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The relationship of individual anaerobic thresholds to total, alactic, and lactic oxygen debts after.. 1980

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THE RELATIONSHIP OF INDIVIDUAL ANAEROBIC THRESHOLDS TO TOTAL, ALACTIC, AND LACTIC OXYGEN DEBTS AFTER A SET TREADMILL RUN by JAMES PRESTON WILEY B.P.E., The University of B r i t i s h Columbia, 1977 A THESIS SUBMITTED IN PARTIAL FULFULLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION i n THE FACULTY OF GRADUATE STUDIES School of Physical Education and Recreation We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA A p r i l 1980 © James Preston Wiley, 1980 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department Of Physical Education The U n i v e r s i t y o f B r i t i s h Columbia 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 DE-6 BP 75-51 1 E ABSTRACT Anaerobic threshold speed was determined for 20 male uni- versity students using a continuous treadmill protocol. The onset of anaerobiosis was determined by analyzing excess C O 2 elimination. The following week, a l l subjects ran at the median speed of 7.25 miles per hour for 10 minutes. Recovery oxygen consumption was monitored after this run. Application of double exponential equations by computer and subsequent integration, calculated Total, Alactic, and Lactic Oxygen Debts. Subjects who ran above their V ^ (group L-V-^) had significantly (p < .05) higher total, lactic and alactic debts than those subjects who ran below their"V-.., (group H-V_,„). The total debt J TAM & r TAM showed a significant (p < .05) negative correlation (r=-.77) to in ; group L'-V_̂ . This appears to be due to the increasing lactic debt, that was also significantly (p < .05) negatively correlated (r=-.73) to V_sll,.' Group H-V_.,, did not exhibit this characteristic. This study TAM r TAM demonstrates that V_.„ is a critical factor in determining oxygen debt TAM and therefore, work above this point results in the onset of metabolic acidosis, which may limit the optimal running speed for a given distance. TABLE OF CONTENTS ABSTRACT i i LIST OF TABLES v LIST OF FIGURES . v i ACKNOWLEDGEMENT v i i i Chapter 1 STATEMENT OF THE PROBLEM . . . . . 1 Introduction . . . . . . 1 Statement of the Problem ; 3 Hypotheses 3 Rationale 4 Assumption 5 Delimitations 5 Limitations 5 Definitions 5 2 REVIEW OF THE LITERATURE 7 I. Historical Considerations 7 II. Anaerobic Metabolism and Oxygen Debt . . . . . 8 III. Anaerobic Threshold . . . . . . . 12 3 METHODS AND PROCEDURES . . . . . . . . . 24 Subjects 24 Testing Procedures 24 Data Analysis 25 4 RESULTS AND DISCUSSION 27 Results 27 Discussion 41 5 SUMMARY AND CONCLUSIONS 46 i i i REFERENCES 48 APPENDIX A Sample Calculation of Oxygen Recovery Debts . . . . 54 APPENDIX B Anaerobic Threshold Curves to Determine Individual V T A M 56 APPENDIX C Individual Oxygen Recovery Curves 78 iv LIST OF TABLES Table 1. Individual Subject C h a r a c t e r i s t i c s 28 2. Individual Double Exponential Equations for Subjects i n Group L - V ^ 29 3. Individual Double Exponential Equations f or Subjects i n Group H-V-.., 30 r TAM 4. Individual A l a c t i c , L a c t i c , T o t a l and Ratio Oxygen Debts f o r Group L-V_ A„ 32 r TAM 5. Individual A l a c t i c , L a c t i c , T o t a l and Ratio Oxygen. Debts f o r Group H-V_._, 33 TAM 6. Means of T o t a l , A l a c t i c , L a c t i c and Ratio Debts for Groups L-V_4.. and H-V_ A„ 38 ^ TAM TAM 7. M u l t i v a r i a t e Analysis of Dependent Variables Total Debt and Ratio Debt 39 8. M u l t i v a r i a t e Analysis of Dependent Variables A l a c t i c and L a c t i c Debts 39 9. Cor r e l a t i o n C o e f f i c i e n t s for Subjects i n Group L - V T A M 40 10. Co r r e l a t i o n C o e f f i c i e n t s f o r Subjects i n Group H-V T A M 40 v LIST OF FIGURES Figure 1. Graph of Total Debt and Individual V_,^ 34 2. Graph of Alactic Debt and Individual V_,̂  35 3. Graph of Lactic Debt and Individual V_..x . 36 • TAM 4. Graph of Individual Ratio Debt and 37 5. AT curve subject CN 57 6. AT curve subject ML 58 7. AT curve subject RR 59 8. AT curve subject TB . . 60 9. AT curve subject DG 61 10. AT curve subject DD 62 11. AT curve subject BV 63 12. AT curve subject GS 64 13. AT curve subject DA 65 14. AT curve subject RF 66 15. AT curve subject HB . . . . . . . . . . . - 67 16. AT curve subject AB 68 17. AT curve subject AO . 69 18. AT curve subject GT . . 70 19. AT curve subject DH 71 20. AT curve subject JL 72 21. AT curve subject JO 73 22. AT curve subject DM 74 23. AT curve subject DW 75 24. AT curve subject SP . . . . 76 25. AT curve subject DH 77 26. Recovery curve subject CN 79 27. Recovery curve subject ML 80 28. Recovery curve subject RR . . 81 29. Recovery curve subject TB . . . 82 30. Recovery curve subject DG 83 31. Recovery curve subject DD 84 32. Recovery curve subject BV 85 33. Recovery curve subject GS 86 34. Recovery curve subj ect DA 87 vi 35. Recovery curve subj ect RF 88 36. Recovery curve subj ect HB . 89 37. Recovery curve subj ect . • 90 38. Recovery curve subj ect . . . 91 39. Recovery curve subj ect 92 40. Recovery curve subj ect 93 41. Recovery curve subj ect JL 94 42. Recovery curve subj ect .. . . . . . . . . 95 43. Recovery curve subj ect . 96 44. Recovery curve subj ect 97 45. Recovery curve subj ect 98 v l l ACKNOWLEDGEMENT The author extends appreciation to the members of the committee (Dr. E. C. Rhodes [Chairman], Dr. K. Coutts, Dr. J . Ledsome, and Dr. R. Schutz) for t h e i r work and e f f o r t that molded t h i s thesis to i t s present form. In p a r t i c u l a r , the author i s indebted to Dr. Rhodes, whose patience and assistance guided the d i r e c t i o n of t h i s t h e s i s . Special thanks are extended to Mr. D. Dunwoody, whose te c h n i c a l assistance, time, and friendship made t h i s thesis possible. v i i i CHAPTER 1 STATEMENT OF THE PROBLEM Introduction Anaerobic metabolism and i t s e f f e c t on recovery was f i r s t i n v e s t i - gated by H i l l , Long and Lupton (1924). At that time, such work l e v e l terms as moderate and severe were used to describe the exercise that pro- duced either immediate or extended recovery oxygen uptake s i t u a t i o n s . Since t h i s c l a s s i c i n v e s t i g a t i o n , researchers have l a b e l l e d the oxygen recovery curve (Margaria et a l . , 1933), quantified the oxygen recovery curve (Henry & DeMoor, 1950), and attempted to explain the oxygen recovery curve (Huckabee, 1958b). However, no one has examined oxygen recovery curves with respect to i n d i v i d u a l onset of anaerobic metabolism. Although some anaerobic metabolic a c t i v i t y c o n tinually occurs during exercise (Graham, 1978), only when l a c t a t e d i f f u s e s into venous blood flow from the muscle tissues i s i t possible to e a s i l y monitor anaerobic a c t i v - i t y . This increase i n venous l a c t a t e production appears to be the r e s u l t of the imbalance between l a c t a t e production and oxidation i n the muscle tissues (Graham, 1978). Lactate i n the venous c i r c u l a t o r y system has been the standard for examining work i n t e n s i t y since Margaria et a l . (1933) f i r s t examined phases of l a c t a t e production and removal. Results of these e a r l i e r i n vestigations (Margaria et a l . , 1933; Margaria & Edwards, 1934b) and more recent research (Hermansen & Stensvold, 1972) demonstrate the following: 1 2 1. there is a greater lactate concentration for higher work intensity, 2. lactate levels stabilize for a l l but the very extreme levels of steady-state work, and 3. long recovery periods are associated with high lactate levels. These early investigations imply that there is a point in the tran- sition from aerobic to anaerobic work intensity where anaerobic metabol- ism starts to play a very important role. This increased role is marked by the appearance of lactate in the blood in excess of resting levels. Initial investigation (Issekutz & Rodahl, 1961; Wasserman et al., 1964; Naimark et al., 1964; Wasserman & Mcllroy, 1964) monitored this phenom- enon and associated cardiovascular-respiratory changes. This resulted in non-invasive procedures involving measurement of respiratory gas exchange to determine the onset of metabolic acidosis. The term "Anaerobic Threshold" (AT) which has become synonymous with the onset of metabolic acidosis, was originally defined by Wasserman et al. (1964) as " . . . the work level (oxygen uptake) above which the subject develops metabolic acidosis." This definition is convenient in that i t is the limit of predominately aerobic energy production (as determined by normal blood lactate levels) but misleading in that no detectable anaerobic activity has occurred (again as determined by blood lactate level). Most studies use Wasserman's definition of the AT but some define the AT as the point where blood lactate production just exceeds its removal (Davis et al., 1976). The study of the role of the AT and its relationship to human per- formance has only just begun. This phenomenon has been used for testing hospital patients (Wasserman & Whipp, 1975), athletes (Costill, 1970), and models of hypernea (Whipp, 1977). However, the role of the onset 3 of anaerobic metabolism and its relationship to recovery analysis has not yet been investigated. Statement of the Problem The purpose of this study was to investigate the effects of individual Anaerobic Threshold Levels on the accumulation of an Oxygen Debt for a set treadmill run. Hypotheses 1. Subjects with an Anaerobic Threshold speed (V--^) above the speed of the treadmill (group -H-V-,̂ ) have a lower Total Oxygen Debt than those with a V m,„ below the speed of the treadmill (group L-V^.^,). TAM TAM 2. Group H-Vm, -has a lower Alactacid Debt than group L-V_,„. 3. Group H-V__„, has a lower Lactacid Debt than group L-V__ f TAM ° y TAM 4. Group H-V_,._, has a lower ratio of Lactacid Debt to Alactacid Debt TAM than group L~V T A M > 5. Group H-V_,̂  has a lower Total Recovery Time than group L-V_,̂ . 6. Within group L-V , Total Oxygen Debt is a decreasing function of V TAM 7. Within group L-V , Alactacid Debt is a decreasing function of 1 JTli 1 V TAM 8. Within group l - ^ ^ ' Lactacid Debt is a decreasing function of VTAM" 9. Within group L - Vrj,^> t n e ratio of Lactacid Debt and Alactacid Debt is a decreasing function of V m.„. 10. Within group L - V „ ^ , To t a l Recovery time i s a decreasing function ° f VTAM' 11. Within group H-V_.„, Total Oxygen Debt and V_,,,, are unrelated. TAM J ° TAM 12. Within group H-V„.„, A l a c t a c i d Debt and V_ A„, are unrelated. & r TAM' TAM 13. Within group H-V..,,,, the Lactacid Debt and V_, w are unrelated. & ^ TAM TAM 14. Within group H-V ̂  , t n e r a t i o of Lactacid Debt to Al a c t a c i d Debt and are unrelated. 15. Within group H-V_.w, Total Recovery time and V_._, are unrelated. a ^ TAM J TAM . Rationale The Anaerobic Threshold i s the threshold of appearance of venous l a c t a t e as a r e s u l t of anaerobic metabolism. As defined, V m . „ i s the TAM running speed above which these metabolites s t a r t to increase. There- fore, a subject running at a speed above his V ̂  w i l l have a larger contribution of anaerobic metabolism as an energy supply, r e l a t i v e to a subject running at a speed below h i s V This suggests that A l a c t a c i d and Lactacid Debts w i l l be larger for the subject running at a speed above his I f t h i s i s true, t h i s implies a larger T o t a l Oxygen Debt and a longer Recovery Time. The d i f f e r e n c e between the tr e a d m i l l speed and (for the sub- j e c t s running fa s t e r than t h e i r V should be r e f l e c t e d i n a larger contribution of anaerobic metabolism to t h e i r a c t i v i t y . This suggests that the components of Oxygen Debt and V^^. w i l l be inversely r e l a t e d . Furthermore, i t i s speculated that t h i s r e l a t i o n s h i p w i l l be approx- imately l i n e a r . 5 This relationship is not expected for those subjects running below their V TAM Assumption That an oxygen consumption during recovery after exercise can be described by a double exponential equation. Delimitations This study is delimited by: 1. the sample type (college age males), 2. the sample size, 3 . the sample's fitness levels, 4. the speed of the treadmill at which the subjects will run, and 5. the length of the time each subject is on the treadmill before recov- ery. Limitations This study's results are limited by: 1. data collection capabilities of the Beckman Metabolic Measurement ,Cart and the Hewlitt Packard Data Acquisition system interfaced with i t , 2. the method of Anaerobic Threshold determination, and 3 . the individuals' metabolic responses to the protocols. Definitions 1. Alactacid Oxygen Debt (Alactic Debt): theOxygen Debt incurred as a result of decreased body oxygen stores and high energy phosphate compounds (the fast exponential recovery phase). 2. Anaerobic Threshold: the point above which excess C O 2 production 6 is associated with elevated blood Lactate levels as a result of anaerobic metabolism. Excess Lactate (XL): as calculated by Huckabee (1958a) is XL = (L -L ) - (P -P )(L /P ) n o n o o o where: L = concentration of blood lactate at time of sampling n L = concentration of blood lactate at rest o P = concentration of blood pyruvate at time of sampling n P = concentration of blood pyruvate at rest o 4. Excess C O 2 ( E X C C O 2 ) : is the excess of carbon dioxide in expired air- (Issekutz & Rodahl, 1961) expressed as: ExcC02 = VC02 - V02ARQ where: C 0 2 is the total expired carbon dioxide O 2 is the total expired oxygen ARQ is the resting RQ (determined by Issekutz & Rodahl as .75). 5. Lactacid Oxygen Debt (Lactic Debt): the oxygen debt in excess of Alactic Debt due to lactate oxidation and higher metabolic rate (the slow exponential recovery phase). 6. Total Oxygen Debt: the total oxygen required during recovery in excess of resting. 7. Total Recovery Time: the time from cessation of exercise until oxygen consumption returns to resting. 8. V_,. : the treadmill speed corresponding to the Anaerobic Threshold. TAM CHAPTER 2 REVIEW OF THE LITERATURE I. H i s t o r i c a l Considerations Early research of anaerobic metabolism and it's r e l a t i o n s h i p to physi c a l a c t i v i t y investigated oxygen uptake curves a f t e r exercise. The f i r s t major study was completed by H i l l , Long and Lupton (1924). In th i s i n v e s t i g a t i o n , the f i r s t attempt at quantifying exercise exertion with regard to recovery time and blood l a c t a t e accumulation was made. The d i s t i n c t i o n between moderate and severe exercise and the possible r o l e of l a c t a t e i n determining oxygen consumption a f t e r exercise was investigated. R. Margaria (Margaria et a l . , 1933; Margaria & Edwards, 1934a, b) further researched oxygen consumption a f t e r exercise and developed recovery oxygen concepts that are s t i l l popular today. These studies supported a two-phase recovery system where the i n i t i a l f a s t recovery component was termed the 'alactacid debt' and the l a t e r , slower recovery component was designated the ' l a c t a c i d debt'. The concept that the fast repayment phase repays fast energy supply systems and the slow repayment phase corresponds to blood l a c t a t e removal was hypothesized. Berg (1947) applied a single exponential equation to oxygen and carbon dioxide recovery curves a f t e r exercise, as suggested e a r l i e r ( H i l l et a l . , 1924). This equation varied dependence between i n d i - viduals and conditions, and Berg advanced no possible i n t e r p r e t a t i o n 7 8 for these results.' Later, Henry and DeMoor (1950) ! applied •-•"1" double exponential equations to the oxygen recovery curve. This double exponential equation f i t the data points extremely well and provided a mathematical way to separate the oxygen recovery curve into alactacid and lactacid components, as first suggested by Margaria et al. (1933). The following year, Henry (1951) postulated that the alactacid component is an essential phase of any physical exertion due to equilibria processes that the exponential function predicts. This added support to his double exponential model. Subsequently, Henry and DeMoor (1956) investigated the effect of varying work intensity on a bicycle ergometer with regard to oxygen debt. Their findings demonstrated that increased work intensity produced a larger oxygen debt and recovery lag. Double exponential equations accurately described a l l recovery curves and showed an increasing lact- acid component with increasing intensity. It is from this model, developed by Margaria et al. (1933) and Henry and DeMoor (1950), that current recovery curve analysis is based. II. Anaerobic Metabolism and Oxygen Debt In 1958, W. E. Huckabee produced a series of articles (Huckabee, 1958a, b, c) that attempted to explain anaerobic metabolism and its relationship to oxygen recovery curves. He proposed, based on lactate: pyruvate equilibria relationships, that oxygen debt is directly related to Excess Lactate (XL) production. Excess lactate traced the oxygen recovery curve exactly and could be used as a predictor for total oxygen debt. This was in direct contrast to the concept of a two-phase recovery curve as supported by Margaria et al. (1933) and Henry and 9 DeMoor (1950). This finding was subsequently investigated by other researchers. Knuttgen (1962), using four different work rates on a bicycle ergometer, observed that past a "critical level of work," there was a rapid increase in oxygen debt. This increase in debt was paralleled by rises in lactate and excess lactate. However, this parallel rise underestimated the oxygen debt. At the lower levels of work, where the fast component of recovery was dominant, the level of lactate or excess lactate could not predict the oxygen debt. Margaria et al. (1963) also observed no increase in venous lactate until a specific exercise intensity. However, below this work inten- sity, an oxygen debt is s t i l l measurable and possibly attributable to the alactacid component. This study once again demonstrated the pos- sible existence of a two-phase oxygen debt payment. An editorial in the Annals of Internal Medicine by R. E. Olson (1963) cautioned the use of "Excess Lactate" as a means of signifying anaerobiosis. The assumption that the lactate/pyruvate ratio reflects the DPNH/DPN ratio in the cell and that the latter reflects aerobic capac- ity at a given time is disputed. The presence of at least two DPNH/DPN pools, with at least one membrane (mitochondrial) separating hydrogen ions, suggests that the lactate/pyruvate ratio may not reflect mitochon- drial deficiency as much as limited hydrogen transfer from the cytoplasm to the mitochondria. Wasserman et al. (1965) also challenged Huckabee's debt explana- tion, as i t directly conflicted with their concept of anaerobic thresh- old (Wasserman & McTlroy, 1964; Wasserman et al., 1964). Their find- ings support the concepts of Knuttgen (1962) and Margaria et al. (1963). This was especially true at the low work levels (subthreshold) where 10 Wasserman et al. (1965) found excess lactate to predict less than ten percent of oxygen debt. Thomas et al. (1965) also investigated the excess lactate concept. In a repetition of Huckabee's original works (with slight procedural modifications), Thomas failed to demonstrate the correlations for excess lactate that Huckabee presented. The investigation did reconfirm the role of lactate and pyruvate as indicators of anaerobic activity, how- ever, made no attempt to further delineate the mechanisms. Research next advanced to the analysis of the compartments of oxygen debt. Piiper et al. (1968), utilizing intact dog gastrocnemius muscle, observed a decreased concentration of high energy'phosphates (specifically creatine phosphate) and oxygenated myoglobin during stim- ulated exercise. They hypothesized that the return to resting values is accomplished during the alactacid phase of recovery (as mathematically predicted by Henry [1951]). DiPrampero and Margaria (1968).conducted a similar experiment with inovivodog gastrocnemius muscle. Their analysis showed a decreasing creatine phosphate concentration with increased exercise intensity while the concentration of ATP and ADP at steady-state remained constant. This decrease and the linear relationship between exercise oxygen uptake at steady-state and alactacid oxygen debt (reflecting phosphagen resyn- thesis half reaction time) supports creatine phosphate's resynthesis role in alactacid oxygen debt. Cerretelli (1969) continued this line of investigation to determine energy equivalents for the lactate and alactic phases (associated with decreased phosphagen stores). The linear equation for energy expendi- ture for these two phases, based on modern hypotheses, does not 11 significantly differ from that calculated by Margaria et al. (1934). This fact supports the two component oxygen debt hypothesis empirically. Direct evidence of creatine phosphate synthesis after exercise was investigated by Piiper and Spiller (1970). Their data shows almost com- plete phosphagen resynthesis in.the first two minutes of recovery. During this time period, the alactacid oxygen recovery component appears to explain the resynthesis of phosphagen. Total oxygen debt over- predicted high energy phosphate resynthesis. In 1970, a very extensive investigation into oxygen debt and sub- maximal exercise was completed by Knuttgen. Oxygen debt was observed after steady-state work performed at varying maximal oxygen uptake percent- ages and at different work durations. In his discussion, he stressed a two-phase recovery system as i t accurately described a l l the results. The slow component increased exponentially, and the fast component increased linearly after an i n i t i a l basal rate as work intensity increased. Only the slow component increased as the time duration : increased at a constant work load. This did not correlate with exercise blood lactate levels, therefore adding more doubt to the postulate that the slow com- ponent is related only to blood lactate levels. Knuttgen (1970) sug- gested that other.factors, such as hormones, body temperature, and elec- trolyte changes might also be considered. A comparison of steady-state and nonsteady-state exercise, employing different time durations for a constant workload was researched by Whipp et al. (1970). Their conclusions suggested that the difference seen in efficiency between short and longer term exercise related to oxygen debt, could be compared to: 1. delay of alactic debt repayment during steady-state, and 2. lactate accumulation during the second and third minutes of 12 exercise due to delay i n oxygen supply. They did not attempt to separate the recovery curve into two components. A s i m i l a r experiment by McMiken (1976) demonstrated work i n t e n s i t y to be a key i n p r e d i c t i n g oxygen debt (r=0.83). He also showed that steady-state and nonsteady-state debt were quite s i m i l a r , but did not imply that the previous i n t e r p r e t a t i o n of Whipp et a l . (1970) was in c o r - r e c t . Current analysis of recovery has centered on supramaximal work (Katch, 1972; diPrampero et a l . , 1973; Freund & Gendry, 1978; Roberts & Morton,.1978). The main thrust of t h i s work has been the examination of the a l a c t a c i d component of recovery. The delay of an exponential return to basal l e v e l xvas seen i n diPrampero's (1973) work which sug- gested a delayed return of metabolism to normal (perhaps an anaerobic recovery phase as suggested by C e r r e t e l l i et a l . [1974]). Roberts and Morton (1978) demonstrated the r e l i a b i l i t y of t h i s technique to deter- mine maximum a l a c t i c debt but so far only a few pieces of a very large puzzle have been found. I I I . Anaerobic Threshold Since Margaria et a l . (1933) monitored l a c t a t e build-up i n the blood, most i n v e s t i g a t i o n has involved the time course of l a c t a t e during and a f t e r exercise. However, i n 1962, Knuttgen (1962) noticed a " c r i t i c a l l e v e l of work" where l a c t a t e f i r s t appears i n the blood. This l e v e l of work had been seen before (Huckabee, 1958), but t h i s i n v e s t i g a - t i o n appears to be the f i r s t to attach s i g n i f i c a n c e to i t . Issekutz and Rodahl (1961) observed a l a c t a t e breakaway using the change i n the Respiratory Quotient and Excess C0 2.. This was the f i r s t 13 attempt at noninvasively following lactate levels in the blood (a corre- lation of 0.918 for lactate and Excess C02 was found). Wyndham et al. (1962) speculated that the onset of metabolic acid- osis limited prolonged physical activity. Their investigation demon- strated that the "trained" individual had a higher tolerance to this anaerobic onset. These ideas were novel, but the use of Huckabee's (1958a) Excess Lactate concept in determining the start of anaerobiosis detracted from their study. Williams et al. (1962) investigated the anaerobic threshold and heat stress. Anaerobic activity appeared to increase at about 1.4 to 1.5 liters per minute of oxygen uptake above resting in the hot environ- ment (about 95°F) and at about 1.6 to 2.2 liters per minute of oxygen up- take above resting in the comfortable environment (about 70°F). This suggests that the anaerobic metabolism mechanism is initiated faster at the higher temperature. Excess lactate determined the onset of anaerobic activity therefore the results must be interpreted with caution. In 1964, three studies from Karlman Wasserman's laboratory in Palo Alto, California, introduced the concept of the "Anaerobic Threshold" (AT). The AT was originally defined by Wasserman et al. (1964) as ". . . the work level (oxygen uptake) above which the subject develops metabolic acidosis." The AT and its relationship to varying levels of work rate was investigated by Wasserman et al. (1964). Their findings reiterated Wyndham et al.'s (1962) postulate, that activity may be prolonged for workloads at or below the AT. The continual observation of blood lactate may be inconvenient, so Naimark et al. (1964) investigated respiratory exchange variables con- comitant with lactate and bicarbonate changes. When lactate and 14 bicarbonate were compared to the Respiratory Quotient and Excess C O 2 production (as similarly done by Issekutz & Rodahl [1961]) identical time of change was observed and a correlation (r) of 0.98 was calculated for excess C02 and bicarbonate concentration. Trained athletes did not exhibit an increase in the Respiratory Quotient until a much higher work level (oxygen uptake) compared to that of the untrained, suggesting a delay in onset of anaerobic activity. Their bike protocol for detecting the AT proved very reliable when checked the following day. The third investigation (Wasserman & Mcllroy, 1964) utilized breath- by-breath analysis of end-tidal gas concentrations to calculate the Respiratory Quotient to determine the AT for patients in a'hospital. AT monitoring procedures were administered to determine some forms of cardiovascular deficiency. This provided an added measure of safety to testing procedures not available under maximal stress test conditions. Wyndham et al. (1965) also investigated the AT comparing normal and hospital patients. Although excess lactate was used to determine the point of onset of anaerobic metabolism, the relationship between maximum oxygen uptake and the AT was introduced. The use of a 'percent' of maximum oxygen uptake would allow comparisons of normal and cardiac patients, however, exclusion of work-load would limit: 1. absolute improvement recognition after rehabilitation, and 2. comparisons to other studies with subjects of.different maximal oxygen uptakes. The result of investigation of the AT and its application to hospital patients was the review of muscular exercise analysis in normal and disease situations (Wasserman & Whipp, 1975). Results of previous investigation, especially relating to the AT, and its application to 15 patient diagnosis was reviewed. Bouhuys et al. (1966) conducted an exhaustive analysis of-the relationships between blood lactate and excess C O 2 , respiratory quotient, blood pH and bicarbonate. Although significant correlations (p < .001) existed between lactate and a l l variables, the highest correlation was to excess C©2 (r=.796). As with a l l predictors, there were discrepan- cies which led these researchers to conclude that the best index of metabolic acidosis is blood lactate. However, they do agree that the respiratory quotient and excess C O 2 are good indicators of 'change' in blood lactate levels. A study relating AT and training was conducted by Williams et al. (1967). This investigation showed that daily exercise of four hours, continuing from four to six weeks, increases the percent of maximum oxygen uptake at which anaerobiosis occurred (maximum oxygen uptake also increased). Analysis of anaerobiosis consisted of excess lactate determination therefore limiting interpretation of the results. The following year, Williams et al. (1968) conducted a similar, but more extensive study on endurance trained males. The results showed that blood lactate and excess lactate levels were significantly different when determined after the sixth and sixtieth minute of exercise. A more important finding was the difference in the AT as predicted by lac- tate and excess lactate (this difference was significant according to the authors, but no confidence limits were given). This again casts doubt on the use of excess lactate as previously discussed. Wasserman et al. (1967) investigated work intensity and duration of exercise on a bicycle ergometer related to the AT. The concepts of "pay-as-you-go" (aerobic) and "credit" (anaerobic) energy supply terms 16 relating to exercise could explain the different metabolic responses. Increased oxygen debt, as a result of increased.work intensity showed an increased debt proportion due to lactate oxygen equivalents. At a sub- threshold (moderate intensity as described by Wells et al. [1957]) work intensity, activity could be maintained by a l l subjects for a minimum fifty minute period. However, only four of ten subjects completed the heavy work intensity (just above the AT) for the fifty minute period. No one completed the fifty minutes at the very heavy work load. This suggests that the AT is the limit of aerobic work capacity and that activity above this work level requires an increasing amount of anaerobic energy supply. The finite limits of energy production from the pyruvate: lactate system and its feedback on aerobic energy supply (Wenger & Reed, 1976) appears to restrict prolonged activity. Nagle et al. (1970) investigated lactate accumulation during runs of 64 to 89 percent of maximum oxygen uptake. The untrained subjects demonstrated higher blood lactate levels for the same work intensity (as also shown by Wasserman et al. [1967]) as compared to the trained sub- jects. This again suggests'that the AT may limit muscular activity as a result of anaerobiosis. Costill (1970) was the first investigator to apply the AT to distance running. ' As might be predicted from previous studies, increased distance produced, decreased steady-state blood lactate levels. The limited energy supply of anaerobic metabolism and discomfort from tissue acidosis (Simonson, 1971) probably determines the optimal running speed for a given race and therefore blood lactate level. The relationship of work intensity above the AT to oxygen uptake time course to steady-state was investigated by Whipp and Wasserman 17 (1972). A slower rise to oxygen uptake steady-state was observed in a l l instances for work intensity above the AT. It was also shown that the trained individual had a higher level of work intensity before anaerobic energy supply started. More recently, Whipp et al. (1979) utilized first order kinetics to demonstrate the oxygen uptake rise to steady-state at subthreshold exercise (time constant about 45 seconds). However, depending on the type of suprathreshold exercise (ramp., sinusoid, or square wave) a two- component rise to steady-state was only occasionally noted. Discrep- ancies between individuals suggested that a two-component or delayed rise is not necessary for suprathreshold activity. The concept of continued anaerobic activity and removal of lactate during submaximal exercise was reviewed by Hermansen and Stensvold (1972). They failed to show lactate production for individuals at a work intensity below 60-80 percent maximum oxygen uptake (normally termed the AT). However, observations during exercise, where blood lactate is produced, showed that the major area for lactate oxidation is in skeletal muscle. Graham (1978), in a comprehensive review of lac- tate changes during exercise, showed that lactate may be produced in muscle but does not necessarily diffuse into the blood, thereby masking anaerobic activity. This suggests lactate's continual oxidation in muscle (active or inactive fibers). Wasserman et al. (1973) summarized breath-by-breath non-invasive techniques for detecting the AT. A most significant result of the study was that for non-invasive AT determination, a one minute work increment rate was found to be optimal for showing the change in metabol- ism at the start of anaerobiosis. This permits stress testing duration 18 to be kept at a minimum. Reproducibility of the AT was shown to be exact over one hour, four hour, one week and nine month intervals. Breath-by-breath analysis (Wasserman et al. [1973]) also solved a major problem of AT detection. Hyperventilation may obscure the AT when observing expired volume or C O 2 . Observation of end-tidal oxygen and carbon dioxide eliminates the chance of misinterpretation. Koyal et al. (1978) researched the feasibility of using oxygen pulse in determining the AT. In a very restricted sample (maximum oxygen uptake less than 3.75 liters per minute), they observed that the curvilinear plateauing of oxygen pulse coincided with the AT. The leveling of oxygen pulse iridicatesvimpending maximum oxygen uptake. An important change in testing technique of the AT was researched by Volkov et al. (1975). He utilized the Excess C O 2 ( E X C C O 2 ) concept of Issekutz and Rodahl (1961) to determine the AT during a speed increase treadmill protocol. The result was a running speed ( V T A M) a t which the AT occurred. Volkov et al. (1975) suggested that this AT speed could be used as an index of running efficiency. Application of the AT to distance running was investigated by Weiser et al. (1978), Sucec (1979) and Farrell et al. (1979). Sucec (1979) used the AT, expressed as milliliters oxygen per kilogram per minute, in a regression equation to predict one and two mile times (the other regression factors were percent body fat, running efficiency, oxygen debt, lean body weight, and maximum oxygen uptake). Correlations of 0.98 and 0.91 were calculated for the one and two mile times respee- t ively. Farrell et al. (1979) determined the running speed at which the "onset of plasma lactate accumulation" (OPLA) occurred. This speed and 19 mean marathon speed were correlated significantly at r=0.98. Mean marathon pace was 0.28 miles per hour above the mean treadmill pace at OPLA. Weiser et al. (1978) also applied this concept and showed a correlation of 0.92 (p < 0.001) for 3.2 kilometer race pace-and treadmill speed at the AT. Wasserman's continued basic AT research (Wasserman et al. 1975) demonstrated the involvement of the carotid body: in"metabolic responses - = during exercise. . The carotid body appears to be the mediator for ventilatory change for suprathreshold activity to maintain blood homeo- stasis. This respiratory compensation is the major factor stabilizing metabolic acidosis. These findings also support the use of non-invasive measurements for AT determination. Whipp's model (Whipp, 1977) of hyperpnea during exercise also used the AT as a division of exercise intensity for determining ventilatory control. The carotid bodies seem to be the main mediators of control for suprathreshold work intensity. Subthreshold mediation of hyperpnea seems to be much more complex (as reviewed by Whipp [1977.]). AT determination for three different modes of exercise was analyzed by Davis et al. (1976). Similar results for maximal oxygen uptake and percent of maximum at the AT were obtained for treadmill walk/run exer- cise and cycling. Significantly lower results were obtained in a l l instances for arm cranking. Their results also show that the AT is reproducible for their three exercise protocols. Wiswell et al. (1979) also investigated the relationship between the AT calculated for a bicycle ergometer and a treadmill. For each modality, oxygen uptake at the AT and the maximum oxygen uptake were significantly correlated, but the AT (expressed as a percent of maximum 20 oxygen uptake) for each exercise was significantly different (p :< 0.01). This suggests that, similar to maximal oxygen uptake (Str̂ mme et al., 1977; McKay & Bannister, 1976), the AT may be exercise specific, as suggested by Davis et al. (1976). However, Stamfor et al. (1978) showed that for one- versus two-legged cycling, the AT occurs at the same relative percent of maximum 0 2 uptake, though at a lower absolute work load. Maximum oxygen uptake was lower for one-legged cycling. These findings suggest that the AT and.maximum oxygen uptake may be influenced differently under the same conditions. MacDougall (1977) investigated the different training techniques of athletes and their AT. His observation suggests that the longer distance trained athletes have a higher AT. He also illustrates a hypo- thetical example of two identical athletes, except for different ATs, who run a marathon. The higher AT individual would have a significant advantage in supplying aerobic energy requirements that could be equated to distance advantage if constant stress to the cardiovascular system was maintained. Comparison of sprinters and endurance runners are described by Roberts et al. (1979). The sprinters exhibited: 1. lower maximum oxygen uptake, 2. lower AT (percent maximum oxygen uptake), 3. lower oxygen uptake at the AT, 4. lower muscular capillarization, and 5. higher percent fast twitch fiber composition. These data suggest that the sprinters have lower endurance capacity, especially when considering the AT and capillarization. However, com- parison of the AT and muscle fiber composition by Green et al. (1979) 21 showed no correlation between the two, thereby limiting conclusions about AT and muscle fiber composition. No muscular sites were reported in this abstract. Davis et al. (1979a, b) investigated the effect of endurance cycle ergometry training on maximum oxygen uptake and the AT for middle-aged men. Both significantly increased over the nine week program. Again this suggests increased AT with endurance type training. Weltman et al. (1978) tested the use of the AT as a measure of submaximal fitness. They observed that the individuals with a high oxygen uptake at metabolic acidosis had: 1. a faster rate to steady-state oxygen consumption, 2. a lower steady-state oxygen uptake, and 3. a faster return to resting values after exercise. These findings are in agreement to those of Whipp and Wasserman (1972). The use of heart rate as a training index was investigated by. Katch et al. (1978). These researchers suggest that the use of the relative percent of maximum heart rate concept is not a good training concept when considering whether or not an individual is producing lac- tate. Individuals appear to have different heart rates corresponding to their AT, therefore caution is stressed until the AT has been deter- mined . Patton et al. (1979) also investigated heart rate and its relation- ship to the AT. Their data suggest that heart rate does not vary between individuals (trained or untrained) at their AT. However, their heart rates at the AT were higher compared to Wyndham et al. (1965) and Wasserman et al. (1973). Ivy et al. (1979) examined the effect of substrate availability 22 on the AT. Increased blood glucose had no effect on the AT. Increased blood free fatty acids significantly lowered the AT and absolute blood lactate. This has definite implications in calculation of the AT and Ivy suggests that standards should be adopted for AT determination. Pendergast et al. (1979) compared performance on an arm crank exercise between kayakers and sedentaries. Kayakers were observed to have higher absolute ATs but not relative ATs (they also had higher maximum oxygen uptake). Their methodology of determining the AT con- sisted of separated exercises at different work loads for different time durations. This resulted in an early.lactate release for some sub- threshold exercises that lasted for :more than thirty seconds. .They suggest that this lactate release may be used with the AT to evaluate muscle training. Kindermann et al. (1979) analyzed the aerobic-anaerobic transition with reference to the AT and blood lactate concentrations. They suggest three categories for this transition as a result of their investigations. This classification system includes: i . The Aerobic Threshold (blood lactate less than 2 mmol/1, similar to the AT) i i . The Aerobic-anaerobic Transition (blood lactate 2 to 4 mmol/1) i i i . The Anaerobic Threshold (greater than 4 mmol/1 blood lactate). These investigators found that under conditions of the Aerobic Threshold, activity could be maintained format least two hours. The Aerobic-anaerobic Transition period'of activity could be maintained for one hour. For conditions of the 'Anaerobic Threshold1 only periods of exercise less than an hour in duration could be maintained. The AT has been applied to many diverse testing situations. The majority seem to be concerned with very specific but unrelated areas of application. .Research of the AT is needed to explain the conclusions of these studies. This would allow applied research to progress with a sound knowledge base. CHAPTER 3 METHODS AND PROCEDURES Subj ects Twenty male subjects were selected for t h i s study from volunteers from the University of B r i t i s h Columbia student population. The p a r t i c i p a n t s were subj e c t i v e l y chosen (from analysis of t h e i r a c t i v i t y patterns) to achieve a continuum of Anaerobic Threshold (AT) l e v e l s . Testing Procedures The t e s t i n g format consisted of two sessions. During the f i r s t week, height, weight, anaerobic threshold speed (V,j,^). arid maximum oxygen consumption ( V O 2 max) were determined for each subject. Resting oxygen uptake ( V O 2 rest) and recovery oxygen uptake a f t e r the set t r e a d m i l l run were determined during the second week. V O 2 max and V were determined using a continuous t r e a d m i l l protocol. As a warm-up, each subject walked on the t r e a d m i l l at 3.5 miles per hour for ten minutes. Subsequently, the t r e a d m i l l was set at 4.0 miles per hour and then increased one-half mile per hour at the end of each minute u n t i l v o l i t i o n a l fatigue. Heart rate was monitored by d i r e c t ECG u t i l i z i n g an Avionics 4000 cardiograph with o s c i l l i s c o p e and ST depression computer and display. Expired gases were continuously sampled and analyzed by a Beckman Meta- b o l i c Measurement Cart (BMMC) interfaced into a Hewlitt Packard 3052A 24 25 Data Acquisition system for fifteen second determination of respiratory gas exchange variables. Maximum oxygen consumption was determined by averaging the highest four consecutive fifteen second oxygen uptake values. The anaerobic threshold speed was determined by examining excess C02 elimination (Volkov et al., 1975). The determination of the AT was consistent with the definition by Wasserman et al. (1964). In order to dichotomize;the subjects into a low and high V grouping a median speed (V^g^) f° r t n e twenty Vmll, scores was calculated as 7.25 miles per hour. TAM Resting oxygen consumption was determined during a ten minute sit- ting period at the start of the week 2 assessment. Each subject then walked on the treadmill at 3.5 miles per hour for five minutes. After the warm-up, each subject ran at for ten minutes, during which time expired gases were continuously monitored by the aforementioned systems. At the completion of the ten minute run, each subject sat until he either returned to his V02 rest (minimum time sitting was set at twenty minutes) or had recovered for thirty minutes. Data Analysis The last four oxygen uptake values were averaged during the median speed run to determine time zero oxygen uptake for recovery. This value, plus each fifteen second value of oxygen uptake during recovery were f i t with a double exponential equation of the form: -ait -a 2t V02 = â e + a2e + a3 where V02 = oxygen consumption at time 't' a 1 = alactic linear parameter a± = alactic non-linear parameter ' \ 26 a2 = l a c t i c l i n e a r parameter 0̂ 2 = l a c t i c non-linear parameter a3 = asymptotic VO2 rest The U.B.C. Computing Centre's program P:3R (Dixon & Brown, 1979) was u t i l i z e d for t h i s computation. I n i t i a l non-linear parameters were based on Henry and DeMoor (1950). Each equation was integrated over t h i r t y minutes to determine.total oxygen debt, a l a c t i c oxygen debt, and l a c t i c oxygen debt (see Appendix A). Each i n d i v i d u a l ' s l a c t i c oxygen debt was divided by the a l a c t i c oxygen debt to give the l a c t i c : a l a c t i c r a t i o ( r a t i o debt). Time to r e s t i n g oxygen uptake (recovery time) a f t e r exercise was determined by observation of four consecutive recovery readings equiv- alent to each subject's i n i t i a l r e s t i n g oxygen uptake. Total oxygen debt and r a t i o debt for subjects with anaerobic threshold speeds above (group H-V ) and below (group L -Vrj,^j) the median speed were analyzed for d i f f e r e n c e between means by the U.B.C. Computing Centre program MULTIVAR (Finn, 1977). S i g n i f i c a n t (p < .05) multivariate F (Hotelling T 2) was followed by u n i v a r i a t e F to determine where s i g n i f i c a n c e occurred. A l a c t i c oxygen debt and l a c t i c oxygen debt were s i m i l a r l y analyzed. Co r r e l a t i o n c o e f f i c i e n t s (r) were calculated f o r the oxygen debt va r i a b l e s and V_.,„ for the H-V_._, and L-V_... groups by the U.B.C. Comput-TAM TAM TAM J ing Centre program SIMCORT (Le, 1979). Each c o e f f i c i e n t was analyzed for s i g n i f i c a n c e from zero. CHAPTER 4 RESULTS AND DISCUSSION Results The twenty subjects were tested, as per the schedule of week 1. One subject (RR) was added to the twenty after the median speed deter- mination to attempt to further complete the AT continuum between 5 and 6.5 miles per hour. Their results are summarized in Table 1. Indi- vidual anaerobic threshold curves and determination of V ̂  appear in Appendix B. Oxygen uptake curves during recovery in week 2 appear in Appendix C. Subject JO experienced coughing during the recovery period there- fore his recovery data are not included in this study. Double exponential equations calculated for each subject appear in Table 2. These functions are represented as a continuous line on each recovery curve in Appendix C. The computer program P:3R did not produce a resting asymptotic value for subjects ML, BV, RF and DW. This appears to be due to insufficient data points at base line oxygen consumption. Therefore, a lower limit for this baseline was set as 0.225 liters of oxygen per minute. This value appears to be a limit for V02 rest. The resulting equations are included in Table 2 and Table 3. The computer program could not initially calculate a double exponential equation for subject GS. Observation of his recovery curve data points showed that three points (at 1.0, 1.24 and 1.50 minutes) seem to deviate from the regular pattern seen in a l l subjects. Removal 27 TABLE 1 Individual Subject Characteristics Age Height Weight VTAM , ™ 2 max , (ml/kg/min.) (mph) Subject (years) (cm) (kg) CN 22 175.6 77.9 4.0 42.6 ML 25 174.0 82.7 5.0 46.6 RR 24 188.4 95.5 6.0 52.2 TB 21 179.5 71.1 6.5 46.3 DG 24 174.0 60.5 6.5 59.2 DD 24 179.1 75.5 6.5 49.1 BV 21 184.5 88.5 6.5 67.9 GS 22 188.7 99.4 6.5 46.6 DA 23 175.6 77.9 7.0 58.5 RF 24 166.1 62.5 7.0 55.4 HB 20 170.2 65.0 7.0 50.0 AB 21 181.1 74.5 7.5 62.5 AO 26 174.9 63:4 7.5 58.6 GT 24 176.7 78.4 7.5 57.0 DH 21 179.3 69.3 8.0 57.4 JL 22 177.5 67.1 8.0 64.8 JO 24 180.8 79.0 8.0 69.2 DM 23 174.9 63.3 8.5 76.2 DW 24 178.6 79.8 8.5 52.0 SP 21 182.1 68.0 10.5 68.0 JH 23 176.4 71.0 11.0 72.7 X 22.8 178.0 74.8 7.3 57.8 SD 1.60 5.37 10.57 1.5 9.4 29 TABLE 2 Individual Double Exponential Equations for Subjects in Group L-V^^. V02 rest T̂AM Subject Exponential Equation (1/min.) 4.0 CN 3.269e" 1 , 0 7 6 t + 1.221e"*168t + .441 .317 5.0 ML 2.923e~1'140t + .181e"'P97t + .225 .273 6.0 RR 3.472e" 1 , 1 6 9 t + .151e""075t + .265 .320 6.5 TB 2.453e" 1 , 5 1 0 t + .391e""206t + .309 .280 6.5 DG 2.417e" 1 - 4 1 1 t + .407e~"185t + .253 .240 6.5 DD 2.985e _ 1'° 9 0 t + .285e""103t + .278 .291 6.5 BV 2.949e" 1 - 0 2 0 t + .210e"'038t + .225 .369 -2 4̂ 41- - 3391-6.5 GS 2.595e ^ - H ^ z + i.056e + .310 .291 7.0 DA 3.228e _ 1' 1 6 8 t + .132e~"079t + .408 .349 7.0 RF 2.038e" 1 , 2 6 4 t + .063e""160t + .225 .223 7.0 HB 1.921e" 1 , 7 8 7 t + .727e~*406t + .277 .259 30 TABLE 3 Individual Double Exponential Equations for Subjects in Group H-V m A„ ^ TAM V02 rest VTAM S u D J e c t Exponential Equation (1/min.) 7.5 AB 2.342e _ 1' 1 6 9 t + .106e~"°32t + .268 .312 7.5 AO 1.181e" 6 , 6 9 0 t + 1.143e~'751t + .289 .286 7.5 GT .609e" 9' 5 6 2 t + 1.941e~ 1 - 1 5 3 t + .272 .246 8.0 DH 1.992e" 1 , 3 9 3 t + .476e"'419t + .273 .230 8.0 J L 2.713e"1'160t + .165e"-068t + .217 .230 8.5 DM 1.515e" 4 , 0 8 3 t + .953e"-709t + .210 .211 8.5 DW 3.189e" 1 , 2 3 6 t + .137e""°23t + .225 .301 10.5 SP 2.052e _ 1" 8 2 0 t + .186t"' 2 2 5 t + .302 .318 -? Q17t- - 559t-11.0 JH 1.729e + .611e ' 3 3 ) , z + .278 .271 31 of the data points at 1.25 and 1.50 minutes allowed for proper curve f i t - ting. Therefore, his results are calculated without these two data points. Each equation was integrated over thirty minutes to determine alactic, lactic, and total oxygen debts (Appendix A). The ratio of lactic to alactic debt (debt ratio) was then calculated for each subject. These results appear in Table 4 and Table 5. Graphs of these results versus individual anaerobic threshold speeds ( V T A M) a r e represented in Figures 1 to 4. It was not possible in this study to determine exact recovery time. The fluctuation of the fifteen second values for oxygen uptake (Appendix C) prevented the attainment of four consecutive equivalent values of resting oxygen uptake. The asymptotic value calculated by the computer program P:3R never exactly matched the resting value determined, there- fore comparison of these two values would not be valid. Thus,, hypotheses 5, 10, and 15 were not tested. TABLE 4 Individual Alactic, Lactic, Total and Ratio Oxygen Debts for Group l - ^ ^ Ratio Alactic Lactic Debt Total Debt Debt (Lactic/ Debt VTAM Subject (liters) (liters) Alactic) (liters) 4.0 CN 3.04 7.22 2.38 10.26 5.0 ML 2.56 1.76 0.69 4.33 6.0 RR 2.97 1.80 0.61 4.77 6.5 TB 1.62 1.89 1.17. 3.52 6.5 DG 1.71 2.19 1.28 3.90 6.5 DD 2.74 2.64 0.97 5.38 6.5 BV 2.89 3.76 1.30 6.65 6.5 GS 1.07 3.12 3.92 4.19 7.0 DA 2.76 1.51 0.55 4.28 7.0 RF 2.19 0.39 0.24 2.00 7.0 HB 1.07 1.79 1.66 2.87 33 TABLE 5 - Individual Alactic, Lactic, Total and Ratio Oxygen Debts for Group H-V . Ratio Alactic Lactic Debt Total Debt Debt (Lactic/ Debt VTAM Subject (liters) (liters) Alactic) (liters) 7.5 AB 2.00 2.04 1.02 4.05 7.5 AO 0.18 1.52 8.44 1.70 7.5 GT 0.06 1.68 27.18 1.75 8.0 DH 1.43 1.14 0.79 2.57 8.0 JL 2.34 2.11 0.90 4.45 8.5 DM 0.37 1.34 3.81 1.72 8.5 DW 2.58 2.97 1.15 5.55 10.5 SP 1.13 0.83 0.73 1.95 11.0 JH 0.59 1.09 1.85 1.69 10 -J Total Debt (liters) 9 8 J 7 -\ 6 J 5 J 4 J 3 J 2 J o o o o o o o o o O Individual scores ® 2 scores O -T T 8 n 1 r 9 10 MED Figure 1. Graph of Total Debt and Individual V, O O 1 11 VTAM(mph) TAM O Individual Scores 4 H A l a c t i c Debt ( l i t e r s ) 3 H O O O O O O 2 H 8 o i H o o -7?- o o V MED Figure 2. Graph of A l a c t i c Debt and Individual V TAM 10 o TAM 11 (mph) O Individual Scores 7 i L a c t i c Debt ( l i t e r s ) 6 5 H 4 1 2 H 1 H O o o o o o o o o o o 8 o o o o r 5 10 MED Figure 3 . Graph of L a c t i c Debt and Individual V, TAM O O 11 V T A M(mph) O Individual Scores ® 2 Scores 4 Scores Ratio Debt 30 H 25 -\ 20 H 15 10 H O 11 0 7 7 ^ o o © 8 o o —I— o o 10 MED Figure 4. Graph of Individual Ratio Debt and V TAM O O TAM (mph) CO 38 Individual oxygen debt values were averaged for those subjects in group L-V and in group H-V . These values appear in Table 6. TABLE 6 Means of Total, Alactic, Lactic and Ratio Debts for Groups L-V T A M and H-V Total Debt Ratio Debt Alactic Debt Lactic Debt Group Mean SD Mean SD Mean SD Mean SD L-V..,, 4.74 2.33 1.34 1.04 2.19 0.77 2.55 1.78 TAM H-V„ 1 U 2.83 1.43 5.10 8.65 1.19 0.95 1.64 0.65 TAM The difference between means for total debt and ratio debt for the two groups show a significant T 2 statistic (p < .05). Univariate t values subsequently calculated for each dependent variable show this significance to be attributable to the difference between total debt means only (p <-:.01). Despite the large difference in means for ratio debt, significance was not obtained due to the large variance in group ~̂̂ TAM ( D r o u 8 n t about by subjects AO and GT). These results are sum- marized in Table 7. These results indicate rejection of the null hypothesis and there- fore acceptance of hypothesis 1; that subjects in group H-V_^ accumu- late a lower oxygen debt compared to those subjects in group ^-V_^. However, the statistical calculation does not indicate acceptance of hypothesis 4; that there is a difference between subjects in groups H-Vm.„, and L-V m A„ in the calculation of a debt ratio (lactic debt/ TAM TAM alactic debt). 39 TABLE 7 Multivariate Analysis of Dependent Variables Total Debt and Ratio Debt Dependent Variable T 2 Total Debt 9.78 .006 4.84 .022 Ratio Debt 1.43 .248 The difference between means for alactic and lactic debt for the two groups also exhibit a significant Hotelling T (p < .01). Univar- iate t values calculated for each dependent variable show this signifi- cance to be attributable to both the difference between alactic debt means (p < .01) and lactic debt means (p < .05). These results are summarized in Table 8. These results indicate acceptance of hypotheses 2 and 3; subjects in group H-Vm,., accumulate lower lactic and alactic debts than subjects ° TAM J in group L-V T A M. TABLE 8 Multivariate Analysis of Dependent Variables Alactic and Lactic Debts Dependent Variable T 2 p< t p< Alactic Debt 12.1 .003 6.02 .01 Lactic Debt 4.6 .047 Pearson correlation coefficients calculated for groups H-V and 40 L-V-.,,, for V_.., with total, ratio, alactic, and lactic debts appear in TAM TAM r r Tables 9 and 10. TABLE 9 Correlation Coefficients for Subjects in Group L-V, TAM Total Debt Ratio Debt Alactic Debt Lactic Debt v TAM -.767* -.210 -.506 -.729* *Significantly different from zero at p < .05. The results in Table 9 indicate acceptance of hypotheses 6 and 8; subjects in group L-V^^ have a negative linear relationship between total and lactic debts and V m.„. These results do not indicate accep- TAM tance of hypotheses 7 and 9, therefore a decreasing function between ratio and alactic debts and V_._- is not evident. It is apparent from TAM observation of Figures 2 and 4, that both alactic and ratio debts are unrelated to V_,̂ . TABLE 10 Correlation Coefficients for Subjects in Group H-V Total Debt Ratio Debt Alactic Debt Lactic Debt v TAM -.279 -.375 -.478 -.098 The probability that the correlation coefficients for group H _ V T A M (Table 10) are different from zero are as.follows (Rohlf & Sokal, 1969): 1. Total debt (r = -.279) .4 < p < .5 2. Ratio debt (r = -.375) .2 < p < .4 41 3. Alactic debt (r = -.478) .1 < p < .2 4. Lactic debt (r = -.098) .5 < p < .9 These probabilities suggest that there is not a linear relationship between total, ratio, and lactic debts and Vm,w. The correlation coef- TAM ficient for alactic debt and V_... is very close to the confidence limit TAM J (p < .05) to reject the null hypothesis, suggesting a linear relation- ship. However, as the correlation coefficient only accounts for 23% of the variance of the sample, there is strong evidence to suggest that there is also no linear relationship between alactic debt and As a result, the null hypothesis is not rejected and remains as stated in hypotheses 12, 13, and 14; there is no decreasing.^function between total, alactic, and lactic debts and V_... in group H-V_A... ' TAM TAM Discussion The computation of double exponential equations to describe recovery oxygen consumption is consistent with the theory of decreasing payment (exponential decay) of alactic and lactic debts. The equations calculated (Tables 2 and 3) are similar to those reported by Henry and DeMoor (1950). The non-linear (a ) and linear (a^ parameters are of the same order of magnitude, except for those subjects in this study with small fast recovery component (subjects AO, GT and DM). Total debt, for a l l individuals, falls within limits of previous studies (Hill et al., 1924; Margaria et al., 1933; Henry & DeMoor, 1950; Knuttgen, 1962). Comparison of computer calculated asymptotic V02 rest values and determined V02 rest values reveal similar results. However, subjects CN, BV, and DW exhibit differences greater than sixty milliliters of 42 oxygen per minute. Subject CN experienced difficulty in completing the 10-minute run, so that an elevated asymptotic V O 2 rest is normal (Hill et al., 1924). The large variation in the resting data of subjects BV and CN may be attributed to the fact that i n i t i a l resting oxygen consump- tion values are not indicative of their true resting state, and secondly, the lower limit of 0.225 liters of oxygen per minute set for the computer may be low. The resulting integration of the equations to determine contribu- tions to the total debt in this investigation, indicates that the pro- cesses involved are not as simple as originally proposed by Margaria et al. (1933). Calculation of debt ratios from the data reported by Mar- garia et al. (1933), Henry and DeMoor (1950), and Knuttgen (1970), show a range from 0 (mildest exercise) to about 2. These ratios do not compare with the ratios of 8.44, 27.18, and 3.81 of subjects AO, GT and DM respectively. Subjects in H-V_,̂  who were working at a mild inten- sity of exercise did not exhibit ratios of 0. At these low intensities of exercise, Berg (1947) argues that the recovery processes are better explained by a single exponential equation, thus supporting H i l l et al. (1924) and Margaria et al. (1933). If this is true, single exponential equations should better describe the recovery curves in group H-V^^. Post hoc analysis of recovery curves in group H-V show a mean residual sum of squares of .79 (SD=-56) for a single exponential curve f i t (computer program P:3R [Dixon & Brown, 1979]). The double exponential curves calculate a mean residual sum of squares of .68 (SD=.37). A correlated t-test of significance show these means to be significantly different at a level of .05. This suggests that the double exponential equation better describes recovery oxygen data points in group This r e s u l t supports evidence by Knuttgen (1970), that t h i s slow recovery phase does e x i s t . This phase may be responsible for a return of ". . . i n t e r r e l a t e d metabolic, thermal, e l e c t o l y t i c and hormonal changes which the body undergoes during exercise . . . " t o non-exercise l e v e l s . P i i p e r and S p i l l e r (1970) also observed t h i s slow phase i n in t a c t dog gastrocnemius muscle stimulated to do exercise that did not produce blood l a c t a t e i n excess of r e s t i n g values. They came to a s i m i l a r conclusion i n t h e i r i n v e s t i g a t i o n . During oxygen d e f i c i t formation, both anaerobicLglycolysis and stored high energy phosphates could be the energy sources. During the repayment phase (oxygen debt), these energy sources would be replenished at a rate dependent on the p h y s i o l o g i c a l make-up and the t r a i n i n g l e v e l of the i n d i v i d u a l . This might account for some of the v a r i a b i l i t y i n debt r a t i o scores. Results of t h i s study i n d i c a t e that recovery oxygen consumption i s adequately described by a double exponential equation. However, to r e f e r to these two phases as t r a d i t i o n a l l a c t i c and a l a c t i c components may be questionable. The remaining discussion w i l l use a l a c t i c and l a c t i c terms to r e f e r to the fast and slow recovery phases r e s p e c t i v e l y . The r e l a t i o n s h i p between anaerobic threshold speed (V^,^) and recovery oxygen consumption i s demonstrated i n the r e s u l t s of the hypo- theses tested. The s i g n i f i c a n t d i f f e r e n c e f o r t o t a l debt means for the two groups i s consistent with observations of Wasserman et a l . (1965) and Wasserman et a l . (1967). The non-significant l i n e a r r e l a t i o n s h i p (r=-.279) calculated for group H-V_^. suggests that running speeds below V_ A M r e s u l t i n a r e l a t i v e l y stable oxygen debt. The s i g n i f i c a n t 44 negative linear relationship (r=-. 767) calculated for group -̂V ^ indicates that running at increasing speeds above V results in JL Jr_C*i increasing total debt. The compartmentalization of total debt, into alactic and lactic debts, also produces a significant difference between the two debt com- ponents of each group (Tables 7 and 8). The only significant negative ; correlation calculated was for lactic debt and V_„, for group L-V < w TAM s v TAM (r=-.729). These results suggest that the increasing total debt for group L-V,-,̂  is a result of increasing lactic debt. This may be attri- butable to increased blood lactate levels as suggested by Margaria et al. (1933), Henry and DeMOor (1950), Wasserman et al. (1967), and Knuttgen (1970). Linear relationships were not observed between alactic debt and V„.„ in group L-V_.„ or between alactic and lactic debts and V m.„ in TAM r TAM TAM group H-Vrj,^. Therefore, the relatively stable alactic component in each group, and the relatively stable lactic component in group ̂ -V suggests the significant difference between debts is a result of running above or below V . , „ . This implies that V_,„ is also critical in deter-TAM r TAM mining alactic and lactic debt components for a constant running speed. Oxygen debt may be used as a criterion of fatigue and therefore used as a measure of work intensity (Simonson, 1971). The relationship between oxygen debt and V_,w in this study shows that Vm..„ is useful in J b TAM TAM determining primarily aerobic work intensity. Its relationship to increased anaerobic activity and resultant metabolic acidosis through increased utilization (recruitment) of fast twitch muscle fibers and/or increased anaerobic activity in slow twitch muscle fibers, may be very important in determining running speed for a given distance. 45 This relationship has recently been investigated by Weiser et al. (1978), Farrell et al. (1979), and Sucec (1979). These investigators illustrated very significant correlations between onset of anaerobic metabolism and race time. This gives strong evidence to the role of V m„, in determining efficient running speed for a given distance. TAM o r . o In conclusion, the anaerobic threshold speed (V ) appears to be the critical speed in determining total oxygen debt in a running exer- cise above V m <„. V_„, also appears to be critical in determining the TAM TAM *^ 6 size of the debt components, alactic and lactic. Further investigation is needed to clarify the mechanisms involved in determining the total debt and its components. Once this is accomplished, the effect of training techniques on V_,_, and the onset of anaerobic metabolism will b ^ TAM be elucidated. CHAPTER 5 SUMMARY AND CONCLUSIONS Work intensity variation has been shown to change oxygen debt after exercise (Hill et al., 1924; Wasserman et al., 1965). Knuttgen (1962) noticed a "critical level" of work intensity which seemed to drastically affect oxygen debt size. This level of work intensity is associated with the onset of metabolic acidosis termed the Anaerobic Threshold (Wasserman et al., 1964). This study attempted to clarify the relation- ship between anaerobic threshold and oxygen debt after a set treadmill run. Twenty male university students were chosen to achieve a continuum of anaerobic threshold levels. Week 1 testing sessions determined each subject's anaerobic threshold running speed (V-^) using a continuous treadmill protocol. ^AM W a s identified by analyzing expired V02 and VC02 (calculated to excess C02 values) every fifteen seconds (Volkov et al., 1975). x̂AM s c o r e s r a n 8 e d from 4.0 miles per hour to 11.0 miles per hour. During the second testing session, each subject ran at the predeter- mined median speed of 7.25 miles per hour for ten minutes, which separated the subjects into two groups: 1. Group H-V —those subjects running below their and 2. Group L-V_.w—those subjects running above their V_..r. Each subject's expired gases during the exercise and recovery stages were analyzed every fifteen seconds by a Beckman Metabolic Measurement Cart 46 47 interfaced into a Hewlitt Packard 3052A data acquisition system. Each individual's recovery oxygen consumption data were described with a double exponential equation by a computer. The resulting equation was integrated to determine total oxygen debt and its alactic and lactic components. The ratio of lactic/alactic debts was also calculated. Analysis for a significance between means (Hotelling T2) for groups H-Vm.„ and L-Vm,w for the debt variables revealed significant (p < .05) TAM TAM & r differences for total, alactic, and lactic oxygen debts. No difference was evident for the ratio of lactic/alactic debt. The subjects in group L - V T A M had larger oxygen debts and debt.components compared with those sub- jects in group H-Vm,.,.. These results suggest that V m,„ is critical in & r TAM TAM determining the oxygen debt after a run. Analysis for a linear relationship between V-^j and oxygen debt for each group showed total oxygen debt (r=-.767), and lactic debt (r=-.729) to be significantly (p < .05) linearly related to V in group L - V T A M only. This suggests that the faster the running speed is above an individual's Vm,„, the larger the total debt. This increasing debt is TAM & • a result of the increasing lactic debt. This was not evident in group H"VTAM- The accumulation of an oxygen debt is indicative of fatigue (Simonson, 1971). The fact that V_._, is a critical factor in determining ' TAM oxygen debt suggests that work above this point results in the onset of metabolic acidosis, which limits the optimal running speed for a given distance. These findings support the evidence by Farrell et al. (1979) and Weiser et al. (1978) that the onset of metabolic acidosis is related to average race running speed. 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Wasserman, K., Burton, G. G., & van Kessel, A. L. The physiological significance of the "Anaerobic Threshold." Physiologist, 7_(3) : 279, 1964. 5.2 Wasserman, K., Burton, G. G., & van Kessel, A. L. Excess lactate con- cept and oxygen debt of exercise. J. Appl. Physiol., 2̂ 0(6): 1299- 1306, 1965. Wasserman, K., & Mcllroy, M. B. Detecting the threshold of anaerobic metabolism in cardiac patients during exercise. Amer. J. Cardiology, 14: 844-852, 1964. Wasserman, K., & Whipp, B. J. Exercise physiology in health and disease. Amer. Rev. Resp. Disease, 112: 219-249, 1975. Wasserman, K., Whipp, B. J., Koyal, S. N. , & Beaver, W. L. Anaerobic threshold and respiratory gas exchange during exercise. J. Appl. Physiol., 35(2): 236-243, 1973. Wasserman, K., Whipp, B. J., Koyal, S. N., & Cleary, M. G. Effect of carotid body resection on ventilatory and acid-base control during exercise. J. Appl. Physiol., 39(3): 354-358, 1975. Wasserman, K., van Kessel, A. L., & Burton, G. G. 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Physiol, eiri schl. Arbeitsphysiol., 2A_: 18-23, 1967. Wiswell, R. A., Girandola, R. N., & de Vries, H. A. Comparison of anaerobic threshold on bicycle and treadmill. Med. Sci. in Sports, 11(1): 88, 1979. (Abstract) Wyndham, C. H., Seftel, H. C., Williams, C. G., Wilson, V., Strydom, N. B., Bredell, G. A. G., & von Rahden, M. J. E. Circulatory mechanisms of anaerobic metabolism in working muscle. S. Afr. Med. J. , _39_: 1008- 1014, 1965. Wyndham, C. H., Strydom, N. B., Williams, C. G., & von Rahden, M. A physiological basis for the 'Optimum' level of energy expenditure. Nature, 195: 1210-1212, 1962. APPENDIX A Sample Calculation of Oxygen Recovery Debts 54 55 Integration of the double exponential recovery curve allows calcu- lation of alactic, lactic, and total oxygen debts. Integration of an exponential function is determined by the formula: t r -ct, JQae dt = a -at a -a -a Integration of subject DH's equation . o o 0 -1.393t , _ ._, -0.419t 1.992e + 0.476e over thirty minutes would be: . 3 0 Alactic debt = / 1.992e 1 0 = 1.43 -1.393t dt = 1.992 -1.393(30) 1.992 -1.393 6 -1.393 Lactic debt 30 / 0.476e ' 0 1.14 -0.419t dt = 0.476 -0.419(30) e 0.476 -0.419 -0.419 Total debt = Alactic debt + Lactic debt = 1.43 + 1.14 = 2.57 Debt ratio = Lactic debt * Alactic debt = 1.14 * 1.43 = 0.79 APPENDIX B Anaerobic Threshold Curves to Determine Individual V 56 EcxCO-. (ml/kg/min) 26 H 24 20 16-H 12 8H AH i | i | i 1 1 1 r- 1 1 1 4 5 6 7 8 9 10 V T A M speed (mph) Figure 5. AT curve subject CN ExcC0 2 (ml/kg/min) 20. 18 16 14 12 _J 10 8 J TAM ~ i n — : — r 10 11 Speed (mph) Figure 6. AT curve subject ML ExcC02 (ml/kg/min) 28 24- 20- 16- X 12- 8- TAM ~~[ 1 1 9 10 Speed (mph) Figure 7. AT curve subject RR ExcCO 20 " (ml/kg/min) - 18 ~ 16 - 14 - 12 - 10 8 - 6 - . 4 - 2 - TAM 10 Speed (mph) Figure 8. AT curve subject TB ExcC02 (ml/kg/min) 1 8 - 1 6 - 1 4 - 1 2 - 1 0 - 8 - 6 - 4 - 0 4 5 6 7 TAM 8 9 10 11 Speed (mph) Figure 9. AT curve subject DG 62 r- o 4= D. e T3 ii CO 00 o 01 n XI 3 W 01 > 3 5 <u u 3 oo «-N CO C CN -a- CM o CN - ] — i 1 1 1 1 1 r- vO CM 00 -3- O CM 00 O _! CJ — a i-i x S 10 ExcC0„ (ml/kg/mln) 8 - 7 - 6 - 5 - 2 -J • * Figure 11. AT curve subject BV TAM 1 1 I 9 10 Speed (mph) ExcC02 (ml/kg/min) 32 - 28- 24- 20- 16- 12 - 4 5 6 7 8 9 10 V T A M Speed (mph) Figure 12. AT curve subject GS 20 ExcCO„ 18 H (ml/kg/mln) 16 H 14 12-̂ 10 J 8-J 4 J 2A T 8 TAM —' 1 10 Speed (mph) Figure 13. AT curve subject DA ExcCO„ 9-1 8" (ml/kg/min) 7 - 6 - 5 - 4- 3 H 2 H H Figure 14. AT curve subject RF TAM 10 Speed (mph) ExcC02 (ml/kg/min) 28 H 24 H 20 16 12 H 8-J 4-̂ "> r 5 10 TAM 11 Speed (mph) Figure 15. AT curve subject HB ExcCO- (ml/kg/min) 28- 26- 24- 20- 16 H 12 H 8 H 4 H T 5 n r 6 Figure 16. AT curve subject AB 10 11 12 Speed (mph) ON CO ExcC0 2 (ml/kg/min) - i 1 r 4 5 1 ' 1 r 6 7 8 V, 1 i — • — r - 1 — r - 1 — r 11 12 13 Speed (mph)-TAM Figure 17. AT curve subject AO ExcC02 (ml/kg/min) 28- 24 H 20 H 16-4 12-4 4-J i i « i — i — i — i — r 4 5 6 7 8 10 ~ ~ i — 1 — r 11 12 13 TAM Speed (mph) Figure 18. AT curve subject GT ExcCO„ 20 (ml/kg/min) 16- 14 H 12 io H 6H 4H 2 H Figure 19. AT curve subject DH TAM —r 10 -• n — n Speed (mph) ExcC02 (ml/kg/min) 18 16 14 H 12 H 10 -1 8H Figure 20. AT curve subject JL TAM T T 10 11 Speed (mph) 73 Q. e o> Cu CO o o 01 1— J - 3 03 01 • > U 3 U 5 01 u 3 00 o eg 00 /—> >_> •H C .-I 00 o u 20 4 ExcCO„ 18 -| (ml/kg/min) 16 -1 14 12 _ 10 _ 8 J 4 J • • • i—1—i—1—i—1—r 6 7 8 9 V TAM 11 12 I  1 1 13 14 Speed (mph) Figure 22. AT curve subject DM ExcC02 (ml/kg/min) 32 - 28 - 24 - 20 16 -\ 12 4 H Figure 23. AT curve subject DW TAM 10 11 Speed (mph) 36 H ExcCO- 32 H (ml/kg/min) 28- 24- 20- 16- 12-J 8 J 4-4 0 1 1 I ' 1 1 I 1 1 ' 1 >~ 5 6 7 8 9 10 , 11 4 Figure 24. AT curve subject SP TAM — ! — • — | — i — | — i — | 12 13 14 15 Speed (mph) 361 ExcC02 32 "i (ml/kg/min) 28- 24- 20- 16- 12- • • - • 1 — ' 1— 1 1 ' — I — ' — I — 1 — I — ' — I — r 7 8 9 10 11 12 13 V TAM ~I 1 1 r ~ 14 15 Speed (mph) Figure 25. AT curve subject DH APPENDIX C Individual Oxygen Recovery Curves 78 Figure 26. Recovery curve subject CN Figure 27. Recovery curve subject ML  Figure 29. Recovery curve subject TB 00  5H Time (min) Figure 31. Recovery curve subject DD Figure 32. Recovery curve subject BV  Figure 34. Recovery curve subject DA 5-4 vo2 (1/min) 4-4 3-4 2 J . I 8 10 12 14 16 18 Figure 35. Recovery curve subject RF ~i r 1 r 1 r 20 22 24 26 28 30 Time (min) CO CO  Figure 37. Recovery curve subject AB 5H 3-J 1 1 r 26 28 30 Time (min) 8 10 12 14 16 18 20 22 . 24 Figure 38. Recovery curve subject AO Figure 39. Recovery curve subject GT Figure 40. Recovery .curve subject DH 5 J o i 1 1 1——i 1 1——i 1 r 1 1 1 1 1 r 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Time (min) Figure 41. Recovery curve subject JL Figure 42. Recovery curve subject DM  5 -A Time (min) Figure 44. Recovery curve subject SP 5-] Time (min) Figure 45. Recovery curve subject JH


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