the treadmill(see Table 7.1 and 7.2 forRM’s analysis resultsforTrTrTventVSWlTrTventandTrWITVentVSWIWITvent).Averaged across alltime intervals meanventilation response was7.6 and 14.2 imin’significantly higherwhenTrTvefltintensity (TrVeTrTveflt=7l.Blmin1andWIVSTrTVSnt=BO.6lmin1)versusWlTventintensity(TrVewITvent=64.2lmin and WIVeWITVent=66.41min) was performed.RM’s analysisofTrTrTVentVSWlTrTventandTrWITvefltVSWIWITventrespectively foundmean Ve averagedover time to be higherin the WI comparedto thetreadmill condition(Figure 11.0 A andC).There was a significantTime main effect (F654=7.09,p<0.O5) with97 percent ofthe variability accountedfor by a significantTime lineartrend as evidencedby the steady linearincrease in mean ventilationfrom 68.5 lminat Ti to 72.7 lminat T7. RN’s analysisof mean VeforTrTrTVentVSWlTrTventand forTrwITVentVSWIWITventfoundsignificantly highermean Ve overtime forTrTvefltcompleted in the WIversus treadmillcondition (p<0.O5),with a significantlinear trendexhibited over time(p<O.O5) (Figure 11.1 Aand B).There was a significantTvent by Timeinteraction (F654=4.09,p<0.O5) with mean ventilationresponse consistantlylower over Time withWlTvent(ie.TrwITVentandWIWITventcombined) versus TrTvent(ie.TrTrTVentandWlTrTventcombined) tests. Ninetyseven percent ofthevariability wasaccounted for by asignificant linear trend(F195.59,p<0.O5) as evidenced bythe steady linearincrease in meanventilation88response inboth theWlTventandTrTveflttests (with mean veTrTventatTl=72.8 lminto T7=79.7 1min andmeanveWITventat Tl=64.2 1minto T7=65.8 lmin1)(Figure 11.2 A and C).There was nosignificant Conditionby Time interaction(F654=O.64,p>O.O5) (Figure 11.2A and B) and Conditionby Tvent by Time interaction(F654=O.79, p>O.O5).See Table 7.0for ventilation RM’sanalysisresults.89A:TventTr WI TotalsTr 71.8 64.2 68.0CONDITIONWI 80.6 66.4 73.5Totals 76 2 65 3e*tB CVe (Imin1)Tr—VeFigure 11 .0. Mean Ve response for Condition and Tvent main effects, andCondition X Tvent interaction. A. Table of the mean Ve response by Conditionand by Tvent. Comparison of the mean Ve response over Condition (Tr vs WI)and over Tvent (TrTvent vs WlTvent) averaged over Time (Conditionand Tventmain effects). C. Comparison of mean Ve response averaged over thesteadystate tests performed on the treadmill (ie. at Tr and WI Tvent) versus the steadystate tests performed in WI (le. at Tr and WI Tvent) (Condition X Tventinteraction).8075QTrTvent•WlTventWI-ye706560Condition Tvent90TRWIVe (Imin’)80 - -75 - -70 - -65 - -Ti T2 T3 T4 T5 T6 T7TIMETrTrTvent TrWlTvent*WITrTvnt WIWITventFigure 11 .1. Mean Ve response over the steady state performance testsovertime. A. Table of mean Ve over time for the 4 steady state tests and meantest. B. Comparison of the mean Ve responseover time for each testcondition and Tvent.TrTventWlTvent68.3 68.6 70.6 70.9 73.1 74.7 76.3TrTvent61.4 63.7 64.0 64.2 65.1 65.5 65.5TimeTi T2 T3 T4 T5 T6 T7.. Mean Test 68.5 69.6 70.4 70.4 71.4 72.3 72.7-WlTvent77.3 79.3 79.9 80.3 81.3 82.9 83.167.0 66.6 67.2 66.0 66.2 66.0 66.091: : t:TIMETi T2 T3T4 T5 T6T7 LTr 64.9 66.267.3 67.6 69.170.1 70.9CONDITION:gWI 72.2 73.073.6 73.2 73.874.5 74.6Tr 72 8 740 75 3 75 677 2 78 9 79 7Tvent::.WI 64.2 65.265.6 65.165.7 65.8 65.8-$4 4:4:1CVe (Imin1)85Tr WITi T2 T3 T4T5 Te T7Ti meFigure 11 .2. MeanVe response forCondition X Time and TventX timeinteractions. A.Table of mean Ve responsefor Condition X Time andTventX Time interactions.5. Comparison ofmean Ve responseover time formean steady statetests completed on thetreadmill (Tr) vs in WI(ie. meanVe at each timeinterval for Tr and WI Tventcombined) (ConditionX Time).C. Comparison ofmean Ve responseover time for meansteady state testscompleted at Tr vsWI Tvent (le. meanVe at each time intervalfor Tr and WIconditions combined)(Tvent X Time).Ve (Imin’)8tTr WI8075:z*rTi T2 Ta T4 T5T6 T7Time924.3.4 Blood LactateConcentrationBlood lactate concentration([BLa]) responses during thesteady stateperformance tests were examinedin relation to [BLa] responseduring theduration of the performancetests in the 2 Conditions (treadmilland WI)and to the 2 Tvent(theTrTventand theWITVent)intensities over theperformance tests’s timeintervals (T2 to T7) and averagedover the Timefactor.There was a significantCondition main effect averaged overthe Tventand Time factors exhibited(F19=5.57, p<O.05).Averaged over the 2Tvent’s and across all timeintervals the mean [Bla]response on thetreadmill (4.86 mmol11)was significantly higherthan in WI (4.13mmoll) (Figure12.0 A and B).There was a significant Tventmain effect averaged overConditionand the Time factorsexhibited (F19=12.29, p<0.05).Averaged over thetwo conditions andacross all time intervalsthe mean [BLa] response onTrTveflt(5.31 mmoll1)was significantlyhigher than OflWITvent(3.68mmoll1) (Figure12.1 A and B). There wasno significant ConditionbyTvent interactionaveraged over the Time factor(F19=0.40,p>O.OS)(Figure 12.0 A andC). See Table 8.0 for [BLa]RN’s results.There was no significantTime main effect (F5451.60,p>O.O5) (seeFigure 12.1 A andB for individual test mean[BLa] responses overTime).There was a significantCondition by Time interaction(F545=6.17,p<O.O5) with mean [BLa] responseconsistantly higher overtime on the93treadmillversus theWI condition.Ninetyeight percentof thevariabilityis accountedfor by asignificantlinear trend(F19=9.83,p<O.O5) as evidencedby the steadylinearincrease inmean bloodlactateresponse onthe treadmilltests and thesteady (small)linear declineexhibitedon the WItests (Figure12.2 A andand B).RM’s analysisofmean [BLa)forTrTrTventvsWlTrTventand for TrwlTventVSWIWITventfound significantConditionby Timeinteractions(p<O.O5).Significantlylower mean[BLa) responsesover time wereexhibitedforTrTventandWlTventintensitytests completedin the WIversus treadmillcondition(p<O.O5), witha significantdecreasing lineartrend overtimeexhibitedforTrTvefltin WI andincreasinglinear trendover timeexhibited inthe treadmillcondition (p<O.05)(see Table8.1 and 8.2forRN’s analysisofTrTrTVentVSWlTrTventandTrWlTvefltvsWIWITventandFigure 12.2A and B).There wasno significantTvent by Timeinteraction(F545=2.l3,p>O.O5)(Figure 12.2A and C).There was nosignificantCondition byTvent byTime interaction(F545=2.12,p>O.O5).94LATventTr WI TotalsTr 5542 49CONDITIONWI 5132 41Totals 5.3 3.7[BLa] (mmolI-1)Figure 12.0. Mean [BLa]response for Condition andTvent main effects,andCondition X Tventinteraction. A. Tableof the mean [BLa] responsebyCondition and byTvent. B. Comparisonof mean [BLa] responseoverCondition (Tr vs WI)and over Tvent(TrTvent vs WlTvent) averagedover Time(Condition andTvent main effects).c. Comparison of mean [BLa]responseaveraged over the steadystate tests performed on thetreadmill (ie. Tr and WITvent) vs the steady statetests performed in WI ( Tr and WI Tvent)(Condition X Tventinteraction).ConditionTventTr-[BLa] Wl-[BLa]95ATimeT2 T3T4 T5T6 T7TrTvent4.7 4.95.4 5.36.2 6.8TRWlTvent3.8 3.83.9 4.44.8 4.4TrTvent5.5 5.35.1 5.04.8 4.8WIWlTvent3.7 3.43.2 3.13.0 2.8Mean Test4.4 4.34.4 4.44.7 4.7[B] (mmolr1)TimeTrTrTvent TrWITvent+WlTrTvent -WWITventFigure 12.1.Mean [BLa]response overthe steady stateperformancetests overtime. A. Tableof mean [BLa]response overtime for the4 steady statetests andmean Test. B.Comparisonof mean [BLa]response overtime for eachtestcondition andTvent.96iei, TIMET2 T3 T4T5 T6 T7Tr 4.2 4.3 4.64.8 5.5 5.6CONDITIONWI 4.6 4.4 4.14.0 3.9 3.8Tr 5.1 5.1 5.25.1 5.5 5.8Tvent, WI 3.73.6 3.6 3.73.9 3.6aNIr-[BLa) (mmolM)Tr WITi T2 T3T4 T5 T6Ti meHFigure 12.2. Mean [BLa]response for Condition X Time andTvent X Timeinteractions. A. Tableof mean [BLa] responses forCondition X Time andTvent X Time interactions.B. Comparison of mean [BLa]over time for themean steady state testscompleted on the treadmill vsin WI (ie. mean [8Lal ateach time interval for Trand WI Tvent combined) (Condition XTime). C.Comparison of mean[BLa] response over time for meansteady state testscompleted at Tr and WITvent (ie. mean [BLa] at eachtime interval for Tr andWI conditions combined)(Tvent X Time).[BLa] (mmoIt1)Tr WI:-4_:_—-j3Ti T2 T3 T4 T5T6Time974.4 HYPOTHESIS VERIFICATION4.4.1 Test of Hypothesis 1The significant T—Test for VO2maxresponse on the treadmill versusWI running doesnot support Hypothesis 1, which predictedsimilarTrvO2mandWIvo2maxresponses among elite distance runnerstrained inWI running (the level ofsignificance as a one—tailed hypothesiswas0.0005, with T-value=4.ll) (Figure8.0).4.4.2 Test of Hypothesis 2The significant T—Test forV02 atTrTvefltversusWlTventsupportsHypothesis 2, which predicteda higherTrTvefltversusWlTventV02. As aone—tailed hypothesis thetests has a level of significanceequal to0.02 (and T—value=2.46).The hypothesis postulatedequal treadmill and WI VO2maxresponses(Hypothesis 1), which washowever rejected. Expression ofthe TventV02s as a percentage oftheir respectiveVO2mresponses, indicatesthat both theTrTventandWlTventoccurred at approximately78 % oftheir respective treadmill andWIVO2maxresponses (see Table3 forvalues and Figure 8.4).Therefore we concludethat although theabsolute mean V02 at TrTvefltwas greater than at WlTvent,expression ofV02 at Tvent as a percentageof their respective treadmilland WIVO2maxreveals that Tvent occurred atthe same mean relativeintensity for thegroup.98The analysisof the Tventtests for HR, V02,ye [BLa] over time willfollow for the hypothesesset forTrTveflt>WlTveflt.4.4.3 Test of Hypothesis3Significant ConditionX Tvent interaction,Condition X TimeandTvent X Time interactions,a significantCondition main effectsandCondition X Timeinteraction for TrTrTVentVSWlTrTventandTrwlTvefltVSWIWITventcomparisons, givesupport to hypothesis3, which predictedhigher HR responsesat bothTrTvefltandWlTvefltintensity when theTventtest was performedon the treadmillversus WI. Higher HRresponses werealso predicted ateach collection intervaland overall, whentheTrTvefltandWlTventintensity were performedon the treadmillversus WI (evenfor theTrTrTVenttest overWlTrTventtest) (Figures9.0 to 9.2).4.4.4 Test of Hypothesis4A significantTvent main effectsuggests that V02atTrTvefltwashigher than at WITveflt,however the nonsignificantCondition X Tvent,Condition X Timeand Tvent X Timeinteractions, andCondition maineffects andCondition X Timeinteractions for TrTrTVentvsWlTrTvefltandTrwlTventVSWIWITventcomparisons donot support Hypothesis4 (Figures10.0 to 10.2).Hypothesis 4 predictedthat V02 wouldincrease over timein WI tests dueto a greater energyexpenditure overtime in WI versustreadmill work,related to the viscocityfriction andturbulance oftheWI environment andthe larger musclemass recruitedfor WI work.994.4.5 Test of Hypothesis5A significant Condition XTvent and Tvent X Time interaction,Timemain effect, and Condition X Timeinteractions forTrTrTventVSWlTrTventandTrwlTvefltVSWIWITventcomparisons support hypothesis 5,which predicted higherVe responses atWlTventandTrTvefltwhen theTvent test (that is thesame absolute intensity) was performedin WIversus on the treadmill.The significant Time main effect,with asignificant Time lineartrend, suggests that over time Veincreased in alinear fashion as the intensityremained constant (Figure 11.1).The significant Tvent XTime interaction, with a significantTvent XTime linear trend suggeststhat the lower ye responseswhich wereexhibited over time , whentheWlTvent(ie. in theTrwlTventandWIWITventtests) versus when the TrTventintensity was applied, were dueto the absolute intensityof the test and the body’sability to copewith the demands placedon it (Figure 11.2 C).The non—significantCondition X Time interactionsupports Hypothesis4, which presupposed thatthe WI condition wouldnot be responsible forVe behaviour, but thatdifferences exhibited wouldbe due to the Tventapplied in the test (Figure11.2 B).4.4.6 Test of Hypothesis6A significant Conditionmain effect suggests a highermean [BLa) onthe treadmill versus WI.This is in conflict withthe expected trend.100Hypothesis6 predictedthat mean [BLaJwould behigher in WI(ieWIWITventandWlTrTvent)versus treadmill(ie.TrWITvefltandTrTrTvent)tests andthat mean[BLa] responsewould increaseover time in WItestsdue to thehigher relativeintensity performedduring theseTvent testswhen completedin WI.The nonsignificantCondition XTvent interactionsuggests thatmean[BLa] at TrTventandWITVentintensitiesrespectively,performedon thetreadmilland the WIconditions didnot differ.The nonsignificantTimemain effectsuggeststhat therewere no differencesin mean [BLa)response overtime. ThesignificantCondition XTime interactionandCondition XTime lineartrend suggesta significantlinear responseof[BLa) overTime. Thetrend is,however contraryto our hypothesis,significantlyhigher inthe treadmilltests with anincreasing trendover timeand significantlylower in theWI testswith a decreasingtrend overtime Figures12.1 B and12.2 B).The nonsignificant TventX Time interactionand suggeststhat mean[BLa] wassimilar overtime whetherthe testintensitycompletedwas theWlTventor the TrTvent(Figure 12.2C). The highermean [Bla]over timeon treadmillperformancetests is contraryto Hypothesis6 and is mostlikelydue to thelaboratoryconditionswith respectto air temperatureand humidity.1014.5 SUMMARY OF HYPOTHESISRESULTSHypothesis 1 : TrVO2max = WIvo2maxREJECTHypothesis 2 : TrTveflt > WlTventACCEPTHypothesis 3 TrHRwirvent > WIHRWITVentACCEPTTrHRTrTVent > WIHRTrTVentACCEPTHypothesis 4 WIVO2WITVeflt>TrVO2WITvefltREJECTWIVO2TrTvent>TrVO2TrTVentREJECTHypothesis 5 : wIvewITvent > TrVewITvefltACCEPTWIVeTrTvent>TrVeTrTvefltACCEPTHypothesis 6: WI[BLa]wITveflt>Tr[BLaJwITvefltREJECTWI[BLaJTrTveflt > Tr(BLa)TrTventREJECT102CHAPTER 55.0 DISCUSSIONThe primarypurpose of thisstudy was to comparethe treadmill andWI running VO2maxvalues and Tventresponses in eliteendurance runnersfamiliar withWI running.A secondary purposewas to monitorthecardiorespiratoryand metabolicresponses to prolongedperformance atexercise intensitiesreflecting thetreadmill andWI Tvent on thetreadmill andduring WI running.It was postulatedthatVO2maxwould besimilar forrunners accustomedto WI running whentested in bothconditions (treadmilland WI). However,it was postulatedthat theTvent (V02 at Tvent)would be lower in WItesting. Thedata do notfully supportthese hypotheses.The simulationof treadmillrunning inthe water, thequality (intensityof exercise inWI running)andfrequency ofWI running trainingsessions, possiblyexplain thedisagreement.Some of the limitationsassociated with WIrunning arethe viscosityfriction ofwater and thesubsequent reducedstridefrequencyand increased upperbody work. Alsothe non—weight bearingnature of WIrunning andsubsequent relianceon concentricwork ofrecruited musculatureare implicated.Prolonged performance(42 minutes) attreadmill andWI Tventwereexplored tocompare cardiorespiratory(HR, ye,V02) and metabolic([BLa]) responsesduring steadystate exercise.The hypothesistestedfor HR statedthat WI wouldproduce a centralshift in bloodvolume.103This would resultin facilitated venous return,preload and strokevolume which wouldbe responsible for the lowerHR exhibited (forsimilar V02) over time atboth exercise intensitiesfor the WI runningtests. Higher Ve and [BLa](for similar V02) werepostulated for the WIcondition for boththe WI and treadmill Tvent.Data did not support allof the study’s hypotheses.5.1 Maximal and Tvent ResponsesfromVO2maxTest ResultsIt was hypothesized thatdistance runners who regularlyperform WIrunning workouts andsimulate land—based runningmechanics in WI runningwould exhibit similartreadmill and WI VO2maxvalues, conforming toprevious studies comparingland vs WI ergometer cycling(Christie et al,1991; Connelly et al,1991; Sheldahl et al,1987; Sheldahi et al,1984;Dressendorfer et al, 1976).The similar post—test[BLa) (obtainedat 30seconds and 5minutes post-test) and VO2maxRPE(RPEmax)for thetreadmill and the WIcondition lend support thatmaximal effort wasachieved in the WIcondition. However, lower VO2maxvalues were notedfor WI versus treadmillrunning. This findingis in agreement withother WI runningstudies (Svedenhag andSeger, 1992; Town andBradley,1991; Butts et al,1991; Welsh, 1988).The premise, forequal WI and treadmill VO2maxvalues was thatdifferences foundbetween the two modalitiesin previousstudies wereprimarily due to thefollowing: a) classificationand definition of anathlete ‘trained in WIrunning’, b) appropriateWI running style,c) WIVO2maxprotocol and d) upperbody musculaturerecruitment. Thepresent104study attemptedto control thesevariables. Also,similar valueson land and WIstationary ergometercycling demonstratethat controllingbody positionand musculature utilizedfor the activityresults innodifferencesbeing exhibiteddue to the differingenvironmental condition(land vs WI)(Christie et al,1991; Connelly etal, 1991; Sheldahietal, 1987;Dressendorfer et al,1976). Consequently,differences inVO2maxexhibited with WIversus treadmillrunning seems to berelated todifferences in WIand treadmill runningstyle and training.However, adherenceto these criteriain controllingfor the otherstudies’ limitationsstill produced alower WI versustreadmillVO2max.To ensure thatthe runnersachieved maximaleffort, Borg’s ratingsofperceived exertion(RPE) and post-testblood lactateconcentration([BLa]) were compared. RPEmaxof 20 at treadmilland WIVO2maxsuggeststhat the subjectsperceived thatthey had achieved maximaleffort. Mean[BLa] exhibitedimmediately post—testand 5 minutespost-test aresimilar with peak[BLa] valuesobserved atmaximal effortby otherstudies (Luhtanenet al, 1990; Witherset al, 1981; Farrellet al, 1979;Costill et al,1973). Itwould thereforeseem that maximaleffort wasattained in bothprotocols.Svedenhag and Seger(1992) noted higher[BLa), whereasTown and Bradley(1991) noted lower[Bla] in the WIcompared tothe treadmill VO2maxcondition. Thediscrepancy betweenstudies maybe related tothe lower WI capabilitiesof the runnersresulting inthe recruitmentof additionalmusculature andconsequentlyhigher [BLa].Another implicationmay be theunfamiliarity oftherunners withWI running incombination withlimitations ofthe WI (4105mm)VO2maxprotocol to elicitmaximal effort(Svedenhag and Seger,1992).A minimum RERmaxof 1.10 also demonstratesthat maximal effortwasachieved inthe WI and thetreadmill protocols.The lower WI RERmax(1.10) comparedto the treadmill‘1max(1.20) suggests dissimilaritiesin the two conditions.Similar values orrelationships werereported bySvedenhag andSeger (1992), and Dressendorferet al (1976) andButts etal (1991) respectively.Town and Bradely(1991) reported aWIRERmaxbelow 1.10 (ie.1.07), whichis below the criterion RERmaXnormally setfor achieving VO2max,and further suggeststhat this samplemay not haveachieved maximaleffort in the WIcondition.It is unclearwhy lowerRERrnaxvalues in WI versustreadmill runningwere exhibitedin this study.The treadmill andWIVO2maxtestprotocols inthis studywere matched forprogressive incrementalloadincreases perminute, and theWI and treadmillmean test durationswerenot statisticallydifferent (15versus 14.5 minutesrespectively).Thiswas not the casewith the protocolsin Svedenhag andSeger (1992) andTown and Bradley(1991) where thetest duration forthe WI VO2maxprotocols were4 minutes andthe subjectswere asked tosubjectivelyincrease theireffort to maximalfor the remaining1—2 minutesof thetest. The treadmillprotocol whichthey utilized,more objectivelycontrolledthe maximum determination.V02 at Tventwas lower inthe WI comparedto the treadmillconditionfor similarRPE and RERresponses. Welsh(1988) also reportedlower106WlTventvsTrTveflt.When V02 at Tvent wasexpressed as a percentageofthe respective WIand treadmillVO2max,no differences wereexhibited.The similar RPE (13and 12) and RER(0.99 and 0.98) valuesat WI andtreadmill Tventsupport that Tventwas identified. This wouldseem tosuggest that differencesin V02 (andRERX)exhibited were possiblyrelated to factorswhich limitedVO2maxin WI. The mainimplicationwould be that inWI there is aninability to simulatetreadmill (land-based) runningstyle due to the viscocityof the water mediumproducinga lower stridefrequency and thus turn—overrate and increased workinthe forward andbackward motion ofthe arms.The lower stridefrequency with asimilar pattern of increaseovertime with increasingload in the WI conditionsuggests the following:a)the runnerswere predominatelyutilizing their lowertrunk musculaturefor the activity,b) the high viscocityfriction of thewater condition,does influencerunning style byinterfering with‘how fast the runnercan run in WI’and by increasingthe work performedby the arms duringthe forwardand backward pumpingaction, and c) the non—weightbearingcharacteristicsof WI running lendsto no push-offphase in the WIrunning cycleand therefore noeccentric contractionof the lowertrunkmusculature.These factors wouldnot affect WIcycling and VO2max(Welsh, 1988).The cyclist isstabilized on thecycle and holdsthehandle bars (therebystabilizing and controllingupper body musclemassinvolvement)whereas in WI runningthe arms are utilizedin a forwardand backwardmotion. Theincremental increasein intensityof exerciseto maximal efforton both theWI and land—basedcycle ergometer wereaccomplished by increasingthe force generationthrough increased107resistance (Sheldahlet al, 1987; Dressendorferet al, 1976). Thus,there is moresimilarity in thework required forcycling in bothconditions thanfor WI and treadmillrunning.Welsh (1988) suggests,however, thatWI running showssimilaritiesto cycling whichpredominatelyinvolves concentriccontraction whichelicits restrictedblood flow (Eikenet al, 1987).Welsh (1988) suggeststhat lower WIVO2maxvalues may be duetotask specificity,which he translatesto: a) the total musclemassrecruited, b) thetype of musclemass recruited, c) thefamiliarity withthe recruitmentpattern, d) the typeof muscular contractionsand e) thestate of muscularadaption. Thisstudy attempted tocontrol the musclemass recruitedby selectingsubjects who simulatedin the WI conditiontreadmill runningstyle. To reduce upperbody muscularrecruitment,subjects wereprovided with a boyuancydevice to wearfor WI running.Analysis ofstride frequency inWI and treadmillrunning showedasimilar increasein stride frequencyover time withincreasing load.This would indirectlyindicate that the legmusculature wasprimarilyinvolved in theactivity. Useof the upper bodymusculature in WIrunning wouldresult in theutilization of musculaturewith a higherfast twitch fibercomposition.The resistanceoffered by the WIcondition wouldincrease upperbody muscular involvementfor similar armrunning movementswithout a neccessaryincrease inrecruitment dueto adifferent patternof movement in theWI condition(Welsh, 1988).Another possibleexplanation for thedifferences in WIand treadmillVO2maxvalues in this studymay lie in WI runningtraining. Thisstudy108attemptedto controlWI running styleand familiaritywith WI running(regular training).Although thisstudy accountedfor the quantityofWI runningtraining completedover time (ie.minimum sessionsper month,duration ofeach workoutand minimum periodinvolved in WIrunning),itdid notaccount forthe runners’quality (intensity)of their personalworkouts(see AppendixE). Thereappears to bea greater magnitudedifferencein WI versustreadmill VO2maxon runners (N=2)whoexclusivelylimit theirWI running work-outsto low intensity(belowTvent)exercise. Subjectswho performedWI running workoutssimilar totheir land—basedtraining (ie. inintensity andprogram type)exhibitedsmaller deviationsin WI andtreadmillVO2max.The lowerHR’s exhibitedat Tvent (by13 bpm) and atmaximal effort(by 15bpm) in the WIcondition areattributed tothe centralshift inbloodvolume (approx.700 ml). Thisresults from thehydrostaticpressuregradient in WI,causing a facilitatedcentral venousreturn andgreaterpreload and strokevolume (Christieet al, 1990;Connelly et al,1991;Arborelius etal, 1972).Lower maximalHR responseshave beenreportedby WI runningstudies (Svedenhagand Seger, 1992;Town andBradley,1991; Buttset al, 1991;and Welsh,1988) and WIergometerstudies(Christieet al, 1991;Connelly etal, 1991;Sheldahl et al,1987;Dressendorferet al, 1976).Welsh (1988)reportedlower HRresponsesat WI Tvent(12 bpm) similarto the presentstudy. LowersubmaximalHR responseshave also beenreported bySvedenhagand Seger(1992),Richie andHopkins (1991),Bishop et al(1991), andYamaji et al(1991)during shortand longerduration WIversus treadmillrunningtests atspecified submaximalintensities(<80%VO2max).109Minute ventilationat maximal effort (Vemax)and atTvent (eTvent)did not differ inthe WI conditioncompared to treadmillrunning. Thisis in agreementwith the studies bySvedenhag and Seger (1992)andSheldahl et al(1987) forVemaxand Welsh (1988) for VemaxandVeTvent.It is in contrastto Butts et al (1991)and Dressendorfer et al(1976)who reported a9 and 11 % lower WI Vemaxwhen comparing land—basedVem.Similar Ve at maximaleffort and Tvent suggestthat the WI conditionand related increasein intrathoracic bloodvolume and hydrostaticchestcompressiondo not restrict Ve.Resting respiratorymechanics areaffected (reduced)by the WI condition(Agostoni et al,1966; Hong etal, 1969; Dressendorferet al, 1976). Ve duringexercise, however,isnot limitedby the WI condition.Expression of yerelative to V02(ventilatory equivalentfor V02, Ve/V02), however,suggests a higherVefor similarV02. A trend for higherVe/V02 at Tvent inthe WI comparedto the treadmillcondition was notedin this study(23.4 vs 21.9,p>O.O5). Asignificantly higherVe/V02 was noted formaximal effort inthe WI comparedto the treadmillcondition (29.4vs 27.8, p<O.05).These findingsconcur with Welsh (1988).This seems tosuggest thatthere is atendency to ventilatemore air, for similarV02 in the WIcondition at maximaleffort. Higher yeis normallyexhibited in linewith higherV02, indicatinga higher musclemass recruitment,or isexhibited with agreater [BLa) and RERmax,however in thisstudyVO2maxandRERmaxwere lower inthe WI condition.110Christie et al (1991)reported higher cardiacindex (cardiac outputper square meterof body surface area)in WI without an elevationinVO2max.Higher cardiac output in WIhas been noted by Sheldahiet al(1984), Nielson etal (1984), Lin (1984), Fahriand Linnarson (1977) andArborelius et al(1972). Christie etal (1991) concluded thattheadditional oxygenconsumption supplied by theheart to the exercisingmuscle is notutilized. This wouldseem to suggest thatoxygenextraction in themuscle is lower or limited inthe WI condition.Thereis some evidence thatmuscle blood flow is increasedin WI (Connelly etal, 1991). Itis also believed thatother vascular beds accomodatethisincreased bloodflow, but there is still noclear evidence onwhichcompartments do so(Christie et al, 1991).Alterations in thebloodflow—metabolicrelationship are implicated(Christie et al, 1991).In summary itappears that differences inWI and treadmill VO2maxand Tvent may beattributed to less familiarityof runners toWIrunning, withrespect to WI trainingregimens (ie. mileageof steadystate exercise perweek, incorporation ofhigh intensity intervalworkouts) and dissimilar(less intense) WIcompared to land—basedtraining.The WI conditionalso accounts for thedifferences exhibited inV02, HR,ye, RER inWI versus treadmillrunning atand Tvent. Therunners perceivedeffort atVO2maxand Tvent is exerciseintensitydependent.RPE and peak [BLa]appear not to beaffected by the WIcondition.1115.2 Comparison ofthe treadmill and WI steadystate Tvent performancetestsThere is paucity of researchliterature available onsteady stateexercise at Tventon treadmill and WI running.Exercise at Tvent forone hour durationhas been reported to maintainsteady state V02, HR,Ve, and [BLa] over time(Loat, 1991). Literaturecomparing treadmilland WI running duringsubmaximal exercise of aprolonged nature haveproduced conflictingresults. These studiesfailed to utilize runnerswho regularlyincorporate WI runninginto their training regimen.Thesubjects subjectivelyselected a preferredexercise intensity forcompleting 30 (Richieand Hopkins, 1991) or 45minute (Bishop et al,1989) WI running tests.The results from theseWI running testswerethen compared tothe subjects’ selected treadmillrunning pace forcompleting a similarduration test. The onlyconclusions, which can bedrawn, are that subjectswere possibly unable toexercise at the similarhigher treadmillintensity in the WIcondition because oftheirunfamiliarity withWI running. Consequently,the WI running pace wasata lower V02,or possibly the subjectswere able to maintain a similarpace in WI for thespecified time period,but due to theirunfamiliaritywith WI runningdid so at a higherV02 in WI.This study is thefirst to compare WI andtreadmill running duringprolonged exercise atsimilar relative andabsolute intensitiesofexercise. The WIand treadmill Tvent’swere expressed as V02,and theV02 at Tvent wasused to determinethe WI and treadmillTventintensities for the 42minute performancetests. The WI conditionwas112not expectedand did not influenceV02 during the perfomancetests. Asmall increasein V02 was notedfor theWlTrTventtest. This increase,however, wasovershadowed bya similar increaseduring the TrTrTventtest. Increasesof greater magnitudein HR, Ve,and [BLa] wereexhibited duringthe treadmilltests (at WI andtreadmill Tvent).This upwarddrift in HR,Ve, and (BLa],with very littlechange inV02, in the treadmillcondition over the42 minutetests (at boththetreadmill andWI Tvent intensities)can possibly beattributed totheenvironmentalconditions inthe laboratory.The presentstudy wasconducted overa seven monthperiod (overthree seasons;summer(June/July), fall (September/October),and winter(December). Duringthe summer andfall testingthe mean temperaturein the laboratorywas26.9 and 23.5degrees celcius(0C) respectively.During wintertestingthe meantemperature inthe laboratorywas lower,18.40C. Thebarometricpressure rangedbetween 764—759mm Hg duringthe 3 testperiods (see AppendixF). Subjectsparticipatingin the summertestperiod were mostaffected by thehot humid conditionsin the laboratory.Similar patternsof cardiorespiratorydrifts exhibitedin this studyduring prolongedexercise in heat,have been reportedin the literature.Martin et al(1981) notedan upward driftin Ve as coretemperaturerose, duringexercise atTvent. Ve and HR(by 23 bpm)increased fromminute 12to 60 withoutchanges exhibitedin [BLa] andpH. Foley etal(1993)compared 60 minutesof submaximalexercise at20° and 32.2°Croom temperature.An increase inCO and HR (by20 bpm) withno changein a—v02 differencewere notedduring exerciseat room temperatureof11332.2° C.Heaney etal (1993) similarilyreported anincreasing yewithincreasingcore temperature,with no changein V02 exhibitedduringprolongedexercise ina hot environment.The authors concludedthatcore temperaturecontributed toye drift.Attemptswere made toprovide adequatecooling (electricfan) andunlimited coolwater was providedto preventdehydration duringthesteady statetreadmill performancetests. Themeasures takenwereunfortunately,unsuccessfulin alleviatingthe heat problemfor thesesubjects,resulting ininflated HR,ye, and [BLa)values. Therewasincreased sweatingduring the treadmillcondition tests.Subject 1 lost2.5 kg followingperformanceof the treadmillTrTvent testat a roomtemperatureof 27.8° C.Perfuse sweatingduring thetreadmill testslikely causeda decreasein plasmavolume, resultingin increasesin HR in anattempt to maintainCO. The increasein core temperaturemay haveresulted inthe increasein lactateproductionand/or the reductionin the lactateconsumed(re—oxidized).The loss inblood volumeas a consequenceof perfusesweating mayalso have resultedin increasesin [BLa]due to haemo—concentration.Ve most likelyincreased dueto the decreasein pH andincrease in(BLa).HR, Ve, and(BLa] responseswere least affectedduring thefirst 15minutes ofthe treadmilltests (similarto the patternsexhibited inMartin etal (1981))and comparisonsare made withthe WI testswiththis treadmilltime period.1145.2.1 Heart-rateHR response wassimilar at WI Tventintensity performedin the twoconditionsover time, whereas HRresponse was lowerat treadmill Tventin the WI comparedto the treadmill condition.Sheldahi et al (1987)observed similarcycle ergometer HRresponses belowworkloadscorresponding to75%VO2maxand lower HR responsesabove this intensity.Similar HR responseshave also beenreported by Connellyet al (1990),Christie et a].(1990) and Svedenhagand Seger (1992)during 5 minuteexercise boutsbelow 60%, 80% and65%VO2maxrespectively. Thepresentstudy noted similarHR response at WITvent intensity correspondingto78% of WIVO2max,but lower HR responseat treadmillTvent correspondingto 84.8% of WI VO2maxin the WI condition.Differences insympatheticneural outflow,baroreceptor activityand cardiac outputhave beensuggested as possibleexplanations (Connellyet al, 1990; Christieetal, 1990; Sheldahlet al, 1987).Connelly et al (1991)suggest apossible relationshipbetween cardiopulmonarybaroreceptor activityandthe increase incentral bloodvolume. The presentstudy does suggestanexercise intensitydependent HR response,which may be relatedto anincrease in muscleglycogenolysis.HR response inthe present study didshow an increasingtrend over the 42minute test at thetreadmill Tventintensity performedin the WIcondition. Thiswould be expectedforexercise aboveones Tvent (toatand Rhodes, 1992;Loat, 1991; Ruskoetal, 1986; Hearst,1982) in that(ie. WI) condition.Determination ofHR at Tvent fromthe WI VO2maxtest produced asignificantlylower HR comparedto the HR at Tventfrom the treadmill115VO2maxtest. The resultsfrom the steadystate performancetestsdemonstrate thatdifferences inHR exhibitedat Tvent duringtheVO2maxtests were simplyrelated to thelower V02 at WITvent comparedto theV02 at treadmillTvent. Consequently,the lower WIHR responseat Tventreported bythe present studyand by Welsh(1988) from theprogressiveincremental load VO2maxtests, were theproduct of thelower absoluteWITvent and notthe result of theWI condition.5.2.2 VentilationAlthough restinglung volumesare reduced inupright WI (WithersandHanidorf, 1989;Hong et al, 1969;Agostoni et al,1966), exerciseye isnot affected.Similar ye responses(when averagedover time) werenotedfor exerciseat WI Tventin both the WIand the treadmillcondition.The WI conditionVe responses duringWI Tvent seemedto be higherif theupward driftin ye during thetreadmill performancewas consideredto berelated toheat stress.This is not inagreement withSvedenhag andSeger (1992)and Sheldahi etal (1984) whoreported similarye in bothconditions during5 minute exerciseintervals atworkloadscorrespondingto 62% and 87%,and 37% and 47%respectively ofWIVO2max.The exerciseintensities inthe abovestudies representabsolute workloads,however,which likelyrepresenthigher relativeintensities ofexercise in theWIcondition.The presentstudy also notedhigher Ve, withan increasingtrendover the 42minutes duringthe treadmill Tventintensity testperformedin WI. Thisis an expectedfinding sincethe runnerswere exercisingabove theirTvent (Loat,1991; Ruskoet al, 1986; Hearst,1982). This116is in conflictwith Svedenhagand Seger (1992),who found no differencein Ve during WIrunning at 87%of WIVO2max.This is most likelyrelated to the smallduration (5 minutes)of the exercise boutandconfounded by thecomparison of absoluteworkloads.The upward drift inye during the treadmillperformance tests (duetothe heat stress) maybe masking (statistically)significantly higheryeresponses in the WIcondition performedat treadmill andpossibly WITvent. It maybe that the reducedvital capacity,total lung capacityand lung complianceexhibited during restingWI (Fahri and Linnarsson,1977; Hong etal, 1969; Agostoniet al, 1966) and greaterincrease inbreathing frequencyto tidal volumeduring WI exerciseversus tidalvolume to breathingfrequency exhibitedduring land exercise(Welsh,1988; Sheldahl etal, 1987) may alsobe responsible forthe higher yeresponses in WI.5.2.3 Blood LactateConcentrationA progressiveincrease in HR, ye andV02, during exerciseaboveone’s Tvent, isrelated to the inabilityof the body tomeet exercisedemands aerobicallyand thereforemust rely more on itsanaerobic systemfor fuel. Thisresults in the productionof lactate at agreater ratethan can be removed(Loat, 1991; Loatand Rhodes, 1991;Rusko et al,1986; Hearst, 1982).A greater increasein V02 would havebeen expectedduring the 42minute test at TrTvefltin the WI condition.Christie etal (1990) noteda higher cardiacoutput at a givenV02 during WIversusland ergometer cyclingexercise at 41%,60%, 83%, and 100% VO2max.Theysuggested thatthe additionaloxygen suppliedis not utilizedby the117exercising muscle.This would seem to indicatethen that there wasgreater relianceon the anaerobic systemfor fuel, and as a resultanincrease in lactateproduction.The higher WI [BLa]values noted by Svedenhagand Seger (1992),however, are most likelyrelated to the higher relativeintensity of theexercise workload inthe WI versus treadmillcondition. The similar(BLa] values noted inConnelly et al (1991)folllowing 5 minuteexercisebouts concur with thisstudy’s finding duringexercise at WI Tventinthe WI conditionfor the first 8-10minutes of the test.The present study notedinitially higher [BLa)in the WI conditionin the TrTventtest, with [BLa] progressivelydeclining during thetest.Similar trend in [BLaJbehavior was noted duringtheWlTventtest in theWI condition.Similar [BLa) valueswere noted in the WITVenttestsperformed on thetreadmill and the WIcondition. [BLa]decreasedprogressively over theduration of thetest in the WI condition.Thisis contraryto [BLa] behavior on landduring steady stateexercise atTvent (Loat, 1991; Ruskoet al, 1986). Stegmannand Kinderman (1982)and Schnabelet al (1982) report[BLa) to initiallyincrease duringexercise (up tothe first 10—20 mmof exercise), and thereaftertolevel off ordecrease.The initialrise in [BLa) isrelated to the oxygendebt incurredduring the onset ofexercise. This is latercorrected by oxidationofthe lactateproduced within themuscle and by removal ofthe lactateinto the bloodstream,where it willbe eliminated (reoxidized)by non118exercising muscles andother tissues (ie cardiac muscle, liver, kidneyetc.) (Favier et al, 1986; Karissonand Jacobs, 1982). In the presentstudy, the subjects performed a self selected warm—up(5—15 minutes)followed by a 5 minute test warm—upand 5 minutes of exercise to set theTvent intensity. Since (BLa]is progressively reduced during WIexercise at treadmill andWI Tvent it would seem to suggest thatthereis either less poolingof lactate in the blood as a result oflowerefflux of lactate from themuscle, or more re—oxidization of lactate inthe muscle primarily by slowoxidative muscle fibers (Goilnick et al,1986). It is also possible that lesslactate is produced in the muscle,or lactate which initiallyappears in the blood is later removedbyorgan tissues and slowoxidative muscle and therefore less appearsinthe blood. The progressive increasein Ve (and decrease in RER, seeAppendix D) seen with declining [BLa]over time supports the view oflactate re—oxidization duringexercise. The process may also behormonally mediated (lowerepinephrine concentration during WIexercise)reducing the rate of muscleglycogenolysis or related to increase inmuscle blood flow in WI.This would result in reduced [BLa]over timeand enhanced aerobic metabolism(Connelly et al, 1990).5.2.4 Respiratory ExchangeRatioRER followed a similarpattern to [BLa]. A progressivedecline inRER over the 42 minuteswas exhibited in the WI conditionfor thetreadmill and WI Tvent (seeAppendix D for RER results).The decline inRER in both WI tests at treadmilland WI Tvent from 0.99to 0.96 doessuggest that the higher initial[BLa]’s exhibited in WI were theresultof greater reliance onanaerobic processes duringthe first 15 minutes119of exercise, resultingin an incurred oxygendebt. The RER pattern ofdecline also suggeststhe reliance on aerobicprocesses for fuel supplyand the re—oxidationof accumulated lactate inthe latter part of theWItests (at WI and treadmillTvent).An increasingtrend in RER over time was expectedfor the WI test attreadmill Tvent intensity.This would have supporteda greater relianceon anaerobicprocesses with increasinglactate over time forexerciseabove one’sTvent. Svedenhag and Seger(1992) noted higherRER during 5minutes of exerciseat 87 percent of WI VO2maxwith higher [BLa] andRPEcompared to treadmillperformance at a similarabsolute V02 (81 percentof treadmill VO2max).The authors concludedthat the higher anaerobicmetabolism duringWI exercise waspartly related to a lowerperfusionpressure in thelegs during WI running,with a declineormaldistribution intotal muscle blood flow.However, the higher[BLa]and RER exhibitedin the WI comparedto treadmill condition,in thestudy by Svedenhagand Seger (1992) maybe solely relatedto therelative intensityof the exercisein the latter condition.Thesubjects were mostlikely exercisingabove their Tvent inthe WIcondition, and soa higher [BLa)and RER as well as RPEresponses wouldbe expected.5.2.5 Ratings ofPerceived ExertionRPE responsesincreased overthe 42 minutes for theWI testcompleted at thetreadmill Tvent.This confirms thefact that thesubjects perceivedthis intensityas more difficult in WIthan on thetreadmill. This isan expected finding,since the subjectswere working120above their Tventfor the WI condition.(BLa] and RERdo not supportthe subject’sperceived effort, althoughan increasing trendover timewas noted for HR andVe.Svedenhag and Seger(1992) reported higherRPE for WI running(RPE=14.6) at aV02 of 3.5 lmin’ (correspondingto 87 % of WI VO2max)compared to treadmillrunning (RPE=12.6)at the same absoluteintensity(correspondingto 81 % of treadmill VO2max).Similar higher RPEvalueswere noted in thepresent study forWI exercise at treadmillTventintensity. Thismay suggest thatthe sample inSvedenhag and Seger(1992) were exercisingabove their Tvent inthe WI condition,and as aresult higher RPE([BLa] and RER)are anticipated andcan be attributedto the intensity ofexercise and not todifferences in physiologicalresponse to theWI condition.In the presentstudy mean RPE responseatWITVentperformed in theWI condition wasequal to theRPE response determinedatWITveflt(RPETventl2)from the WI VO2maxtest. Perceived effortatWITvefltwassimilar for the42 minute teston the treadmill andWI condition. Thisfinding furthersubstantiates thathigher RPE valuesreported for WIrunning by Svedenhagand Seger (1992) andRichie and Hopkins(1991) arerelated to therelative intensityof exercise and alsofamiliarity withWI runningand are not relatedto the WI condition.In summary itappears that HR,Ve, RER and [BLa]responses toexercise at WIand treadmillTvent are affectedby the WI condition.HRis lower inWI at exerciseintensities aboveWI Tvent. Thedeclining121trend over timeexhibited inRER and [BLa]may be partially accountedfor by the WIcondition.Ve appears to beslightly higherin the WIcondition.It is, however,unclear whether thisis related tothe WIcondition orthe relativeexercise intensity.The runners’ perceivedeffort of theactivity is intensitydependent.122CHAPTER 66.0 CONCLUSIONS1) WI V02at Tvent andmaximal effortwere lowerthan treadmillresponses inelite distancerunners who regularlyincorporate WIrunningin theirtraining regimens,for similar peak [BLaIand RPE.2) Althoughland-based runningstyle was simulatedby the runnersduring WI runningthe viscosityfriction ofthe water mediumreducedstride frequencyto 60-65% of the treadmillvalues.3) Heart—rateat Tvent andmaximal effortwere lower inthe WI versusthe treadmillcondition. Thelower HR at Tventdetermined fromthe WIVO2maxtest, however,was relatedto the lower V02at WI Tventand notto the WIcondition.There is anintensity dependentresponse forsubmaximalHR in waterimmersion tothe neck. HRresponse inWI issimilar to treadmillvalues forV02 at and belowWI Tvent and lowerinWI duringexercise aboveWI Tvent eventhough an upwarddrift associatedwith increasedreliance onanaerobic metabolismis noted.4) Ventilationat Tvent andmaximal effortwere not affectedby the WIcondition; responseswere similar inWI and treadmillrunning.Veduring steadystate exerciseat and above WITvent in the WIconditionwas notaffected bythe WI condition,but differencesexhibited wererelated to theexercise intensity.1235) [BLa] responseduring steady state exercise may beaffected by theWI condition; a decreasingtrend over the 42 minute tests in [BLa]wasexhibited in the WI conditionat and above WI Tvent.6) Differences in RPEon the treadmill and WI conditionare related tothe relative intensity ofexercise and the subjects’ familiaritywith WIrunning and not the WI condition.6.1 RECOMMENDATIONS FOR FUTURERESEARCH1) To studyVO2maxlevels during water immersion tothe neck (WI) andtreadmill running amongrunners who incorporate WIrunning in theirtraining regimens andmeet all other criteria for WI running setby thisresearcher’s study. Inthe proposed study the runnerswill bedistinguished into groupsaccording to the intensity oftrainingutilized in their WI runningworkouts. Runners should be distinguishedinto at least two groups,that is: a) Runners who’s WI runningworkoutsare limited to exercising atand below ventilatory threshold(Tvent) andb) Runners who’s WIrunning workouts incorporateexercising at and aboveTvent level.In this manner the relationshipbetween the intensity ofexercisefor WI running workoutsand the magnitude of the differencein WI versustreadmill running VO2maxand Tvent can be explored.2) To study the cardiorespiratoryand metabolic adapations toWI runningtraining and the implicationsto land—based running performance.124a) To study cardiorespiratoryand metabolic adapations toWIrunning followinga long term WI running trainingregimen in individualspreviously untrainedin WI running. This groupsimprovements would becompared to a controlgroup who will have been prescribeda similarintensity trainingprogram for land-basedrunning. A treadmillandcycle ergometer wouldboth be used for pre—and post—testing at TventandVO2mlevel.b) To compare cardiorespiratoryand metabolic adapationsto WIrunning, shallowwater (weight—bearing)running and treadmill runningfollowing long termtraining. A treadmilland cycle ergometerwouldboth be used for pre—and post-testing at Tventand level.3) To compareWI and treadmill runningstyle via biomechanical(kinematic) analysiscombined with cardiorespiratoryand metabolicanalysis.4) To replicatethe Tvent steady stateperformance test portionof thisresearchers study. WIrunning, or a cycleergometer immersed in thewater could be usedas the mode of exercisefor the WI conditioncompared to treadmilland stationaryergometer exercise onland,respectively. Also toensure that land—basedlaboratory environmentalconditions donot produce heat stressin the subjects.V02, HR, Ve,[BLa), RER, RPEresponses would be monitoredto determine whetherWIresponse patternsexhibited in this studyare reproduceable.Additionalvariables thatshould be consideredfor collection includethefollowing:125a) Blood glucose andplasma catecholamine levelsto provide someindication of theenergy sources utilized forexercise and therebyprovide additional informationregarding [BLa] behavior.b) Body weight beforeand after WI testing to determinethemagnitude of fluidloss due to diuresis in WIversus sweating duringtreadmill testing.4) To study HR responseto various intensities ofexercise in WIcompared to land exerciseto elucidate HR response in theWI condition.That is, to study HR responsesin WI at rest, during exercisebelow WITvent, at WI Tvent andabove WI Tvent to maximaleffort intensitiescompared to similar absoluteintensity exercise (matchedfor V02) onland.6.2 TRAINING I1PLICATIONS1) WI running styleand the ability to simulateland-based runningmotion in deep water. WIrunning can be used to complementa runner’straining regimen. Itis, however, important thatland—based runningstyle be simulated inthe WI condition to ensureperipheral trainingadaptations in themusculature utilized forland running. Turn—overrate (stride frequency)will be 30—40% lower in the WIcondition relatedto the water resistance.The upper body energy expenditurefor similararm motion to land—basedrunning will be higher in theWI condition andthis is related to theincreased resistanceencountered in the waterversus encountered bythe air during land—basedrunning. Upper bodywork can further be increasedin the WI condition byutilizing the arms126and hands to propel the body forward, byreaching forward and cuppingthe water. This action will be visually and kinesthetically evident,because it results in an extreme forward lean of the body to an almosthorizontal orientation. It is, therefore, important to maintain properrunning form in the water. Unlike land running where improper runningstyle (eg. extreme forward lean, improper arm motion, etc.) can resultin a fall, this is unlikely with WI running. The ability topushthrough water is reduced with running in the water versus swimmingandthis may lead to the use of the upper body, as discussed above,tomaintain the head above the water level. Utilizing a limitedboyancydevice can enhance simulating land—based running style in WI.Theboyancy device will provide enough boyancy to keep thehead above thewater level and therefore the runner can concentrate onsimulating land—based running motion during WI running sessions.2) Training intensity of WI running sessions.The purpose ofincorporating WI running in a runner’s training regimenshould be thefollowing: a) to reduce stress on the joints by runningsome her weeklytraining mileage in the water and b) duringinjury as a method ofmaintaining physical conditioning and possibly continuingone’s trainingimmediately following injury and during the rehabilitationprocess. WIrunning training must incorporate similar work—outs ascompleted duringland—based training with respect to exercise durationand intensity tobe effective.3) The use of HR to monitor thetraining intensity of WI running workouts. In using HR to set the trainingintensity of a WI running work—127out session itis important toaccount for the following:a) HR valuesat low submaximalintensities, belowWI Tvent level arenot affected bythe WI condition,b) HR values aboveWI Tvent are likelylower in the WIcondition versusthe land responsefor similar intensityof exercise(ie. matched for V02).A 10-13 bpm lower HRresponse should be expectedand accountedfor when setting the trainingHR values for one’sworkout. For exampleif you know thatRunner A has a HRof 165 bpm at hisland-based Tvent,orHRmaxof 186 bpm and wouldlike him to completeaninterval workout,or a run in the WIcondition at 10% abovehis Tvent,or at 90% ofhisHRmaxyou would then wantthe runner to havethefollowing target HRvalues:a) for 10% above therunner’s land—basedTvent (ie. 165 bpm),the targetHR would be thefollowing: 165 bpm - 11bpm (adjusting forthe lower WIHR response) =154 bpm154 bpm X 10% = 15.4bpm , therefore thetarget HR for theexercisesession would be: 154bpm + 15.4 bpm = 169bpm.b) for 90% ofthe runner’s land—basedthe target HRwould be thefollowing: 186 bpm- 11 bpm (adjustingfor the lower WIHR response)=175 bpm175 bpm X 90% = 158bpm.4) Trainingimplications ofthe declining (BLa]and RER responsesduring prolongedWI running exercise.According to the[BLa] and RERresponses duringprolonged exerciseat and above WITvent in the WIcondition, the abilityto exercise at a‘harder’ intensityfor a longerduration in WI seemsto be suggested.More research is neededto lookat lactate behaviourduring exercise inWI. 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Thesubject’s calculatedTrTvent pace was10.0 mph.VariableTreadmillWIHeight (cm)180180Weight (kg)67 7 677VO2max (I/mm)4 24 415VO2max (mI/kg/mm)62 661 6HRmax (bpm)200 180Vemax (I/mm)131 11234RERmax118 116RPEmax20 2030 sec post-test[BLa]11 2 1125 mmpost-test [BLa]11 5111Max duration(mm)16 00 1700V02 at Tvent(I/mm)3 65 326V02 at Tvent(mI/kg/mm)54 048 2HR at Tvent(bpm)176161Ve at Tvent (1/mm)87 0 732RER at Tvent0.96 0.99RPE at Tvent1613Time of Tvent9 30 500137Stride frequency from Tr and WI VO2max tests.Time point in testMinute 1 Tvent Minute VO(in strides/mm)Treadmill VO2max test 82 88inute1WI VO2max test 48 50 66Prolonged performance tests.TIMETi T2 T3T4T5 T6 T7TrTrTvent 171 174 175 180 182 187 187• HR TrWlTvent 153 162 163 165 169 172 173WlTrTvent 157 161 160 159 165 166 163. WIWITvent 146 146 144 146 144 150 147TrTrTvent 53.4 54.5 54.1 54.8 54.8 55.5 55.2V02 TrWlTvent 47.7 49.7 49.5 49.5 49.8 50.4 51.2WlTrTvent 52.4 54.2 54.6 54.3 55.4 55.6 56.1WIWITvent 48.2 48.3 48.6 48.4 47.9 49.9 48.9TrTrTvent 90.0 91.5 92.4 93.8 98.0 102.4 104.7Ve TrWlTvent 77,0 83.1 85.5 85.9 87.4 88.5 88.0WlTrTvent 90.2 92.2 96.9 98.37 100.7 101.8 103.5WIWITvent 79.9 79.8 82.1 82.0 78.3 82.5 80.1TrTrTvent 7.2 8.4 8.3 8.4 8.8 9.4(BLa] TrWTvent 3.2 4.2 3.8 3.7 3.4 3.1WlTrTvent 3.6 3.4 5.7 5.3 5.5 2.9WIWTvent 5.9 6.1 3.4 3.3 3.1 5•5138:::: Ti T2 T3T4T5 T617TrTrTvent 0.970.95 0.950.95 0.960.97 0.97RER TrWlTvent0.97 0.970.96 0.96 0.960.95 0.95WlTrTvent 1 031 00 0 99 0 990 98 0 99 0 99WIWITvent 0.970.96 0.96 0.960.94 0.960.95TrTrTvent 1314 15 1616 17 18:•RPE TrWlTvent12 13 1313 1414 14WlTrTvent 1315 15 1617 17 17WIWITvent13 1313 14 1414 14139UBJECT2:1Male subject, 29yrs old. Competes in10 km and marathonruns. Has been waterrunning for 10 yrs.For the 6 months prior toparticipating in thestudy he hadbeen WI runningat least 12 times per month,45-60 minuteduration per session.WI running sessionsconsisted of steady stateruns at his WlTventHR. Thissubject used a HRmonitor during his WItraining to control hisworkoutintensity. Used nofloatation device.Comparison of thesubject’s race pacefrom an event completedclose to the timeparticipating in thestudy found him tohave completed amarathon at 10.2 mphpace. The subject’scalculated TrTventpace was 10.4 mph.VariableTreadmill WIHeight (cm)182 0 182 0Weight (kg)78 0 78 0VO2max (1/mm)4.85 4.40VO2max (mI/kg/mm)60 0 56 0HRmax (bpm)190 178Vemax (1/mm)126 9 109 4RERmax1 20 1 14RPEmax20 2030 sec post-test[BLa] 9 69 85 mm post test[BLa] 109 10 5Max. duration (mm)15:30 20:00V02 at Tvent (1/mm)3.87 3.74V02 at Tvent (mI/kg/mm)48 9 47 6HR at Tvent (bpm)163 149Ve at Tvent (1/mm)97 9 93 5RER at Tvent1 01 1 00::RPE at Tvent15 12:..Time of Tvent10:00 10:00140Stride frequency for Trand WIVO2maxtests.p oint in testMinute 1 Tvent MinuteVO(in strides/mijI2rntestnute180 92test 5050Prolonged performancetests.TIMETi T2 T3T4T5 T6 17TrTrTvent 158 169169 174 183 183184HR TrWlTvent 154161 168 171 174176 178WlTrTvent 155 157161 159 155 158157WIWITvent 153152 152 144 146146 149TrTrTvent 50.450.3 52.4 52.2 53.2 55.757.6V02 TrWlTvent 47.248.0 49.6 49.449.5 50.6 51.0WlTrTvent 49.053.8 54.3 53.2 52.553.3 51.8WIWITvent 47.548.0 46.8 44.5 44.944.9 45.5TrTrTvent 90.4 94.995.9 105.0 109.1 115.463.3Ve TrWlTvent 80.288.1 92.1 90.997.4 96.5 101.4WlTrTvent 105.0 108.3111.6 106.4 105.4104.9 98.3WIWITvent 99.7101.2 98.0 85.9 86.5 83.583.2TrTrTvent4.8 6.4 8.8 6.9 9.78.8[BLa] TrWlTvent6.5 5.1 6.4 6.17.3 8.3WiTrTvent6.8 7.2 6.7 6.25.3 4.4WIWITvent 5.34.8 3.9 3.4 3.13.1141TIMETi T2T3T4T5 T6 T7TrTrTvent 1.001.00 1.02 1.01101 0.99 0.99ER TrWlTvent0.98 0.99 1.001.01 1.02 1.000.99WlTrTvent 1.051.03 1.04 1.011.00 1.00 0.98WIWITvent 1.020.99 0.99 0.940.93 0.91 0.92TrTrTvent 1414 14 1516 19 19RPE TrWlTvent13 13 1313 14 1517WlTrTvent 1414 14 1414 14 14WIWITvent 1313 1313 13 1313142UBJECT 3Female subject, 22 yrsold. Competes in 3, 5,10 km and cross country runs.Has been water runningfor 1 .5 yrs. For theprevious 6 months prior toparticipating in the study shehas been WI runningat least 12 times permonth, 30-60 minuteduration per session. WIrunning consistedpredominately of progressiveruns resulting in exhaustionby the end of thesession. Also did someinterval type training (15 mm)when she missed ahard land trainingsession and finished hersession with steady state WIrunning (15-20 mm).Used no floatation device.No comparisonwith race pace from an eventcompleted close to the timesheparticipated in the study waspossible for she wasnot competing at that time(during the summermonths).VariableTreadmill WIHeight (cm)168.2 168.2Weight (kg)61 .1 61 .1VO2max (I/mm)3.17 3.03VO2max (mI/kg/mm)51 .8 49.6HRmax (bpm)194 186Vemax (1/mm)88.5 91.7RERmax1.03 1.08RPEmax20 2030 sec. post-test [BLa]10.2 11.05 mm. post-test [BLa]8.2 11.0Max. duration (mm)11:00 11:00V02 at Tvent (I/mm)2.77 2.57V02 at Tvent (mI/kg/mm)45.3 42.0HR at Tvent (bpm)181 168Ve at Tvent (1/mm)65.4 72.9RER at Tvent0.98 0.97RPEatTvent16 12Time of Tvent7:00 5:30Time point in testMinute 1 Tvent Minute VO2maxMinute(in strides/mm)Treadmill VO2max test84 8892WI VO2max test52 5458143SUBJECT4IMale subject,25 yrs old.Competes in10 km andmarathon runs. Hasbeen waterrunning for 8months. For the6 months priorto participatingin the studyhe hadbeen WI runningat least 16times per month,40-50 minute durationper session. WIrunning trainingconsisted of intervaltraining abovehis HR at WlTvent(15-20 mmduration) andsteady stateruns at hisWlTvent HRand above (20-50mm duration).This subjectused a HRmonitor duringhis WI trainingto control his workintensity.Uses a floatationdevice (‘aquajogger).Comparisonof the subject’srace pace froman event completedclose to thetimeparticipatingin the studyfound him to havecompleteda marathonat 9.3 mph pace.The subjectscalculated TrTventpace was9.0 mph.VariableTreadmillWIHeight (cm)183.3183.3Weight (kg)71 .6 71.6VO2max (I/mm)4.714.47VO2max (mI/kg/mm)65.762.4HRmax (bpm)183175Vemax (1/mm)123.1126.7RERmax1.201.10RPEmax20 2030 sec. post-test[BLa]10.412.85 mm. post-test[BLa]8.111.2Max. duration(mm)13:3016:00V02 at Tvent(1/mm)3.833.32V02 at Tvent(mI/kg/mm)53.4 46.4HR at Tvent(bpm)160140Ve at Tvent(1/mm)76.778.6RER atTvent0.990.99RPE at Tvent15 13Time of Tvent8:306:00144tJBJECT5Female subject,20 yrs old. Competesin 3, 5, and 10 kmruns, and crosscountry. Hasbeen water runningfor 3 yrs. For the previous6 months prior toparticipating inthe study she had beenWI running at least 7times per month,30-60 minuteduration of eachsession. WI runningtraining consistedof 15minute intervaltraining sessions and30-60 minute steadystate runningsessions.VariableTreadmill WITime point in test.Minute 1 Tvent MinuteVO2max Minute(in strides/mm)Treadmill VO2max test78 8494WI VO2max test44 5464Height (cm)163.2 163.2Weight (kg)51 .7 51 .7VO2max (J/mi,)3.15 2.76VO2max (mIlkg/miri)61.0 53.3HRmax (bpm)191 180Vemax (1/mm)88.5 75.4RERmax1.19 1.14RPEmax20 2030 sec. post-test[BLa] 8.07.75 mm. post-test [BLa]8.0 7.2Max. duration (mm)14:00 15:30V02 at Tvent (1/mm)2.32 2.25V02 at Tvent (mI/kg/mm)45.0 43.5HR at Tvent (bpm)164 148Ve at Tvent (l/mmn)51 .7 49.6RER at Tvent1 .03 1 .00RPE at Tvent14 12Time of Tvent8:00 8:00145Prolonged performance tests.TIMETi T2 13T4T5 16 17TrTrTvent 155 161 164 170 173 174 175HR TrWlTvent 151 153 157 161 163 164 167WlTrTvent 151 161 154 162 164 166 166WIWITvent 150 156 158 154 153 160 155TrTrTvent 45 5 44 3 45 2 44 8 44 7 45 0 44 7V02 TrWlTvent 43 5 44 0 43 4 44 0 44 9 44 3 44 5WlTrTvent 454 50 3 504 49 1 51 1 52 2 48 2V WIWITvent 43.0 44.5 43.1 43.2 42.7 42.6 41.0 HTrTrTvent 56.4 55.0 59.4 61.0 60.2 61.7 63.3Ve TrWlTvent 50.8 53.3 53.8 56.6 56.0 55.7 57•5WlTrTvent 53.2 65.2 63.9 63.9 64.5 65.7 60.2WIWITvent 54.6 58.2 57.3 56.9 56.0 55.8 53.6TrTrTvent 4.1 4.5 3.4 4.9 7.7 11.3[BLa] TrWlTvent 2.2 2.7 1.9 2.7 4.6 5.3WlTrTvent 3 6 3 1 4 1 3 6 3 1 3 2.. WIWITvent 2.5 2.0 2.0 2.0 1.8 1.6:. TIME,• Ti T2 T3T4T5 T6 T7TrTrTvent 1.00 1.00 0.99 1.00 0.99 0.98 1.00RER TrWlTvent 0.92 0.92 0.94 0.93 0.91 0.91 0.91VWlTrTvent 1.02 1.05 1.01 1.02 1.00 1.00 1.00WIWITvent 1.06 1.08 1.07 1.07 1.05 1.05 1.02HTrTrTvent 14 15 17 17 17 17 17 LRPE TrWlTvent 13 13 13 13 13 13 13WlTrTvent 13 15 15 15 15 15 15WIWITvent 13 13 13 13 13 13 13146UBJECT 6Female subject, 26 yrs old. Competes in 5 and 10 km runs and cross country runs.Has been water running for 2 yrs. For the previous 6 months prior to participating inthe study she has been WI running at least 12 times per month, 45-60 minutedurationof each session. Used no floatation devise. WI running training consisted ofintervaltraining above her WI Tvent HR and also completed steady state runs around herWITvent HR (60 mm).Comparison of the subject’s race pace from eventcompleted close to the time whenparticipating in the study found her to have completed a 10 Km race at 8 mph pace.The subject’s calculated TrTvent was 7.7 mph.Variable Treadmill WIHeight (cm) 166.0 166.0Weight (kg) 51.5 51.5VO2max (I/mm) 2.60 2.43VO2max (mI/kg/mm) 50.5 49.2HRmax (bpm) 190 178Vemax (1/mm) 80.5 89.4RERmax 1.19 1.20RPEmax 20 2030 sec. post-test [BLa] 12.4 12.95 mm. post-test [BLa] 10.7 13.3Max. duration (mm) 10:15 13:00V02 at Tvent (1/mm) 2.09 1 .72V02 at Tvent (mI/kg/mm) 40.5 33.4HR at Tvent (bpm) 172 149Ve at Tvent (1/mm) 50.8 39.2RERatTvent 1.01 1.00RPE at Tvent 11 7Time of Tvent 5:00 4:30r——Time point in testMinute 1 Tvent Minute VO2max Minute:(in strides/mm)Treadmill VO2max test 84 88 92WI VO2max test 56 60 70147Prolonged performancetests.11 ‘IETi T2 T3T4T5 T6 T7 HTrTrTvent 170 176175 175 179181 184HR TrWlTvent147 150 153154 156 158 159. WlTrTvent 161161 159 162 163164 160H WIWITvent145 143 140 150151 151 153TrTrTvent 40.0 42.643.2 40.0 40.841.6 41.4V02 TrWlTvent33.1 33.5 33.0 33.133.8 34.1 32.7WTrTvent 40.8 40.440.3 40.4 41.0 40.840.3HWIWITvent 33.3 29.731.9 33.3 35.135.9 35.5;TrTrTvent 48.753.9 55.9 47.852.9 57.1 57.9Ve TrWlTvent37.5 40.4 36,3 37.139.3 38.9 40.4WlTrTvent 59.255.8 58.0 60.963.3 66.4 66.6. WIWITvent 43.735.6 40.6 44.746.8 51.3 49.3HTrTrTvent8.2 6.3 7.35.6 6.6 8.6[BLa] TrWlTvent4.7 2.8 2.32.8 2.2 3.2WlTrTvent5.9 5.8 5.64.9 5.3 5.7WIWITvent2.4 2.3 3.1 3.23.3 2.7TIMETi T2 T3T4T5 T6 T7TrTrTvent 0.980.97 0.97 0.920.95 0.96 0.96RER TrWlTvent0.92 0.94 0.910.91 0.92 0.91 0.94WlTrTvent1.03 0.96 0.98 0.970.97 0.97 0.95WIWITvent1.03 0.95 0.98 0.990.98 1.00 0.98TrTrTvent 1213 13 1416 17 18RPE TrWlTvent7 9 1111 13 1212WlTrTvent 69 10 1213 15 17WIWITvent 89 9 10 1011 11148LJBJECT 7Male subject, 29yrs old. Competesin marathons.Has beenwater running for9 months.For the previous6 months priorto participatingin the studyhe has been WI runningatleast 16 times permonth, 30-60minute durationof each session.WI running trainingconsisted solelyof low intensitytraining belowhis WI TventHR (30-60mm). Used aflotation devise(water ski belt).Comparison ofthe subject’s racepace from an eventcompleted closeto the time ofparticipating inthe studyfound him to havecompleted a marathonat 10.7 mph pace.Thesubject’s calculatedTrTvent pacewas 10.8 mph.VariableTreadmillWIHeight (cm)182.0182.0Weight (kg)67.967.9VO2max (I/mm)4 943 82VO2max (mI/kg/mm)72.755.9HRmax (bpm)183148Vemax (1/mm)115.1108.8RERmax1.141.09RPEmax202030 sec. post-test[BLa]1 1 .26.75 mm. post-test[BLa]8.7 6.8Max. duration(mm)16:4516:00V02 at Tvent(1/mm)3.98 2.00V02 at Tvent(mI/kg/mm)58.844.0HR at Tvent (bpm)1 67 130Ve at Tvent (1/mm)71.371 .8RER at Tvent0.900.93RPEatTvent1214Time of Tvent1 1 :458:30Time point intest.Minute 1 TventMinute VO2maxMinute(in strides/mm)Treadmill VO2maxtest889498WI VO2maxtest605868149Prolonged performancetests.TI ME: Ti T2 T3T4T5 T6 T7TrTrTvent 163 167 168168 172 174 177HR TrWlTvent 133 132131 134 134 133 150WlTrTverit 151 149148 148 148 148152WIWITverit 126 131 128130 129 129 128TrTrTvent 58,2 60.559.4 58.2 59.6 59.060.5V02 TrWlTvent 44.344.4 44.0 44.2 43.945.4 44.9WlTrTvent 57.9 56.956.7 56.4 53.9 54.742.0WIW?Tvent 43.744.8 44.6 44.2 45.845.1 43.1TrTrTvent 75 6 81 3 818 81 9 81 4 83 6 85 6Ve TrWlTvent 57.657.1 57.1 54.7 56.156.3 55.6WlTrTvent 109.4 106.2106.2 108.7 105.6 95.71 101.1WIWITvent 71.8 77.277.3 78.5 77.7 73.469.2TrTrTvent 3.53.9 3.3 4.1 4.04.6[BLa] TrWlTvent4.6 5.2 4.5 5.9 6.43.9WlTrTvent 6.9 6.15.5 5.8 4.6 4.9WIWITvent2.4 2.2 1.9 1.8 1.91.8TIMETi T2 T3T4T5 T6 T7TrTrTvent 0.97 0.99 0.960.96 0.94 0.97 0.97RER TrWlTvent 0.830.84 0.81 0.81 0.840.81 0.82WlTrTvent 0.94 0.930.90 0.90 0.89 0.880.90WIWTvent 0.92 0.94 0.950.95 0.91 0.91 0.92TrTrTvent 13 13 1313 14 1414RPE TrWlTvent9 9 9 99g9WlTrTvent 16 18 1818 19 1920WIWITvent 12 13 1313 13 1313150UBJECT8Male subject,22 yrs old. Competesin 10 km,half marathonand cross countryruns, istraining formarathon distances.Has beenwater runningfor 4.5 yrs.For the previous6 months priorto participatingin the studyhe has beenWI running atleast 6 timesper month, 30-60minute durationof each session.Uses no floatationdevise mostofthe time, sometimesuses a ‘waterski belt’.WI running trainingconsistedof intervaltraining and‘hard’ steady stateruns.VariableTreadmillWIHeight (cm)1 87.71 87.7Weight (kg)69.869.8VO2max (1/mm)4.273.86VO2max (mI/kg/mm)61.155.2HRmax (bpm)197172Vemax (1/mm)11211096RERmax1.161.11RPEmax202030 sec. post-test[BLaI 8.27.25 mm. post-test[BLa]7.0 6.2Max. duration(mm)16:3014:00V02 at Tvent(1/mm)2.753.00V02 at Tvent(mI/kg/mm)39.443.0HR at Tvent (bpm)164153Ve at Tvent(1/mm)58.672.2RER at Tvent0.980.99RPEatTvent910Time of Tvent7:306:30R______________-II Time point in testMinute I TventMinute VO2maxMinuteI(in strides/mm)jTreadmill VO2maxtest 808490jWI VO2max test363640151UBJECT 9Male subject, 34 yrs old.Competes in marathon and ultramarathonruns, and triathloris(2.4 mile swim-114.0 milecycle-26.4 mile run). Has beenwater running for 4 yrs. Forthe previous 6 months priorto participating in the study hehas been WI running atleast 10 times per month,30-60 minute duration of eachsession. Uses a floatationdevise sometimes (‘aquajogger’),but not always. WI running trainingconsisted solelyof low intensity exercise belowWI Tvent HR.Comparison of the subject’srace pace from event completedclose to the time whenparticipating in the studyfound him to have completeda 50 mile run at 9.4 mph pace.The subject’s calculatedTrTvent pace was 9.0 mph.Variable TreadmillWIHeight (cm)174.7 174.7Weight (kg)69.3 69.3VO2max (1/mm)4.18 3.40VO2max (mI/kg/mm)60.3 49.1HRmax (bpm)176 168Vemax (1/mm)124.3 117.5RERmax1.37 1.11RPEmax20 2030 sec. post-test [BLa]14.1 13.8L5 mm. post-test [BLa]13.5 13.3HMax. duration (mm)14:00 14:00V02 at Tvent (1/mm)2.90 2.49V02 at Tvent (mI/kg/mm)42.0 35.9HR at Tvent (bpm)156 146Ve at Tvent (I/mm)60.1 59.2RER at Tvent1 .02 1 .01RPE at Tvent13 111Time of Tvent8:30 5:30-Time point in test(in strides/mm)Minute 1 Tvent Minute VO2max MinuteTreadmill VO2max test82 8496WI VO2max test52 62701 52Prolonged performance tests.TIMETi T2 T3T4T5 T6 T7: TrTrTvent 148 149 151 154 156 158 159 :• HR TrWlTvent 131 132 133 133 133 133 134:. WlTrTvent151 149 149 149 153 155 158: WIWITvent 137 135 138 136 135 138 140.TrTrTvent 42.3 42.1 41.7 42.2 43.7 43.5 43.4V02 TrWlTvent 36.4 36.0 36.9 36.4 36.4 36.9 35.8WlTrTvent 41.4 41.3 41.6 40.6 40.8 43.1 44.2:WIWTvent 36,2 36.0 36.2 35.8 36.1 36.3 36.5TrTrTvent 65.1 63.5 63.5 68.1 72.2 73.5 72.4Ve TrWlTvent 51.7 52.5 52.6 52.1 50.7 54.2 49.8. WlTrTvent 76.3 77.0 79.8 78.9 84.4 98.6 105.3:WIWITvent 60.6 56.4 58.9 55.4 54.8 54.0 56.7. TrTrTvent 6.0 6.6 6.6 7.5 8.2 9.4::[BLa] TrWlTvent 5.4 5.4 8.3 6.3 9.0 7.8:WlTrTvent 9.6 9.6 8.9 9.1 8.9 9.6.::WIWITvent 5.0 4.6 3.9 3.5 3.2 2.9TIMETI T2 T3T4T5 T6 T7TrTrTvent 0.98 0.95 0.94 0.99 0.99 0.99 0.99RER TrWlTverit 0.98 0.96 0.95 0.92 0.91 0.94 0.91WlTrTvent 1.02 1.02 1.01 0.97 1.01 1.00 1.03WIWITvent 0.97 0.94 0.95 0.92 0.91 0.92 0.93TrTrTvent 13 12 13 15 15 15 15RPE TrWlTvent 11 9 8 9 9 9 9WlTrTvent 15 15 15 15 15 15 17WIWITvent 10 10 10 10 10 10 101 53UBJECT 10Male subject, 22yrs old. Competesin 800, 1500 m, 5 and 10km runs. Has been waterrunning for 2yrs. For the previous6 months prior to participatingin the study he hasbeen WI runningat least 10-12 times permonth, 50-60 minteduration of each session.Used no floatationdevise. WI running trainingconsisted of intervaltraining and steadystate runs about hisWI Tvent HR.VariableTreadmill WIHeight (cm)191.0 191.0Weight (kg)79.479.4VO2max (I/mm)5 03 4 63VO2max (mI/kg/mm)63.3 59.1HRmax (bpm)194 184Vemax (1/mm)131.2 123.6RERmax1.24 1.16RPEmax20 2030 sec. post-test[BLa] 1 1.3 8.95 mm. post-test [BLa]12.4 7.5Max. duration(mm) 15:3012:00V02 at Tvent (1/mm)3 57 3 96V02 at Tvent (ml/kg/mmn)45.0 50.5HR at Tvent (bpm)148 1 64Ve at Tvent (1/mm)69.7 77.0RER at Tvent0.95 1 .02.: RPE atTvent10 13Time of Tvent7:30 4:30154Prolonged performance tests.TI ME:::Ti T2 T3T4T5 T6 T7* TrTrTvent 147 150 152 157158 159 160HR TrWlTvent 161164 166 171 174176 178WlTrTvent 146 145 145146 152 152 150WIWITvent 162 163 164165 168 170173TrTrTvent 45 0 45 945 0 45 8 44 8 453 45 7V02 TrWlTvent 50 651 8 50 1 51 8 515 51 7 52 2WlTrTvent 45 2 452 45 1 45 6 447 46 7 45 2: WIWITvent50.6 50.1 50.5 50.750.4 52.7 54.0TrTrTvent 77.6 78.178.8 81.0 80.0 78.080.2Ve TrWlTvent 88.893.8 90.7 94.693.2 92.3 92.3WlTrTvent 72.9 71.870.8 69.6 70.7 74.168.8WIWITvent 79.5 79.380.4 81.7 79.584.7 87.8 HTrTrTvent 3.94,2 2.7 2.0 3.63.3[BLa] TrWlTvent4.2 3.8 3.25.1 5.0 2.8WlTrTvent3.6 3.4 3.23.4 3.6 3.1WIWITvent 4.74.4 4.3 4.5 4.53.7TIMETi T2 T3T4T5 T6 T7TrTrTvent 1.000.99 1.00 0.99 0.98 0.980.99RER TrWlTvent1.01 1.01 1.00 1.011.01 1.01 1.00WlTrTvent 0.95 0.950.94 0.92 0.94 0.950.91WIWITvent 0.960.96 0.95 0.95 0.940.94 0.95TrTrTverit 11 1212 13 13 1313RPE TrWlTvent 1212 13 14 1414 14WlTrTvent 10 1112 12 12 1212WIWITvent 11 1212 12 13 1513155ubject:111Female subject, 35 yrs old.Competes in 10 km and marathonruns. Has been waterrunning for 3 yrs. For theprevious 6 months prior toparticipating in the study shehad been WI running at least 6 timesper month, 45 minute durationof each session.Used no floatation devise. WI runningtraining consisted ofsteady state runsaroung WI Tvent HR.Comparison of subject’s racepace from event completed closeto the time ofparticipating in the study foundher to have completed a marathonat 8.7 mph. Thesubject’s calculated TrTventpace was 8.5 mph.VariableTreadmill WIHeight(cm)1709 1709Weight (kg)57 6 57 6VO2max (1/mm)3 02 2 89VO2max (mI/kg/mm)52 4 49 1HRmax (bpm)180 166Vemax (I/mm)87.13 87.7RERmax1.28 1.10RPEmax20 2030 sec post-test [BLa]8 7 8 05 mm post-test [BLa]8 0 7 2Max duration (mm)13 00 14 00V02 at Tvent (1/mm)2 35 2 24V02 at Tvent (mI/kg/mm)40.8 38.0HR at Tvent (bpm)159 152Ve at Tvent (I/mm)48 4 47 0RER at Tvent0 99 1 01RPEatTvent14 12Time of Tvent7 00 6 00156Prolonged performance tests.TIME:: Ti T2 T3T4T5 T6 T7TrTrTvent 162 159158 159 162 163 164HR TrWlTvent 147146 147 146 149 151 150HWlTrTvent 154 155155 155 157 155 160:.WIWITvent 149 149 148149 148 148 151TrTrTvent 40.8 40.9 39.840.0 40.5 40.1 40.3V02 TrWlTvent 38.038.2 38.3 38.2 38.6 37.9 38.9WlTrTvent 40 9 40 2 40 540 6 41 3 42 4 42 0WIWITvent 38 4 38 238 5 38 7 38 1 37 8 38 2TrTrTvent 58 1 57 6 55 657 8 57 5 57 2 56 2Ve TrWlTvent48 2 49 0 48 6 48 6 48 647 6 47 4WlTrTvent 61 0 58 5 572 58 2 62 1 64 0 65 3WIWITvent 53.0 52.9 52.553.5 52.5 51.8 54.3TrTrTvent2 7 1 7 2 9 2 3 1 92 4[BLa] TrWlTvent1 5 1 8 2 2 2 3 2 41 5WlTrTvent 3 2 3 13 0 3 0 3 3 3 5:•WIWITvent 2.6 2.72.5 2.6 2.4 2.5TIMETi T2 T3 T4T5 T6 T7TrTrTvent 1 .05 1 .02 1 .021 .04 1 .03 1 .03 1 .02RER TrWlTvent 0.970.98 0.97 0.97 0.960.95 0.94WlTrTvent 0.97 0.910.90 0.90 0.90 0.91 0.91WIWITvent 0.930.93 0.92 0.92 0.92 0.910.92TrTrTvent 12 1212 12 12 1212RPE TrWlTvent 1212 12 12 1212 12WlTrTvent 13 1313 13 13 1313WIWITvent 12 12 1212 12 12 12157UBJECT 12Female subject, 20 yrs old. Competes in 3-10 km track runs and cross country runs.Has been water running for 1 yr. For the previous 6 months prior to participating inthe study she has been WI running at least 6 times per month, 40 minute duration persession. Used no floatation device. WI running training consisted of interval andsteady state runs at and above WI Tvent HR.Comparison of the subject’s race pace from event completed close to the time whenparticipating in the study found her to have completed a 10 km race at 9.4 mph pace.The subject’s calculated TrTvent pace was 7.5 mph.Variable Treadmill WIHeight (cm) 159.7 159.7Weight (kg) 49.2 49.2VO2max (1/mm) 2.60 2.47VO2max (mI/kg/mm) 52.9 50.9HRmax (bpm) 211 199Vemax (1/mm) 71 .0 80.0RERmax 1.181.10RPEmax 20 0.9930 sec. post-test [BLa] 11.9 9.15 mm. post-test [BLa] 8.77.8Max. duration (mm)12:30 16:00V02 at Tvent (1/mm) 1 .87 1.87V02 at Tvent (mI/kg/mm) 38.5 38.6HRatTvent(bpm) 177 174Ve at Tvent (I/mm) 43.4 45.7RER at Tvent 1 .00 0.99RPEatTvent 12 12Time of Tvent 5:306:30158Prolonged performancetests.HR Tr(Tr/WI)TventWI(Tr/WI)TventV02 Tr(Tr/WI)TventWI (Tr/WI)TventVe Trfrr/WI)TventWI (Tr/WI)Tvent[BLa] Tr(Tr/WI)TrTventWI(Tr/WI)TventTr(Tr/WI) TventRER WI(Tr/WI)TventTr(Tr/WI)TventRPE WI(Tr/WI)Tverit38.9 38.5 38.438.1 39.2 39.051.7 49.7 52.050.4 52.1 52.7TI0.991 .0112IiT20.991 .031213T31.011 .04131319416938.538.350.447.43.93.1TI METi T2 T3T4T5 T6 T7175169180 184169 16918717019016819216738.338.551.,8 38.538.7 38.151.6 51.552.5 51.54,3 5.43.2 T61.001.021.011 .02T71.001.0113131 .001 .00131313131313159UB]ECTIMale subject, 29 yrsold. Competes in marathons.Has been water running for 3 yrs.For the previous 6 monthsprior to participating in the studyhe had been WI runningat least 6-8 times permonth, 60 minute duration of eachsession. Uses floatationdevice (‘aquajogger’). WIrunning training consisted ofinterval training above WITvent HR and steady stateruns at WI Tvent HR.Comparison of the subject’srace pace from an event completed closeto the time whenparticipating in the study foundhim to have completed a marathon at 10.2 mphpace.The subject’s calculated TrTventpace was 10.0 mph.VariableTreadmill WlHeight (cm)179 6 179 6Weight (kg)68 4 68 4VO2max (I/mm) 4 224 04VO2max (mI/kg/mm) 61 760 2HRmax (bpm)177 163Vemax (I/mm)1376 1329RERmax1 26 1 12RPEmax20 2030 sec post-test [BLa]8 22 8 55 mm post-test [BLa]8 8 7 9Max. duration (mm)17:00 16:00V02 at Tvent (1/mm) 348 3 05V02 at Tvent (mI/kg/mm)50.8 45.4HR at Tvent (bpm)152 140Ve at Tvent (1/mm)82 2 73 2RER at Tvent1 .02 0.91RPEatTvent13 13Time of Tvent 1 130 5 30Time point in testMinute 1 Tvent Minute VO2maxMinute(in strides/mm)Treadmill VO2max test 7686 94WI VO2max test50 5056160Pro’onged performance tests.TIMETI T2 T3T4T5 T6 T7TrTrTvent 153 156 160 162 162 166167HR TrWlTvent 140 142 142 142 144 146145WlTrTvent 140 146 147 147 148 147151WIWITvent 142 141 141 139 141 141 142TrTrTvent 50.6 50.1 51.3 50.4 49.5 50.450.9V02 TrWlTvent 45.9 46.0 46.7 45.5 45.8 49.945.9WlTrTvent 49.5 50.3 49.7 50.9 50.3 51.051.6WIWITvent 45.7 46.1 45.5 44.8 45.1 45.0 46.0:TrTrTvent 70.6 67.4 70.4 69.7 72.3 73.8 77.1Ve TrWlTvent 71.0 70.3 71.7 69.9 70.673.7 72.3WlTrTvent 95.4 102.7 102.4 105.2 104.7 104.8 108.5WIWITvent 77.2 74.2 72.0 69.4 78.3 69.9 72.3TrTrTvent 4.1 3.5 5.9 5.9 6.25.8[BLa] TrWlTvent 3.0 3.2 2.2 3.42.4 2.3WlTrTvent 5.1 5.2 5.0 5.2 5.25.2H WIWITvent4.1 4.0 3.7 3.4 3.5 3.4TI METi T2 T3T4T5 T6 T7TrTrTvent 0.95 0.92 0.93 0.92 0.940.95 0.96RER TrWlTvent 0.98 0.98 0.98 0.98 0.980.99 0.99WlTrTvent 0.95 0.97 0.96 0.94 0.950.94 0.95WIWITvent 1.05 1.00 0.98 0.95 0.980.96 0.96TrTrTvent 12 12 13 13 13 1414RPE TrWlTvent 10 ii ii ii ii11 iiWlTrTvent 14 14 15 15 16 16 17WIWITvent 13 13 14 14 1515 151 61Appendix B : Repeatedmeasures analysis forHR, V02, ye and[BLa).162Table 4.0. 2 X 2 X 7Repeated Measures AnalysisResults for Heart-rate.SOURCE SSDF MSF-RATIO P-VALUEMEAN6934099.89 1 6934099.892428.95 0.0001El25692.93 9 2854.77CONDITION6634.89 16634.89 19.350.03E23085.36 9342.82TVENT6791.58 1 6791.586.48 0.03E39434.39 9 1048.27CON X TVENT450.09 1 450.096.88 0.03E4588.45 9 65.38TIME2358.29 6 393.0540.34 0.001E5526.14 54 9.74TIME (1)23337.43 1 2337.4362.82 0.001E(l)334.85 937.21CON XTIME786.19 6131.03 10.960.001E6645.8154 11.96CON X TIME (1)745.891 745.89 14.230.004E(1)471.90 9 52.43TVENT X TIME69.80 611.63 2.600.03E7241.49 544.47CON X TVENT X TIME5.59 60.93 0.260.95E8192.13 54 3.56163Table 4.1. 2 X 7 RepeatedMeasures Analysis Results TrTrTVentV5WlTrTventfor Heart-rate.SOURCE SSDF MSF-RATIO P-VALUEMEAN3687456.01 1 3687456.013553.31 0.0001El9339.78 91037.75CONDITION5270.58 15270.58 34.910.0002E21358.64 9150.96TIME 1594.646 265.7738.78 0.0001E3370.07 546.85TIME (1)1567.80 1 1567.8075.41 0.0001E(1)187.11 920.79CON XTIME396.07 666.01 10.270.0004E4347.21 546.43CONXTIME(1)382.80 1382.80 16.970.003E (1)202.97 922.55Table 4.2. 2X 7 Repeated MeasuresAnalysis Results for TrWlTvefltVSWIWITventforHeart-rate.SOURCESSDF MSF-RATIO P-VALUEMEAN3253435.461 3253435.461 1 35.47 0.0001El25787.54 9 2865.28CONDITION1814.40 11814.40 7.050.03E22315.17 9257.24TIME833.44 6138.9118.87 0.0001E3397.56 547.36TIME (1)828.14 1828.14 26.190.0006E(1)284.59 931.62CON X TIME395.70 665.95 7.260.004E4490.73 549.09CON XTIME (1)363.22 1363.2210.04 0.01E (1)325.59 936.18164Table 5.0. 2 X 2X 7 RepeatedMeasures AnalysisResults of Oxygen Consumption.SOURCESSDF MSF-RATIO P-VALUEMEAN565630.851 565630.85610.84 0.0001El25692.93 9925.99CONDITION8.531 8.531.14 0.31E267.50 97.50TVENT1243.30 11243.30 7.270.03E31538.38 9170.93CON X TVENT7.34 17.34 0.680.43E497.44 910.83TIME27.346 4.564.70 0.003E552.3154 0.97TIME (1)19.76 119.76 6.960.03E5 (1)25.56 92.84CON X TIME2.28 60.38 0.250.84E681.68 541.51TVENTXTIME2.77 60.460.47 0.71E753.09 540.98CON X TVENT XTIME 4.346 0.720.82 0.50E847.62 540.88165Table 5.1. 2 X 7Repeated MeasuresAnalysis ResultsforTrTrTVentVSWlTrTventforOxygen consumption.SOURCESSDF MSF-RATIO P-VALUEMEAN309955.89 1309955.89 515.850.0001El5407.82 9600.87CONDITION0.022631 0.02263 0.000.97E2130.20 914.47TIME21.51 63.592.92 0.05E366.41 541 .23CON X TIME3.53 60.590.42 0.78E475.42 541.40Table 5.2. 2X 7 Repeated MeasuresAnalysis ResultsforTrWlTvefltVSWIWITventforOxygen consumption.SOURCESSDF MSF-RATIOP-VALUEMEAN256918.251 256918.25517.92 0.0001El4464.49 9496.05CONDITION15.84 115.85 4.100.07E234.74 93.86TIME8.59 61.431.98 0.12E338.99 540.72CON X TIME3.09 60.510.52 0.66E453.8854 0.99166Table 6.0.2 X 2 X 7 RepeatedMeasures AnalysisResults for Ventilation.SOURCESSDF MSF-RATIOP-VALUEMEAN1401356.291 1401356.29174.21 0.001El72398.299 8044.25CONDITION2130.061 2130.063.87 0.08E24953.249 550.36TVENT8250.781 8250.789.260.01E38023.309 891.48CON X TVENT759.791 759.795.330.05E41282.189 142.46TIME537.996 89.667.090.003E5682.5554 13.64TIME (1)522.911 522.9111.830.007E5(1)397.879 44.21CON XTIME110.436 18.400.640.70E61553.2654 28.76TVENT XTIME265.896 44.314.090.03E7584.5254 10.82TVENT X TIME(1) 257.491 257.495.590.04E7 (1)414.749 46.08CONXTVENTXTIME36.846 6.140.790.51E8421.0054 7.80167Table 6.1. 2 X7 Repeated MeasuresAnalysis Results TrTrTVentVSWlTrTventforVentilation.SOURCESSDF MSF-RATIO P-VALUEMEAN812331.571 812331.57172.32 0.0001El42425.69 94713.97CONDITION2717.091 2717.095.50 0.04E24443.11 9493.68TIME768.716 128.127.63 0.007E3906.3954 16.79TIME (1)757.141 757.1410.34 0.01E (1)685.899 73.21CON X TIME48.32 68.050.38 0.69E41130.6354 20.94Table 6.2. 2 X7 Repeated MeasuresAnalysis Results for TrWlTventVSWlwlTventforVentilation.SOURCESSDF MSF-RATIOP-VALUEMEAN597275.511 597275.51141.480.0001El37995.90 94221.77CONDITION172.761 172.760.87 0.38E21792.309 199.14TIME35.166 5.860.880.49E3360.6754 6.68CON X TIME98.956 16.491.060.37E4843.6454 15.62168Table 7.0. 2 X 2 X6 Repeated MeasuresAnalysis Results for BloodLactate Concentration.SOURCE SSDF MSF-RATIO P-VALUEMEAN4850.64 1 4850.64125.26 0.0001El 348.519 38.72CONDITION31.62 131.62 5.890.04E248.29 9 5.37TVENT 158.891 158.8912.29 0.007E3 116.359 12.93CON X TVENT 3.951 3.95 0.400.55E4 89.929 9.99TIME 5.765 1.151.60 0.20E532.45 45 0.72CON XTIME37.30 5 7.466.17 0.004ES54.42 451.21CON X TIME (1)36.59 136.59 9.830.01E (1) 33.489 3.72TVENTXTIME4.55 5 0.912.13 0.08E7 19.2245 0.43CON X TVENT XTIME 3.04 50.61 2.080.10E813.17 45 0.29169Table 7.1. 2 X 7 Repeated MeasuresAnalysis ResultsTrTrTVentVSWlTrTventfor BloodLactate concentration.SOURCE SS DF MSF-RATIO P-VALUEMEAN 3382.68 1 3382.6887.96 0.0001El 346.11 938.46CONDITION 6.611 6.61 0.82 0.39E2 72.68 98.08TIME 8.75 51.75 2.24 0.08E3 35.0945 0.78CON X TIME 28.46 5 5.696.67 0.002E4 38.4145 0.85CON X TIME (1) 27.301 27.30 11.54 0.008E(l)21.30 9 2.37Table 7.2. 2 X 7 Repeated MeasuresAnalysis Results forTrWITvefltVSWIWITventforBlood Lactate concentration.SOURCE SSDF MS F-RATIOP-VALUEMEAN 1626.851 1626.85 123.290.0001El 118.76 913.20CONDITION 28.971 28.97 3.980.08E2 65.52 97.28TIME 1.56 50.31 0.85 0.52E3 16.5845 0.37CON X TIME 11.885 2.38 3.660.03E4 29.1945 0.65CONXTIME(1) 11.081 11.08 5.770.04E(1) 17.29 91.92170Appendix C : Stride Frequency171Comparisonof Stride Frequencyduring theTreadmill andWIVO2maxtestStride frequencywas measured duringthe treadmilland the WIVO2mtests. Stridefrequency wasmeasured each minutein both tests,andcommenced 15seconds followingloading for 30second measurementperiodsfor each minute(values werethen multiplied by2 for minutecadencevalues) of thetests. Threetime points duringthe tests were usedforcomparison oftreadmilland WI stridefrequency, minute1, minuteatwhich Tventoccurred and thelast minute ofthe tests at maximaleffort(VO2m).A 2 X 3 withinsubject repeated measuresanalysis of variancewith trend analysiswas usedto analyze the data,with the levelofsignificanceset at 0.05.The analysisrepresentsdata collectedfromonly 12 of the13 subjects dueto technical problemsduring WI testdatacollection forone subject.A significantCondition maineffect was exhibitedfor stridefrequency(p<O.O5). Averagedacross the threetime intervalsmeanstride frequencywas significantlylower in theWI (54 strides/mm)compared to thetreadmill(88 strides/mm)condition (FigureCl.0 B).A significantincrease in meanstride frequencyover timewasexhibited (Timemain effect, p<O.O5)with 98 percentof the variabilityin time accountedfor by asignificant timelinear trend(p<O.O5). Asimilar steadylinear increasein mean cadencewas exhibitedfor boththe treadmilland the WI VO2maxtests (FigureCl.0 A, lines).172There wasno significantCondition byTime interaction(p>O.O5)andthereforeconclude thata similarpattern of increasewas exbibitedinboth conditions(see Figure Cl.OA and Band see TableC1.O for RWsanalysis results).Increasesover time perinterval weresimilarforthe 2 conditionswith a 4.5 (4.3)and 6.8 (8.2)percent increasefromminute 1 toTvent andfrom TventtoVO2maxfor the treadmilland WI (WIvalues are inparentheses)conditions.A totalpercent increaseinstride frequency(from minute1 toVO2max)of 2.3 and3.9 was exhibitedin the treadmilland WI conditionsrepectively.The WI stridefrequencyat minute1 toVO2maxrepresented59, 61, and65 % of thetreadmillstride frequency.173Stride Frequency (strides/mm)Figure C1.O. Comparison ofstride frequency (strides/mm) duringthe treadmill vsthe WI VO2ytests. Comparisons weremade ror stride frequency duringthe firstminute of each test, at Tventtime and at maximal effort (V02m8jtime. A.Plot ofmean stride frequency (+1std) at each of the 3 intervals on the treadmill(Tr) andwater immersion (WI), includingplot of the change over time (lines). B.Table ofmean stride frequency overtime (at minute 1, Tvent and VO2m) andtotals for thetreadmill and the WI VO2mtest conditions.Minute 1 TventVO2mTime Point in VO2max testsTreadmillMinute 1CONDITIONWITv ent83VO2max87 94Mean total498853 61 541 74Appendix D : Repeatedmeasures analysisfor RER and RPE.175Dl.O Respiratory ExchangeRatioRESULTSRespiratory exchange ratio(RER) responses during the steadystatetests were examined inrelation to RER response during theperformancetests in the 2 conditions(treadmill and WI) andto the 2 Tvent (theTrTvefltandWlTvent)intensities over the performancetest’s timeintervals and averaged overthe Time factor. A 2 X 2 X 7within subjectrepeated measures analysisof variance with trend analysis,with a=O.05was used to analyze thedata.Averaged over the two Tvent’sand across all timeintervals, themean RER response on thetreadmill (RER=O.96) wassimilar to the meanresponse in WI (RER=O.97)(Condition main effect; F1,9=O.27,p>O.O5)(Figure Dl.l A).Averaged over the twoconditions and across alltimeintervals mean RER responseatTrTveflt(RER=O.97) was similarto theWlTvent response (RER=O.96)(Tvent main effect; F1,9=l.93,p>O.O5)(Figure Dl.l A).Averaged across all timeintervals mean RER responsewas similarwhen Tvent intensity wasperformed on the treadmill (RERTrTventO.98andRERWITventO.95)versus WI(RERTrTVent=O.97andRERWITventO.97)(Condition by Tventinteraction; F19=O.65, p>O.OS)(see Figure Dl.l B).There was a significantTime main effect (F654=8.82,p<O.O5) with89 percent of the variabilityaccounted for by asignificant Time linear176trend as evidenced by thesteady linear response in mean RERover time.Mean RER remained relativelyconstant over time for TrTvent and WITVentintensity tests performedon the treadmill. Mean RER exhibitedadecline over time inthe two WI tests (performed at TrTvefltandWlTvent).The pattern of decline isin line with [BLa] response in WIand supports thearguement of an oxygen debt incurredduring the onsetof WI exercise, whichwas most likely re-oxidized duringthe latter partof these tests (see discussion).A mean change in RERvalues of 0.01 during treadmillperformance attreadmill and WI Tventdoes not represent a physiologicalchange ordifference in fuelutilization. During the WI testsat treadmill and WITvent, a significant decliningtrend for RER was exhibited. Achange inRER from 0.99 duringthe initial 15 minutes of bothtests to an RER of0.96 in the latterpart of both tests was noted.This pattern ofdecline does not representa major physiological changein fuelutilization, althoughdoes suggest glycogenolysis as themajor processof fuel utilization duringthe initial 15 minutes ofWI exercise.The significant Time(F654=3.86, p<O.05), Timelinear trend(F1,9=8.01, p<O.05)and Condition by Time interaction(F6543.54,p<O.O5) for RN’s analysis of TrTrtvefltversusWlTrTventconfirm that adifferent response overtime was exhibited at TrTvefltin the twoconditions. Thenon-significant Condition byTime interaction(F6,542.14, p>O.O5),with a significant Time (F654=7.59,p<O.O5) andTime linear trend (F19=19.92,p<O.O5) for the RN’s analysisfor177TrwlTvefltversusWIWITventdenotes the changeover time in mean RER,butno difference inBER response relatedto the WI condition(Figure Dl.2).See Table Dl.Ofor RER RN’s results andtables D1.1 and Dl.2 forRERRN’s results for TrTrtvefltversusWlTrTvefltandTrwlTventversusWIWITventrespectively.178RER (VCO2NO)Figure Dl .1. Mean RER responsefor Condition and Tventmain effectsand Condition X Tventinteraction. A. Comparisonof mean RER responseover Condition(Tr vs WI) and over Tvent(TrTvent vs WlTvent) averagedover time. B. Comparisonof mean RER responseaveraged over thesteady state tests performedon the treadmill ( Tr and WI Tvent)versus the steady state testsperformed in WI ( Tr and WI Tvent).RER (VCO2/V0)O.9!J TrTvent•WlTvent0.94ConditionTventTr-RER WI-RER179;:TimeTi T2 T3 T4 T5 T6 T7TrTvent 0.98 0.97 0.97 0.97 0.970.98 0.98:TRWlTvent 0.96 0.96 0.95 0.950.95 0.95 0.95:TrTvent 0.99 0.99 0.98 0.96 0.960.96 0.96WIWlTverit 0 99 0 98 0 98 0 97 0 960 96 0 96Figure Dl .2. Mean RER response overthe steady state performance testsover time. A. Table of mean RER over time for the4 steady state tests. B.Comparison of mean RER response over timefor each test condition andTvent.RER (VCO2NO)10.990.980.970.960.950.94zz:Ti T2 T3 T4 T5 T6T7TimeTrTrTvent TrWlTvent*WlTrTvent WIWlTvent180Table Dl .0. 2 X 2 X 7 RepeatedMeasures Analysis Results for Respiratory Exchange Ratio.SOURCE SS DFMS F-RATIO P-VALUEMEAN 262.08 1262.08 11145.68 0.001El 0.21 90.02CONDITION 0.0041 0.004 0.27 0.61E20.15 9 0.02TVENT 0.01 10.01 1.93 0.20E3 0.06 90.01CON X TVENT 0.01 10.01 0.65 0.43E4 0.11 90.01TIME 0.01 60.002 8.82 0.001E5 0.0254 0.0003CON X TIME 0.01 60.00 1 3.63 0.006E6 0.0254 0.0003TVENT X TIME 0.00 1 60.0002 0.880.45E7 0.00154 0.0002CON X TVENT X TIME 0.00 1 60.000 1 0.85 0.50E8 0.0154 0.0002181Table Dl .1. 2 X 7 Repeated Measures Analysis Results TrTrTVent V5 WlTrTventforRespiratory Exchange Ratio.SOURCE SS DF MS F-RATIO P-VALUEMEAN 132.89 1 132.8912361.27 0.0001El 0.09 9 0.01CONDITION 0.00021 0.0002 0.02 0.90E2 0.12 9 0.01TIME 0.005 6 0.0009 3.86 0.004E3 0.01 54 0.0002TIME (1) 0.004 1 0.004 8.01 0.02E (1) 0.004 9 0.0005CON X TIME 0.003 6 0.0006 3.54 0.009E4 0.009 54 0.0002Table Dl .2. 2 X 7 Repeated Measures Analysis Results for TrWITvefltVSWlWITventforRespiratory Exchange Ratio.SOURCE SS DF MSF-RATIO P-VALUEMEAN 129.19 1 129.196617.18 0.0001El 0.18 9 0.02CONDITION 0.011 0.01 0.79 0.40E2 0.14 90.02TIME 0.009 6 0.0027.59 0.0001E3 0.0154 0.0002TIME (1) 0.009 1 0.00919.92 0.002E (1) 0.004 9 0.0005CON X TIME 0.004 6 0.00062.14 0.10E4 0.02 54 0.0003182D2.O Ratingsof Perceived ExertionRESULTSRatings ofperceived exertion(RPE) responsesduring the steadystate testswere examined inrelation to RPEresponse duringtheperformancetests in the 2conditions (treadmilland WI) and tothe 2Tvent (the TrTventandWlTvent)intensities overthe performanceteststime intervalsand averagedover the Time factor.A 2 X 2 X 7withinsubject repeatedmeasures analysisof variance withtrend analysis,witha=O.05 was usedto analyze the data.Averaged overthe two Tventsand acrossall time intervals,themean RPE responseon the treadmill(RPE=l2.5) wassimilar to themeanresponse in WI(RPEl3) (Conditionmain effect;F19=l.38,p>O.O5)(Figure D2.l A).Averaged over thetwo conditions andacross all timeintervalsmeanRPE responseatTrTveflt(RPE=13.5)was similar totheWITveflt(RPE12)(Tvent main effect;F1,g=]..97, p>O.OS)(Figure D2.l A).Averaged acrossall time intervalsmean RPE responsewas similarwhen Tvent intensitywas performedon the treadmill (RPETrTventl3andRPEwITventl2)versus WI(RPETrTventl4andRPEWITVeflt=l2)(Condition byTvent interaction;F19=O.53, p>O.O5).RM’s analysis ofmean RPE for183TrTrTVentVSWlTrTventand forTrwlTvefltVSWIWITventfound nosignificant differencesin RPE response (Figure D2.1 B).There was a significant Timemain effect (F654=11.O1,p<O.05) with98 percent of the variabilityaccounted for by a significantTime lineartrend as evidenced by thesteady linear increase inmean RPE over time(Figure D2.2).There was no significantCondition by Time interaction(F654=O.65,p>O.O5). There was a significantTvent by Time interaction(F654=4.74,p>O.O5) with mean RPEresponse lower over timewith WlTvent (ie.WlTrTventandTrwITveflt)versus TrTvent (ie.TrTrTventandWlTrTvent).Ninety eight percentof the variability wasaccounted for by asignificant linear trend (F19=7.31,p<O.05) as evidenced by thesteadylinear increase in mean RPEresponse over time,averaged over the twoconditions, in both the WITventandTrTVeflttests.RMs analysis of TrTventintensity performed on thetreadmillcompared to in WIreported a mean RPEincrease over time for boththetreadmill and WI testsat treadmill Tvent.Mean RPE atTrTvefltincreased from 11.4at Ti to 13.6 at T7and from 12.5 at Ti to15.5 atT7 performed on thetreadmill and WIcondition respectively.Thissuggests that theTrTVentintensity in the WI conditionwas perceivedby the subjects to bemore difficult. Progressivelyover time perceivedexertion ratings increasedfor the subjects. The[BLa] and RER,however, do not conformwith the subjects perceivedeffort. The RPE atTrTventintensity performed onthe treadmill showed asmall increase in184RPE over time,but this increase is mostlikely attributed tothelaboratory conditions(ie. heat and humidity)and is in line withthe(increased) [BLa],Ve and HR responses exhibited.The similar mean RPEatWlTventin both the WI and treadmillconditions suggest thattheexercise was perceivedas_moderate.See Table D2.O forRRE RM’s results andtables D2.l and D2.2 forRPERM’s results for TrTrtventversusWlTrTventandTrwlTvefltversusWIWITventrespectively.185RPERPEFigure D2.1. MeanRPE responsefor Condition and Tventmain effects andCondition X Tventinteraction. A.Comparison of meanRPE responseoverCondition (Tr vsWI) and over Tvent (TrTvefltV5WlTvent)averaged overtime. B.Comparison of meanRPE responseaveraged over thesteady state testsperformedon the treadmill ( Tr and Wi Tvent)versus the steadystate testsperformed inWI (ie. at Tr andWI Tvent).ConditionTventTr-RPE Wl-RPE1 86LATimeTi T2 T3 T4 T5T6 T7:TrTvent 11.4 11.6 12.112.6 13.2 13.5 13.6TR, WlTvent 11.1 11.311.6 11.8 12.2 12.2 12.4TrTvent 12.5 13.7 14.014.3 14.7 14.9 15.5wIWlTvent 11.6 11.6 12.212.4 12.6 12.9 12.7RPE161311T2T3T4T5T6T7Time°-TrTrTvent TrWITvent *WlTrTvent WIWlTventFigure D2.2. Mean RPE responses over the steady state performancetestsover time. A. Table of mean RPE over time for the4 steady state tests. B.Comparison of mean RPE responses over time for each testcondition andTvent.1 87Table D2.O. 2 X 2 X 7 Repeated MeasuresAnalysis Results for Ratings of PerceivedExertion.SOURCE SSDF MS F-RATIO P-VAUJEMEAN 45441.03 145441.03 1375.99 0.0001El297.22 9 33.02CONDITION 85.80 185.80 1.38 0.27E2 558.88 962.10TVENT 122.23 1122.23 1.97 0.19E3 558.59 962.07CON XTVENT 21.181 21.18 0.53 0.49E4 362.36 940.26liME 113.09 618.85 11.08 0.001E5 92.41 541.71TIME (1) 110.63 1110.63 12.990.006E (1) 76.62 98.51CON X TIME 2.62 60.44 0.65 0.55E6 36.45 540.68TVENTXTIME 13.09 62.18 4.740.01E7 24.84 540.46TVENT X TIME (1) 12.86 612.86 7.310.02E(1)15.82 54 1.76CON X TVENT X TIME 1.85 60.31 0.710.48E8 23.3654 0.43188Table D2. 1. 2 X 7Repeated Measures Analysis Results TrTrTVentV5WlTrTventfor Ratingsof Perceived Exertion.SOURCE SSDF MS F-RATIO P-VALUEMEAN 25138.401 25138.40 366.92 0.0001El 616.609 68.51CONDITION96.11 1 96.111.04 0.33E2 830.609 92.29TIME 101.106 16.85 11.390.002E3 79.9054 1.47TIME (1) 99.461 99.46 13.50 0.005E (U 66.299 7.37CON X TIME3.59 6 0.590.81 0.44E4 39.7054 0.74Table D2.2. 2 X 7 RepeatedMeasures Analysis ResultsforTrWlTventVSWlWlTventforRatings of Perceived Exertion.SOURCE SSDF MS F-RATIOP-VALUEMEAN 20424.861 20424.86 768.470.0001El239.21 9 26.58CONDITION 10.861 10.86 1.080.32E2 90.649 10.07TIME 25.096 4.18 6.050.01E337.34 54 0.69TIME (1)24.03 1 24.038.27 0.01E(1)26.15 9 2.91CON XTIME0.89 60.15 0.400.84E4 20.1154 0.37189Appendix E : Quality ofWorkouts.190(Tr-WI)VO2max(ml1kgmin)Interval/steady(...HR at WIvent)HARDSteady state(<HR atWlTvent)LIGHTQuaIty of WI WorkoutsFigure E1.O. Comparison of the quality of the subjects’ WI running workoutscompared to the magnitude of difference in WI and treadmillVO2max(in mV1kgmin).Although all the subjects met the present study’s criteria for accetable WI runningstyle and quantity of WI running (le. # of sessions per month and duration of eachworkout for the previous 6 months prior to participation in the study),the type of WIworkouts performed (hard vs light) distinguished the subjects. Subjectswhoperformed exclusively low intensity workouts(HR at WlTveflt) during their WIworkouts exhibited much lowerWlvo2maxcompared to theirTrvQ2maxresponse(difference ranging btwn 11.2-16.8 mI1kg’’min). The differences were smaller for thesubjects performing hard WI workouts (ie. at.HR at Wltvenj, differences of 1-5.9 and3.3-7.7 ml1kgmin for interval/steady and steady state respectively.Steady state(.HR at WlTvent)HARD191Appendix F : LaboratoryTemperature and BarometricPressure over TestSessions.192Temperature(°C)Barometric Pressure(mm Hg)Figure Fl .0.Graph ofthe mean laboratoryroom temperature(bars) andbarometricpressure(*)during steady stateTvent performancetests. Thetemperature inthe lab rangedbetween 23.2-30°C during June/Julytesting andmean HR fortheTrTrTveflttests increasedfrom Ti to T7by 19 bpm(N=4). Thetemperaturein the lab duringSeptember testingranged between22-25° C andmean HR forthe TrTrtvefljtests increasedfrom Ti to T7by 13 bpm (N=2).Thetemperature inthe lab duringDecember testingranged between13-19.8° Candmean HR forthe TrTrTveflt increasedfrom Ti to T7 by12 bpm (N=4).The hot labenvironmentaffected thesubjects’ 42 minutetreadmill performancetests. HR,Veand [BLa] exhibitedan upward driftover the 42 minutetreadmill testsat Tr and WITvent intensity.The subjectswere performingat and belowtheir Tventlevel.The exerciseintensity ofthe 2 tests shouldhave taxed predominatelytheir aerobicsystem. Evaluationof the subjects’field race performancesduring theperiod oftheir participationin this studydid substantiatetheir treadmillTvent levelswhichwere determinedfrom the treadmill VO2mtests.20272523211017754782700756758754752750..J un/J ulySeptern berDecm ber193Appendix G Determination of Tvent fromVentilatory Parameters.1943328Ve/V022. (mm)HR (bpm)Figure Gi.0. Determinationof Tventfrom ventilatoryparameters(ExCO2andVeNO2).Tvent is definedas the pointof non-linearincreasein ExCO2.TheVe/V02curve overtime wasalso usedto confirmthe Tventlevel.Nonmetabolic(excess)C02 resultsfrom thebuffering oflactateand will begeneratedfor as longas the rateof lacticacid productionis increasing.This generatesadditionalhydrogenions to bufferand becausethehydrogenion and CO2can readilydiffuse fromwithin themusclecell intothe bloodstream,increases inexcess 002will bedetectedsooner thantherise in bloodlactateconcentration.Consequentlyexcess CO2will moreaccuratelyreflect musclelactate productionand accumulation(Rhodes andAnderson,1989; Wassermanet al, 1973).The minuteV02 (in mlkg1min)(and HR,Ve) at thepoint ofTvent wasthencalculated andused to determinethe workloadof the prolongedperformancetests at treadmilland WI Tvent.V02 over the VO2mtest isshown onthe top figurewith theexcess CO2curve and HRis plottedwiththe Ve/V02curve.2318131 2 34 5 6 78 9 1011 12 1314 15 16.Time (mm)1 2 34 5 6 78 9 10 1112 13 1415 16.195Appendix HSubject InformedConsent Form196THE UNIVERSITY OF BRITISH COLUMBIASchool of Human Kinetics210, War Memorial Gym________6081 University Boulevard_______Vancouver, B.C. Canada V6T 1ZJTel: (604) 822-3838 Fax: (604) 822-6842CARDIORESPIRATORY ANDMETABOLIC RESPONSES OFTREADMILLVERSUS WATER RUNNINGIN ELITE DISTANCE RUNNERSINFORMED CONSENT FORMInvestigators:1. Dr. Edward C. Rhodes (officetel # 822-4585), Principal Investigator and FacultyAdvisor2. D. Daisy Frangolias, Co-Investigator3. Dr. Angelo Belcastro4. Dr. Kenneth Coutts5. Dr. Jack C. Taunton6. Dr. Igor MekjavicPurpose:The purpose of this study is to investigatedifferences in response to treadmillvswater immersion to the neck (WI)exercise (running) in elite endurance maleand femalerunners, familiar with water running.Specific questions to be addressed are: a)Can runnersfamiliar with WI running perform toa similar maximal level (ie. VO2max) inthe WI as on thetreadmill condition?, b) Are theredifferences in the ventilatory threshold (Tvent)levels in WIversus treadmill running?, c) Is theWI condition responsible for physiological differencesexhibited during WI compared to treadmillrunning? Differences inVO2maxand ventilationthreshold(Tvent),and responses to 42 minutes of runningon the treadmill and WITvent’Swill be examined in this study.Tventis the intensity of exercise above whichfatigue begins to set in, whenworking atTventintensity you are able to continue exercisingaerobically for a long duration(ie. complete a marathon). VO2maxis the maximum amount of oxygen your musclescanconsume and show no further increasein oxygen uptake workload.VO2maxprovides agood indication of your aerobicfitness. The higher your aerobic fitness, thegreater theworkload you can achieve before exhaustion setsin during aVO2maxtest.Methodology:You will perform a total of 6 tests, 3 on thetreadmill and 3 in the deep endof thepool attached to a ‘WI Ergometer’ and wearing a‘Water Ski Belt’ around your waist. The197THE UNIVERSITY OF BRITISH COLUMBIASchool of Human Kinetics________210, War Memorial Gym6081 University Boulevard_______Vancouver, B.C. Canada V6T 1Z1Tel: (604) 822-3838 Fax: (604) 822-6842WI Ergometer Consists of aseries of pulley systems with a bucket,which is loaded withweights (400-750 grams on specified intervals) onone end and a belt which attaches toyour waist on the other end. Specifically you will performthe following tests within a onemonth period:1. You will perform a 5-10 mm warm-up followed bya TreadmillVO2maxtest(protocol: initial velocity 5 mph, increased by 0.5mph/mm until volitional fatigue; ifvolitional fatigue is not experienced within 15 minutes oftreadmill running the velocity willremain at 12 mph and the grade will be increased by 2%per mm until volitional fatigue).Blood lactate samples will be drawn from your finger (byfinger pricking) at 30 sec and 5mm post-test. Complications during such a test are few andusually clear quickly with littleor no treatment. You may stop the test when you wish to becauseof personal feelings offatigue or discomfort. There will be a spotter by your side for the durationof the test tosupport and catch you if you loose your balance whilerunning on the treadmill. Every effortwill be made to conduct the test in such a way to minimize discomfort and risk.2. You will perform a 5-10 mm warm-up followed by aWIVO2maxtest (protocolfor female and (male) subjects: 500 (750) grams initialbucket weight, increased by 400grams/mm until volitional fatique; if volitional fatigue is notexperienced, within 1 5 minutesthe weight will be increased from minute 16 by 500 (750)grams/mm until volitionalfatigue). Blood lactate samples will be drawn at 30 secand 5 mm post-test, as stated in 1.Underwater running motion (from the neck down only)will be videotaped, for analysis ofwater running style. Please refer to 1 above for symptoms andpossible risks. There is norisk of ingesting water during the test, because you will bewearing a mouth piece and noseclip for the duration of the test.3. You will be asked to run at Tvent intensity (determinedfrom the treadmillVO2maxprotocol) for 42-50 mm continously and expired gases and blood lactatesamplesobtained at 7 minute intervals on the treadmill and WI (a total of 6 blood samples/test),onseparate days.4. You will be asked to run at Tvent intensity (determined from the WI VO2maxprotocol) for 42-50 mm continously and expired gases and blood lactate samplesobtained at7 minute intervals on the treadmill and WI (a total of 6 blood samples/test), on separatedays.198THE UNIVERSITY OF BRITISHCOLUMBIASchool of Human Kinetics________210, War Memorial Gym6081 University BoulevardVancouver, B.C. Canada V6T 1Z1Tel: (604) 822-3838 Fax: (604) 822-6842For all tests you will wear a nose clip and breath into amouth piece attached viahoses to a Beckman Metabolic cart (which will measure yourexpired breaths for expiredoxygen, carbon dioxide and amount of air you ventilateper minute) and wear a heart ratemonitor around your chest. Slight discomfort may beexperienced from finger pricking tocollect the (20 microliter) blood samples. A totalof 6 hours (1 hour/test) will be required toperform all tests within a 2.5 to 4 week period, on separate days.All information/datacollected will be confidential and a copy of your results and reportof your performance inthe study will be provided for you. All data collected and videotapeof your water runningperformance will be coded by a number from 01 to 15and no reference to your identity willever be made in order to maintain confidentiality. Data collectedwill be used for myMasters thesis in Human Kinetics and for possible publicationin a scientific journal. There isno monetary compensation available for your participation in this study, exceptfor mygratitude.Consent:At any time before or during testing you may withdrawfrom the study. Every effortwill be made to ensure that you do not experience any unnecessary discomfort.If you haveany questions concerning the procedures, or anythingelse regarding this study, please feelfree to ask me. Daisy Frangolias (my home phone number is 734-1912and the J.M.Buchanan Lab phone # is 8224356), or my Advisor Dr. E.C. Rhodes (officephone 822-4585).In signing this consent form you will have stated that you have read theconsentform (and received a copy for your own records) and understood the description of thetestsand that you have entered willingly and may withdraw at any time. Ihave read the abovecomments and understand the explanation and wish to proceed with allthe tests in. thisstudy.Date:_______________________Subject’s signature:________________________Witness’s signature:_________________________199


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