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Health-related physical fitness and its relationship to objectively measured physical activity in children 2007

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H E A L T H - R E L A T E D P H Y S I C A L F I T N E S S A N D ITS R E L A T I O N S H I P T O O B J E C T I V E L Y M E A S U R E D P H Y S I C A L A C T I V I Y I N C H I L D R E N by K A R E N A S H L E E M C G U I R E B.Sc . Kinesiology, University of Alberta A T H E S I S S U B M I T T E D I N P A R T I A L F U L F I L L M E N T O F T H E R E Q U I R E M E N T S F O R T H E D E G R E E O F M A S T E R OF S C I E N C E in T H E F A C U L T Y OF G R A D U A T E S T U D I E S (Human Kinetics) T H E U N I V E R S I T Y OF B R I T I S H C O L U M B I A August 2007 © Karen Ashlee McGuire , 2007 11 A B S T R A C T During chi ldhood, phys ica l activity (PA) builds the foundation for a healthy body and is an important determinant of chronic d isease risk. Recen t reports indicate that chi ldren in C a n a d a do not participate in sufficient amounts of P A for optimal health and wel l-being. Furthermore, certain ethnic groups may be at higher risk of developing chronic d isease due to extremely low levels of P A and physical f i tness. Literature delineating the relationship between P A and health-related physical f i tness in chi ldren is inconsistent and has been inhibited by P A measurement tools. Object ive measures of P A may overcome many of the limitations assoc ia ted with other P A measurement tools. The purpose of this investigation was to objectively measure habitual P A , examine dif ferences in P A and health-related physical f i tness between A s i a n and C a u c a s i a n chi ldren, and determine the relationship between P A and health-related physical f i tness. One-hundred seventy boys (n = 79) and girls (n = 91) in g rades 4 and 5 from five schoo ls in the Greater Vancouve r Reg ion participated. M e a s u r e s of body composit ion (Body M a s s Index and waist c i rcumference), vascu lar health (blood pressure), resting heart rate, musculoske le ta l f i tness (grip strength, s i t -and-reach, curl-ups and push-ups) cardiorespiratory f i tness (Leger shuttle run) and habitual P A (via accelerometry) were obtained over a 1-week per iod. Resu l ts indicated that boys participated in 134 minutes and girls accumulate 114 minutes of moderate-to-vigorous phys ica l activity ( M V P A ) per day. Only 30 minutes and 15 minutes per day were accumulated in bouts exceeding 5 minutes in duration in boys and girls respectively. During the school day the percentage of t ime spent in M V P A for recess , lunch hour and Phys ica l Educat ion c lass w a s 28%, 3 5 % and 1 3 % in boys and 18%, 2 7 % and 16% in girls. C a u c a s i a n girls accumulated more M V P A per day, had significantly higher counts per minute and had higher aerobic f itness than A s i a n girls (p<0.05). There w a s no signif icant dif ference in musculoskeleta l f i tness. C a u c a s i a n boys had significantly higher counts per minute, higher aerobic f i tness, and significantly higher musculoskeletal f i tness sco res (p<0.05) than A s i a n boys. Phys ica l activity did not significantly predict cardiorespiratory or musculoskeleta l f i tness in either boys or girls. Th is investigation demonstrated that phys ica l activity during the schoo l day w a s low. C a u c a s i a n boys and girls obtained higher P A and f i tness levels than A s i a n boys and girls. T h e s e findings suggest that all chi ldren may be at higher risk for health compl icat ions assoc ia ted with low levels of P A , especia l ly those of A s i a n ethnicity. T A B L E O F C O N T E N T S A B S T R A C T T A B L E O F C O N T E N T S LIST O F T A B L E S \ LIST O F FIGURES vi ABBREVIATIONS i: OPERATIONAL DEFINITIONS R E F E R E N C E S F O R O P E R A T I O N A L DEFINITIONS x A C K N O W L E D G E M E N T S x i C H A P T E R I Introduction C H A P T E R II Literature Review 2.1 Phys ica l Activity Pat terns in Chi ldren 2.1.1 Gene ra l Phys i ca l Activity Patterns 5 2.1.2 Gu ide l ines for Phys ica l Activity 7 2.1.3 Summary 10 2.2 Ethnicity, Phys ica l Activity and Phys ica l F i tness 10 2.2.1 Ethnic Dif ferences in Phys ica l Activity 11 2.2.2 Ethnic Dif ferences in Heal th-Related Phys ica l F i tness 12 2.2.3 Summary 12 2.3 Phys ica l Activity in Relat ion to Heal th-Related Phys ica l F i tness 12 2.3.1 Phys i ca l Activity and Weight Status 13 2.3.2 Phys i ca l Activity and Vascu la r Status 16 2.3.3 Phys i ca l Activity and Musculoskeleta l F i tness 16 2.3.4 Phys i ca l Activity and Cardiorespiratory F i tness 17 2.3.5 Summary . 18 2.4 Motor Per formance in Chi ldhood 19 2.4.1 Muscu la r Strength and Endurance 20 2.4.2 Cardiorespiratory F i tness 20 2.4.3 Flexibil ity 21 2.4.4 Summary 21 2.5 A s s e s s i n g Phys i ca l Activity 21 2.5.1 Sel f -Repor t 22 2.5.2 Direct Observat ion 22 2.5.3 Heart Rate Monitoring 23 2.5.4 Pedomete rs 23 2.5.5 Indirect Calor imetry 23 2.5.6 Doub ly -Labe led Wate r 24 2.5.7 Acce lerometry 24 2.5.8 Summary . 2 5 C H A P T E R III Methodology 26 3.1 Part icipants 26 3.1.1 Genera l Part ic ipant Character ist ics 26 3.2 Card iovascu la r D i s e a s e Risk A s s e s s m e n t s 27 3.2.1 Anthropometry 27 iv 3.2.2 Vascu la r Health 27 3.2.3 Muscu loske le ta l F i tness 27 3.2.4 Card iovascu la r F i tness 28 3.2.5 Phys ica l Activity 28 3.3 Procedure 29 3.3.1 Day 1: Weight Status, Vascu la r Health and Heal th-Related Phys ica l Fi tness Measu res 30 3.3.2 Day 2: Activity Monitor Distribution 31 3.3.3 Day 7: Activity Monitor P ick -Up 32 3.3.4 Phys i ca l Activity Data Reduct ion 32 3.3.5 Statist ical Ana lys i s 33 C H A P T E R IV Results 36 4.1 Genera l Subject Character is t ics 36 4.2 Phys ica l Activity Patterns 37 4.3 Ethnic Di f ferences in Phys ica l Activity and Heal th-Rela ted Phys i ca l F i tness 38 4.4 Regress ion Ana lys is 39 4.5 Intraclass Correlat ion 40 C H A P T E R V Discussion 43 5.1 Phys ica l Activity Patterns in Chi ldren 4 3 5.1.1 Genera l Phys ica l Activity Patterns 4 3 5.1.2 G e n d e r Dif ferences in Phys ica l Activity and Heal th-Related Phys ica l Fi tness 44 5.1.3 Phys ica l Activity Guide l ines 45 5.2 Ethnicity, Phys ica l Activity and Phys ica l F i tness 47 5.2.1 Ethnic Di f ferences in Phys ica l Activity 47 5.2.2 Ethnic Dif ferences in Heal th-Related Phys ica l F i tness 49 5.3 Phys ica l Activity and Phys ica l F i tness 51 5.3.1 Phys ica l Activity and Musculoskeleta l F i tness 51 5.3.2 Phys ica l Activity and Cardiorespiratory F i tness 52 5.3.3 Phys ica l Activity and Phys ica l Fi tness 53 5.3.4 Phys i ca l Activity and Weight Status 53 5.3.5 Phys ica l Activity in Relat ion to Vascu la r Health 54 5.4 Future Direct ions 55 5.5 Limitations 55 5.6 Conc lus ions 56 Footnotes 57 C H A P T E R VI References 58 A P P E N D I C E S 70 Appendix A 70 Appendix B 83 Appendix C 87 Appendix D 88 Appendix E 89 Appendix F 90 Appendix G 92 Appendix H 94 V Appendix 1 9 5 Appendix J 96 Appendix K 9 7 Appendix L .110 V I LIST OF TABLES Table 2.1. Phys ica l activity guidel ines for children 8 Tab le 2.2. Phys i ca l activity and weight status 15 Table 2.3. Phys ica l activity and cardiorespiratory f i tness 19 Tab le 3.1. Classi f icat ion of physical activity intensity 29 Table 4 .1 . Part icipant character ist ics ^ 36 Table 4.2. Correlat ions 37 Tab le 4.3. Phys i ca l activity ou tcome var iables 38 Table 4.4. Resul ts of hierarchical multiple regression model for cardiorespiratory fitness in As ian and C a u c a s i a n girls 41 Table 4.5. Resu l ts of hierarchical multiple regression model for musculoskeleta l f i tness in A s i a n and C a u c a s i a n girls 41 Tab le 4.6. Resu l ts of hierarchical multiple regression mode l for cardiorespiratory f i tness in As ian and C a u c a s i a n boys 42 Tab le 4.7. Resu l ts of hierarchical multiple regression model for musculoskeleta l f i tness in A s i a n and C a u c a s i a n boys 42 Table D.1 Ave rage 'on ' and 'off t imes 89 Tab le E.1 Health-related physica l f i tness and physical activity data in girls 93 Table E.2 Health-related physical f i tness and physical activity data in boys 94 Table E.3 Health-related physical f i tness data in children without physical activity data95 Tab le K.1 . T-tests performed between genders 98 Table K.2. A N O V A performed between girls with and without val id physical activity data 98 Table K.3. A N O V A performed between boys with and without val id physical activity data 99 Tab le K.4. A N O V A performed between schoo ls to determine intraclass correlation 99 Table K.5. A N C O V A used to examine differences between C a u c a s i a n and As ian boys 100 Tab le K.6. A N C O V A used to examine differences between C a u c a s i a n and A s i a n girls 100 Tab le K.7. P C A of musculoske le ta l f i tness components in all chi ldren 101 Table K.8. P C A factor loadings of musculoskeleta l f i tness components in all children 101 Table K.9. P C A of musculoskeleta l f i tness in girls 101 Tab le K.10. P C A factor loadings of musculoskeleta l f i tness components in girls 101 Table K.11. P C A of musculoskeleta l f i tness components in boys 102 Tab le K.12. P C A factor loadings of musculoskeleta l f i tness components 102 Tab le K.13. P C A of f i tness components in all chi ldren. . 102 Tab le K.14. P C A factor loadings of f i tness components in all chi ldren 102 Tab le K.15. P C A of health-related physical f i tness components in all chi ldren 103 Table K.16. P C A factor loadings of health-related physical f i tness components in all children 103 Tab le K.17. Forward s tepwise regression of cardiorespiratory f i tness in girls 103 Tab le K.18. Forward s tepwise regression of cardiorespiratory f i tness in boys 104 Tab le K.19. Hierarchical regress ion of health-related phys ica l f i tness component in boys 104 Tab le K.20. Hierarchical regression of health-related physical f i tness component in girls. 105 Tab le K.21. Hierarchical regression of push-ups in boys 105 Tab le K.22. Hierarchical regression of push-ups in girls 106 v i i Table K.23. Hierarchical regression of curl-ups in boys 106 Table K.24. Hierarchical regression of curl-ups in girls 107 Table K.25. Hierarchical regression of sit-and-reach in boys 107 Table K.26. Hierarchical regression of sit-and-reach in girls 108 Table K.27. Hierarchical regression of grip strength in boys 108 Table K.28. Hierarchical regression of grip strength in girls 109 Table K.29. Hierarchical regression of systolic blood pressure in boys 109 Table K.30. Hierarchical regression of systolic blood pressure in girls 110 viii LIST OF FIGURES Figure 3.1. Schemat i c of test ing procedure 30 Figure 3.2 Day 1: Schemat i c outlining the testing procedure 31 Figure 3.3. Dec is ion tree for data reduction 33 ix ABBREVIATIONS AS! BC Action Schools! BC BMI body mass index BP blood pressure CSEP Canadian Society for Exercise Physiology CVD cardiovascular disease DBP diastolic blood pressure EE energy expenditure HR heart rate KKD kilocalories per kilogram MVPA moderate-to-vigorous physical activity PA physical activity PE physical education SBP systolic blood pressure SD standard deviation TEE total energy expenditure U.K. United Kingdom WC waist circumference OPERATIONAL DEFINITIONS Accelerometer : A dev ice worn on the body that provides an objective measurement of phys ica l activity. It consists of p iezoelectr ic technology that when accelerated, emits a voltage that is proportional to the accelerat ion of the body. The resulting information provides health-related information about phys ica l activity s u c h as f requency, intensity and duration (1). Act ion Schoo ls ! B C ( A S ! B C ) : A best-practice physical activity model des igned to assist e lementary schoo ls in creating individualized action plans to promote healthy living. It provides resources and recommendat ions for the creation of individualized Act ion P lans that integrate physical activity and healthy eating into the schoo l environment (for more information visit www.act ionschoolsbc.ca) . Act ive: Having an average daily energy expenditure (EE) between 3.0 - 5.9 ki localories per ki logram (KKD) of body weight. Wa lk ing for one hour per day would result in an E E of approximately 3.0 K K D (2). Bouted Activity: A n y activity that is accumulated in durations of 5 minutes or more and is related specif ical ly to original data from this document . Canad ian Society for Exerc ise Physio logy ( C S E P ) : A non-profit organizat ion composed of professionals interested and involved in the scientif ic study of exerc ise physiology, exerc ise biochemistry, f i tness and health (for more information visit www.csep.ca) . Cardiovascular /Cardiorespi ratorv Fi tness: The ability to transport and use oxygen during prolonged, st renuous exerc ise or work. It reflects the combined eff iciency of the lungs, heart, vascu lar system and exerc is ing musc les in the transport and use of oxygen (3). Chi ldren: Chi ldren refer to boys and girls between the a g e s of 5 - 12. Compl iance : The act of adher ing to the physical activity guidel ines set forth by a governing body. Epoch : The time period over which accelerometer counts are averaged (4). Ethnicity: A term which represents a shared history, s e n s e of identity, geography and cultural similarit ies amoung individuals (5). Fract ional izat ion: Method of segment ing the time spent at different intensities of physical activity. Heal th-Related Phys ica l F i tness: The components of phys ica l f i tness that are related to health status, including cardiovascular f i tness, musculoske le ta l f i tness, body composi t ion and metabol ism (3). Inactive: V a l u e s of average daily E E less than 1.5 K K D . Walk ing for no more than one quarter hour would result in an E E less than 1.5 K K D (2). Ki localorie: the quantity of heat required to raise the temperature of 1 kg (1 L) of water 1° C (specif ically from 14.5 to 15.5° C) (6). Moderately Act ive: Having an average daily E E between 1.5 - 2.9 K K D . Walk ing for one half hour per day would result in an E E of approximately 1.5 K K D (2). Musculoskeleta l F i tness: The f i tness of the musculoskeleta l sys tem, encompass ing muscular strength, muscular endurance, muscu lar power, flexibility, back f i tness and bone health (3). Phys ica l Activity: A l l leisure and non-leisure body movements resulting in an increased energy output f rom the resting condit ion (3). Phys ica l F i tness: A physiologic state of wel l-being that al lows one to meet the demands of daily living or that provides the basis for sport performance, or both (3). R a c e : A term which impl ies biological traits indicative of meaningful genet ic similarities in a group of individuals (5). Sporad ic Activity: A n y activity data that is accumulated in durat ions lasting less than 5 minutes and is related specif ical ly to original data from this document . Tracking: The main tenance of relative rank or position within a group over t ime (i.e., those participating in the least amount of P A a s chi ldren will participate in the least amount of P A as adults). A s a general guide, correlat ions <0.30 are cons idered low; those between 0.30 and 0.60 are moderate; and those >0.60 are high (7). R E F E R E N C E S FOR OPERATIONAL DEFINITIONS 1. Es l iger D W , Cope land J L , Barnes J D , Tremblay M S . Standardiz ing and optimizing the use of accelerometer data for free-living physica l activity monitoring. Journa l of Phys ica l Activity and Health 2005;3:366-383. 2. Cameron C , Cra ig C , Paol in S . Local opportunities for physical activity and sport: t rends from 1999 - 2004. In: Phys ica l Activity Benchmarks Program; 2004. 3. Warburton D E R , Whi tney Nicol C , Bredin S S D . Health benefits of physical activity: the ev idence. C M A J 2006; 174(6):801 -809. 4. C h e n K Y , Basset t J D R . The technology of acce lerometry-based activity monitors: current and future. M e d Sc i Sports Exerc 2005;37(11(Suppl ) ) :S490-S500. 5. Tremblay M S , P e r e z C E , Ardern CI, Bryan S N , Katzmarzyk P T . Obesity, overweight and ethnicity: Statist ics C a n a d a ; 2004 June . 6. McArd le W , Katch F, Katch V . Essent ia ls of Exerc ise Phys io logy. 2 ed . Balt imore, Mary land: Lippincott Wi l l iams & Wi lk ins; 2000 . 7. Mal ina R M . Phys ica l activity and fi tness: pathways from chi ldhood to adulthood. Amer i can Journa l of Human Biology 2001;13:162-172. Xll l A C K N O W L E D G E M E N T S There are numerous individuals who have assisted me in var ious ways throughout the duration of my Masters and to whom I am very thankful. I appreciate the personal and academic support from e a c h and every one . To the C P R and L E A R N lab members , (Ben, J e s s , D o m , Lesl ie , L indsay, Shir ley, Marc , S teph , and Mika) I owe a spec ia l thank-you for the cons iderab le amount of moral support and fr iendship that was offered over the past few years . I would like to s incerely thank my committee members, Dr. Heather M c K a y and Dr. P J Naylor for their adv ice and intellectual contributions to this investigation. I am very thankful to Act ion Schoo ls ! B C for al lowing me to be a part of such a fantastic initiative and hope it cont inues to thrive and be success fu l . I a lso appreciate the support from the staff and students at the B o n e Heal th Resea rch Group throughout data col lect ion and data analys is. I am espec ia l ly grateful for the enthusiast ic chi ldren who participated in the accelerometry portion of the A S ! B C initiative. T h e project would not have been completed without their willing participation. I am deeply indebted to both Dale Esl iger for his w isdom, t ime and pat ience, and his programmer, Er ic Finlay who (with Dale 's help) provided me with an amaz ing program to optimize my accelerometry data. I would like to thank Dylan, my family and friends for their cont inued support and encouragement. I must thank my superv isor and co - supervisor, Dr. S h a n n o n Bredin and Dr. Darren Warbur ton, for we lcoming me into their laboratories, providing me with end less opportunit ies, and offering support and gu idance throughout the duration of the investigation. C H A P T E R I 1 Introduction Ninety-one percent of Canad ian children are not meet ing C a n a d a ' s Phys ica l Activity Gu ide l ines for Chi ldren and Youth (8). This is an indication that many of Canad ian chi ldren are not physical ly active enough to maintain an optimal health status (9). Phys ica l activity (PA) is required to maintain normal growth and development and health-related physica l f i tness (3) throughout chi ldhood. Rout ine P A is an effective primary and secondary preventive strategy against many types of chronic d i sease (3, 10). During chi ldhood, P A bui lds the foundation for a healthy body and can help to reduce the onset of risk factors assoc ia ted with poor health (11-13). Phys i ca l activity is a lso an important determinant of coronary heart d i sease risk in youth (14) such that risk dec reases in a graded fashion as P A level increases (15). Clear ly , a physical ly active lifestyle is an important component of a chi ld's regular routine. In C a n a d a , ev idence indicates that certain ethnic groups are accumulat ing extremely low levels of regular P A (16-18). Studies have reported that both A s i a n girls and boys participate in less P A than age-matched C a u c a s i a n peers (17, 18). In Britain, investigations have also reported that As ian children have lower cardiorespiratory f i tness than their A n g l o - S a x o n counterparts (19). Low levels of P A and low cardiorespiratory f i tness are both assoc ia ted with card iovascular d i sease risk (14) and suggest that chi ldren of A s i a n ethnicity may be a group more vulnerable to ill health. It is therefore important that P A and fitness be evaluated in chi ldren of different ethnic backgrounds to target preventative measures appropriately. Literature del ineat ing the relationship of P A to components of health-related physical f i tness is inconsistent in chi ldren. There is an increasing amount of ev idence demonstrat ing that body composi t ion is inversely related to habitual P A (20-22). No relationship has been reported between P A and vascu lar status (measured a s blood pressure) (14, 23, 24). Weak- to-moderate relat ionships have been detected between P A and musculoskele ta l f i tness (25, 26) and recent studies have shown significant positive relat ionships between P A and aerobic f i tness (27-29). In adults, relationships between P A and components of health-related physical f i tness have been wel l - establ ished whereby P A is assoc ia ted with more favourable ou tcomes (3, 30). 2 To date, limitations assoc ia ted with P A measurement tools have inhibited the analysis of P A and health in chi ldren (15). The tempo of chi ldren's activity is one of rapid change and is typically unstructured and sporadic in nature (31). T h e s e factors make capturing activity difficult in this population. A s wel l , chi ldren have less developed cognitive skil ls than adults and are less able to effectively use traditional methods of P A measurement such as self-report quest ionnaires (32). Therefore, P A assessmen ts for children must be improved to advance research in chi ldhood P A (32) and its connect ion to health benefits. Object ive measu res of P A are able to overcome many of the limitations associated with var ious other P A measurement tools. To accurately a s s e s s chi ldren's activity patterns, the evaluat ive instrument must be sensit ive enough to detect, c o d e ; or record sporadic and intermittent activity (32, 33). The accelerometer is a unique and useful p iece of technology that is able to capture and store activity patterns in smal l time intervals over a period of days or weeks . It can also provide a measure of important health-related d imens ions of P A (frequency, intensity, duration). T h e s e advantages make the accelerometer an ideal tool to use for the assessmen t of P A in children, especial ly when examin ing relationships to health-related physica l f i tness or card iovascular health. Accordingly, the purposes of this investigation were to obtain an objective measure of habitual P A in C a n a d i a n chi ldren, examine the di f ferences in P A and health-related physical f i tness between A s i a n and C a u c a s i a n chi ldren, and determine the relationship between P A and health-related physical f i tness. W e hypothes ized that: 1) T h e majority of chi ldren in the present investigation will not meet C a n a d a ' s Phys ica l Activity Gu ide l ines for Chi ldren and You th . Th is hypothesis is based on reports f rom Heal th C a n a d a stating that less than 5 0 % of chi ldren ach ieve optimal amounts of P A (9). 2) C a u c a s i a n chi ldren will have higher P A levels than A s i a n chi ldren living in the s a m e geograph ica l location and will ach ieve higher health-related physical f i tness scores . Th is is based on current ev idence wh ich indicates that individuals of A s i a n ethnicity are less active than C a u c a s i a n individuals (16, 17, 34) and ach ieve lower sco res on cardiorespiratory f i tness tests (19). 3) Chi ldren that participate in more moderate-to-vigorous phys ica l activity ( M V P A ) per day will have higher health-related physical f i tness scores . Th is hypothesis is 3 based on previous literature reporting posit ive relat ionships between P A and var ious components of health-related physical f i tness (25, 26, 29). The present investigation w a s conducted in col laboration with Act ion Schoo ls ! B C (AS! B C ) . This initiative is a best pract ices P A model des igned to assist elementary schools in creating individual ized school action plans to promote healthy living. The vision of A S ! B C is to integrate P A into elementary schoo ls to ach ieve long-term, measurab le and susta inable health benefits. This is a comprehens ive study that was being conducted in order to a s s e s s the health status of chi ldren in British Co lumbia and to determine whether the A S ! B C model is an effective means to positively change schoo l environments, health-related behaviours and the health of chi ldren when del ivered ac ross geographical ly d iverse regions and cultures over a three year period. The participants of the P A (by accelerometry) component of the A S ! B C initiative were a sub-sample of 1459 students and included a multi-ethnic population of 579 children in grades 4 to 5 from schoo ls (n = 9) in the Greater Vancouve r Reg ion . Measurements were col lected throughout the schoo l year from students enrol led in schoo ls participating in the A S ! B C initiative. Al l participants were a part of the full evaluation component of the A S ! B C initiative which, in addit ion to the measures being taken for the proposed investigation, included quest ionnaires about family history, nutritional intake and knowledge, P A participation, and psycho-soc ia l health. One hundred seventy chi ldren (79 boys; 91 girls) from five schoo ls were retained for this investigation. Measuremen ts of body composit ion (body m a s s index and waist c ircumference), vascu lar health (resting blood pressure) , resting heart rate, musculoskeleta l f i tness (grip strength, curl-ups, pushups, and si t-and-reach), card iovascular f i tness (Leger shuttle run), and physica l activity (accelerometry) were obtained over a 1-week per iod. Fol lowing the Introduction, a Rev iew of the Literature will be presented in Chapter 2, which is relevant to the speci f ic hypotheses of the present investigation. A detai led Methodology will be presented in Chapters 3, fol lowed by the Resu l ts and D iscuss ion in Chapters 4 and 5, respectively. Final ly, nine append ices are inc luded; A ) ethics forms for the investigation, B) Heal th History Quest ionnaire, C ) musculoske le ta l f i tness test protocols, D) average 'on ' and 'off t imes used to classi fy val id d a y s of accelerometry wear, E) information sheet for parents and/or guard ians of part icipants, F) Activity Log , G) summary of outcome var iables in girls and boys, H) summary of outcome var iables in children without val id accelerometry data, I) abstract entitled 'Captur ing physical activity tempo in e lementary-school -aged chi ldren, J) abstract entitled 'Phys ica l activity and antecedents of card iovascular d i sease risk in chi ldren, ' K) statistical ana lyses, and L) raw data. Upon complet ion of this thesis, this data will be submitted for publication in Medic ine & S c i e n c e in Spor t & Exerc ise as three separa te manuscr ipts. 5 C H A P T E R II Literature Review Throughout chi ldhood P A is required to maintain normal growth and development, health-related physica l f i tness (3), and to establ ish lifestyle patterns that will reduce the risk factors for health compl icat ions later in life (13). Phys ica l activity is a lso an important determinant of coronary heart d i sease risk in youth (14) such that risk dec reases in a graded fashion as P A level increases (15). A physical ly active lifestyle is an important component of chi ldren's regular routine and plays a critical role in chi ldren's health. In the following review, chi ldren's genera l activity patterns, physical activity guidel ines for chi ldren, ethnic differences in P A , and P A in relation to health- related f i tness are d i scussed . 2.1 Phys ica l Activity Pat terns in Chi ldren Chi ldren display unique P A patterns in which activity is highly transitory and is rarely sustained for per iods greater than 10 minutes in duration (35). There are specif ic t imes of the day and days of the week in which activity is more likely to be observed in children (35, 36). A g e and gender are two factors consistent ly recognized in the literature as affecting P A levels in chi ldren (37, 38). A l though there are numerous guidel ines currently avai lable in which to a s s e s s P A in chi ldren; very few of the recommendat ions are reflective of chi ldren's actual behaviour. A s such , the purpose of this sect ion is to examine in further detail the general physical activity patterns of chi ldren, a s wel l a s physica l activity guidel ines commonly used to a s s e s s P A in chi ldren. 2.1.1 Genera l Phys ica l Activity Patterns T h e tempo of chi ldren's P A is one of rapid change. Activi t ies at all levels of intensity are highly transitory and have a mean duration of 6 seconds as determined by direct observat ion in chi ldren a g e s 6 - 1 0 years of age (31). Chi ldren 's P A consists of short bursts of intense activit ies that are interspersed by brief intervals of low or moderate intensity activity (31). Hoos et a l . (35) est imated that chi ldren (ages 8 - 1 1 years) spend approximately 1 9 % of their total active time on high intensity activit ies, such as playing or running outside, and over half of their waking t ime in low intensity activities, such a s playing computer games , even though they change activities and the level of intensity at 6 frequent intervals (31, 35). More recently, Baquet et a l . (39) observed that chi ldren only spent approximately 1 0 % of their t ime in activities of moderate intensity or greater and a mere 2 .4% of that t ime w a s spent in v igorous activity (39). Moderate-to-v igorous P A has been most commonly observed during schoo l break t imes and s e e m s to be less prominent during the after-school hours(40) and during physical educat ion (PE) lessons (40-42). S leap and Warbur ton (40) have shown that only 31 % of chi ldren performed a sustained 5 minute bout of M V P A and even fewer participated in a bout susta ined for 10 minutes during P E lessons (40), a time when it is assumed that chi ldren are achieving substantial amounts of quality exerc ise. The amount of t ime al located to P E in British Co lumb ia for g rades 4 and 5 students is on average, 40 minutes three t imes per week. It is est imated that during each P E sess ion , chi ldren is only likely to be aerobical ly active for 6 % of the allotted 30-40 minutes of t ime (42). The recommendat ions from the British Co lumb ia Ministry of Educat ion are to spend approximately one half of P E time ( 1 5 - 2 0 minutes) practicing activities that encourage active living and enhance health (43). This ev idence suggests that these guidel ines are not being met. Despi te participating in greater amounts of M V P A during recess than during P E , more than 5 0 % of recess time is spent in activities of light or sedentary intensity (44). Al though children participate in more activity during the schoo l day, the total amount of P A during that time period is still unacceptably low. A l s o somewhat alarming is the f inding that P A outside of schoo l hours (40, 45) and on weekends w a s low (36, 46). S i nce children spend significantly more time at home than at schoo l this sugges ts that chi ldren will engage in sedentary activities more often unless the st imulus or opportunity to be active is a part of a regimented schedule (40). Exist ing data indicates that there may be substantial variation in P A levels in adults and chi ldren. Phys ica l activity monitored over the course of a week may be precise but may not represent usual activity (47). In adults, anywhere from two to nine P A measures are recommended throughout the year (depending on the measurement tool) to obtain rel iable measu res of P A (47). Similarly, in chi ldren there is substantial instability in P A levels over a one year period as measured by accelerometry even with 6 or 7 days of wear per col lect ion time (48). Kr is tensen et a l . (36) found that there was a significant variation in activity depending on the day of the week and month of the year P A was measured in 8 to 10 year old children . The greatest amount of intra- individual variation occurred on the weekends . During the winter months (36, 48) or 7 during less p leasant months (49) less activity was accumula ted. However, in an environment without marked seasona l variability, seasonal i ty p lays a limited role in P A levels and a single measure of P A is sufficient to est imate habitual activity levels (50). Signif icant gender dif ferences are common in P A levels. Boys display higher levels of P A than girls of the s a m e age (11, 38, 51) and boys spend significantly more time in vigorous P A than girls (11, 39, 52). Boys a lso participate in a greater number of longer bouts of higher intensity activity (39). Rowlands et a l . (53) sugges ted that v igorous intensity P A may explain the dif ferences in total activity between genders . S leap and Warburton (40) found no difference in P A levels between boys and girls aged 5-11 years, however their f indings showed that boys primarily p layed g a m e s such as soccer and girls were more likely to participate in games s u c h a s danc ing , gymnast ics and netball. There is a trend for the total amount of P A to decl ine in both genders as a function of age whereby girls show a more rapid decrease in levels than boys (37, 38, 46). A decrease in P A of 8 3 % from age 9 or 10 to age 18 or 19 has been reported in girls (54). Part of this decl ine in P A can be attributed to increased demands being p laced on children throughout the educat ion process, specif ical ly with t ime spent sitting at school and amount of homework given to be completed after schoo l (45). Behavioura l research has suggested that girls participate in less P A than boys due to less soc ia l support from family members and fr iends, lower self-eff icacy and activity competence scores , and less enjoyment in sporting activities (55-57). 2.1.2 Guide l ines for Phys ica l Activity W h e n assess ing P A patterns in children it is important to clearly define what 'being active' is (32) and to understand how P A is accumulated in order to determine compl iance with a speci f ic P A guidel ine (1). Conc lus ions regarding P A status are heavily dependent on the P A guidel ines selected to examine the populat ion of interest (58). There are currently numerous variations of guidel ines avai lable and there is currently debate as to which set is optimal for chi ldren (52) (see Tab le 2.1 for a descript ion of the guidel ines). 8 Tab le 2.1. Descr ipt ion of physical activity guidel ines for chi ldren. Source Guideline Description Health Canada & Canadian Society for Exercise Physiology 60 minutes of moderate activity and 30 minutes of vigorous activity each day. Accumulate activity in bouts of 5-10 minutes. Decrease sedentary activity by 90 each day. Examples of moderate activity are brisk walking and bike riding. Examples of vigorous activity are running or playing soccer. Healthy People 2010, goal 22.6 30 minutes of moderate activity on 5 or more days of the week. Accumulate in bouts of at least 1 minute. Activity of an intensity of 3 or more METs. Healthy People 2010, goal 22.7 20 or more minutes of vigorous activity that promotes the development of cardiorespiratory fitness on at least 3 days of the week Activity of an intensity of 6 or more METs. United States 30-60 minutes of accumulated moderate intensity activity per day. Moderate intensity activity on most or all days of the week. International Consensus Conference on Physical Activity Guidelines for Adolescents 20 minutes of moderate-to-vigorous activity at least 3 times per week in addition to minimal amount of activity (i.e. 30 minutes of moderate activity) Daily activity as part of lifestyle activities. American College of Sports Medicine Opinion Statement 20-30 minutes of vigorous activity per day. Recreational and fun aspects of activity should be emphasized. United Kingdom Expert Consensus Group 60 minutes of activity that is at least moderate intensity per day. Activity of an intensity of 3 or more METs on at least 5 days per week. T h e Amer i can Co l l ege of Spor ts Medic ine ( A C S M ) deve loped the first formal guidel ines for ado lescents and chi ldren based on adult guidel ines. Th is organizat ion recommended that chi ldren ach ieve 20 - 30 minutes of v igorous exerc ise e a c h day (59). It is a s s u m e d , however, that the P A requirements for opt imal health in chi ldren are different than those needed by adults (32) because chi ldren are less physical ly deve loped and typically do not engage in the s a m e types of activity patterns (35). For example, adults are more likely to participate in structured activit ies s u c h a s a 30 minute jog whereas chi ldren are more apt to engage in unplanned g a m e s throughout the day (40). Investigations by S l e a p and Warburton (40) indicate that only 8-14% of 5 - 11 year-old chi ldren regularly participate in aerobic exerc ise bouts that exceed 10 minutes in duration. In contrast, Armstrong and W e l s m a n (46) determined (using heart rate monitoring) that 8 9 % of boys and 6 9 % of girls beginning schoo l ach ieved one 10-minute bout of P A over the measurement period of 3 days. A lmos t all chi ldren achieved at least one 5-minute bout. Sus ta ined 20 minute bouts of either moderate or v igorous activity were rare in all age groups (46). Accord ing to this ev idence, a bout of activity prescr ibed to chi ldren shou ld be no greater than 10 minutes in duration. Health C a n a d a and the Canad ian Society for Exerc ise Phys io logy ( C S E P ) created revised P A guidel ines for chi ldren and youth in 2002 (9) that address s o m e of the issues present in other guidel ines. T h e s e guidel ines state that chi ldren should incorporate an addit ional 60 minutes of moderate P A and 30 minutes of v igorous P A into their current daily routines. Cons is tent with current research, they recommend that the P A be accumulated in bouts of 5 - 10 minutes throughout the day. T h e s e guidel ines a lso recommend that chi ldren dec rease their current amount of t ime spent in sedentary activities by 90 minutes per day. This recommendat ion is under the assumpt ion that chi ldren spend more than 90 minutes per day involved in sedentary activities. T h e s e guidel ines are based on expert opinion and are in accordance with international guidel ines which state that between 3.0 - 5.9 K K D need to be expended daily to be considered active (2). The wide variation in guidel ines used to determine P A levels makes obtaining the prevalence of compl iance in chi ldren extremely difficult. Furthermore, uncertainty in the accuracy of these measures is increased due to the numerous limitations associated with data acquisi t ion of P A (58). For example, Pate et a l . (58) examined the compl iance of students (grades 1-12) to three different P A guidel ines: Healthy Peop le 2010, Object ive 22.7; Heal thy Peop le 2010, Object ive 22.6; and United Kingdom Expert C o n s e n s u s Group (refer back to Tab le 2.1). The percentage of students meeting the specif ic criteria of the three guidel ines were < 3%, 9 0 % and 69 .3%, respectively. Using accelerometry, R iddoch et al . (38) found that virtually all 9 year old chi ldren meet the United K ingdom Expert C o n s e n s u s Group P A recommendat ions and J a n z et a l . (60) a lso found that most chi ldren were meeting the P A guidel ines put out by the International C o n s e n s u s Confe rence on Phys ica l Activity for Ado lescen ts . Converse ly , Armstrong et a l . (52) determined through heart-rate monitoring that many children have adopted the sedentary lifestyle that is assoc ia ted with a dec rease in cardiovascular health and are therefore not participating in acceptable amounts of P A . This clearly demonstrates the confus ion in the current literature assoc ia ted with determining P A levels in chi ldren. 2.1.3 Summary Chi ldren's activity is typically intermittent and sporadic in nature between the ages of 5 - 1 1 years of age (31). It consists of short bursts of intense activity interspersed with intervals of low activity (31) and is quite variable over a 1-year period (36, 48). Chi ldren are the most act ive during schoo l break t imes (61) however recent ev idence indicates that activity during this time is still quite low (44). Boys are consistently more active than girls (38, 51) and with age, there is a decrease in activity levels (37, 38). There are numerous guidel ines avai lable and there is currently debate as to which provide children with the optimal amount of P A for posit ive health status. It has been recommended that guidel ines for children be tailored to their unique P A patterns (32). Determining the preva lence of P A in children is difficult due to the use of various guidel ines. Accord ing ly , the first objective of this investigation w a s to measure habitual P A and determine the percentage of chi ldren meeting the C a n a d i a n Phys ica l Activity Guide l ines for Chi ld ren and You th . T h e s e guidel ines are currently the only ones avai lable that are tailored specif ical ly to the intermittent activity patterns in chi ldren. W e hypothesize that the majority of children will not meet these guidel ines. 2.2 Ethnicity, Phys ica l Activity and Phys ica l F i tness Var ious reports indicate dif ferences in unfavourable health behaviours between ethnic groups (16, 34). Th is il lustrates the need to obtain measu res of P A and fitness in a group of multicultural chi ldren. It is a lso important to identify vulnerable groups at higher risk of developing chronic health compl icat ions for both personal and public benefits. In V a n c o u v e r there is a large population of A s i a n individuals however, the literature descr ib ing the difference in P A levels and health-related physical f i tness between A s i a n and C a u c a s i a n children is sparse . Ava i lab le data demonstrate a less- favourable health profile in A s i a n children compared to the C a u c a s i a n children (19, 62). 11 This sect ion will examine the existing literature and compare P A and f i tness between C a u c a s i a n and A s i a n chi ldren. 2.2.1 Ethnic Dif ferences in Phys ica l Activity Data descr ib ing di f ferences in P A between C a u c a s i a n and A s i a n ethnic groups of all ages residing within the s a m e city are limited and reports are conflicting. Information obtained from the C a n a d i a n Communi ty Health Survey (2000/01 and 2003) on adults indicated that the preva lence of P A was lowest in South and W e s t A s i a n groups and highest in C a u c a s i a n groups. South As ian groups are include Eas t Indian, Pakistani , and Sri Lankan , whi le W e s t A s i a n groups are includef A fghan and Iranian (16). Dif ferences in P A between ethnic groups in youth have been detected but are not consistent ac ross studies. In a Vancouver -based investigation, MacKe lv ie and co l leagues (17) reported that 9 - 10 year old C a u c a s i a n females participated in significantly more loaded P A (defined as activity with a higher impact than walking) and considerably more extracurricular sporting activities than age-matched As ian girls. Data from the National Longitudinal Study of Ado lescent Health in the United States showed that a substant ial number of A s i a n females (n = 922, g rades 7 -12) accumulated less than two 20-minute sess ions of M V P A per week (34). Converse ly , M c K a y et al. (18) found no difference in P A between As ian and C a u c a s i a n girls living in the same geographical location. Information from the National Longitudinal Study of Ado lescen t Health indicated that in ado lescents boys (n = 6701 , grades 7 -12) the difference in P A between ethnic groups was present but smal l (63). MacKe lv ie et a l . (64) reported no difference in P A between As ian and C a u c a s i a n boys. However, in an earl ier study conducted in Vancouver , signif icant di f ferences in P A were found. A s i a n boys were 1 5 % less active than C a u c a s i a n peers (18). Despi te d iscrepanc ies between studies, there is a trend for C a u c a s i a n children to participate in more P A than age-matched As ian chi ldren. S i nce the investigations in children utilized quest ionnaires requiring activity recall , it is poss ib le that P A is not accurately measured . With a less subjective and more sensi t ive instrument to measure P A , a more clearly def ined trend may emerge in both boys and girls. Furthermore, ethnic dif ferences in P A have been reported to persist into adulthood (65) suggest ing that in C a n a d a , the low levels of P A will continue throughout the l i fespan unless interventions are implemented. This highlights the importance of further examining the ethnic di f ferences in P A . 2.2.2 Ethnic Dif ferences in Heal th-Related Phys ica l F i tness Limited research has been conducted on the components of health-related physical f i tness (musculoskeleta l and cardiorespiratory fitness) and how they differ between A s i a n and C a u c a s i a n chi ldren living in the s a m e geographica l location. In the United K ingdom, lower levels of phys ica l f i tness in A s i a n as compared to Ang lo -Saxon children have been observed (66). Chi ldren of Indian (South As ian) background ach ieved lower scores than chi ldren of other ethnicit ies in the cardiorespiratory, test (power output against load at 8 5 % of the max imum heart rate) utilized in the study (19). In previous investigations from our study group, it w a s documented that C a u c a s i a n children completed more laps in the 20 m Leger shuttle run test, indicating higher aerobic f i tness, than A s i a n chi ldren (67). No differences in weight status or vascu lar health between ethnicit ies were reported, however, the latter study demonstrated a less favourable card iovascular health profile, as measured by heart rate variability, in the A s i a n chi ldren (67). T h e trends were the s a m e for boys and girls in both investigations. 2.2.3 Summary There is a trend for C a u c a s i a n children to participate in greater amounts of P A than age-and-sex-matched A s i a n peers. In Britain and C a n a d a , A s i a n children are less aerobical ly fit than C a u c a s i a n chi ldren. However, for the most part, no studies have looked at the dif ference in musculoskeleta l f i tness between C a u c a s i a n and As ian chi ldren. In a multicultural city such as Vancouver , these observat ions warrant further investigation. Accordingly , the second objective of this study w a s to examine ethnic differences in P A levels and health-related physical f i tness. W e hypothesize that C a u c a s i a n chi ldren will have higher P A levels and will ach ieve higher health-related physical f i tness sco res than A s i a n chi ldren. 2.3 Phys ica l Activity in Relat ion to Heal th-Related Phys ica l F i tness Phys ica l activity and health-related physical f i tness are independent indicators of health status. In chi ldren, P A and components of health-related f i tness have only a weak to moderate relationship (7). Th is is attributed to the difficulty in obtaining 13 measurements in chi ldren, the variable nature of chi ldren's P A , normal growth and development, and the effect of soc ia l , cultural, and environmental factors. There is keen interest in establ ishing this relationship because research sugges ts that if P A and fitness are establ ished in chi ldhood, the active chi ldren will b e c o m e active adults and benefit from posit ive health outcomes (25). The following sect ion reviews the current literature descr ib ing the relat ionships between P A and components of health-related physical f i tness. 2.3.1 Phys ica l Activity and Weigh t Status Body m a s s index (BMI) and waist c i rcumference (WC) are both wel l-establ ished predictors of C V D risk factors amoung children. Body m a s s index is thought to be a good indicator of overal l adiposity whereas W C is an indicator of v isceral ad ipose t issue (68, 69). Ev idence in adults indicates that W C can predict health risk beyond that predicted by BMI a lone (69). In adults, risk for C V D increases in a graded fashion with a move from one BMI category to the next BMI category. Within e a c h BMI category, those with a high W C have a less favourable card iovascular profile than those with a normal W C (70). E v e n though preliminary research in chi ldren has demonstrated patterns similar to those of adults, the added var iance above that predicted by BMI alone or W C alone w a s minimal and of no clinical s igni f icance (69) . In this investigation, BMI and W C were first used to predict risk factors for coronary artery d i sease (blood l ipids, g lucose, and insulin levels) in chi ldren (n = 2597, ages 5 - 1 8 years). In the second ana lys is chi ldren were stratified accord ing to weight status and risk factors were compared for groups with low and high W C va lues (69). Weight status a lso remains stable over time. Indicators of obesity and adipose t issue distribution (BMI, W C , S u m of 5 Skinfolds) remained relatively constant across a seven-year t ime span in the Canad ian population (14). In a four year study in Texas the strongest predictor of BMI at the end of the study w a s BMI at the beginning of the study (71). Th is data impl ies that the risk factors assoc ia ted with adiposity will a lso track from chi ldhood into adulthood and therefore, will predict adult C V D outcomes (72). Thus , it is imperative to target chi ldren with preventative strategies and intervention initiatives to reduce the inc idence of adult obesity and cardiovascular compl icat ions (73). With the use of more objective P A measures , there is an increasing amount of ev idence demonstrat ing that body composit ion, a s s e s s e d either by BMI or percentage 14 fat, is inversely correlated with habitual P A . Chi ldren in the top fertile of P A have statistically signif icantly lower BMI sco res and lower percentage body fat than children in the lowest tertile of P A (20, 22, 27, 74) (see Tab le 2.2). In an international compar ison of overweight and P A in chi ldren, it was observed that the likelihood of being overweight was significantly lower in a dose- response relationship with higher P A levels a s measured by self-report (74). Simi lar ev idence was d iscovered in a cross-sect ional investigation between objectively measured P A and obesity measured as fat m a s s (assessed by dual x-ray absorptiometry) and BMI (75). There is a trend for chi ldren who spend the most t ime engaged in M V P A to have healthier body composi t ion profi les than those chi ldren who spend the least amount of time participating in M V P A (22, 76). Dencker and co l leagues (77) reported that it w a s time spent specif ical ly in v igorous activity and not moderate activity that was linked to low obesity status. The relation between body composi t ion and P A levels are general ly not gender specif ic, with both boys and girls demonstrat ing the s a m e trends. A few studies have detected gender differences in this relationship but it is not consistent between studies (22, 27, 78). Gir ls typically carry more fat than boys and are a lso typically less act ive (27). 15 Table 2.2. Description of investigations examining the relationship of PA and weight status. PA=physical activity, HR=heart rate, BMI=body mass index Author (Year) Subjects Measurement Tools Results Raitakari et al. (1997) N = 2358 Boys = 1114, Girls = 1244 Age: 9-24 years Height, weight, subscapular skinfold, P A questionnaire. Higher P A levels were associated with lower BMI in males and skinfolds in males and females. Rowlands et al. (1999) N = 34 Boys= 17, Girls = 17 Ages: 8.3-10.8 years Height, weight, skinfolds, Tritrac RT3 accelerometer, pedometer (worn 6 days), HR telemetry (worn 1 day). P A measures from the Tritrac and pedometer had significant inverse correlations with fatness. Ekelund et al. (2001) N = 82 Boys = 42, Girls = 40 Age: 14.8 years Height, weight, skinfolds, HR monitoring (3 days) converted to total energy expenditure. No significant relationships between PA variables and body fat. Abbott & Davies (2004) N = 47 Boys = 23, Girls = 24 Age: 5-10.5 years Height, weight, ' °0 dilution space (body fat), doubly -labelled water (10 day urine collection), Tritrac R3D (worn for 4 days). P A was significantly inversely correlated with percentage body fat and BMI. Janssen et al. (2005) N =137593 No gender differenentiation Age: 10-16 years Self-report questionnaire to obtain height, weight, PA. Significant inverse relationship between PA and BMI classification in 29/34 countries. Dencker et al. (2006) N = 248 Boys= 126, Girls = 101 Age: 8.6-11.0 years Height, weight, dual energy x-ray absorptiometry, Actigraph accelerometer (worn 4 days). Children with higher percentage body fat were significantly less active. Only vigorous PA was linked to obesity status. 16 2.3.2 Phys ica l Activity and Vascu la r Status Epidemiologica l studies have demonstrated that physical ly inactive adults have higher blood pressure (BP) than their physical ly active counterparts and have an increased risk of developing hypertension (30). S ince hypertension is a primary risk factor for C V D , the d iagnosis , treatment, and prevention of high B P is important (79). Wareham et a l . (30) sugges ts that low habitual energy expendi ture (PA) is c losely related to increasing B P and that it would only take a 30 minute walk most days of the week to ach ieve a signif icant drop in systol ic blood pressure ( S B P ) va lues in the adult population. Ove r a seven-year span in the Canad ian populat ion the best predictor of B P at the end of the seven years was the basel ine B P measure (79). In females, P A levels were a lso a signif icant predictor of follow-up B P (79). Interventions a imed at increasing P A levels (and consequent ly decreas ing the preva lence of C V D risk in children) have the potential to result in long-term health benefits. In the Card iovascu la r Risk in Young Finns Study, there were no differences in systol ic or diastol ic blood pressure between active and inactive chi ldren (14) which would suggest that P A has little effect on vascu lar health in chi ldren or that the detrimental effects of an inactive lifestyle on the vascu lar sys tem are not advanced enough to be detected by measures of B P in chi ldren. Other investigations have a lso found that dai ly P A in youth w a s not related to either S B P or diastol ic b lood pressure (DBP) (23, 24) or the assoc ia t ions found were weak (80). S o m e studies have noted a lower B P in the more act ive chi ldren. W h e n body fat w a s accounted for in these studies, the relationship d isappeared (12). Studies examin ing changes in B P , both S B P and D B P , measures over t ime are equivocal with s o m e detecting a secu lar increase and others reporting a dec rease in children (81). A difference has been detected between genders with boys having a slightly higher S B P than girls of the same age (82). 2.3.3 Phys ica l Activity and Musculoskeleta l Fi tness High levels of musculoskeleta l f i tness in adults are assoc ia ted with posit ive health status (83) and are a lso related to independence, and functional performance in elderly individuals (3, 83). In J a p a n e s e men poor muscular f i tness w a s assoc ia ted with an increased risk of mortality (84) and in work by Katzmarzyk and Cra ig (85), an increased risk of a l l -cause mortality w a s found in men and women in the lower quartile for sit-up performance. Handgr ip, another indicator of musculoskeleta l f i tness, is a lso a 17 significant predictor of mortality in adult men (86). Al though current ev idence states that musculoskeleta l f i tness is protective against C V D risks and compl icat ions, more research is required to clarify the distinct relationships between the var ious measures of musculoskeleta l f i tness and the health-related benefits they provide. Recent data suggests that increasing musculoskeleta l f i tness may help to prevent unhealthy weight gain in the C a n a d i a n populat ion (87). The relationship between musculoskeleta l f i tness and P A is inconsistent in chi ldren and has not been researched extensively. A few studies have demonstrated a significant but weak- to-moderate relationship between P A and var ious measu res of musculoskeleta l f i tness (25, 26). Longitudinal studies of ado lescents demonstrate a posit ive influence of habitual P A on upper body muscular endurance (88). In chi ldren, g rades 4 to 6, it was found that tracking for s i t -and-reach and pull-ups was high, and for sit-ups w a s moderate over a three year time period (89). In the Canad ian populat ion, there is moderate-to-high stability of si t-ups, grip strength, and sit- and-reach over a seven-year time frame (84). This study sugges ted that musculoskeleta l f i tness tracks better than P A levels and that the stability increases in adulthood. There are however, consistent dec reases throughout the years in all measures of musculoskeleta l f i tness indicators beginning at approximately the mid- teens to early 20 's (84). 2.3.4 Phys ica l Activity and Cardiorespiratory F i tness Ev idence support ing the importance of chi ldhood physica l f i tness and P A as protective against health-related complicat ions is becoming increasingly prevalent (60). Cardiorespiratory f i tness and P A are thought to be important determinants of C V D risk in youth (14). S i nce both cardiorespiratory f i tness and P A track at moderate levels across the l i fespan (7) early measurement and prevention is imperative to increase P A and f i tness in later years (60). It is already establ ished that low cardiorespiratory f itness in adults is a strong predictor of C V D and a l l -cause mortality (3). Fortunately, even when C V D risk factors are present in men, high levels of cardiorespiratory f i tness offer some degree of protection against premature mortality (7). In cross-sect iona l and longitudinal studies and in studies of large samp le s i ze (n £ 186) it has been demonstrated consistently that more act ive youth perform better in card iovascular endurance tasks (7, 27, 90). Recen t studies of varying sample s izes 18 have been more consistent in detecting a significant relationship between aerobic f i tness and P A in chi ldren when objective measurement tools were util ized. This relationship becomes stronger when aerobic f i tness is related to time spent in vigorous P A as opposed to all t ime spent in P A (29, 91), but this a lso is not consistent across studies (28). T h e relat ionship between aerobic f i tness and P A levels w a s found to be similar between genders (27, 29, 60, 92) despite boys attaining higher aerobic f itness scores and P A levels than girls (see Table 2.3). 2.3.5 Summary In chi ldren, there is increasing ev idence of a posit ive relat ionship between weight status and P A (21, 22), and cardiorespiratory f itness and P A (26, 29). T o date, there is no ev idence of a relationship between vascular health and P A (12) and the relationship between musculoskele ta l f i tness and P A is weak to moderate at best (25, 26). These trends are general ly simi lar in both genders . Measurement of both P A and f i tness components are difficult in chi ldren and may partially expla in why stronger relationships have not been detected. A s such , the third objective of this investigation is to determine the relationship between P A and health-related physical f i tness using an objective P A measurement tool. W e hypothesize that children that participate in more M V P A per day will have higher health-related physical f i tness scores . 19 Tab le 2.3. Descr ipt ion of investigations examining the relationship between P A and cardiorespiratory f i tness. EE=energy expenditure, TEE=tota l daily energy expenditure « n u = a C ^ £ e J l e r g y e x P e n d i t u r e - PWC150=phys ica l working capaci ty at a heart rate of 150bpm, HR=heart rate. Author (Year) Subjects Measurement Tools Results Dencker et al. (2006) N = 477 Boys= 140, Girls = 108 Age: 8-11 years BMI, self-evaluated Tanner Stage, MTI model 7164 accelerometer (worn 4 days), indirect measurement V02peak on cycle ergometer. A weak but significant relationship between V0 2 peakand mean daily PA. The correlation between V 0 2 p e a k and vigorous PA was stronger. Rowlands et al. (1999) N = 34 Boys = 17, Girls = 17 Age: 8.3-10.8 years Height, weight, skinfolds, Trirac Rt3 accelerometer, pedometer (worn 6 days), HR telemetry (worn 1 day), endurance time on Bruce Maximal Protocol Test. Output measures from Tritrac and pedometer were significantly and positively correlated with aerobic fitness. HR had a weaker correlation to fitness. Ekelund et al. (2001) N = 82 Boys = 42, Girls = 40 Age: 14.8 years Height, weight, skinfolds, HR monitoring (3 days) converted to T E E , indirect measures of V0 2 peak on treatmill, maturity. V0 2 peak was significantly and positively related to A E E . Pate et al. (1990) N = 1558 Boys = 776, Girls = 782 Grades: 3-4 2 questionnaires, 1 completed by teacher and 1 by parent (PA), skinfolds, 1.6km run/walk time test. P A and physical fitness were significantly and positively associated. 2.4 Motor Per fo rmance in Ch i ldhood Throughout middle chi ldhood and ado lescence , di f ferences exist between genders and age groups in motor performance (93), which affects the ability of the children to participate in P A and perform the health-related f i tness tasks. Thus , the relationship between habitual P A and f i tness may be confounded by changes assoc ia ted with normal growth and maturation (25). Cross-sec t iona l data has indicated that more active boys have better levels of motor performance (94). Per fo rmance steadi ly improves in 20 boys until 17 or 18 years of age and in girls, performance plateaus at 14 years of age (95). Until age 14, girls' performance is on average within one standard deviation of boys ' performance. E x c e s s body fat negatively affects motor performance, especial ly when movement of the entire body is required. However , the bigger chi ld is typically the stronger child (93). Th is sect ion examines the development of the components of health-related physica l f i tness throughout chi ldhood and ado lescence . 2.4.1 Muscu la r Strength and Endurance Strength inc reases linearly with chronological age and fol lows a growth pattern that is similar to the growth spurt pattern that occurs in ado lescence (96, 97). There are sex differences in the development of strength (95, 97), with boys demonstrat ing greater strength than girls (93) and having greater gains in performance (98). Fo r example, grip strength in ma les inc reases by over 3 0 0 % from a g e s 7 to 17 years (99) whereas grip strength in females increases by approximately 2 6 0 % (100). Th is difference in strength is not substant ial until after approximately 13 years of age (97). S e x differences may be due in part to the greater s ize and fat-free mass advantage of boys. In addition, boys tend to demonstrate greater strength per unit of musc le a rea than girls (93). Increases in muscu la r endurance are similar to those in strength and occur until around age 17 in boys and age 13-15 in girls as measured by the f lexed arm hang (98) and sit-up test (101). Per fo rmance in boys exceeded that of girls in both tests (98). In the f lexed arm hang boys improved by 143% from ages 5 to 10 whereas girls improved only 9 7 % during the s a m e time span (98). 2.4.2 Cardiorespiratory F i tness Max imal oxygen consumpt ion, a measure of aerobic endurance, improves until the late teens (102), however when reported relative to body weight va lues remain stable in boys from 8 to 18 years at around 48 - 50 ml-kg" 1 min" 1 but dec l ine in girls from 4 5 - 35 ml-kg" 1-min" 1 (102). Be tween the a g e s of 10 - 12 years , boys ' va lues are approximately 1 2 % higher than girls. More specif ic to performance tests of aerobic endurance, running speed increases linearly from 5 years until 17 years in boys and 11 or 12 years in girls with only a slight change thereafter (93). After 9 years of age ma les have better running sco res than females . In tests of maximal oxygen consumpt ion and running 21 speed , the per formance dif ference between ma les and fema les b e c o m e s magnif ied during ado lescence (93). 2.4.3 Flexibility In ma les , flexibility a s measured by the si t -and-reach test, dec l ines after age 8 until approximately age 12 after which it increases until age 18. In females, flexibility increases to age 14 years (93). The differential increase in flexibility in boys and girls at ages 13 and 11 respectively, paral lels their respect ive growth spurts in trunk length (98). Overal l , ma les exper ience a net loss in flexibility whereas fema les exper ience a slight increase to age 14 or 15 (98). Fema les are more f lexible than males at all ages (93, 98). 2.4.4 Summary Motor per formance may affect the ability of chi ldren to perform P A and components of the health-related phys ica l f i tness tests, thereby confounding the relationship between P A and f i tness. B o y s outperform girls on most tasks, excluding flexibility, and this difference b e c o m e s magnif ied throughout ado lescence . Per formance in girls typically p lateaus around ages 12 to 14 whereas boys cont inue to improve until age 17 or 18. More research is needed to provide a clear and definitive relationship between P A levels in chi ldren and measures of health-related physica l f i tness. A s wel l , research specif ical ly a imed at examin ing the difference in P A patterns and health-related f i tness var iables within ethnic groups are in need because there is the potential for genetic susceptibil ity to card iovascular risk factors in some populat ions. Motor performance affects the ability of chi ldren to participate in and perform var ious phys ica l tasks and therefore is an important considerat ion when examining these relat ionships in chi ldren. 2.5 A s s e s s i n g Phys ica l Activity Object ive measures of P A need to be obtained from chi ldren in order to correctly a s s e s s their current level of P A and its relationship to measu res of health-related physical f i tness. A s s e s s i n g P A in children is more chal lenging than in adults due to the unique developmental and behavioural aspects of chi ldren. A study by Bai ley et al. (31) found that while observing children 9 5 % of the v igorous activities lasted less than 15s 22 and 9 5 % of the rest per iods were less than 15s. F rom this data the author deduced that short, intermittent bouts of v igorous activity with frequent rest periods of longer duration are typical of chi ldren. Similarly, Baquet et a l . (39) determined that 8 0 % of the M P A bouts and over 9 3 % of the V P A bouts in chi ldren lasted less than 10s. Al though there are many instruments avai lable for P A measurement , few are able to capture children's activity accurately. The following sect ion descr ibes methods avai lable for monitoring P A and reviews the strengths and limitations of e a c h . 2.5.1 Sel f -Report Quest ionnai res and surveys have traditionally been used to measure P A levels and although these methods appear to be acceptable to use in adult studies, their accuracy with respect to chi ldren is highly quest ionable (103). It has been documented that chi ldren less than 12 years of age are not able to recall activit ies accurately or quantify the t ime-frame of activity (104). Th is is because chi ldren have less deve loped cognitive skills and therefore are less able to effectively use self-report quest ionnaires. V igorous P A is general ly overest imated using self-report methods due to a chi ld 's exaggerated perception of t ime and/or effort and the difficulty in correctly capturing sporadic bouts of activity (32, 105). However , P A of moderate intensity can be ach ieved through many daily activities wh ich are not typically thought to contribute to P A , are non-planned, less memorable and quantif iable, and therefore more likely to be underest imated by self- report methods util ized with children (15, 38). 2.5.2 Direct Observat ion Direct observat ion of P A has distinct advantages over other methods of assess ing P A with the most signif icant one being the high resolution at wh ich P A is recorded. Trained observers have the ability to measure the duration, intensity, and frequency of speci f ic activit ies in a variety of environments and are a lso able to capture sporadic or short bouts of activity (31). Th is method al lows for comprehens ive information to be gathered about the subject 's P A patterns. The limitations of this technique are that it requires a substant ial amount of t ime for adequate staff training and data collection (31) and is therefore costly (46). In addition, subject reactivity may be problematic due to the presence of a trained observer (46). The observat ion technique is not feasib le in large investigations due to t ime constr ict ions. A lso , studies utilizing direct observat ion as the 23 method of a s s e s s i n g P A are less than 12 hours in duration (21). Th is el iminates the possibil ity of looking at habitual P A patterns and temporal or seasona l variations. 2.5.3 Heart Rate Monitoring Heart rate (HR) monitoring has been accepted a s a val id and reliable measure of P A but it is an indirect measu re that indicates the relative s t ress p laced on the cardiovascular sys tem (106). It is based on the assumpt ion of a l inear relationship between H R and oxygen consumpt ion. Heart rate data is strongly related to energy expenditure, can be util ized in large studies and can collect data in smal l time intervals over a relatively long time period (32, 51). Th is l inear relat ionship between H R and oxygen consumpt ion al lows intensity of activity to be determined. Unfortunately this relationship is no longer l inear at high intensities of activity and is therefore less accurate during v igorous activity. Another downfal l of this method is that H R is sensit ive to emotional s t ress, environmental stress, and body posit ion. A s wel l , s ince H R response tends to lag behind changes in physical movement , the rapid transitions between intensity of movement in children may be masked (51, 105). 2.5.4 Pedomete rs Pedometers provide an objective measure of total step counts over a given period but most do not have the ability to look at f requency or intensity of P A , t ime stamp the step counts (32) or store data for extended periods (107). Newer models are time- s tamped, thus overcoming s o m e of the previous limitations. T h e y are not ab le to record counts during cycl ing or increases in energy expenditure due to increased load or movement up an incline (46). They are a lso known to underest imate v igorous intensity P A (53) and are relatively e a s y to tamper with. They are however, inexpensive, re- usable and non-react ive tools suitable for use in large-scale investigations (108). 2.5.5 Indirect Calor imetry Under control led laboratory condit ions indirect calorimetry is used to determine energy expenditure assoc ia ted with resting metabol ic rate, the thermic effect of food, and the thermic effect of exerc ise (32). More recently, portable, lightweight metabol ic sys tems have been introduced. They can be used under free-living condit ions but this is still too cumbersome to be undertaken with children (46) and is not a feasib le option in a 24 large sca le study. A major limitation of this technique is its inability to examine the specif ics of P A patterns (32). 2.5.6 Doub ly -Labe led Wate r Doubly- labeled water is cons idered to be the gold standard measurement of energy expenditure or P A in free-living situations (46). Doubly- labeled water g ives a direct measure of carbon dioxide production and d isappearance rates of the isotopes in the urine, blood, or sa l iva (4). Th is yields est imates of energy expenditure, taking the thermic effect of food into considerat ion. It is based on the difference in rates of turnover of hydrogen and oxygen in body water (4). It is non- invasive and can measure activity over a per iod of 1 - 2 w e e k s (32) and has low reactivity (46) but is a lso expens ive (32). A n important considerat ion is that energy expenditure is a physiological consequence of P A and the two are distinct constructs so it cannot directly measure P A (46). Us ing this method it is impossible to determine speci f ic P A patterns (32, 46). 2.5.7 Acce lerometry T o accurately a s s e s s chi ldren's activity patterns, the instrument must be sensit ive enough to detect, code, or record sporadic and intermittent activity (32, 109). The accelerometer is a unique and useful p iece of technology that is able to capture and store activity patterns in smal l t ime intervals over an extended period of t ime. Th is dev ice is a lso smal l and unobtrusive, (110) permitting participant f reedom of movement. The accelerometer is able to measure the intensity of body or body segment accelerat ions through s o m e form of piezoelectr ic or p iezoresist ive accelerat ion sensor technology (1). T h e senso r cons is ts of a piezoelectr ic e lement and a se ismic mass . W h e n the senso r undergoes accelerat ion the se ismic m a s s c a u s e s the piezoelectr ic element to bend and a voltage signal that is proportional to the appl ied accelerat ion is emitted (4). Reco rded accelerat ions are converted to a quantif iable digital s ignal referred to as a 'count' (46). Frequency-fi l tering techniques are incorporated into the units to exc lude accelerat ions unlikely to be generated by human movement (1). The accelerometer is able to measure important health-related d imensions of P A such as f requency, duration, and intensity of movement, and provide a chronological recording of these components (103). A downfall of this dev ice is that not all activity is reflected in accelerat ion and decelerat ion such as upper body movements , movement 25 up an incline, and cycl ing (32, 110). Despite these limitations the accelerometer has been found to be a valid tool to use when measur ing P A in chi ldren (103, 111) because the most common activit ies participated in by children are locomotor in nature (such as soccer , brisk walk ing, and general play or chas ing games) (40). 2.5.8 Summary Numerous tools are avai lable to a s s e s s P A , e a c h assoc ia ted with speci f ic limitations and strengths. T h e acce lerometer appears to be an ideal measurement tool to use for assessmen t of chi ldren in field studies due to its ability to capture sporadic activity in short t ime intervals over extended time periods. A robust and accurate P A measurement tool, such as the accelerometer, is required to obtain a thorough understanding of the unique P A patterns observed between ethnic groups and to examine the relationship between P A and var ious components of health- related physical f i tness in chi ldren. C H A P T E R III Methodology 3.1 Part icipants Part icipants were a sub-sample of the 1459 involved in the A S ! B C initiative and included a multi-cultural group of 579 boys (n = 284) and girls (n = 295) in grades four to five (ages 8 to 11) from schoo ls (n = 9) in the Greater Vancouve r Reg ion . Of these chi ldren, 36 students were absent on the day the activity monitors were distributed, 11 technical errors occurred with the dev ices , seven chi ldren moved between the time of consent and data col lect ion, and one child refused to wear the device. F rom this group, 106 of the chi ldren wore the monitor during a week in which a Profess iona l Development Day occurred. Initial examinat ion of the data sugges ted that the Profess ional Deve lopment Day altered the P A profile and therefore these children were removed from the analys is . O n e school (n = 44) wore the monitors over a different time period (Friday to Tuesday) due to technical difficulties. A s a result the children had only one full weekday of wear and thus, were also removed from the analys is . Chi ldren (n = 12) with less than 3.5 days wore the monitor for an average of two hours less per day and were a lso removed. In the remaining group of chi ldren, only those that wore the monitor during the average 'on ' and 'off' t imes were retained for analys is . One of these children was removed due to physiological ly unlikely B P data (143/128), two participants had B P readings that exceeded 120/80, three chi ldren had no data for the health-related phys ica l f i tness measures , and 17 chi ldren were of ethnic groups other than C a u c a s i a n or A s i a n . One-hundred seventy part icipants (n = 79 boys and n = 91 girls) from five schoo ls were retained for the final analys is . Written informed consent w a s obtained from the parents and/or local guardians of the chi ldren. The investigation was carried out accord ing to the ethical guidel ines set by the University Cl in ical Resea rch Ethics Board for research involving human participants (see Append ix A for ethics forms). 3.1.1 Genera l Part ic ipant Character is t ics Birth-date, gender and ethnicity were provided by the parents and/or guardians on the Health History Quest ionnai re (see Append ix B). Ch i ldren 's ethnicity w a s determined, for example , a s being North Amer ican and/or Eu ropean if both parents or 27 all four grandparents were born in North Amer i ca or Europe. If the ethnicity data provided on the quest ionnaire w a s not clear or was incomplete the child w a s asked to classify their parents and grandparents birthplace to determine ethnicity. If the information w a s still incomplete, any child that had, for example , both parents or all four grandparents born in C a n a d a (and/or Europe) the child w a s cons idered 'North Amer ican /European ' . For the purposes of this investigation, chi ldren were classif ied as : 1) C a u c a s i a n (European decent), 2) As ian (South, Eas t and Southeast) or 3) other. Only chi ldren in the first two classi f icat ions were used in the ana lys is because the sample lacked sufficient participants from other ethnic groups. 3.2 Card iovascu lar D i s e a s e Risk A s s e s s m e n t s 3.2.1 Anthropometry Height (cm) w a s measured to the nearest 1 m m with a portable stadiometer. Weight (kg) was recorded to the nearest 0.1 kg on an electronic sca le ( S E C A Germany) . S h o e s were removed for both of these measures . Two measurements of height and weight were averaged for analys is . BMI (kg/m 2) w a s calculated from these measures . Classi f icat ions of our part icipant's weight to height status w a s def ined by internationally establ ished va lues (112). Wa is t c i rcumference w a s taken midway between the iliac crest and the bottom of the r ibcage with an anthropometric tape (113). This measure was taken over top of a light shirt. Two measurements were taken and averaged for analys is. 3.2.2 Vascu la r Heal th Part ic ipants had their B P taken using an automatic sphygmomanometer (left arm). Rest ing heart rate w a s obtained simultaneously. Systo l ic and diastol ic B P (mmHg) and resting H R (bpm) measurements were used in these ana lyses . Chi ldren with resting B P above the 9 5 t h percenti le (120/80) were exc luded from further testing. 3.2.3 Musculoske le ta l F i tness The musculoskeleta l f i tness component of this investigation w a s compr ised of grip strength, push-ups, cur l -ups and si t -and-reach. The a s s e s s m e n t protocols are modified vers ions of those deve loped by C S E P (114). For a detai led descript ion of testing 28 instructions refer to Append ix C . Chi ldren were asked to complete as many push-ups and curl-ups as possib le. Max imum grip strength was determined by summing the maximum score from the greater of two trials of the right and left hand. Si t -and-reach scores were determined by the maximum distance reached over two trials. Max imum grip strength (kg) and s i t -and-reach (cm) scores were used in these ana lyses . 3.2.4 Card iovascu lar F i tness Card iovascu lar f i tness w a s measured via the shuttle run which has been found to be reliable in chi ldren (115). For the Leger shuttle run, the chi ldren were required to run back and forth between a 20 m distance and touch the 20 m line s imultaneously with a sound s ignal that emitted from a prerecorded tape. T h e starting speed is 8.5 km/hr and is increased by 0.5 km/hr every minute. The test w a s completed w h e n the child w a s not able to maintain the set pace . T h e total number of laps performed by each child w a s recorded and further used in the analysis. T h e shuttle run permitted as many as 15 - 20 children to run simultaneously. 3.2.5 Phys ica l Activity Phys ica l activity w a s measured objectively for 5 days using the G T 1 M Activity Monitor. It is des igned to ascertain normal human movement without impeding activity (103) and has been shown to provide valid and reliable est imates of chi ldhood P A (71). The G T 1 M is smal l and compact weighing 27 g and has d imens ions of 3.8 x 3.7 x 1.8 cm. It is equipped with 1 Megabyte of non-volatile f lash memory and a rechargeable 3.7 V Lithium Ion battery. It is des igned to detect accelerat ion s ignals ranging in magnitude from 0.05 to 2.00 g with a frequency response of 0.25 - 2.50 Hz. This f requency is able to detect normal human motion and reject motion from other sources such as riding in a vehicle. E a c h sample is summed over a user-speci f ied epoch (116). For this investigation the epoch w a s set at 15 seconds and provided both accelerat ion and step-counts. A short epoch w a s chosen in order to capture the short bouts of higher intensity activity performed by chi ldren. T h e activity monitor w a s attached to an elast ic belt and worn at the waist above the il iac crest. Part ic ipants were asked to wear the monitors for 5 consecut ive days (3 weekdays and 2 weekend days) for 12 consecut ive hours each day (8 am-8 pm was the suggested time interval) as this is within the four to seven day recommended time frame for obtaining a reliable est imate of habitual P A (r = 0.80) (117). The children were instructed to remove the monitors at night and while swimming, bathing, or shower ing. The G T 1 M Activity Monitor measured the duration, f requency, and intensity of P A which was a s s e s s e d throughout the weekday and weekend days . Specif ical ly for this project, the outcome var iables used were: 1) average counts per day, 2) average counts per minute, 3) average M V P A accumulated per day, 4) average M V P A accumulated per weekday, 5) average M V P A accumulated per weekend day, 6) average sporadic M V P A accumulated per day, 7) average minutes of M V P A accumulated in bouts of 5 minutes or more, and 8) M V P A accumulated throughout the schoo l day. Age-spec i f ic cut points were obtained from Trost et a l . , (118) who performed a rigorous calibration study on children of similar age with indirect calorimetry as the criterion measure . S ince these cut points were establ ished using 1 minute epochs , the va lues were divided by 4 for use with the shorter epoch length utilized in this investigation (see Tab le 3.1 for cut-points and classif icat ion of P A ) . Tab le 3.1. Age-spec i f i c classif icat ion of physical activity intensity by M E T s and counts (per 15 seconds) . Cut-points obtained from Trost et a l . (118). Intensity METs Counts (8yrs) Counts (9 yrs) Counts (10 yrs) Counts (11 yrs) Sedentary <1.5 0-49 0-56 0-62 0-70 Light 1.5-2.99 50-200 57-226 63-254 71-283 Moderate 3-5.99 201-827 227-874 255-293 284-976 MVPA 3+ 201-32767 227-32767 255-32767 284-32767 Vigorous £6 828-32767 875-32767 924-32767 977-32767 3.3 Procedure Part icipants were evaluated over a one week per iod. A trained research team of approximately three to four A S ! B C investigators conducted anthropometry, vascular health, musculoskeleta l f i tness and cardiovascular f i tness measures . For each day of measurements , chi ldren were temporari ly excused from their c lass rooms in groups of 10 to 15 at a time. Test ing took place in the gymnas ium of the schoo l . Day 1 consisted of measurements of anthropometry, vascu lar health, musculoskeleta l f i tness, and card iovascular f i tness (see Figure 3.1). Day 2 involved the distribution of G T 1 M Activity 30 Monitors to all of the participating children in the schoo l . Day 7 consis ted of monitor pickup and gift distribution to the children who returned the monitors Figure 3.1. Schemat i c of testing procedure. Day One Measurement of health- related fitness variables Day Two Distribution of G T 1 M Activity Monitors Day Three G T 1 M Activity Monitor pick- up and gift distribution 3.3.1 Day 1: Weight Status, Vascu la r Health and Heal th-Related Phys ica l Fi tness Measures The first day of assessmen ts compr ised of anthropometry, vascu lar health, musculoskeleta l f i tness and cardiorespiratory f i tness measurements (see Figure 3.2). Measurements of weight and W C are potentially sensit ive i ssues with some children. To help alleviate any emot ional anxiety children may exper ience during these measurements , each child had his or her weight status taken individually to ensure privacy. Vascu la r health measurements were taken prior to physical testing. Musculoskeleta l testing (i.e., grip strength, push-ups, curl-ups and sit-and-reach) was conducted next, fol lowed by the shuttle run. It is important that the shuttle run be completed last because it requires maximal physical exert ion and the fatigue the children exper ience after it is completed may negatively affect the musculoskeleta l tests. T h e s e tests took approximately one hour. Figure 3.2 Day 1: Schemat i c outlining the testing procedure. 31 Vascular Health Weight Status Resting Blood Pressure Height i Weight Waist Circumference Musculoskeletal Fitness Cardiorespiratory Fitness Grip Strength 1 Leger Shuttle Run Sit-and-Reach Push-ups Partial Curl-up 3.3.2 Day 2: Activity Monitor Distribution Day Two a lways occurred on a Wednesday . O n this day schoo ls were entered in the morning and up to 75 students were fitted with monitors. E a c h c lass room of students that participated in the study was given a detai led talk instructing them as to how and when the monitors needed to be worn. Then each child w a s individually fitted with a monitor and given an information package for their parent(s)/guardian(s). This took approximately 30 minutes per c lassroom. Parents /guard ians were provided with an information letter and contacted by phone on the evening that their child was fitted with a monitor to provide an opportunity for clarif ications to be made about the purpose and desired outcome of the study and for general quest ions (see Append ix E for information letter). The parents were also asked to complete a log which indicated the time the monitor w a s p laced on the child in the morning and the t ime it w a s removed in the evening, the t imes (if any) that the monitor was removed during the day, as well as any unusual c i rcumstances in which the child's regular routine w a s significantly affected (i.e., i l lness, weather) (see Appendix F for log). 32 3.3.3 Day 7: Activity Monitor P i ck -Up Monitors were returned to researchers the following Monday morning at the school . In exchange for returning the monitor the students were given a smal l gift and had their name entered into a draw for a larger prize. 3.3.4 Phys ica l Activity Data Reduct ion After each week of data col lect ion, the data were immediately downloaded to a laboratory computer. Da ta were then scanned for spur ious measures , malfunctioning units, and compl iance with wear guidel ines. Monitor on (time the child put the monitor on in the morning) and off (time the child removed the monitor before bed) t imes were determined using both the log sheets and a visual inspect ion of the file. In the case where the information on the log sheet did not match the data in the file or the log sheet was not returned, the objective information in the file w a s used . Only 1 3 % of the participants (54.5% girls and 45 .4% boys) with usable P A data did not return the log sheet. The participants were required to wear the monitor for at least 3 days of wear to be valid for analys is (see Figure 3.1) and initially it w a s dec ided that 8 hours would constitute a full day of wear (45). However, due to the large variability in the number of hours of wear (the range w a s 8 - 1 7 hrs) and hours of the day the monitor was worn, a day was cons idered valid if it fell within ± 2 standard deviat ions (SD) of the average 'on' and 'off t ime for that day. The average on and off t imes for each day were calculated to determine the new hours of acceptab le wear (see Append ix D for average wear hours per day). If a child wore the monitor too long (i.e., the monitor w a s put on before the average on time or removed after the average off time) the extra wear time w a s exc luded from the analys is so that all children were wear ing the monitor during the s a m e time f rame If fi les met the criteria for analys is, the data were subjected to custom software des igned to opt imize and standardize the production of P A outcome var iables. This software al lows the user to specify cut-points, t ime per iods of interest to be examined, and fractionalizations of P A for further statistical ana lyses . Figure 3.3. Dec is ion tree for data reductiorj. 33 3.3.5 Statist ical Ana lys i s M e a n s and standard deviat ions (SDs) were calculated for all ou tcome variables. A l l var iables were tested for normal distribution (i.e., skewness or kurtosis) and were transformed when necessary . Bivariate correlations were used to determine the relationships between all var iables. Ana lys is of Var iance ( A N O V A ) was chosen to determine if there were any dif ferences in weight status, vascu lar or health-related physical f i tness between the chi ldren who had acceptab le P A data and those that did not. T-tests were used to determine if gender dif ferences existed between var iables. Ana lys is of Covar iance ( A N C O V A ) was used to investigate the associat ion between ethnic groups (Caucas ian and As ian) and average M V P A per day, counts per minute, and health-related physica l f i tness scores . The P A outcome var iables were chosen to compare an index of the amount and intensity of activity. Prev ious literature has demonstrated that boys and girls are not a homogenous group (11, 27, 38, 52); therefore, A N C O V A s were performed separately for boys and girls. The covariates were chosen based on their known or observed relationship to P A in chi ldren. Factors that may affect the relationship of P A to health-related physica l f i tness and cardiovascular health in chi ldren are: 1) weight (an increase in weight has been related to decreased P A (22, 27, 74)), 2) height (52), and 3) age (as age increases P A dec reases (37, 38, 52)). A musculoskeleta l f i tness composi te score w a s created using Pr incipal Component Ana lys is . Var iab les were transformed into z -scores before being subjected to principal component analys is to s tandard ize units. The first principal component of the musculoskeleta l f i tness sco res (sit-and-reach, curl-ups, push-ups, grip strength) w a s retained for further analys is . T h e first principal component expla ined 3 9 % of the var iance in the original var iables. T h e correlations between the original var iables and the first principal component are reported as factor loadings representing their percentage contribution to the overal l score . T h e factor loadings were 0.380 (sit-and- reach), 0.762 (curl-ups), 0.678 (push-ups), and 0.612 (grip strength). Push-ups , curl- ups and grip strength contributed significantly to the overal l sco re with si t-and-reach contributing very little. F rom the factor loadings, a total musculoske le ta l f i tness score is der ived using the fol lowing formula (sit-and-reach * 0.380) + (curl-ups * 0.762) + (pushups * 0.678) + (grip strength * 0.612). This sco re is used to compare musculoskeleta l f i tness between the ethnic groups and to determine the relationship between P A and musculoskele ta l f i tness. Initially, ana lyses were carr ied out separately for boys and girls, however, s ince the factor loading w a s within 0.1 for all components, the components contributed similarly to the overall score and there w a s approximately only a 1% dif ference in expla ined var iance between boys and girls, the groups were co l lapsed into one to create the composi te score. Hierarchical regress ion w a s used to est imate the contribution of ethnicity and P A to health-related phys ica l f i tness components. Var iab les were entered in the following order: 1) age , height, weight (control variables), 2) ethnicity ( independent variable), 3) counts per minute ( independent variable), 4) M V P A per day ( independent variable). The order of var iable input into the regression analys is w a s determined through establ ished relat ionships between age, weight, height (maturity) and the health-related physical f i tness components . Ethnicity was entered a s the second step in the model and the P A outcome var iables was entered last to examine the unique relationship between P A and f i tness without the influence of the previous var iables. Intraclass correlat ion ( ICC) w a s calculated to examine the magni tude of variation between schoo ls . A 1-way A N O V A was run to obtain the s u m of squares for between school di f ferences and within schoo l dif ferences for total laps run in the Leger shuttle run, the musculoskeleta l f i tness score, average counts per minute and average M V P A per day. The calculat ion of ICC for each variable was as fol lows: = S u m of squares for between school dif ferences (Sum of squares for between school + within schoo l differences) Data were ana lyzed using S P S S statistical software, W indows Vers ion 14.0. Signi f icance w a s set at p< 0.05 for all statistical ana lyses . C H A P T E R IV Results 36 4.1 Genera l Subject Character is t ics Descript ive var iables for boys and girls that remained in the final analysis are summar ized in Tab le 4.1. Of the 170 children used in the ana lyses , 17 .6% were classif ied as overweight (56.7% boys and 66 .7% Asian) and 3 .5% were classif ied as obese (50% boys and 6 6 . 7 % As ian) using age and sex-speci f ic cut-off va lues (119). Tab le 4.1. M e a n s and S D s of participant characterist ics. Body M a s s lndex=BMI, SBP=sys to l i c blood pressure, DBP=diasto l ic blood pressure, M S K Score=musculoskeleta l f i tness score. N Boys N Girls Age (years) 79 10.0 ±0 .6 91 10.0 ±0 .6 Height (cm) 79 141.3 ±7.6 91 141.2 ±7 .5 Weight (kg) 79 36.6 ± 8.0 91 35.3 ±7 .7 BMI (kg/m z) 79 18.2 ±2 .8 91 17.6 ±2 .6 S B P (mmHg) 77 98.2 ± 7.0 91 96.9 ±9 .1 DBP (mmHg) 77 63.1 ±7 .1 91 62.0 ± 8.9 Heart Rate (bpm) 76 87.2 ± 10.9 89 87.7 ± 12.7 Total Laps 79 25.1 ± 14.8 91 21.3± 11.6 M S K Score 79 -.0434 ± 1.4677 91 -.0336 ± 1.8757 There were signif icant correlat ions between weight status, the musculoskeleta l f i tness score, total laps run (Leger shuttle run test) and P A outcome var iables (see Table 4.2). There were no signif icant correlations between vascu lar health and P A or weight status and P A . Data were examined for normal distribution and tests to detect skewness or kurtosis were completed. Minutes per day of bouted activity, total laps and BMI were negatively skewed and therefore log transformed. The curl-up and push-up data demonstrated a one-s ided distribution and underwent reciprocal transformation. 37 Table 4.2. Signif icant correlat ions between anthropometric, f i tness and physical activity var iables. (**) denotes p < 0.001, (*) denotes p < 0.05 M S K Score=musculoskeleta l composi te score, CPM=coun ts per minute, MVPA=moderate- to-v igorous physical activity Height Weight Age MSK Score Total Laps C P M MVPA Height 1 .752 .461** NS NS NS NS Weight .752** 1 .270** NS -.192* NS NS Age .461** .270** 1 NS NS -.177* -.306** MSK Score NS NS NS 1 .507** .171* .152* Total Laps NS -.192* NS .507** 1 .221** .189* C P M NS NS -.177* .171* .221** 1 .925** MVPA NS NS -.306** .152* .189* .925** 1 There were no di f ferences observed in weight status, vascu lar or health-related physical f i tness var iables between the groups who met the inclusion criteria for P A data and those who did not (in both the girls and the boys). There were 52 boys and 47 girls who did not have valid P A data of which 3 8 % and 5 7 % , respectively, were Caucas ian . There w a s no signif icant difference in weight status, vascu la r or health-related physical f i tness between boys and girls. 4.2 Phys ica l Activity Patterns O n average, the monitors were worn for 13.5 ± 1.1 hours per day with boys accumulat ing 408499.7 ± 106831.0 and girls accumulat ing 343807.8 ± 106912.8 counts per day (see Tab le 4.3 for P A outcome var iables in boys and girls). Boys obtained significantly more counts per minute on average than girls (p < 0.001), average M V P A per day (p < 0.001), average M V P A per weekend (p < 0.03) and weekday (p < 0.001), and accumulated more bouted minutes of M V P A than girls (p < 0.001). There w a s no signif icant difference in minutes of sporad ic M V P A between the genders. In both genders , significantly more M V P A occurred on the weekdays than on weekend days (p < 0.001). One child (Asian male) met C a n a d a ' s Phys ica l Activity Guide l ines for Chi ldren and You th . 38 Tab le 4.3. M e a n s and S D s of all P A outcome var iables. Avg=average, MVPA=moderate- to-v igorous physical activity, PE=phys ica l education. Boys (N = 79) Girls (N = 91) Avg Hours of Wear Per Day 13.5 ± 1.12 13.4 ±1 .1 Avg Counts Per Day 408499.7 ± 106831.0 343807.8 ± 106912.8 Avg Counts Per Minute 503.6 ± 122.7 429.8 ± 140.7 Avg Minutes of M V P A Per Day 133.9 ±33.9 113.5 ±35.9 Avg Minutes of M V P A Per Weekday 149.0 ±37.4 124.6 ±40.4 Avg Minutes of M V P A Per Weekend Day 112.7 ±45.0 98.4 ± 43.9 Avg Minutes of Sporadic M V P A Per Day 104.7 ±24.0 98.0 ± 27.8 Avg Minutes of Bouted M V P A Per Day 29.2 ± 20.9 15.5 ± 12.5 Total Minutes of School Day M V P A 65.1 ±21.0 52.4 ± 17.5 Total Minutes of Recess M V P A 5.1 ±4 .3 3.4 ±3 .1 Total Minutes of Lunchtime M V P A 16.5 ±7 .4 12.6 ±5 .2 Total Minutes of P E M V P A 5.3 ±6 .2 6.5 ±7 .1 In boys, 2 6 . 7 % of morning recess (5.1 ± 4.3 minutes) w a s spent in M V P A , 35.4% of lunch hour (16.5 ± 7.4 minutes), and only 13 .1% of P E (5.3 ± 6.2 minutes). Gir ls accumulated M V P A for 18 .3% of recess time (3.4 ± 3.1 minutes), 2 7 . 1 % of lunch hour (12.6 ± 5.2 minutes) and 16 .0% of P E (6.5 ± 7.1 minutes) in M V P A . Total minutes of M V P A during the schoo l day accounted for 24 .6% (65.1 ± 21.0 minutes) and 20 .8% (52.4 ± 17.5 minutes) of the total school day in boys and girls, respectively. 4.3 Ethnic Dif ferences in Phys ica l Activity and Heal th-Related Phys ica l Fi tness 39 C a u c a s i a n girls ran significantly more laps than A s i a n girls in the Leger shuttle run (p < 0.01), had significantly higher counts per minute (p < 0.001), and average minutes of M V P A per day (p < 0.001). There w a s no significant ethnic difference in the musculoskeleta l f i tness score for girls. C a u c a s i a n boys ran significantly more laps than A s i a n boys in the Leger shuttle run (p < 0.01), had significantly higher counts per minute (p < 0.03) and ach ieved significantly higher scores on the musculoskeletal f i tness score (p < 0.01). There were no significant ethnic di f ferences in the average minutes of M V P A per day in boys. Initially, the difference in each individual component of musculoskeleta l f i tness was examined between ethnic groups. Due to the large variation in scores between both male and female ethnic groups, the homogeneity of var iance tests were not met for push-ups and si t -and-reach in girls and curl-ups and grip strength in boys (see Appendix J) . 4.4 Regress ion Ana l ys i s The var iance in health-related physical f i tness (total laps run and the musculoskeleta l f i tness score were examined separately) expla ined by P A (average counts per minute and M V P A per day) w a s examined by entering the following independent var iables sequential ly into a hierarchical regress ion: 1) age, height, weight, 2) ethnicity, 3) counts per minute and, 4) M V P A per day. Resu l ts are presented in Tab les 4.4 - 4.5 (girls) and Tab les 4.6 - 4.7 (boys). In girls, age , height, and weight accounted for 11 .2% of the var iance in total laps run in the Leger shuttle run (p < 0.01), with ethnicity contributing another 8 .3% (p < 0.03). Neither counts per minute or M V P A per day contributed signif icantly to the model . None of the independent variables significantly predicted the musculoskeleta l composi te score in girls. In boys, age, height, and weight accounted for 19 .7% of the var iance in total laps run (p < 0.001) and ethnicity accounted for 7 .8% more (p < 0.01). Neither counts per minute or M V P A per day significantly contributed to the model . Ethnicity was the only independent var iable that significantly contributed to the prediction (8.4%) of the musculoskeleta l composi te score (p < 0.01). T w o other composi te scores were created to: 1) examine the relationship between the combinat ion of musculoskeleta l f i tness components and total laps run to P A and 2) examine the relationship of a composi te score of all health-related physical f itness 40 components and P A (see Append ix J). The correlation between both of these fitness scores and P A w a s lower than the individual components of health-related physical f i tness and P A and the correlation between P A and the musculoskele ta l composi te score reported. The factor loadings of the individual components within the final score can explain this. For example , in the composi te score that included all health-related physical f i tness components , BMI and W C had the highest factor loadings. Body mass index and W C had very weak and non-significant correlat ions to P A . W h e n these more heavi ly-weighted components were added to the rest of the scores , the components (such as total laps) that were more highly correlated to P A became diluted. Forward s tepwise regression w a s a lso used to examine the relationship between P A and health-related physical f i tness. The same independent var iables that were entered into the hierarchical regression (height, weight, age, ethnicity, M V P A per day and counts per minute) were entered simultaneously into the stepwise equat ion. In girls, weight and ethnicity significantly predicted fitness and in boys, height, weight, and ethnicity predicted f i tness (see Append ix J) . 4 .5 Intraclass Correlat ion Intraclass correlat ions were as follows: 0.27, 0.07, 0.07, and 0.07 for total laps run, musculoskeleta l composi te score , average counts per minute and average M V P A per day, respectively. 41 Table 4 . 4 . Resu l ts of hierarchical multiple regression model for cardiorespiratory fitness (total laps run in the Leger Shutt le Run test) in A s i a n and C a u c a s i a n girls. CPM=coun ts per minute, MVPA=moderate- to-v igorous physical activity. Fitness Variable in Model Standardized Beta Unstandardized Beta Adjusted R 2 R 2 Change Total Laps Run Height (p < 0.02) .349 .025 0.112 0.141 Weight (p < 0.002) -.461 -.033 0.112 0.141 Age (p < 0.03) -.258 -.234 0.112 0.141 Ethnicity (p < 0.03) -.250 -.275 0.189 0.083 C P M (p < 0.28) .369 .001 0.179 0.000 M V P A (p < 0.28) -.358 -.005 0.181 0.011 Table 4 . 5 . Resul ts of hierarchical multiple regression model for musculoskeleta l f i tness in As ian and C a u c a s i a n boys. CPM=coun ts per minute, MVPA=moderate- to-v igorous physical activity. Fitness Variable in Model Standardized Beta Unstandardized Beta Adjusted R 2 R 2 Change Musculoskeletal Score Height (p < 0.26) .189 .044 -0.008 0.025 Weight (p < 0.85) -.030 -.007 -0.008 0.025 Age (p < 0.99) .001 .003 -0.008 0.025 Ethnicity (p < 0.37) -.105 -.368 0.014 0.033 C P M (p < 0.96) -.016 .000 0.045 0.040 M V P A (p < 0.46) .259 .013 0.040 0.006 42 Table 4.6. Resu l ts of hierarchical multiple regression model for cardiorespiratory fitness (total laps run in the Leger Shutt le Run test) in A s i a n and C a u c a s i a n boys. CPM=coun ts per minute, MVPA=moderate- to-v igorous physica l activity. Fitness Variable in Model Standardized Beta Unstandardized Beta Adjusted R 2 R 2 Change Total Laps Run Height (p<0.01) .459 .036 0.164 0.197 Weight (p< 0.001) -.614 -.045 0.164 0.197 Age (p < 0.64) -.055 -.053 0.164 0.197 Ethnicity (p<0.01) -.274 -.322 0.235 0.078 C P M (p < 0.78) -.069 -.001 0.233 0.008 M V P A (p < 0.45) .187 .003 0.229 0.006 Table 4 . 7 . Resul ts of hierarchical multiple regression model for musculoskeleta l f i tness (composite score) in A s i a n and C a u c a s i a n boys. CPM=coun ts per minute, MVPA=moderate- to-v igorous physical activity. Fitness Variable in Model Standardized Beta Unstandardized Beta Adjusted R 2 R 2 Change Musculoskeletal Score Height (p < 0.06) .362 .071 0.048 0.084 Weight (p<0.16) -.248 -.046 0.048 0.084 Age (p < 0.23) -.151 -.370 0.048 0.084 Ethnicity (p < 0.004) -.340 -1.008 0.123 0.084 C P M (p < 0.40) -.225 -.003 0.129 0.017 M V P A (p < 0.74) .089 .004 0.118 0.001 43 C H A P T E R V Discussion 5.1 Phys ica l Activity Patterns in Chi ldren 5.1.1 Genera l Phys ica l Activity Patterns The general trends in our data are consistent with publ ished literature (40, 120). In boys, almost 8 0 % of average M V P A per day is spent in sporad ic activity and in girls almost 90%, illustrating the highly transitory nature of chi ldren's P A . Similar to our results, S leap and Warbur ton (40) and Epstein and co l leagues (51) reported that children accumulated approximately two hours per day of M V P A , however very little of this time w a s spent in susta ined bouts of activity. Signif icantly more activity occurred throughout the weekdays as compared to the weekend days. In boys, approximately 150 minutes of M V P A per day were achieved on the weekday compared to 115 minutes on the weekend day. The average accumulated amount of M V P A per day on the weekdays w a s 125 minutes in girls compared to 100 minutes on the weekend . Recommendat ions from British Co lumbia and the United States mandate that 5 0 % of P E time should be dedicated to active time (43, 121). Stratton and Mul len (122) extended these recommendat ions with the suggest ion that recess time should a lso consist of 5 0 % active time. W e found that total minutes of M V P A during the school day accounted for 2 4 . 6 % and 20 .8% of the total school day in boys and girls, respectively. In boys, 2 6 . 7 % of morning recess was spent in M V P A and in girls, 18 .3%. During lunch hour (which includes both a lunch and recess time) boys spent 34 .5% of the time in M V P A and girls spent 2 7 . 1 % . During P E girls accrued M V P A for 1 3 . 1 % of c lass and boys 16.0%. T h e boys are recording a similar number of minutes of M V P A during recess and P E despi te P E being twice the length of recess . Th is indicates that boys participate in greater amounts of P A during free play t imes as opposed to structured c lass time dedicated to P A . Our data shows that children in Vancouve r are not meeting the recommendat ions for activity participation during either P E or recess t imes. In the U.K., percentage t ime observed in M V P A at recess w a s 32 .9% in boys and 2 5 . 3 % in girls (44). T h e s e percentages are higher than our observat ions but still far from achieving the guidel ines. T h e s e results become even more alarming consider ing that it 44 is during these schoo l break t imes when M V P A has been most commonly seen in children (40). Schoo l s in Cal i fornia report that 4 0 % of a 30 minute P E c lass is dedicated to M V P A (123), and although this is still below recommended levels, it is much higher than that reported in British Co lumb ia . W e found that 1 3 % (boys) and 16% (girls) of the allotted P E time w a s spent in M V P A whereas Parce l et a l . (42) est imated that children were aerobical ly active for 6% of P E time. Using pedometers to a s s e s s P A , it was found that the steps accumulated during P E accounted for 8 and 1 1 % of total s teps per day in boys and girls, respectively (124). It is c lear that P E c lass is not providing sufficient opportunity for P A and insufficient P A is occurring during recess . Recent research has shown that chi ldren who were least active during the schoo l day were also the least active after schoo l hours and on the weekend days (61). Th is information highlights the necessi ty of schoo l -based interventions to supplement regular schoo l day activity and to provide children with the skills to be more act ive throughout the whole day. 5.1.2 Gende r Dif ferences in Phys ica l Activity and Heal th-Related Phys ica l Fi tness W e found that boys participated in significantly more M V P A per day and on average, had higher counts per minute (indicating more time spent in P A of higher intensity) than girls. G e n d e r di f ferences in P A have been fairly wel l -establ ished with boys displaying higher levels of P A than girls of the same age (11, 34, 36, 38, 51) and boys spending significantly more time in v igorous P A than girls (11, 39, 52). Ev idence has also shown that boys participate in a greater number of longer bouts of higher intensity activity than girls (39). Speci f ical ly in this investigation, boys accumulated double the amount of bouted M V P A minutes than did girls. Rowlands et a l . (53) sugges ted that vigorous intensity P A may explain the differences in activity that occurs between genders. In addit ion, our results a lso imply that time spent in bouted M V P A a lso accounts for the disparity between boys and girls s ince we found no significant dif ference between average minutes of sporad ic M V P A per day. This information suggests that boys may be more likely than girls to participate in structured, p lanned P A at high intensities. Boys general ly perform better in cardiorespiratory f i tness tests (26, 27, 60, 125) and in musculoskeleta l f i tness tests (26, 98) than age-matched girls. Al though our observat ions were not found to be significant, there w a s a trend for boys to complete 45 more laps in the shuttle run test. Our group previously reported no significant differences in card iovascular f i tness between boys and girls in a similar group of participants (67). The results of other studies may not be directly comparable to the present study due to dif ferences in cardiorespiratory and musculoskeleta l tests and participant character ist ics. 5.1.3 Phys ica l Activity Guide l ines Our data from V a n c o u v e r is even more alarming than that reported in the 2007 Report Ca rd on Phys ica l Activity for Chi ldren & Youth . They found that only 9% of Canad ian children met the guidel ines while in our study, only one child met the guidel ines of 90 minutes of M V P A per day. Despi te boys participating in approximately 134 minutes and girls accumulat ing 114 minutes of M V P A per day, only 30 and 15 minutes of average M V P A per day in boys and girls, respect ively w a s accumulated in activities lasting 5 or more minutes in duration. In other words, boys on average are only accumulat ing one third of the amount recommended and girls, one sixth. In a study of s imi lar ly-aged chi ldren, Andersen et al . (15) reported more positive data, indicating that the top three most active quintiles of chi ldren in the U.K. were achieving over 90 minutes of activity per day in durations of 5 to 10 minutes. Chi ldren in the lowest quintile of P A were still accumulat ing more activity in susta ined periods than the children in the present study. Resul ts are not directly comparab le due to the difference in cut-points and epoch lengths used between studies. Andersen et al . (15) used a threshold of 2000 c p m from a 1-minute epoch to def ine M V P A whereas we used age-speci f ic cut-points deve loped by Trost and co l leagues (118). A n investigation in S w e d e n demonstrated the effects on accumulated activity assoc ia ted with using different epoch lengths. Epoch lengths of 5, 10, 20, 40 and 60 seconds were used and minutes spent in 10-minute bouts were compared. No 10-minute periods of cont inuous activity were recorded in the 5 and 10-second bouts however, a lmost 3 bouts were recorded using the 1-minute epoch (126). This difference is quite dramatic and suggests that with the short epoch that was chosen for this study, bouted activity is not as likely to be observed . Furthermore, the magnitude of the epoch effect is amplif ied in the most highly active chi ldren (126) s ince the 1-minute epoch is known to dilute the chi ldren's v igorous intensity (38). 46 In addition to varying epoch lengths and cut-points, there is no cons is tency in the interpretation of results from studies determining chi ldren's compl iance with P A guidel ines depending on whether assessmen ts are based on intermittent, accumulated or sustained durat ions of activity. Methods of P A data acquisit ion and reduction are highly variable (and the latter is rarely reported) and can have significant effects on the data. In many studies, actual minutes of P A and criteria for qualifying data as acceptable are not publ ished. Finally, guidel ines used to a s s e s s chi ldren's activity level differ between studies (refer back to Table 2.1). Comb ined , these limitations in make compar isons between studies reporting P A difficult. S ince sporad ic activity is typical in children of this age (31) and constitutes such a large percentage of total M V P A time, it is extremely va luable information. Short epochs were used for the col lect ion of the P A data to ensure that the intermittent and short bouts of activity were captured (see Appendix I). In addit ion, we utilized accelerometry to measure P A so the data obtained is objective and is both date and t ime-stamped. W e are confident that our data provides an accurate representation of physical activity patterns in the populat ion examined. To determine activity intensity, we used age- specif ic cut-points deve loped by a group of influential researchers in the field of accelerometry (118). A n investigation comparing the utility of three commonly used cut- points in chi ldren documented that these specif ic cut-points are able to accurately categor ize activity into the correct intensity categor ies (127). In addit ion, our group analyzed the P A data with custom des igned software which al lowed us to examine the P A patterns in great detail . For example, we were able to determine the number of M V P A minutes that occurred during e a c h segment of the schoo l day and we were ab le to fractionalize the M V P A minutes to determine the amount that occurred in bouts. Furthermore, dec is ions regarding inclusion and exclus ion criteria were based on the average day of a child in our study. The average 'on ' and 'off t imes were calculated for each day and only those chi ldren who wore the monitor within those hours were retained in the analys is . Al though this decreased our sample s ize , it a lso eliminated bias that might occur with var iable wear hours. The 'on ' and 'off t imes that were used to determine valid days are normal wear hours for the children and were not arbitrarily chosen . Thus , the data presented is representing what occurs in an average day for the chi ldren. Finally, w e examined P A compl iance using the only guidel ines avai lable that 47 consider the speci f ic character ist ics of P A in chi ldren. T h e s e guidel ines are based on expert opinion. The avai lable data suggest ing that children are not meeting the physical activity guidel ines support our first hypothesis. Addit ional reports showing that children are not meeting activity recommendat ions within the school day provides clear ev idence that children are not acquir ing enough P A . 5.2 Ethnicity, Phys ica l Activity and Phys ica l F i tness 5.2.1 Ethnic Dif ferences in Phys ica l Activity W e found that C a u c a s i a n girls accumulate greater amounts of higher intensity activity (as indicated by the average counts per minute) than A s i a n girls and participated in significantly more M V P A per day. In a study of 10 year-old A s i a n and Caucas ian girls in Vancouver , C a u c a s i a n girls engaged in almost double the number of extracurricular or sport activities and double the amount of loaded activity (defined as activity that has a greater impact than walking) than the A s i a n girls. The difference in general activity, a s s e s s e d by the Phys ica l Activity Quest ionnaire for Chi ldren, was only slight (17). Investigations based in the United States a lso showed A s i a n s participating in less v igorous intensity exerc ise than Ang lo -Saxon individuals (128) and achieving lower scores on P A quest ionnaires (62). Gordon-Larsen et a l . (34) d iscovered that almost 5 0 % of the A s i a n girls in their study engaged in 2 or less bouts of M V P A per week. Of the 3 ethnic groups examined, the non-Hispanic white females were most likely to participate in M V P A and the As ian girls were least likely to participate in M V P A . Only one study from the Vancouve r region did not exhibit a significant difference in P A between the A s i a n and C a u c a s i a n girls (18). Resul ts from this investigation indicate that A s i a n boys participate in less high intensity activity than C a u c a s i a n boys. The data indicating that there is no difference in total amounts of accumulated M V P A per day between A s i a n and C a u c a s i a n boys is consistent with data presented by MacKe lv ie et al . (64) who found, using the Phys ica l Activity Quest ionnaire for Chi ldren, that there w a s no significant difference in P A between 10 year - old A s i a n and Caucas ian boys in Vancouver . In addit ion, information from the National Longitudinal Study of Ado lescent Health in the United States reported that in ado lescent boys, there w a s minimal difference in P A (as measured by self- 48 report) between A s i a n boys and boys of other ethnicit ies (34). Ev idence from M c K a y et al . (18) Vancouve r -based study demonstrated that C a u c a s i a n boys were significantly more active than their A s i a n peers and approximately five t imes as many Caucas ian boys participated in extracurricular sport activities (18). R e a s o n s for these disparit ies could stem from the methods utilized to obtain est imates of P A . In our investigation, P A data was measured objectively using accelerometry whereas self-report quest ionnaires were used in the other studies. The benefits of accelerometry are demonstrated in our results. In boys we found a difference in the intensity of activity between ethnic groups in the absence of a difference in M V P A per day. The accelerometer detects accelerat ion of the body and provides a direct measure of P A intensity in counts. It is therefore better able to capture high intensity activity in compar ison to measures of self-report which were used in the other investigations. Th is el iminates some of the limitations and bias assoc ia ted with self-report and may be the reason a difference was detected. It is possib le that the activity levels of the A s i a n children in our study were underest imated based on MacKe lv ie et a l . (17) who reported that in general , A s i a n girls living in Vancouver more commonly participate in swimming lessons than other sports. The accelerometer is not waterproof and therefore is not able to be worn for water -based activities. Despite this, the difference in P A w a s very highly significant (p < 0.001) indicating that very high amounts of swimming would need to be accumulated to account for the difference in P A . Other factors that may contribute to why As ian children are less active than C a u c a s i a n chi ldren have been considered within the literature. Psycho logy research suggests that A s i a n children (both male and female) perceive a lack of control over engaging in P A and therefore are less likely to participate in P A (129). Th is lack of control may be due to factors such as being required to allot a greater amount of time to academic endeavors (129). For example, As ian children are twice as likely as C a u c a s i a n chi ldren to spend time in academic lessons (i.e., mus ic lessons , mathematics, etc.) after schoo l as opposed to sporting activities (18). Specif ical ly in girls, culture may cons ider st renuous activity to be unacceptable and activity is therefore not encouraged (62). Soc ia l factors, such as parental support or level of activity of the parent(s) may a lso inf luence P A behaviours in chi ldren (130). Posi t ive associat ions between parental encouragement of P A and chi ldren's immediate activity have 49 consistently been shown (131, 132). Statistics C a n a d a reported that As ian men and women in C a n a d a a lso accumulate lower levels of P A than C a u c a s i a n men and women (16), thus there is the potential for this to influence the level of M V P A in As ian children. 5.2.2 Ethnic Dif ferences in Heal th-Related Phys ica l F i tness Limited research has been conducted on the components of health-related physical f itness and how those differ between As ian and C a u c a s i a n chi ldren living in the same geographical location. In the U.K., lower levels of physical f i tness in A s i a n as compared to Ang lo -Saxon children have been reported (66). More specif ical ly, in Britain, one third of children of Indian (South As ian) background were unable to complete the cardiorespiratory test (power output against load at 8 5 % of the max imum heart rate) utilized in the study. Moreover , those that did complete the test ach ieved lower scores than children of other ethnicit ies (19). This trend was the s a m e for both genders. Al though we found that A s i a n girls completed significantly fewer laps in the Leger shuttle run test than C a u c a s i a n girls we found no difference in the musculoskeleta l f i tness score between ethnicit ies in girls. In boys, there w a s a significant difference with the C a u c a s i a n boys complet ing more laps and achieving higher musculoskeletal f i tness scores than A s i a n boys. Our data supports previous research from our group demonstrat ing lower cardiorespiratory f i tness in A s i a n boys and girls (67). Signif icant correlat ions between P A , (average counts per minute), and total laps run in the Leger shuttle run (r = 0.230, p < 0.001) suggest that those children who participate in higher intensity activity are more likely to obtain a higher score in the Leger shuttle run. Activity at high intensity is thought to contribute more to healthy levels of cardiorespiratory f i tness than lower levels of activity (133). In both the boys and girls, those of C a u c a s i a n ethnicity had significantly greater counts per minute than children of A s i a n ethnicity. In prepubertal chi ldren, di f ferences in f i tness levels can be partially expla ined by dif ferences in P A (92). Consequent ly , this may be one underlying reason why C a u c a s i a n chi ldren performed better in the shuttle run test. Other possible reasons for the dif ference in cardiorespiratory f i tness between ethnic groups are the s a m e as s o m e of those outlined previously as being reasons for the difference in P A . As ian children are more likely to spend free time engaging in activities with a more academic focus than C a u c a s i a n children (18) and cultural norms may d iscourage participation in v igorous activities which promote physical f i tness (62). Furthermore, if 50 C a u c a s i a n chi ldren are participating in more organized sport (18), they may be enhancing cardiorespiratory f i tness to a greater extent than if they were just being regularly active on their own. The musculoskeleta l f i tness score was significantly higher in Caucas ian boys than As ian boys. The s a m e reasons that Caucas ian boys completed more laps in the shuttle run than A s i a n boys could explain why C a u c a s i a n boys a lso have a higher musculoskeleta l f i tness score . The Caucas ian girls, despi te participating in greater amounts of high intensity activity and total P A , and complet ing more laps in the Leger shuttle run, did not have a significantly greater musculoskeleta l f i tness score. Due to a difference in var iance between the Caucas ian and A s i a n chi ldren (in both boys and girls) some of the individual components of musculoskeleta l f i tness did not meet the assumpt ion of homogenei ty of var iance, (see Append ix J for statistics). Therefore, the aggregate score to compare musculoskeleta l f i tness between ethnic groups was used. The technique that w a s used weights each of the components based on their relationship to each other and this weighting is used to calculate the final value of the score (refer back to sect ion 3.3.5). It is possib le that the use of this composi te scoring system masked the individual dif ferences of the var ious musculoskeleta l f i tness components between ethnicit ies in girls. For example , in the formula used, pushups and grip strength were similarly weighted. If the C a u c a s i a n girls completed more pushups on average than the As ian girls but there w a s no difference in average grip strength scores , the difference in pushup scores between ethnicit ies would be diluted. The results reveal ing dif ferences in P A and f i tness between A s i a n and Caucas ian children support our second hypothesis. W e are confident that the significant dif ferences observed between As ian and Caucas ian chi ldren were not due to body s ize or age s ince di f ferences remained after weight, height, and age were entered as covariates into the A N C O V A . The covariates were chosen based on previous literature or observed relat ionships in the present dataset. There is a clearly defined relationship between age and P A whereby P A decreases with increasing age (37, 38, 46) and this relationship w a s detected in the correlations between age and P A variables. Most were significant and negat ive (r = -0.160 - (-0.306)). Height w a s used as an index of maturity. A s individuals mature, P A dec reases (52). Final ly, a substantial amount of literature has demonstrated that weight is significantly and inversely related to P A (22, 51 74). Al though we found no relationship between weight status and P A , it was still entered based on f indings in the literature. To our knowledge, this is the first study in C a n a d a using accelerometry to compare P A levels between A s i a n and Caucas ian chi ldren. It is a lso the first to examine differences in musculoskeleta l f i tness between ethnic groups living in the same geographic region. It therefore provides extremely important information regarding fitness and activity in these two diverse groups and will contribute significantly to the limited literature regarding ethnic differences in P A and health-related physical f itness and P A patterning in chi ldren. 5.3 Phys ica l Activity and Phys ica l F i tness 5.3.1 Phys ica l Activity and Musculoskeleta l F i tness Investigations relating P A to indicators of musculoskeleta l f i tness in children report equivocal results (88). Sal l is et a l . (26) reported that the combinat ion of a physical activity index (multiple measures of P A were taken and combined to create one variable) and gender accounted for 9 .1%, 6.7%, and 5 . 1 % of the var iance in pull-ups, sit-ups, s i t -and-reach scores , respectively in fourth-grade chi ldren. In compar ison, P A did not significantly predict our aggregate score of musculoskeleta l f i tness components in either girls or boys. There was little difference in the correlat ions between the musculoskeleta l f i tness score and the individual components of musculoskeleta l f i tness that were significantly related to P A (push-ups was the largest and only musculoskeleta l f i tness component significantly related to PA) so it is unlikely that the use of the individual components would result in substantial di f ferences to the f indings reported, (see Append ix J for statistics). Correlat ions between the musculoskeleta l f i tness score and P A in the present study were weak, but significantly related (r = 0.152 - 0.172, p < 0.05). T h e s e relat ionships are similar to those reported by Katzmarzyk et a l . (25) between M V P A (measured by self-report) and individual components of musculoskeleta l f i tness. O n e study has also reported no signif icant relationship between P A and musculoskeleta l f i tness (assessed as maximal musc le strength of the legs) in chi ldren (125). The f i tness var iables differ between studies and may represent slightly different domains of musculoske le ta l f i tness, as did the participants, making direct compar isons 52 difficult and possib ly affecting the results. Al though measurement of P A was more comprehens ive in the investigation by Sal l is and co l leagues (26) and provided a more holistic picture of the chi ldren's P A patterns, the correlat ions between individual P A components were quite low. The participants in the present investigation were not an ethnically homogenous group and we had less power which could also contribute to the difference. 5.3.2 Phys ica l Activity and Cardiorespiratory Fi tness In contrast to our f indings that P A (counts per minute and M V P A per day) did not contribute to the prediction of cardiorespiratory f i tness in chi ldren, previous research has demonstrated signif icant f indings whereby P A accounts for 10 - 2 1 % of the var iance in cardiorespiratory f i tness. Dencker and co l leagues (29) conc luded that the combinat ion of mean daily P A and vigorous P A expla ined 1 0 % (1% and 9%, respectively) of the var iance in V02Peak in a group of 8 to 11 year-old chi ldren. Sal l is et a l . (26) reported that the combinat ion of a physical activity index (multiple measures of P A were taken and combined to create one variable) and gender accounted for 1 1 % of the var iance in the mile run test. Pate et al . (134) a lso used numerous measures of P A combined with age and gender as the independent var iables to account for 2 1 % of the var iance in the 1.6-km run/walk test. There are a variety of reasons to explain this difference. None of the studies mentioned entered weight into the regression model . Weight had a weak but significant correlation to total laps run (r = 0.192, p < 0.05) in the present investigation, significantly contributed to our model (p < 0.001 in boys and p < 0.002 in girls) and has an establ ished relationship to f i tness outcomes in chi ldren (125). Th is information suggests that it may confound the relationship between P A and physical f i tness and should be accounted for when explaining the var iance between these factors. Participant characterist ics a lso differed; participants of the present study were of two different ethnicities whereas participants of the other studies were a more homogenous group. In the latter study a smal l percentage of the participants were of different ethnicity than the majority group however, this was not accounted for in the statistical ana lyses . Ethnicity contributed signif icantly in the present investigation, account ing for 7.8 - 8 .3% of the var iance in cardiorespiratory f i tness independent of height, weight and age. Different tests of cardiorespiratory f i tness were used in the studies however the correlations 53 between M V P A per day and the aerobic f itness tests used were similar between studies. This sugges ts that the inconsistent results should not be attributed to the measurement tools. 5.3.3 Phys ica l Activity and Phys ica l Fi tness The correlation between the musculoskeletal f i tness score and total laps run (r = 0.507, p < 0.001) is suggest ive that the musculoskeleta l f i tness score may be a better predictor of cardiorespiratory f itness (or v ise versa) than measures of P A . (See Appendix J , for statistics). Phys ica l activity is a behaviour (7) and is therefore prone to variation (36) and inf luence from numerous environmental , cultural (7) and social situations. Leve ls of P A may be transient and hence, more difficult to relate to a variable or condit ion at one time period. Phys ica l f i tness is a physiological state (7) or attribute (125), making it a more stable entity and less prone to variation and influence from external factors. Phys ica l f i tness is thought to develop as a result of prolonged P A . Al though f i tness does change , measurement at one time point may be more likely to accurately represent the physiological state of an individual. Th is is indicated by tracking studies which show that physical f i tness has higher inter-age correlations and more stability over t ime than indications of P A (7). Moreover , a recent tracking study in children reported that when sources of variation are control led, results showed moderate stability of P A (120), thereby demonstrat ing its more variable nature. Factors such as biological and behavioural domains of change assoc ia ted with normal growth and maturation, environmental or cultural sett ings in which subjects were raised (25), genet ics (135), diet, and motivational (26) or psychosoc ia l aspects have also been suggested as contributors to the var iance in physical f i tness. 5.3.4 Phys ica l Activity and Weight Status There is an increasing amount of ev idence in the literature demonstrat ing that body composi t ion, a s s e s s e d either by BMI or percentage fat, is inversely correlated with habitual P A (20, 22, 27, 74). W e found no significant relationship between any P A var iables and indices of weight status (BMI and W C ) and no trends were evident in the data. P reva lence of overweight in this dataset was 6 % lower in girls and 12% lower in boys than previously publ ished reports during the pilot phase of this project (136). Thus , there may not have been sufficient numbers of overweight chi ldren to detect a 54 difference in P A , especia l ly s ince the P A data was quite var iable. Alternatively, the overweight chi ldren in the sample may be as active as normal weight chi ldren. In support of our data, one of the major f indings in a study by Grund et a l . (125) was that there are no dif ferences in P A between normal weight, overweight and obese children. The measurement tools used should not have contributed to the difference in results between our study and those that did report a significant difference. Indices of weight status used in this investigation (BMI) have been found to be inversely related to P A levels in other cohorts using a variety of tools for P A assessmen t . It is possib le that in this cohort of chi ldren, dietary factors may contribute more significantly to the development of overweight in chi ldren, or overweight chi ldren may be engaging in more P A as a form of weight control (26). Alternatively (or additionally), in overweight or obese individuals, the accelerometer is further from the body 's centre of gravity than on a normal weight individual. This results in the accelerometer exper iencing greater accelerat ion for any given movement. It is possib le that in the obese chi ldren, the accelerometer w a s recording excess ive movement which may contribute to the higher P A . 5.3.5 Phys ica l Activity in Relat ion to Vascu la r Health In normal weight chi ldren, P A may have little effect on vascu lar health as indicated by previous investigations that reported no significant f indings (14, 20). W h e n body weight is accounted for, studies that did report lower B P va lues in more active children found that the relationship d isappeared (12). Chi ldren with lower P A had greater body fat which w a s responsib le for the high B P values (12). Alternatively, the detrimental effects of an inactive lifestyle on the vascu lar sys tem may not be advanced enough to be detected by a B P machine. W e recently revealed that P A accounts for 6 % of the var iance in smal l artery compl iance as measured by arterial tonometry (see Appendix G) suggest ing that the use of a dev ice more sensit ive to blood vesse l change may be better able to establ ish this relationship. Al though the relat ionships between P A and the components of health-related physical f i tness did not support our third hypothesis, our results contribute important information to the exist ing literature. Var ious statistical tests were completed to thoroughly examine the data. Within our regression ana lyses we controlled for factors (height, weight, age and ethnicity) known to contribute to the relationship between P A and physical f i tness and we are therefore confident in the data we are reporting. The fitness measures util ized in the present investigation are r igorous, are commonly used in children (115), and provide pertinent information regarding f i tness, especial ly s ince we utilized a variety of health-related physical f i tness tests to obtain a comprehensive profile of the chi ldren. A s has previously been mentioned in the document, the accelerometer is a sensit ive and objective tool that is ideal for P A measurement in chi ldren. W e did not find P A to be a significant predictor of f i tness in children however our results suggest that musculoskeleta l f i tness may be a stronger predictor of cardiorespiratory f i tness than P A . 5.4 Future Directions This study provides important basel ine information for A S ! B C to which the effects of the intervention can be compared . Fol low-up investigations may provide important ev idence regarding the contribution of bouted activity to health outcomes, the implications assoc ia ted with P A patterning, and between ethnic groups, detect where the difference in activity is occurr ing. Further exploration of the relationship between musculoskeleta l and cardiorespiratory f i tness is a lso warranted. 5.5 Limitations The method of P A measurement and protocol of obtaining habitual P A data in this investigation is based on the assumpt ion that chi ldren's P A habits are relatively constant and that we are able to accurately capture this constant level of P A in only a few days. Due to the immense interest in P A patterning in chi ldren, there has recently been substantial research in the numerous sources of natural variation in this behaviour. Kr is tensen et a l . (36, 120) determined severa l variat ions that could significantly affect P A levels in 8 to 10 year-olds and Mattocks et a l . (48) conc luded that intra-individual variation and seasona l variation were substant ial . S ince we are estimating habitual P A from one time-point, there is the potential for variation error within our data. For example , data collection occurred over the months of early November to early February. In the month of January the city of Vancouve r exper ienced excess i ve amounts of rain. Prev ious literature has demonstrated that children are more active during the more pleasant months of the year (36) so during this time period, chi ldren may have had lower P A levels than normal. Th is variation may 56 partially explain why we found no relationship between P A and health-related physical f i tness. The ICC w a s used to est imate the effects of schoo l on the P A and health outcome measures used in the analys is . For total laps run the ICC w a s 0.27 suggest ing that there was substant ial effect of the schoo l . The variation may be due to the school environment or it may indirectly be due to the community the school is in (61). The ICC was low (0.07) for the other components indicating that there w a s more variation between the participants than between the schoo ls in the data. 5.6 Conc lus ions Only one child in the present investigation met the recommendat ions of C a n a d a ' s Phys ica l Activity Gu ide l ines for Chi ldren. Moreover, chi ldren are not meeting activity level recommendat ions during the school day. Low levels of M V P A suggest that many children in Vancouve r may be at risk for poor health due to insufficient P A . Our results demonstrated that Caucas ian children had higher levels of P A and physical f i tness than A s i a n chi ldren. Low levels of P A and low fi tness levels are important modif iable risk factors for cardiovascular d i sease risk and are assoc ia ted with various health compl icat ions. The lower levels of P A and f i tness in A s i a n children indicate that this ethnic group may be a vulnerable group at a higher risk for assoc ia ted card iovascular and health compl icat ions with increasing age . Phys ica l activity w a s not a significant predictor of f i tness in this cohort of chi ldren. Our results suggest that musculoskeleta l f i tness may be a more powerful predictor of cardiorespiratory f i tness (and v ise versa). Comb ined , these f indings suggest that implementation of interventions are warranted to encourage P A participation in chi ldren and ass is t in the prevention of chronic health compl icat ions. 57 Footnotes 1. R a w data is attached in Append ix 58 C H A P T E R VI References 1. Es l iger D W , Cope land J L , Barnes J D , Tremblay M S . 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Ottawa: Canad ian Society for Exerc ise Physio logy; 1996. 72 Action Schools! BC Consent Form for Families Please read the following with your child, and if you and your child would like to participate please sign the attached form and return the signed form in the stamped, addressed envelope provided. You may keep the other pages for your records. Procedures. Your child's participation in the Action Schools! B C (AS! B C ) Research Study w i l l involve two in-school testing sessions in the Fal l and Spring of the next two school years. A l l children w i l l participate in the Anthropometry and Questionnaire components and a smaller random sample of students w i l l participate in the Cardiovascular Health and Musculoskeletal Fitness component. 1. Anthropometry: Measures of height, weight and calf and waist circumference w i l l be taken. Total Time - 10 minutes: Fal l and Spring. 2. Questionnaires: Your child w i l l be assisted in the completion of questionnaires that w i l l assess their physical activity, nutrition, self-esteem and attitudes and perceptions about physical activity. A trained research assistant w i l l discuss the importance of these assessments with the children. Total Time - 1 hour: Fal l , Winter and Spring. 3. Cardiovascular Health and Musculoskeletal Fitness: We w i l l evaluate aerobic fitness using a shuttle run in which students repeatedly run 20 meter laps in time with a clearly audible "beep" until they become tired and choose to stop. Musculoskeletal fitness (i.e. muscle strength and power) w i l l be assessed using a hand held dynamometer. A research assistant w i l l provide clear instructions for each procedure to the students. Resting blood pressure and heart rate w i l l be recorded before all fitness procedures. A smaller group of students (25%) w i l l be recruited for this portion of the study. Total Time - 45 minutes: Fal l and Spring. Health History Questionnaire: If you and your child agree to participate in the A S ! B C Research Study, you wi l l be asked to complete the attached Health History Questionnaire to determine i f there are any health reasons to exclude your child from the research study and to identify any conditions or medications that may affect study outcomes. Possible Harms: None. 74 Consent Form - September 2006 Please Jill out both sides of this form and return it in the stamped, addressed envelope provided. Please keep the other pages for your records. Parent's Consent Statement: I/We ' the (Please print the name of one or both parents/guardians) parents/guardians of have received and read all (Please print child's first and last name) 6 pages of the information letter and consent form and understand the purpose and procedures of the Action Schools! B C Research Study as described. Please check (S) one. I agree to have my child participate in the 3-year Act ion Schools! B C Research Study (anthropometry, questionnaires) with the understanding that my child may or may not be randomly selected to participate in the cardiovascular health and musculoskeletal fitness portion of the study. I do not agree to have my child participate in Action Schools! B C Research Study. I understand that at any time during the 3-year Action Schools! B C Research Study we w i l l be free to withdraw without jeopardizing any medical management, employment or educational opportunities. I understand the contents of all six pages of this form and the proposed procedures. I have had the opportunity to ask questions and have received satisfactory answers to all inquiries regarding this program. Signature of Parent or Guardian Date Printed name of the Parent or Guardian signing above (Continued on other side) 75 Child's Statement: I have talked with my parents/guardians about the Act ion Schools! B C Program and Research Study and I understand what I w i l l be asked to do. I understand that i f I want to I can stop being in the research study at any time and I wi l l still be able to participate in activities at my school. I have had the chance to ask questions and have received satisfactory answers to all of my questions. Signature of Child Date Printed name of child School Name Grade and Division 78 Action Schools! BC Consent Form for Families Please read the following with your child, and if you and your child would like to participate please sign the attached form and return the signed form in the stamped, addressed envelope provided. Y o u may keep the other pages for your records. Procedures. Your child's participation in the Action Schools! B C (AS! B C ) Research Study wi l l involve two in-school testing sessions in the Fal l and Spring o f the next two school years. A l l children w i l l participate in the Anthropometry and Questionnaire components and a smaller random sample o f students w i l l participate in the Cardiovascular Health and Musculoskeletal Fitness and Accelerometer components. 4. Anthropometry : Measures of height, weight and calf and waist circumference wi l l be taken. Total Time - 10 minutes: Fa l l and Spring. 5. Questionnaires: Your child w i l l be assisted in the completion o f questionnaires that w i l l assess their physical activity, nutrition, self-esteem and attitudes and perceptions about physical activity. A trained research assistant w i l l discuss the importance of these assessments with the children. Total Time - 1 hour: Fal l and Spring. 6. Cardiovascular Health and Musculoskeletal Fitness: We w i l l evaluate aerobic fitness using a shuttle run in which students repeatedly run 20 meter laps in time with a clearly audible "beep" until they become tired and choose to stop. Musculoskeletal fitness (i.e. muscle strength and power) w i l l be assessed using a hand held dynamometer. A research assistant w i l l provide clear instructions for each procedure to the students. Resting blood pressure and heart rate w i l l be recorded before all fitness procedures. A smaller group of students (25%) w i l l be recruited for this portion of the study. Total Time - 45 minutes: Fal l and Spring. 7. Accelerometers: We w i l l monitor children's physical activity with accelerometers. Children wi l l wear the accelerometer (on a belt around their waist) from the time they get up until the time they go to bed (approximately 12 hours) for 5 consecutive days. A research assistant wi l l provide clear instructions for how to wear the accelerometer. A small group of students (25%) who participate in the cardiovascular component (item 3 above) w i l l be recruited for this portion o f the study. Total time - 45 minutes in the Fa l l for a session on accelerometer instructions. Accelerometers w i l l be worn for 5 days in the Fa l l and Spring. 80 Consent Form - September 2006 Please fill out both sides of this form and return it in the stamped, addressed envelope provided. Please keep the other pages for your records. Parent's Consent Statement: I/We the {Please print the name of one or both parents/guardians) parents/guardians o f have received and read all {Please print child's first and last name) 6 pages of the information letter and consent form and understand the purpose and procedures of the Action Schools! B C Research Study as described. Please check (S) one. I agree to have my child participate in the 3-year Act ion Schools! B C Research Study (anthropometry, questionnaires) with the understanding that my child may or may not be randomly selected to participate in the cardiovascular health and musculoskeletal fitness and accelerometer portions of the study. I do not agree to have my child participate in Action Schools! B C Research Study. I understand that at any time during the 3-year Action Schools! B C Research Study we w i l l be free to withdraw without jeopardizing any medical management, employment or educational opportunities. I understand the contents of all six pages of this form and the proposed procedures. I have had the opportunity to ask questions and have received satisfactory answers to all inquiries regarding this program. Signature of Parent or Guardian Date Printed name of the Parent or Guardian signing above (Continued on other side) 81 Chi ld ' s Statement: I have talked with my parents/guardians about the Action Schools! B C Program and Research Study and I understand what I w i l l be asked to do. I understand that i f I want to I can stop being in the research study at any time and I w i l l still be able to participate in activities at my school. I have had the chance to ask questions and have received satisfactory answers to all of my questions. Signature of Child D a t e Printed name of child School Name Grade and Division 82 The University of British Columbia Office of Research Services Clinical Research Ethics Board-Room 210, 828 West 10th Avenue, Vancouver, BC V5Z 1L8 ETHICS CERTIFICATE OF EXPEDITED APPROVAL: RENEWAL PRINCIPAL INVESTIGATOR: Heather A. McKay DEPARTMENT: UBC CREB NUMBER: H02-70537 INSTITUTION(S) WHERE RESEA N/A Other locations where the research will be < N/A RCH WILL BE CARRIED OUT: :onducted: CO-INVESTIGATOR(S): Kate Reed Darren Warburton Parti-Jean Naylor Karim Miran-Khan Ryan Rhodes Heather Macdonald SPONSORING AGENCIES: Provincial Health Services Authority - "Action Schools! BC: Hormones Children" - "Action Schools! B C " UBC Start-up Funds - "Action Schools! B C " & Lipids in Action Schools! BC PROJECT TITLE: Action Schools! BC EXPIRY DATE OF THIS APPROVAL: December 4,2007APPROVAL DATE: December 4, 2006 CERTIFICATION: In respect of clinical trials: 1. The membership of this Research Ethics Board complies with the membership requirements for Research Ethics Boards defined in Division 5 of the Food and Drug Regulations. 2. The Research Ethics Board carries out its functions in a manner consistent with Good Clinical Practices. 3. This Research Ethics Board has reviewed and approved the clinical trial protocol and informed consent form for the trial which is to be conducted by the qualified investigator named above at the specified clinical trial site. This approval and the views of this Research Ethics Board have been documented in writing. The Chair of the U B C Clinical Research Ethics Board has reviewed the documentation for the above named project. The research study, as presented in the documentation, was found to be acceptable on ethical grounds for research involving human subjects and was approved for renewal by the U B C Clinical Research Ethics Board. Approval of the Clinical Research Ethics Board by one of: Dr. Bonita Sawatzky, Associate Chair 1.2 1.3 1.4 How long have you lived in North America? Years: Months: Where did your family live before moving to North America? How would you classify your family ethnically? (i.e., Caucasian-Canadian, Japanese-Canadian, etc.) 84 A B O U T Y O U R C H I L D : Child's birth weight Circle one: Grams or Lbs/Ozs 2.0 Nutrition History: 2.1 Who prepares your child's meals (i.e. mother, father, grandmother, nanny)? 2.2 Does your child drink milk every day? YES: if yes: How many cups per day? Has your child always drank milk every day (after being weaned from breast or bottle)? yes no if no, at what age did she/he start drinking milk every day? years old. NO: if no: Has your child ever drank one or more cups of milk per day (after being weaned from breast or bottle)? yes: at what age did she/he stop drinking milk every day? years old. How many cups did he/she drink until that age? cups per day no: (never drank milk on a daily basis after being weaned) 2.3 Is your child on a special diet? Yes No If yes: vegetarian low sodium low cholesterol other Please specify: 85 3.0 Medical History and Status: 3.1 Has your child ever been treated for any of the following conditions? Yes No food allergies 0 0 hypothyroidism 0 0 other allergies 0 0 hyperthyroidism 0 0 asthma 0 0 other conditions (please list) 3.2 Is your child currently taking any medications? Yes No If yes, what medication(s) is your child taking? What are these medication(s) for? 3.3 Has your family doctor ever said that your child has a heart condition and that he/she should only do physical activity recommended by a doctor? Yes No 3.4 Does your child complain of chest pain when they are doing physical activity? Yes No 3.5 In the past month, has your child complained of chest pain when they were not doing any physical activity? Yes No 3.6 Does your child have a bone or joint problem that could be made worse by a change in their physical activity? Yes No 3.7 Does your child lose their balance because of dizziness or do they ever lose consciousness? Yes No 3.8 Do you know of any other reason why your child should not participate in physical activity? Yes No 86 4.0 Bone History: 4.1 Has your child ever been hospitalized, confined to bed or had a limb immobilized (i.e., arm in a cast)? Yes No If yes: list condition, approximate date and time involved (Example: wrist fracture summer, 1990 10 weeks) Reason Date Time Involved 4.2 Is there a history of wrist, hip, or spine fractures in your family? Yes No If yes: indicate who was affected mother father maternal grandmother paternal grandmother maternal grandfather paternal grandfather 4.3 Is there a history of osteoporosis in your family? Yes No If yes: indicate who was affected mother father maternal grandmother paternal grandmother maternal grandfather paternal grandfather 4.4 Is there a history of any other bone disease in your family? Yes No If yes: please indicate the family member(s) affected 1. 2. What is the name of the condition(s) affecting this family member? 1. 2. 5.0 Physical Activity: 5.1 How would you rate the physical activity level of your child? Physical activity is defined as vigorous activity that makes them sweat and/or breathe hard. Inactive Sometimes active Moderately active Often active Very active THANK YOU FOR YOUR PARTICIPATION 87 Appendix C Sit-and-Reach The participant will begin by performing two 15 second stretches per leg before proceeding to the sit and reach measurement . The participant will remove their shoes and sit with their feet flat against the sit and reach block. Thei r feet will be p laced just wider than the width of the sliding mechan ism. The participant will p lace one hand on top of the other and situate their fingertips at the edge of the sl iding mechan ism. A s they breathe out, the participant will reach forward a s far a s poss ib le keeping their legs straight. Th is measurement will be repeated and the highest score (cm) will be recorded (137). Grip Strength The participant will s tand holding the dynamometer in their hand with the arm holding the dynamometer abducted 45° from their body. Wh i le breathing normally, they will s q u e e z e the dynamometer as hard as possib le. T w o measurements will be taken for each hand and the highest score on either hand will be recorded (137). Push-ups The participant will lie in a prone position and p lace their hands on the floor just wider than their shoulders (finger tips pointing forward). Their feet will be p laced together and their legs and body will be held in a straight line. T h e participant will begin with their body lifted off of the floor with only their hands and toes in contact with the ground. Us ing their toes as a fulcrum the participant will bend their arms to lower their body towards the floor. They will lower their body until their arms reach a 90° angle at the e lbow joint after which, they will straighten their arms to return to the starting posit ion. The participant will complete as many consecut ive push-ups as possib le in a rhythmical fash ion. The push-up assessmen t will be terminated for the following reasons: volit ional fatigue, incorrect technique for more than two consecut ive push-ups, inability to maintain a rhythmical pace (137). Curl-ups The participant will lie supine with their arms at their s ides , knees bent to 90°, feet together and flat on the floor. They will curl their body upwards while sliding their f ingers along the ground towards their feet. T h e participant will curl-up until their f ingers have travelled 10cm from their starting position. Cur l -ups will be performed keeping pace with the rhythm of a metronome. The metronome pace will be set at 40 bpm. The participants will perform a s many curl-ups a s possib le. T h e curl-up assessmen t will be terminated for the following reasons: volitional fatigue or inability to curl-up the required 10 cm (137). 88 A p p e n d i x D Table D.1 Average 'on' and 'off times for each morning and evening during the measurement of habitual physical activity. Day of the Week Morning (on time) Standard Deviation Range Evening (off time) Standard Deviation Range Wednesday N/A N/A N/A 21:44:00 0:58:00 20:45:45- 22:42:00 Thursday 7:38:00 0:44:55 6:53:15- 8:23:00 21:20:00 1:11:00 20:09:00- 22:31:00 Friday 8:06:00 1:06:27 6:59:30- 9:12:30 21:58:30 1:26:45 20:31:00- 23:39:00 Saturday 9:04:30 1:25:45 7:38:45- 10:30:15 22:01:15 1:37:45 20:23:30- 23:39:00 Sunday 9:15:07 1:24:36 7:50:30- 10:39:45 21:14:44 1:15:15 19:59:30- 22:30:00 90 Appendix F Acfi<!n-Schools/Be ACTION SCHOOLS! BC 5-DAY ACTIVITY LOG - Spring 2006 Name: School: Grade: Division: Directions: 1) Please have your child wear the motion sensor under their clothing. 2) The motion sensor should be fitted snugly on the waist with the sensor positioned in the front above the hip. The belt should feel comfortable but not floppy. 3) The motion sensor should be worn for 12 hours (8 AM - 8 PM) and should only be removed during that period if the child is going swimming, having a bath or a shower. It is not waterproof. 4) Please note the time when the motion sensor is first put on the child and when it is taken off daily on the log on the reverse side of this form as well as anything that affected your child's movement patterns on any given day. 5) The motion sensor is like a smart 'pedometer' but it is very valuable. Please have your child put on the motion sensor on Monday morning to take it into school and an AS! BC researcher will collect them from the classroom. Thank you very much for you help! 91 Monitor: Wednesday Thursday Friday Saturday Sunday Dates On Time AM Off Time PM Did weather change your routine? No No No No No Yes Yes Yes Yes Yes Did illness change your routine? No No No No No Yes Yes Yes Yes Yes Was motion sensor removed during wear time? No No No No No Yes Yes Yes Yes Yes If yes, what time? : to : to : to : to : to Why was the monitor removed? Any problems? Please explain. 92 Appendix G Table E.1 Description of health-related physical fitness and physical activity data in Caucasian and Asian girls. BMI=body mass index, MVPA=moderate-to-vigorous physical activity. Variable N Caucasian Girls N Asian Girls Age (years) 38 10.0 ±0 .6 53 10.0 ±0 .6 Height (cm) 38 1.41.5± 7.6 53 140.9 ±7.5 Weight (kg) 38 35.4 ± 6.4 53 35.2 ± 8.6 BMI (kg/mO 38 17.6 ±2 .0 53 17.5 ±3 .0 Waist Circumference (cm) 38 62.6 ± 5.7 53 62.9 ± 7.9 Systolic Blood Pressure (mmHg) 38 96.7 ± 9.3 53 97.0 ±9 .0 Diastolic Blood Pressure (mmHg) 38 62.0 ± 9.7 53 62.0 ± 8.4 Pulse Rate (bpm) 36 86.8 ± 14.0 53 88.4 ± 11.8 Total Laps Run 38 26.0 ± 13.0 53 18.0 ± 10.0 Sit-and-Reach (cm) 38 26.0 ± 10.0 53 29.0 ±7 .0 Curl-ups 38 14.0 ± 18.0 53 9.0 ±9 .0 Push-ups 38 6.0 ±9 .0 53 2.0 ±5 .0 Grip Strength (kg) 38 33.0 ± 8.0 53 32.0 ±7 .0 Musculoskeletal Fitness Score 38 0.3852 ±2.3157 53 -0.2762 ± 1.0910 Average Counts Per Minute 38 499.1 ± 158.3 53 380.1 ± 102.0 Average M V P A Per Day 38 127.0 ±40.8 53 103.9 ±28.6 93 Table E.2 Descr ipt ion of health-related physical f i tness and physical activity data in As ian and C a u c a s i a n boys. BMI=body m a s s index, MVPA=moderate- to-v igorous physica l activity. Variable N Caucasian Boys N Asian Boys Age (years) 35 10.0 ±0 .6 44 10.0 ±0 .6 Height (cm) 35 142.4 ±6 .5 44 140.4 ±8.3 Weight (kg) 35 36.2 ± 7.4 44 36.9 ±8 .5 BMI (kg/m z) 35 17.7 ±2 .3 44 18.6 ±3 .0 Waist Circumference (cm) 35 63.4 ± 6.6 44 65.7 ± 8.0 Systolic Blood Pressure (mmHg) 34 97.3 ±7 .0 43 98.9 ± 7.0 Diastolic Blood Pressure (mmHg) 34 62.1 ±6 .0 43 63.9 ± 7.9 Pulse Rate (bpm) 33 85.3 ± 10.5 43 88.7 ± 11.1 Total Laps Run 35 31.0 ± 15.0 44 21.0± 12.0 Sit-and-Reach (cm) 35 24.0 ±6 .0 44 25.0 ±7 .0 Curl-ups 35 21.0 ±22.0 44 8.0 ±7 .0 Push-ups 35 7.0 ±8 .0 44 4.0 ±5 .0 Grip Strength (kg) 35 36.0 ± 6.0 44 34.0 ± 7.0 Musculoskeletal Fitness Score 35 0.5858 ± 1.6407 44 -0.4660 ± 1.1581 Average Counts Per Minute 35 540.2 ± 120.6 44 474.5 ± 117.8 Average M V P A Per Day 35 140.1 ±32.5 44 129.0 ±34.6 94 Appendix H Table E .3 Descr ipt ion of health-related physical f i tness data in chi ldren without physical activity data. BMI=body m a s s index. V a r i a b l e N B o y s N G i r l s Age (years) 52 10.0 ±0 .5 46 9.8 ±0 .8 Height (cm) 50 141.4 ±6 .9 47 141.0 ±7 .3 Weight (kg) 50 37.3 ± 9.7 46 35.6 ±6 .8 BMI (kg/m') 50 18.5 ±3 .4 46 17.8 ±2 .8 Waist Circumference (cm) 50 65.6 ± 9.4 47 62.2 ± 6.6 Systolic Blood Pressure (mmHg) 47 96.5 ±9 .5 41 96.2 ± 10.8 Diastolic Blood Pressure (mmHg) 47 63.3 ±8 .6 41 63.5 ± 11.1 Pulse Rate (bpm) 46 89.9 ± 12.5 41 89.6 ± 12.8 Total Laps Run 48 26.6 ± 13.3 42 23.3 ± 12.1 Sit-and-Reach (cm) 49 24.0 ±7 .0 42 28.0 ± 7.0 Curl-ups 49 13.0 ± 15.0 42 11.0±8.0 Push-ups 49 7.0 ±8 .0 42 5.0 ±5 .0 Grip Strength (kg) 48 35.0 ± 7.0 42 32.0 ± 7.0 Musculoskeletal Fitness Score 48 0.1016 ± 1.6751 42 0.0729 ± 1.1230 95 Appendix I Capturing Physical Activity Tempo in Elementary School-Aged Children K. A s h l e e M c G u i r e 1 , L indsay A . Nett lefold 1 , Shannon S . D . B red in 1 , Heather A . M c K a y 1 , Pat t i -Jean Nay lor 2 , Darren D.E. Warbur ton 1 . 1 Univers i ty of British Co lumb ia , Vancouver , B C ; 2 Univers i ty of Victor ia, Victor ia, B C T h e tempo of chi ldren's activity has been documented to be sporad ic and rapidly changing. T h e s e character ist ics make data acquisit ion in this age group chal lenging. Acce lerometers are popular in the assessmen t of phys ica l activity in youth however data is commonly captured in 1 minute epochs , consequent ly mask ing sporadic activity. Therefore, the purpose of this investigation w a s to determine the tempo of chi ldren's physical activity using a 15 second epoch with a speci f ic emphas i s on the time spent in moderate-to-vigorous intensity phys ica l activity ( M V P A ; £3 M E T s ) . T o a s s e s s habitual physical activity, chi ldren (8-11 yrs) wore a G T 1 M activity monitor at the hip during waking hours over a 5 day per iod. A l l chi ldren were part of a larger investigation (Action Schoo ls ! B C ) . To be included in the analysis, chi ldren were required to wear the monitor for at least 8 hours per day on at least 4 days . O n e hundred fifty-seven chi ldren met the criteria. Age-spec i f i c cut-points developed by Trost and co l leagues were revised for use with 15 s e c o n d e p o c h s and data w a s ana lyzed us ing cus tomized software. Our results indicate that chi ldren spend 1 5 % of their monitored time in M V P A . Eighty-five percent of the total t ime spent in M V P A w a s accumulated in bouts of activity less than 5 minutes in duration and on average, these bouts lasted only 31 seconds . Eight percent of the activity bouts lasted between 5 and 10 minutes; 5 % in 10 to 20 minute bouts; and 2 % in bouts lasting greater than 20 minutes. Only 2 9 % of the children registered at least 1 bout lasting greater than 20 minutes, whi le 6 8 % registered at least 1 bout of activity lasting 10 to 20 minutes and 9 7 % accumulated activity in bouts of 5 to 10 minutes in durat ion. T h e results of this investigation sugges t that a 15 second epoch has sufficient resolution to detect the sporadic activity that is typical of chi ldren. 96 Appendix J Physical Activity and Antecedents of Cardiovascular Disease in Children A . M c G u i r e 1 , S . S . D . B red in 1 , H.A. M c K a y 1 , P . J . Nay lor 2 , L.T.L. Hor i ta 1 , D .E .R . Warbur ton 1 . 1 University of British Co lumbia , Vancouver , British Co lumb ia 2 University of Victor ia, Victor ia, British Co lumbia Background: Reduced arterial compl iance is an important predictor of cardiovascular d isease . It p recedes the development of traditional card iovascular d i sease risk factors. In adults, increased physical activity is assoc ia ted with improved arterial compl iance. However, it is unknown whether regular daily phys ica l activity in chi ldren exerts a similar positive inf luence on arterial compl iance. Purpose: The primary purpose of this investigation w a s to examine the relationship between moderate-to-vigorous physical activity ( M V P A ) and arterial compl iance in chi ldren. Methods: T o a s s e s s habitual phys ica l activity, chi ldren (n=115, 8-11 yrs) wore a G T 1 M Activity Monitor for 13 hrs (on average) daily over a 5 day per iod. W e also obtained concurrent measu res of blood pressure (mmHg), arterial compl iance (small and large artery, ml /mmHg) and weight status (Body M a s s Index, kg/m 2 ) . Data were ana lyzed using Pea rson Part ial Correlat ion. Resul ts : 16 .5% were c lassi f ied as overweight and 5 .2% were hypertensive. M V P A (counts per minute corresponding to £3 M E T S ) accounted for approximately 6% of the var iance in smal l artery compl iance independent of Body M a s s Index, systol ic blood pressure, age and gender. Conc lus ion : There w a s a posit ive relationship between M V P A and vascular health in this group of general ly healthy chi ldren. This extends our previous f indings by showing that objectively measured physical activity is a lso predictive of vascu lar health. A n intervention des igned to test the effect of M V P A on arterial compl iance would further del ineate this relationship. 97 A p p e n d i x K Table K .1. T-tests performed between genders. (*) denotes signi f icance. MVPA=moderate- to-v igorous physical activity Variable Boys (Mean) Girls (Mean) Significance Level Musculoskeletal Fitness Score 0.1501 -.1303 p < 0.26 Total Laps 25.0 21.0 p < 0.06 Sit-and-Reach (cm) 25.0 28.0 p < 0.06 Grip Strength (kg) 35.0 32.0 p < 0.04 Height (cm) 141.3 141.2 p < 0.89 Weight (kg) 36.6 35.3 p < 0.25 Body Mass Index (kg/m*1) 18.2 17.6 p<0.12 Systolic Blood Pressure (mmHg) 98.0 97.0 p < 0.28 Diastolic Blood Pressure (mmHg) 63.0 62.0 p < 0.23 Heart Rate (bpm) 87.0 88.0 p < 0.86 Counts Per Minute 503.6* 429.8 p < 0.001 Minutes of M V P A Per Day 133.9* 113.5 p< 0.001 Minutes of M V P A Per Weekday 149.0* 124.6 p < 0.001 Minutes of M V P A Per Weekend Day 112.7* 98.4 p < 0.04 Minutes of Sporadic M V P A Per Day 104.7 98.0 p < 0.09 Minutes of Bouted M V P A Per Day 29.2* 15.5 p < 0.001 Table K.2. A N O V A performed between girls with and without val id physical activity data. Variable Girls Without PA Data (Mean) Girls With PA Data (Mean) Significance Level Age (years) 9.8 10.0 p<0.09 Height (cm) 141.0 141.2 p<0.71 Weight (kg) 35.6 35.2 p < 0.58 Total Laps 23.0 21.0 p < 0.68 Musculoskeletal Fitness Score 0.0729 -0.0336 p<0.16 98 Tab le K.3. A N O V A performed between boys with and without val id physical activity data. Variable Boys Without PA Data (Mean) Boys With PA Data (Mean) Significance Level Age (years) 10.0 10.0 p < 0.82 Height (cm) 141.4 141.3 p < 0.59 Weight (kg) 37.3 36.6 p < 0.42 Total Laps 27.0 25.0 p < 0.70 Musculoskeletal Fitness Score 0.1016 -0.0434 p < 0.43 Table K.4. A N O V A performed between schools to determine intraclass correlation. MVPA=moderate- to-v igorous physical activity Variable Between Schools Variance Within Schools Variance Total Variance Intraclass Correlation Counts Per Minute 1.073 13.901 14.974 0.07 Musculoskeletal Fitness Score 17.030 226.045 243.075 0.07 Body Mass Index (kg/m2) 0.188 3.363 3.551 0.07 Total Laps 14.700 39.933 54.633 0.27 Minutes of M V P A Per Day 1.074 14.631 15.705 0.07 9 9 Table K . 5 . A N C O V A used to examine differences between C a u c a s i a n and As ian boys. A g e , weight and height were entered as covariates. MVPA=moderate- to-v igorous physical activity Variable Significance Level Levene's Test (Significance) Musculoskeletal Fitness Score p < 0.007 p < 0.09 Total Laps p < 0.03 p < 0.84 Curl-ups p < 0.04 p < 0.001 Push-ups p < 0.20 p < 0.62 Sit-and-Reach (cm) p < 0.28 p < 0.66 Grip Strength (kg) p<0.31 p<0.01 Systolic Blood Pressure (mmHg) p < 0.36 p<0.19 Diastolic Blood Pressure (mmHg) p < 0.69 p < 0.23 Heart Rate (bpm) p<0 .19 p < 0.92 Body Mass Index (kg/rr^) p < 0.22 p < 0.08 Waist Circumference (cm) p < 0.24 p < 0.09 Counts Per Minute p < 0.03 p < 0.68 Minutes M V P A Per Day p<0.12 p<0.41 Table K.6. A N C O V A used to examine differences between C a u c a s i a n and As ian girls. A g e , weight and height were entered as covariates. MVPA=moderate- to-v igorous physical activity Variable Significance Level Levene's Test (Significance) Musculoskeletal Fitness Score p < 0.09 p<0.01 Total Laps p<0.01 p < 0.06 Curl-ups p < 0.32 p < 0.004 Push-ups p < 0.009 p < 0.23 Sit-and-Reach (cm) p < 0.78 p < 0.04 Grip Strength (kg) p < 0.58 p < 0.26 Systolic Blood Pressure (mmHg) p < 0.79 p < 0.95 Diastolic Blood Pressure (mmHg) p < 0.97 p < 0.20 Heart Rate (bpm) p < 0.59 p < 0.29 Body Mass Index (kg/m^) p < 0.76 p < 0.004 Waist Circumference (cm) p < 0.68 p<0.17 Counts Per Minute p< 0.001 p< 0.001 Minutes M V P A Per Day p< 0.001 p< 0.001 100 Tab le K.7. Pr incipal Componen t Ana lys is in the whole group. O n e component extracted from the musculoskeleta l f i tness components. Component Eigenvalue Percentage Variance 1 1.560 38.994 Table K.8. Factor loadings based on one component for the musculoskeleta l f i tness score in the whole group. Factor Factor Loading Sit-and-Reach 0.380 Curl-ups 0.762 Push-ups 0.678 Grip Strength 0.612 Table K.9. Pr incipal Componen t Ana lys is in girls only. O n e component extracted from the musculoskeleta l f i tness components. Component Eigenvalue Percentage Variance 1 1.566 39.158 Table K.10. Factor loadings based on one component for the musculoskeleta l f i tness score in girls. Factor Factor Loading Sit-and-Reach 0.495 Curl-ups 0.758 Push-ups 0.680 Grip Strength 0.534 Table K.11. Pr incipal Componen t Ana lys is in boys only. O n e component extracted from the musculoskeleta l f i tness components. Component Eigenvalue Percentage Variance 1 1.585 39.616 Table K.12. Factor loadings based on one component in the musculoskeleta l f i tness score in boys. Factor Factor Loading Sit-and-Reach 0.435 Curl-ups 0.744 Push-ups 0.654 Grip Strength 0.643 Table K.13. Pr incipal Componen t Ana lys is in the whole group. O n e component extracted from the musculoskeleta l and cardiorespiratory f i tness components. Component Eigenvalue Percentage Variance 1 2.098 41:952 Table K.14. Factor loadings based on one component in the musculoskeleta l and cardiorespiratory f i tness score in the whole group. Factor Factor Loading Sit-and-Reach 0.351 Curl-ups 0.686 Push-ups 0.828 Grip Strength 0.467 Total Laps 0.774 102 Table K.15. Pr incipal Componen t Ana lys is in the whole group. Two components extracted from all health-related physical f i tness components . Component Eigenvalue Percentage Variance 1 2.479 35.416 2 1.817 25.959 Table K.16. Factor loadings based on two components for the total health-related physical f i tness score . Factor Factor Loading (Component 1) Factor Loading (Component 2) Sit-and-Reach 0.356 0.118 Curl-ups 0.504 0.463 Push-ups 0.664 0.486 Grip Strength -0.037 0.767 Total Laps 0.666 0.415 Body Mass Index -0.770 0.533 Waist Circumference -0.787 0.535 Table K.17. Forward s tepwise regression of cardiorespiratory f i tness in girls. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R* Change Total Laps M S K Score (p< 0.001) .460 .618 .184 .193 Weight (p < 0.006) -.257 .139 .242 .066 103 Table K.18. Forward s tepwise regression of cardiorespiratory f i tness in boys. CPM=coun ts per minute, MVPA=moderate- to-v igorous physica l activity, MSK=muscu loske le ta l Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R1 R* Change Total Laps Weight (p<0.01) -.375 -.697 .400 .446 Height (p<0.17) .210 .412 .400 .446 C P M (p < 0.70) .083 .010 .400 .446 M V P A Per Day (p < 0.49) .148 .065 .400 .446 M S K Score (p< 0.001) .528 5.284 .400 .446 Ethnicity (p < 0.63) -.049 -1.447 .400 .446 Table K.19. Hierarchical regression of health-related physica l f i tness component in boys. CPM=coun ts per minute, MVPA=moderate- to-v igorous physica l activity, HRPF=heal th- re la ted physica l f i tness Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R* Change Total H R P F Score Weight (p< 0.001) -.579 -.216 .157 .189 Height (p < 0.01) .439 .173 .157 .189 Age (p<0.91) -.013 -.067 .157 .189 Ethnicity (p < 0.003) -.330 -1.967 .243 .093 C P M (p < 0.46) -.191 -.005 .233 .000 M V P A Per Day (p < 0.45) .198 .017 .229 .006 104 Tab le K .20. Hierarchical regression of health-related physica l f i tness component in girls. CPM=coun ts per minute, MVPA=moderate- to-v igorous physica l activity, HRPF=heal th- re la ted physica l f i tness Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R' Change Total H R P F Score Weight (p< 0.001) -.352 -.143 .043 .075 Height (p<0.01) .321 .133 .043 .075 Age (p<0.91) -.108 -.557 .043 .075 Ethnicity (p < 0.003) -.202 -1.269 .111 .076 C P M (p < 0.46) .122 .003 .130 .028 M V P A Per Day (p < 0.45) .067 .006 .120 .000 Table K .21. Hierarchical regression of push-ups in boys. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R' Change Push-ups Weight (p < 0.008) .461 .895 .147 .191 Height (p < 0.32) -.182 -1.395 .147 .191 Age (p < 0.94) -.010 -.066 .147 .191 Ethnicity (p<0.17) .169 -1.269 .156 .020 C P M (p < 0.75) .037 .003 .146 .001 105 Table K.22. Hierarchical regression of push-ups in girls. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R' Change Push-ups Weight (p < 0.53) -.098 -.192 .095 .136 Height (p < 0.48) .118 .901 .095 .136 Age (p < 0.23) .136 .901 .095 .136 Ethnicity (p < 0.04) .259 .212 .153 .064 C P M (P < 0.27) -.122 -.162 .155 .012 Table K.23. Hierarchical regression of curl-ups in boys. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted Rz RzChange Curl-ups Weight (p< 0.001) .250 .410 .062 .110 Height (p<0.01) -.159 -1.034 .062 .110 Age (p<0.91) -.074 -.425 .062 .110 Ethnicity (p < 0.003) .222 .153 .086 .035 C P M (p < 0.46) .042 .059 .075 .001 106 Table K.24. Hierarchical regression of curl-ups in girls. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R2 R̂  Change Curl-ups Weight (p< 0.001) .128 .228 .053 .096 Height (p<0.01) -.243 -1.691 .053 .096 Age (p < 0.91) .210 1.267 .053 .096 Ethnicity (p < 0.003) .039 .029 .049 .006 C P M (p < 0.46) -.147 -.177 .055 .017 Table K.25. Hierarchical regression of si t -and-reach in boys. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted Rz Rz Change Sit-and-Reach Weight (p < 0.53) .108 .154 .120 .165 Height (p < 0.33) -.178 -1.007 .120 .165 Age (p < 0.03) -.261 -1.304 .120 .165 Ethnicity (p < 0.39) -.107 -.065 .111 .003 C P M (p<0.14) -.177 -.214 .126 .025 107 Table K.26. Hierarchical regression of s i t -and-reach in girls. CPM=coun ts per minute. F i tness Var iab les in Model Standardized Beta Unstandardized Beta Ad jus ted R* R ' Change Sit-and-Reach Weight (p < 0.34) .154 -.259 .107 .148 Height (p < 0.92) -.016 -.107 .107 .148 Age (P < 0.32) -.116 -.665 .107 .148 Ethnicity (p < 0.23) .155 .110 .104 .007 C P M (p < 0.23) .138 .159 .109 .015 Tab le K.27. Hierarchical regression of grip strength in boys. CPM=coun ts per minute. F i tness Var iab les in Model Standardized Beta Unstandardized Beta Ad jus ted R* R* Change Grip Strength Weight (p<0.71) .059 .060 .247 .286 Height (p < 0.003) .524 2.095 .247 .286 Age (p < 0.52) -.073 -.257 .247 .286 Ethnicity (p < 0.30) -.121 -.051 .242 .005 C P M (p < 0.34) -.105 -.090 .243 .011 108 Tab le K.28. Hierarchical regression of grip strength in girls. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R' Change Grip Strength Weight (p < 0.02) .306 .352 .397 .425 Height (p < 0.003) .416 1.877 .397 .425 Age (p < 0.56) -.055 -.215 .397 .425 Ethnicity (p < 0.92) -.010 -.005 .394 .004 C P M (p < 0.06) .174 .136 .412 .023 Table K.29. Hierarchical regression of systol ic blood pressure in boys. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R' Change Systolic Blood Pressure Weight (p < 0.006) .458 .154 .230 .270 Height (p < 0.86) .030 .040 .230 .270 Age (p < 0.64) .055 .066 .230 .270 Ethnicity (p < 0.57) .068 .010 .223 .004 C P M (p < 0.98) .002 .001 .212 .000 109 Table K.30. Hierarchical regression of systol ic blood pressure in girls. CPM=coun ts per minute. Fitness Variables in Model Standardized Beta Unstandardized Beta Adjusted R* R' Change Systolic Blood Pressure Weight (p < 0.20) .211 .096 .036 .270 Height (p < 0.56) .104 .184 .036 .270 Age (p < 0.33) -.118 -.181 .036 .270 Ethnicity (p < 0.99) -.002 .000 .029 .004 C P M (p<0.10) -.196 -.061 .049 .000 110 A p p e n d i x L R a w Data C2E2ID My ID T1 Gender s th t c weightC BMI wa is tC B P S Y BPDIA 1101 mpama4maf1 M 154.25 43.45 18.26163 70.5 105 64 1168 fqupa5bc1 F 141.5 40.7 20.32739 66.5 99 61 1169 fhusy4maf1 F 141.1 32.8 16.47479 67.2 111 68 1207 mpawi4maf1 M 127.8 24.4 14.93923 55.9 92 61 1233 fscha4wf1 F 138.6 31.6 16.4498 55.15 99 58 1283 fbaha5wf1 F 138.25 31.9 16.69016 60.55 82 55 1325 mkhsa5moc1 M 148.15 33.4 15.21749 62.15 90 51 1349 mdudo5moc1 M 132.7 30.5 17.3204 65.55 96 66 1397 fmoro5bc1 F 140.35 30.85 15.66139 59.05 107 72 1457 fdrma4maf1 F 136.45 27.3 14.66275 58.3 91 52 1491 ffial5bc1 M 154.7 44.95 18.78231 66.35 101 69 1508 mmijo4bc1 M 135.25 31.7 17.32945 57.8 98 66 1844 mfrju5wf1 M 139.8 29.4 15.04295 57.95 99 56 2080 mchma4nc1 M 142.8 49.75 24.39701 79.65 104 65 2124 marki4wf1 M 144.9 39.7 18.90835 65.9 92 66 2147 ferol4maf1 F 133.45 26.9 15.10481 59.35 109 61 2314 mmash4maf1 M 136.85 33 17.62075 63.35 98 66 2345 mdema4moc1 M 144.15 44.9 21.60812 79.45 107 75 2383 fdhsu5moc1 F 145.8 45.05 21.19238 71.9 99 53 2432 myada4maf1 M 141.15 32.1 16.11177 61 100 61 2488 mrami5bc1 M 147.55 40.25 18.48789 64.3 102 69 2521 mgrka5moc1 M 158.15 42.4 16.95225 61.35 90 69 2556 fmcsa5wf1 F 139.5 30 15.41604 58 92 48 2650 fgugo5moc1 F 144.25 33 15.85924 61.9 91 59 2668 falsa5bc1 F 134.6 27 14.903 54.5 92 56 2693 fmoch5nc1 F 146.7 32.6 15.14807 62.6 99 60 2713 mromi5maf1 M 150.2 38.8 17.19855 63.35 102 61 2887 mgolu4maf1 M 145.2 41.45 19.66035 69.9 94 59 2892 fpjal5maf1 F 151.05 34.8 15.25239 58.85 103 68 2921 fmica5maf1 F 140.35 34.1 17.31129 61.4 106 72 3038 fnggl4moc1 F 128.4 26.2 15.89173 60.3 92 57 3161 fchgi5maf1 F 146.45 46.1 21.49424 69.85 108 76 3180 mfejo5wf1 M 147.25 37.3 17.20276 65 99 55 3284 mrojo4moc1 M 132.15 40.4 23.1338 79.05 92 57 3286 mgeda5maf1 M 139.15 28.6 14.77065 57.75 99 73 3292 mtajo4nc1 M 130.05 29.8 17.61958 60.85 102 73 3319 mslmi5maf1 M 147.4 44.8 20.61973 68.6 89 68 3349 mcabr4maf1 M 148.75 72.6 32.81124 94.85 119 . 79 3411 myoke5maf1 M 156.35 64.2 26.26269 85.35 107 61 3423 fdhpo5moc1 F 143.5 33.55 16.29254 63.2 86 54 3455 mjapr5moc1 M 142.95 37.95 18.57135 68 102 64 3558 fmiam4moc1 F 130.35 27.05 15.92008 54.9 99 50 3594 fsish4bc1 F 130.4 28.7 16.87822 61.45 84 44 3627 fchan4maf1 F 132.6 35.1 19.96274 69.25 93 61 3678 fchgr5maf1 F 135.2 33.8 18.49112 63.75 83 67 3693 fdhma4moc1 F 144.7 32.7 15.61747 55.3 94 60 3758 mvejo4wf1 M 141.05 42.3 21.26151 70.45 102 66 3767 fdhsh4moc1 F 159.3 53 20.88547 72.85 93 60 3810 fshlu5maf1 F 149.55 38.3 17.12482 64.5 110 78 I l l R a w Data 3811 fjale5nc1 F 148.5 46.55 21.10896 72.6 102 71 3820 mmibr4bc1 M 134.85 28.75 15.81015 57.2 92 64 3826 fwaer5maf1 F 128.25 23.2 14.105 52.9 93 73 3853 mhake5maf1 M 140.55 31.9 16.14838 58.6 87 63 3941 mdupa4moc1 M 137.4 26.7 14.14288 56.75 89 51 3974 frova4nc1 F 136.7 24.9 13.32485 51.7 85 66 4023 fswra5bd F 164.2 48.6 18.02561 64.35 104 60 4106 msaka5moc1 M 143 31.1 15.20857 59.05 92 56 4221 msudi4moc1 M 133.05 31.85 17.99201 65.7 96 64 4229 mpabr5maf1 M 143.8 32.95 15.93447 61.25 108 61 4303 fpeha5bd F 149.45 40 17.90887 62.6 104 74 4319 mkike5bc1 M 130.25 30.3 17.86023 58.55 91 56 4338 fmema4maf1 F 150.95 37.3 16.36977 65.6 92 46 4427 fjema5wf1 F 135.15 37.6 20.58523 68.35 90 61 4470 fkras5bc1 F 138.05 30.6 16.05642 54.15 91 56 4675 fatpr5moc1 F 154.5 38.9 16.29644 58.55 99 52 4678 fhilu5moc1 F 149.1 43.8 19.70239 62.9 97 68 4866 mleso5wf1 M 149.25 35.2 15.80207 57.1 94 59 4896 flaja4maf1 F 138.55 35.7 18.59753 64.95 95 55 4922 mluli5moc1 M 151.65 54.7 23.78496 78.5 116 67 5014 fdama5moc1 F 150.5 47.75 21.08145 71.8 109 87 5053 fgrti5wf1 F 144.6 38.4 18.36516 68 91 68 5116 fprga5maf1 F 138.05 27.9 14.63967 55.1 95 58 5119 fanel4wf1 F 138.05 36.75 19.28344 65.9 112 76 5125 fhoma5bc1 F 147.75 40.8 18.68982 63.85 93 51 5208 fdech5bc1 F 145.7 39.4 18.55996 62.45 99 68 5216 fgisa5bc1 F 150.45 44.9 19.83636 67.5 99 63 5302 mpoma5bc1 M 140 30.1 15.35714 55.5 101 66 5313 fsujo4maf1 F 149.35 42.3 18.964 68.75 109 68 5323 fhona5maf1 F 133 26.1 14.75493 57.5 100 60 5380 mlipa4bc1 M 126.15 25.2 15.83529 56.5 93 60 5430 flija5moc1 F 145.6 29.45 13.89193 53.45 95 61 5521 marno5moc1 M 152 39.8 17.22645 69.4 94 52 5544 fcsju4wf1 F 142.75 34.9 17.12668 60.45 103 71 5573 mgral4wf1 M 142 36.35 18.02718 64 84 51 5583 fsuan4maf1 F 126.85 27.2 16.90394 56.9 93 53 5689 mgudo4wf1 M 134.6 37.2 20.53302 71.05 100 67 5733 malst5wf1 M 146.65 36.5 16.97183 64.1 99 58 5735 mzhaa5maf1 M 143.3 41.7 20.3069 65.25 107 65 5800 monal4moc1 M 139.15 33 17.04306 59.5 96 60 5805 mfljo5maf1 M 143.55 37.7 18.29511 67.6 96 57 5831 fxizh5maf1 F 146.5 32.3 15.04968 62.6 93 54 5868 mmran5maf1 M 147.25 41.5 19.1398 65.05 102 64 5945 mbada4nc1 M 144.65 47.65 22.7733 72.2 110 71 5949 mmacy5bc1 M 137.35 36.7 19.45399 66.2 89 55 6027 fraa!4bc1 F 138.35 34.9 18.23338 ' 62.05 77 47 6039 mliju5bc1 M 130.05 26 15.37279 51.7 98 70 6081 mkaap5moc1 M 141.75 47.4 23.59023 76.2 102 84 6108 fpeje4bc1 F 141.25 33.6 16.84079 64.85 93 57 6195 fwaas4wf1 F 126.85 29.5 18.33332 59 91 68 6247 fphsa4maf1 F 132.6 31.8 18.0859 63.35 113 74 112 R a w Data 6333 fkelo5wfl F 134.65 33.7 18.58734 65.25 87 51 6367 mlija5nc1 M 141.9 34.3 17.0345 63.3 98 57 6543 mmita4bc1 M 135.1 28.7 15.7243 57.6 87 57 6565 femmi4bc1 F 131.65 29.05 16.76117 57.55 87 64 6572 fsuan5maf1 F 140.45 31.2 15.81653 64.1 111 71 6655 mshra4moc1 M 134.5 25.4 14.04071 52.1 97 58 6673 fchje4bc1 F 129.25 25.2 15.0848 51.9 116 97 6721 fduar5nc1 F 149.05 58 26.10742 82.95 84 66 6758 fhoch5maf1 F 134.05 26.5 14.74729 56.25 107 68 6760 fgoch5bc1 F 134.2 29.05 16.13025 62.1 94 69 6788 myary4wf1 M 135.35 30.9 16.86716 56.4 103 69 6834 fhehe5bc1 F 146.4 40.3 18.80282 69.05 86 56 6845 mhyra5moc1 M 157 53.5 21.70473 74.1 107 54 6998 mwaba5maf1 M 144.75 33.3 15.89304 58.05 103 57 7034 fkwkr5bc1 F 140.6 30.4 15.37811 57.85 85 56 7058 msoje5maf1 M 159.35 51 20.08473 72.5 110 60 7102 mneia4maf1 M 148.85 44 19.85889 75.9 99 58 7225 mclad4bc1 M 131.4 27.35 15.84042 58.35 84 54 7247 merim4bc1 M 137.4 29.9 15.8379 59.4 91 60 7376 fchro5moc1 F 139.1 38 19.63945 68.8 94 56 7386 mchch4maf1 M 151.45 48.95 21.34097 75.9 108 62 7533 mmore4maf1 M 147.4 37.5 17.25982 62.7 96 56 7558 mlavi5maf1 M 144.15 47 22.61875 74.55 96 65 7658 mheth4wf1 M 147.45 40.5 18.62797 65.95 94 63 7662 mgrde5maf1 M 135.65 28.6 15.5427 59.2 103 63 7664 fmaha4bc1 F 137.7 27.6 14.55597 57.25 80 52 7673 mchth4maf1 M 140.2 41.4 21.06223 71.1 102 59 7717 fnoem5wf1 F 147.15 52.6 24.29211 83.6 107 53 7864 mkobr5maf1 M 142.45 37.3 18.38163 67.25 108 81 7932 flaja5maf1 F 139.45 39.55 20.33806 72.25 105 73 7938 fluda5moc1 F 147.2 51.75 23.88332 84.85 107 69 7977 mwoke4maf1 M 139.4 33.8 17.39367 62.1 103 75 8021 fkwwi4moc1 F 151.1 30.5 13.35891 60.55 94 53 8035 fstmi4maf1 F 136.6 35.3 18.91792 66.9 112 65 8073 fgrsu5moc1 F 140.45 38.05 19.28906 64.05 99 67 8313 fluca5maf1 F 139.35 30.8 15.86123 60.05 86 60 8436 mloet5wf1 M 137.45 30.4 16.09104 59.05 88 53 8480 fmobr4maf1 F 131.05 27 15.72135 55 80 60 8508 ftase4maf1 F 135.85 31.25 16.93288 58.95 88 52 8538 fleyo5maf1 F 147.55 54.8 25.1711 76.95 109 57 8579 fhech4maf1 F 140.45 32.6 16.52624 58.65 86 67 8591 fbash5nc1 F 148.65 48.9 22.12988 76.2 103 61 8664 marju4nc1 M 133.1 28.1 15.86172 61.7 88 73 8703 mbhka4moc1 M 139.6 26.55 13.62366 54 102 62 8714 floem5wf1 F 155.25 43.45 18.02713 63.95 116 77 8728 fraha5moc1 F 139.85 30.65 15.67132 54.7 94 58 8867 mzike5wf1 M 139.05 38.05 19.67944 64.95 101 75 8910 mhush5nc1 M 138.5 47.1 24.55395 81.45 107 66 8915 mchhu4maf1 M 124.8 25.1 16.11553 55.85 95 60 8943 fphda4nc1 F 140.5 37.05 18.76876 63.55 95 59 8947 fwosa5bc1 F 138.05 25.9 13.59023 52.95 90 61 113 8981 fdhpa5moc1 F 9000 fbaly5maf1 F 9032 fchch4maf1 F 9038 mtrda5nc1 M 9147 fyaka4maf1 F 9170 mchda4maf1 M 9546 fboda4wf1 F 9584 fzava5maf1 F 9585 mther5bc1 M 9605 fmema5moc1 F 9607 mmako4maf1 M 9676 fjije4moc1 F 9693 frojh4maf1 F 9710 mvelo4wf1 F 9733 mjuma5maf1 M 9808 fsoan5maf1 F 9869 mwomo4bc1 M 9916 flash4moc1 F 1017 mveda4maf1 M 1176 mchjo4maf1 M 1275 fhama4bbf1 F 1464 mriia5bbf1 M 1700 fbrma4wf1 F 1864 filan5maf1 F 2053 mpapa4mf1 M 2066 finke5bbf1 F 2265 ffrka4mf1 F 2273 mzhje5maf1 M 2415 mswan5mf1 M 2649 fsaje4nc1 F 2701 fwage5wf1 F 2709 fcala5bf1 F 2714 fhash4mf1 F 2879 mwaco4bc1 M 2995 melli4maf1 M 3050 mhora5maf1 M 3054 floca4bbf1 M 3437 mchto5ma1 M 3651 mroro4nc1 M 3682 mkijo5maf1 M 3685 mbaru4maf1 M 3692 fhaki4bbf1 F 3770 faral5wf1 F 3856 mfavi5nc1 M 3991 mdebh4moc1 M 4011 manbr5nc1 M 4066 fmcme5wf1 F 4233 fzhli4maf1 F 4247 mlaro5bf1 M 4381 flesa5bf1 F 4593 mahav4moc1 M R a w Data 145.1 39.5 18.76127 72.5 91 55 154.55 49.4 20.68183 66.4 102 57 140.2 36.1 18.36586 63.1 110 68 149.6 46.5 20.77733 70.7 107 75 145.55 40 18.88146 66.75 95 60 133.65 28.2 15.78742 59 86 53 143.05 33.6 16.41964 60.75 100 59 147.6 41.5 19.04914 66.7 95 56 141.35 34.4 17.21737 62.95 104 70 138.75 28.85 14.9858 52.25 84 55 138.75 31.8 16.51814 60.25 109 60 134.45 29.7 16.4299 55.9 93 59 130.15 25.95 15.31966 57.95 107 61 138.7 32.9 17.10185 58.65 105 66 136.15 36.5 19.69054 68.05 95 72 132.45 29.9 17.04383 66.2 99 64 135.8 40.45 21.93406 72.3 95 71 134.65 27 14.89193 50.85 94 67 145.15 43 20.40959 69.75 105 80 141.45 36 17.99271 61.1 #NULL! #NULL! 128.1 24.3 14.8084 55.35 86 66 150 60.3 26.8 95.05 104 69 131.25 31.7 18.40181 62.45 86 50 143.9 38.8 18.73743 55.85 97 61 143.45 32.8 15.93943 60.85 100 71 146 39.95 18.74179 71.4 93 59 138.6 29.55 15.38265 58.95 #NULL! #NULL! 149.05 49.1 22.10129 75.35 113 70 147.25 33.25 15.3349 60.05 100 61 137.1 37.2 19.79101 70.05 96 65 134.15 26.9 14.94758 56.25 99 56 135.35 24.3 13.26447 57.05 89 68 134.7 30.1 16.58942 59 102 68 144.1 34.2 16.47017 62.5 84 50 138.15 41.85 21.92773 74.95 #NULL! #NULL! 136.75 30.5 16.30967 62.8 #NULL! #NULL! 142.5 38.1 18.7627 64.45 91 62 143.7 37.2 18.0148 63.45 93 58 136.35 42.55 22.88702 70.45 100 72 143.9 32.6 15.74331 58.1 105 68 146.45 34.5 16.08571 62.45 95 56 134.6 35.1 19.3739 59.85 87 60 145.05 42.7 20.29516 71.6 80 60 138.85 49.9 25.88265 89.5 97 66 143.1 31.45 15.35824 56.8 95 80 144.1 31.3 15.07358 62.7 87 49 140.35 35.9 18.22509 63.9 94 75 142.45 30.2 14.88271 56.35 99 64 134.5 32.15 17.772 61.5 92 55 141.65 35.7 17.79242 61.75 95 69 133.65 30.4 17.01906 62.8 88 69 114 Raw Data 4625 mnipe4maf1 M 145.75 33.6 15.81693 64.45 96 63 4908 mstha5mf1 M 139.5 30.1 15.46743 57 93 55 5011 mdisu4moc1 M 136.9 26.55 14.16634 53.6 86 59 5160 mlira5maf1 M 144.95 40.7 19.37126 67.2 101 62 5180 mlhlo4wf1 F 130.7 24.85 14.54706 56.35 91 61 5187 fsije4maf1 F 144.85 34 16.20473 56.75 97 54 5264 myeto5maf1 M 163.55 74.9 28.00146 90.45 122 84 5400 fjokrtlfl F 146.35 35.05 16.36449 61.85 85 59 5609 fhuda4bbf1 F 144.45 51.1 24.48983 80.85 103 67 5765 mzhal5maf1 M 145.65 42.6 20.08115 68.55 98 60 5932 fbash4bc1 F 135.75 45.05 24.44641 80.1 105 63 5961 morba4bf1 M 138.1 33.8 17.72268 60.8 70 46 5996 mshaa4bbf1 M 134.5 29.8 16.47296 60.55 93 59 6058 fbrsh5maf1 F 154.85 40.6 16.93182 61.95 #NULL! #NULL! 6060 flesh5maf1 F 136.3 29.9 16.09457 55.6 103 67 6062 mmach4bbf1 M 133.35 25.8 14.50887 54.95 105 51 6109 fwija5moc1 F 140.45 42 21.29148 64.05 #NULL! #NULL! 6152 fmcky5mf1 F 151.4 47.2 20.59161 72.15 106 64 6177 mhabo4maf1 M 132.45 32.5 18.52591 65.95 80 52 6208 fkran4wf1 F 132.2 27.1 15.50624 56.75 97 59 6251 fkoma5maf1 F 161.15 35.8 13.7855 62.25 135 120 6279 fnesh5mf1 F 148.45 37.2 16.88039 63.4 104 54 6301 fnosa4bc1 F 137.6 28.9 15.26374 56.6 98 58 6344 mmobr5maf1 M 143.15 36.9 18.0071 64.45 90 75 6529 mpajimafl M 150.85 41.2 18.10534 62.5 97 63 6631 mmemi5bbf1 M #NULL! #NULL! #NULL! #NULL! 106 73 6723 mczig5mf1 M 145.7 32.5 15.30961 57.1 101 68 6814 fruvi4bc1 F 141.35 #NULL! #NULL! 65.95 84 48 6936 fgrme4bbf1 F 139.8 30.5 15.60578 55.8 92 58 7077 mquph5lf1 M 147.55 40 18.37306 65.45 93 56 7175 fdeta5maf1 F 140.75 33.1 16.70826 60.05 93 61 7204 mgash5lf1 M 140.5 28.7 14.53882 56.45 #NULL! #NULL! 7264 fzhci4maf1 M #NULL! #NULL! #NULL! #NULL! 102 72 7293 flodi5maf1 F 151.55 42.7 18.59157 61.9 101 63 7465 floma4bc1 M 145.65 53.4 25.17215 80.55 93 54 7563 fraem4maf1 F 136.35 29.9 16.08277 54.6 #NULL! #NULL! 7577 mwede4bc1 M 146.1 39.8 18.64587 63.9 92 56 7631 fkyme4maf1 F 134.4 28.7 15.88852 56.45 #NULL! #NULL! 7880 fviha5nc1 F 149.9 39.7 17.66799 60.7 110 65 7911 mstda4bbf1 M 137.45 38.5 20.37845 73.9 96 60 7941 mfast5nc1 M 133.9 32.6 18.18262 63.8 96 59 8043 mgabe4bbf1 M 132.85 33.2 18.81113 59.45 91 61 8171 mtuda4mf1 M 148.25 37.2 16.92597 62.05 98 61 8308 mbrma4bbf1 M 144.2 46.1 22.17024 79.85 109 73 8409 fchsy4moc1 F 127.85 29.9 18.29236 58.9 101 65 8411 fwaan5bbf1 F 140.6 32.9 16.64276 61.7 85 54 8466 fholi4bbf1 F 142.1 42 20.79989 68.85 73 57 8520 mvake4bc1 M 122.25 21.4 14.31911 48.8 #NULL! #NULL! 8524 figan5maf1 F 150.7 32.6 14.3546 55.8 88 57 8573 frani5maf1 F 140.15 44.1 22.45186 68.55 109 70 8583 mmefe4mf1 #NULL! #NULL! #NULL! #NULL! 97 63 115 R a w Data 8599 fhije4wf1 F 143.45 31.3 15.21049 55.7 96 60 8629 fbrar5maf1 F 152.55 51.4 22.0871 73.1 99 61 8894 fcaar4maf1 F 136.6 42.4 22.72294 73.4 #NULL! #NULL! 8926 mlaja4bbf1 M 136.95 34.7 18.50143 58.85 #NULL! #NULL! 8982 mlowe4bf1 M 133.45 28.7 16.11554 61.35 110 67 9099 mzech5bbf1 M 143.25 41.3 20.12615 68.6 93 55 9102 ftoda5maf1 F 147.25 43.3 19.96996 64.5 108 71 9139 mstky5wf1 M 139.45 29.9 15.37567 58.05 88 64 9388 mbayo5lf1 M 136.45 30.3 16.27405 59.85 100 75 9433 mfoma4bbf1 M 132.3 27.9 15.93986 62.85 75 59 9496 frecl4maf1 F 134.75 30.05 16.54958 57.6 95 59 9553 fguca4maf1 F 136.45 38 20.4097 63.05 113 82 9651 fobfr4bbf1 F 148.65 41.6 18.82624 61.45 83 60 9669 fsaev4maf1 F 135.8 31.4 17.02669 58.65 88 64 9934 mulma5mf1 M 139.45 41.3 21.23797 73.6 106 67 9996 mguan4mf1 M 154.6 59.3 24.81051 78.1 108 66 116 R a w Data P R S R M A X Cur lups P u s h u p s Gr ipTot Lapsrun D O B Start Date Age 98 23 37 3 37 45 3/29/1996 12/7/2005 9.69 87 23 4 5 22 28 8/22/1995 11/16/2005 10.24 99 17 9 14 32 51 1/24/1996 11/30/2005 9.85 84 28 9 3 27 41 10/25/1996 12/7/2005 9.12 103 15 23 2 25 24 3/1/1996 11/2/2005 9.67 74 36 16 8 33 44 10/4/1995 11/2/2005 10.08 90 27 8 0 42 14 7/6/1995 2/1/2006 10.58 104 25 22 2 19 14 5/20/1995 2/1/2006 10.70 99 25 12 2 30 19 11/28/1995 11/16/2005 9.97 83 34 23 21 29 31 8/2/1996 11/30/2005 9.33 84 31 28 2 43 43 8/26/1995 11/16/2005 10.23 86 38 8 3 33 30 4/20/1996 11/16/2005 9.57 86 25 20 28 30 61 6/25/1995 11/2/2005 10.36 93 29 0 0 25 4 7/12/1996 1/11/2006 9.50 92 28 32 10 44 36 10/12/1996 11/2/2005 9.06 #NULL! 27 7 5 29 26 12/2/1996 12/7/2005 9.01 91 32 9 6 34 35 4/29/1996 11/30/2005 9.59 86 19 8 15 38 22 10/6/1996 2/1/2006 9.32 94 24 0 1 41 10 7/25/1995 2/1/2006 10.52 93 26 14 12 40 54 4/22/1996 12/7/2005 9.63 89 28 27 2 50 18 3/19/1995 11/16/2005 10.66 94 21 0 0 41 13 10/3/1995 2/8/2006 10.35 63 21 8 7 39 44 5/6/1995 11/2/2005 10.49 85 14 0 0 30 16 7/14/1995 2/8/2006 10.57 76 31 5 10 31 44 11/9/1995 11/16/2005 10.02 103 16 11 0 30 20 9/10/1995 1/11/2006 10.34 83 21 8 1 38 18 2/16/1995 11/30/2005 10.79 67 24 21 10 33 31 5/2/1996 12/7/2005 9.60 91 16 0 0 37 28 4/13/1995 11/30/2005 10.63 106 29 2 0 24 17 4/6/1995 12/7/2005 10.67 112 34 0 0 19 9 8/12/1996 2/1/2006 9.47 82 22 15 8 43 17 1/24/1995 11/30/2005 10.85 73 6 15 0 33 19 7/17/1995 11/2/2005 10.30 85 33 4 0 42 8 5/5/1996 2/1/2006 9.74 95 25 11 6 26 21 5/31/1995 12/7/2005 10.52 94 37 9 10 37 10 7/4/1996 1/11/2006 9.52 79 28 14 0 42 31 10/19/1995 12/7/2005 10.14 84 28 0 0 36 10 10/20/1995 12/7/2005 10.13 86 25 7 0 40 28 2/10/1995 11/30/2005 10.80 97 28 4 0 31 15 7/8/1995 2/1/2006 10.57 85 15 22 2 46 17 11/29/1995 2/8/2006 10.20 80 22 3 0 30 12 10/28/1996 2/8/2006 9.28 67 20 16 5 25 34 4/28/1996 11/16/2005 9.55 86 25 0 3 26 14 7/1/1996 12/7/2005 9.43 77 27 0 1 32 26 11/15/1995 12/7/2005 10.06 116 30 20 0 46 26 4/21/1996 2/8/2006 9.80 96 16 10 4 41 25 2/27/1996 11/2/2005 9.68 92 28 18 0 41 16 2/18/1996 2/1/2006 9.95 84 39 9 13 45 28 6/4/1995 11/30/2005 10.49 101 32 5 0 42 8 12/18/1995 1/11/2006 10.07 98 29 94 14 27 30 7/1/1996 11/16/2005 9.38 97 29 0 0 22 28 12/12/1995 11/30/2005 9.97 11 Raw Data 78 20 7 7 30 26 1/6/1995 11/30/2005 10.90 109 31 4 0 33 17 10/18/1996 2/8/2006 9.31 92 35 0 0 25 22 8/23/1996 1/11/2006 9.39 72 26 15 1 53 36 9/19/1996 11/16/2005 9.16 95 13 4 15 36 26 5/26/1995 2/8/2006 10.71 108 22 0 0 29 11 1/11/1996 2/1/2006 10.06 92 16 29 2 37 27 2/15/1995 12/7/2005 10.81 91 28 5 3 37 41 1/22/1995 11/16/2005 10.82 71 22 5 1 31 43 4/28/1995 11/16/2005 10.55 74 26 10 7 39 49 2/18/1996 11/30/2005 9.78 81 14 4 0 27 7 8/18/1995 11/2/2005 10.21 67 48 94 42 42 38 8/4/1995 11/16/2005 10.29 66 15 14 0 40 12 2/22/1995 2/8/2006 10.96 101 23 0 0 47 10 7/17/1995 2/8/2006 10.57 66 18 11 12 44 43 2/6/1995 11/2/2005 10.74 91 26 23 9 42 29 11/10/1997 12/7/2005 8.07 111 29 1 0 42 7 8/23/1995 2/1/2006 10.44 81 8 0 0 35 8 2/6/1995 2/8/2006 11.01 86 18 8 5 30 8 10/31/1995 11/2/2005 10.01 92 38 29 0 25 22 11/19/1995 11/30/2005 10.03 77 31 12 3 25 15 10/27/1996 11/2/2005 9.02 65 49 10 2 51 14 9/29/1995 11/16/2005 10.13 80 33 15 8 42 44 2/18/1995 11/16/2005 10.74 88 35 0 2 44 28 4/25/1995 11/16/2005 10.56 69 21 3 1 34 17 7/18/1995 11/16/2005 10.33 88 33 18 0 31 12 1/23/1996 12/7/2005 9.87 87 23 2 0 23 23 9/15/1995 11/30/2005 10.21 83 31 20 0 25 23 11/21/1996 11/16/2005 8.99 87 33 0 0 25 8 9/18/1995 2/8/2006 10.39 75 34 11 2 44 20 1/4/1995 2/8/2006 11.10 #NULL! 29 3 2 31 14 8/29/1996 11/2/2005 9.18 86 27 15 15 34 28 5/26/1996 11/2/2005 9.44 74 28 13 10 25 24 12/28/1996 11/30/2005 8.92 78 28 10 12 36 20 6/21/1996 11/2/2005 9.37 62 21 25 30 42 60 4/20/1995 11/2/2005 10.54 87 26 19 0 36 22 7/30/1995 12/7/2005 10.36 99 23 1 2 25 20 4/6/1996 2/8/2006 9.84 92 30 21 6 40 17 2/13/1995 11/30/2005 10.80 71 35 4 2 30 26 3/6/1995 12/7/2005 10.76 101 25 20 9 37 47 11/28/1995 11/30/2005 10.01 86 27 12 0 40 12 6/25/1996 1/11/2006 9.55 91 31 2 0 33 25 12/28/1995 11/16/2005 9.89 89 41 27 12 40 12 4/9/1996 11/16/2005 9.60 75 24 18 10 25 16 4/28/1995 11/16/2005 10.55 100 23 0 0 40 10 1/25/1995 2/1/2006 11.02 92 20 10 0 33 10 5/31/1996 11/16/2005 9.46 90 25 12 4 23 13 5/19/1996 11/2/2005 9.46 102 32 1 0 26 19 10/11/1996 12/7/2005 9.16 86 37 12 9 34 25 9/14/1995 11/2/2005 10.14 69 20 11 3 35 21 1/17/1995 1/11/2006 10.98 98 33 95 1 31 23 7/1/1996 11/16/2005 9.38 98 25 12 0 21 17 1/30/1996 11/16/2005 9.80 79 29 3 0 32 16 4/23/1995 12/7/2005 10.63 118 R a w Data 86 21 8 1 36 13 1/5/1996 2/1/2006 10.08 93 34 7 1 26 11 11/18/1996 11/16/2005 8.99 72 18 0 0 31 8 10/26/1995 1/11/2006 10.21 94 21 0 10 25 17 9/15/1995 11/30/2005 10.21 128 21 0 0 17 12 1/5/1995 11/16/2005 10.86 97 34 20 12 28 35 9/13/1996 11/2/2005 9.14 69 31 14 0 37 11 8/25/1995 11/16/2005 10.23 78 19 0 0 39 22 12/1/1995 2/8/2006 10.19 86 23 51 20 44 63 10/21/1995 12/7/2005 10.13 70 26 9 0 21 8 8/28/1995 11/16/2005 10.22 95 24 20 0 25 21 3/25/1995 11/30/2005 10.69 82 19 0 4 40 26 5/17/1996 12/7/2005 9.56 94 29 4 0 31 21 10/14/1996 11/16/2005 9.09 96 35 0 9 32 26 2/3/1996 11/16/2005 9.79 80 20 5 0 32 11 7/16/1995 2/8/2006 10.57 88 18 0 0 28 12 1/7/1996 12/7/2005 9.92 69 28 17 16 48 81 4/17/1996 12/7/2005 9.64 89 25 8 9 42 13 11/17/1995 11/30/2005 10.04 98 16 17 2 34 11 5/26/1996 11/2/2005 9.44 78 24 7 16 35 40 8/8/1995 12/7/2005 10.33 82 30 2 0 21 17 8/5/1996 11/16/2005 9.28 72 18 6 0 41 12 11/25/1996 12/7/2005 9.03 98 5 0 0 27 5 11/11/1995 11/2/2005 9.98 89 35 17 0 36 19 12/5/1995 12/7/2005 10.01 93 31 10 1 29 28 12/22/1995 12/7/2005 9.96 70 29 20 0 48 12 4/19/1995 2/1/2006 10.79 94 19 0 0 39 12 11/6/1996 12/7/2005 9.08 89 22 18 0 23 26 4/12/1996 2/8/2006 9.83 90 27 6 8 35 36 6/26/1996 12/7/2005 9.45 82 30 32 2 39 14 3/5/1995 2/1/2006 10.91 90 37 3 1 27 14 9/23/1995 11/30/2005 10.19 80 11 3 0 26 16 7/21/1995 11/2/2005 10.29 93 38 4 6 35 33 9/9/1996 11/30/2005 9.22 103 23 19 5 32 24 3/2/1996 11/30/2005 9.75 79 36 9 2 32 19 11/23/1995 12/7/2005 10.04 93 23 11 6 40 33 2/8/1996 11/30/2005 9.81 94 31 0 0 30 10 8/10/1995 1/11/2006 10.42 87 21 0 2 25 22 6/21/1996 1/11/2006 9.56 112 23 7 4 27 26 8/30/1996 2/8/2006 9.44 114 16 25 5 38 20 1/24/1995 11/2/2005 10.77 119 16 0 0 26 8 1/8/1995 2/8/2006 11.09 97 23 36 3 39 38 4/29/1995 11/2/2005 10.51 85 16 2 0 24 6 10/29/1995 1/11/2006 10.20 91 27 0 11 21 48 7/9/1996 11/30/2005 9.39 91 36 2 0 37 16 10/10/1996 1/11/2006 9.25 84 40 7 0 30 15 3/16/1995 11/16/2005 10.67 73 30 9 0 37 12 3/5/1995 2/8/2006 10.93 90 31 5 2 41 20 3/8/1995 11/30/2005 10.73 92 26 11 4 35 26 8/11/1996 11/30/2005 9.30 80 21 12 0 39 10 1/19/1995 1/11/2006 10.98 92 27 12 1 37 15 4/5/1996 12/7/2005 9.67 79 33 12 14 33 32 8/22/1996 12/7/2005 9.29 80 18 19 8 31 40 2/7/1995 11/2/2005 10.74 119 R a w Data 81 29 75 10 47 27 6/1/1995 12/7/2005 10.52 78 23 5 0 30 15 12/6/1995 11/16/2005 9.95 92 39 9 16 28 12 7/5/1995 2/8/2006 10.60 #NULL! 23 11 13 40 14 7/18/1996 11/30/2005 9.37 109 37 30 0 25 8 11/17/1996 2/8/2006 9.23 79 29 26 19 30 53 7/3/1996 12/7/2005 9.43 74 27 25 37 41 46 11/21/1995 11/2/2005 9.95 67 41 11 14 36 42 4/14/1995 12/7/2005 10.65 83 42 18 0 29 17 8/16/1995 12/7/2005 10.31 88 20 0 0 20 11 9/2/1996 11/16/2005 9.20 92 32 0 0 25 16 3/22/1996 2/1/2006 9.86 88 25 19 0 38 21 1/16/1996 11/30/2005 9.87 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 6/17/1996 11/30/2005 9.45 79 22 0 2 23 20 11/9/1996 1/20/2006 9.20 93 12 0 10 45 21 12/9/1995 1/20/2006 10.12 66 30 21 14 23 19 3/1/1996 11/2/2005 9.67 94 31 18 4 32 17 11/30/2005 ##### 105 29 20 18 30 28 9/24/1996 11/23/2005 9.16 79 17 0 13 34 44 1/22/1995 1/20/2006 11.00 #NULL! 17 5 4 27 45 11/23/2005 6.62 92 25 17 0 32 24 1/3/1995 11/30/2005 10.91 79 19 13 14 40 41 2/22/1995 11/23/2005 10.75 95 28 0 0 26 7 3/22/1996 1/11/2006 9.81 62 22 4 13 26 12 6/21/1995 11/2/2005 10.37 84 29 28 5 23 12 10/25/1995 11/9/2005 10.04 85 21 11 8 22 12 11/7/1996 11/23/2005 9.04 80 22 4 1 37 10 7/27/1996 11/16/2005 9.31 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 8/6/1996 11/30/2005 9.32 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 4/12/1995 12/7/2005 10.66 83 20 0 0 34 29 11/5/1996 1/20/2006 9.21 85 32 11 0 35 13 4/15/1995 11/30/2005 10.63 89 25 0 2 36 9 2/16/1996 1/11/2006 9.90 86 34 .7 0 31 21 8/8/1995 11/30/2005 10.31 85 24 42 24 37 53 1/30/1996 12/7/2005 9.85 99 19 1 0 35 18 4/24/1996 1/20/2006 9.74 66 28 10 0 31 20 9/17/1995 11/2/2005 10.13 104 21 1 2 30 10 8/28/1995 1/11/2006 10.37 98 30 0 0 33 27 6/20/1996 2/1/2006 9.62 108 15 22 5 34 18 5/19/1995 1/11/2006 10.65 77 26 14 15 30 36 1/6/1995 11/2/2005 10.82 96 41 11 1 33 22 3/27/1997 12/7/2005 8.70 75 35 17 26 33 51 10/28/1995 11/9/2005 10.03 84 37 13 14 35 3 8 ? 11/9/2005 10.72 93 30 0 0 31 20 10/9/1996 2/1/2006 9.31 84 23 11 3 31 18 6/26/1996 12/7/2005 9.45 81 26 38 31 40 40 9/8/1995 11/23/2005 10.21 97 27 15 0 22 13 5/9/1996 2/8/2006 9.75 88 34 8 8 33 20 9/29/1995 11/30/2005 10.17 94 33 10 6 34 34 10/30/1996 11/2/2005 9.01 108 27 20 2 32 15 10/6/1996 12/7/2005 9.17 #NULL! 20 0 0 #NULL! NULL 6/4/1995 11/30/2005 10.49 87 27 11 9 34 15 5/8/1996 11/9/2005 9.51 109 25 4 0 40 11 8/19/1996 1/20/2006 9.42 120 R a w Data 75 26 16 0 36 16 12/13/1995 11/30/2005 9.97 83 32 0 0 24 16 6/3/1996 11/16/2005 9.45 96 31 10 9 40 32 2/16/1995 11/9/2005 10.73 80 17 7 4 35 33 5/30/1996 1/20/2006 9.64 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 5/4/1995 12/7/2005 10.60 84 38 12 3 24 26 8/4/1995 12/7/2005 10.34 103 33 17 12 34 34 7/13/1995 1/20/2006 10.52 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 9/8/1995 2/8/2006 10.42 94 17 22 17 39 20 4/21/1995 11/23/2005 10.59 84 29 1 2 17 19 11/15/1996 12/7/2005 9.06 110 21 4 2 26 34 5/30/1996 11/2/2005 9.43 79 31 17 10 41 22 11/17/1995 . 11/30/2005 10.06 78 9 23 10 35 20 2/27/1995 11/23/2005 10.74 76 36 2 0 24 11 12/11/1996 11/16/2005 8.93 92 32 7 6 43 30 1/31/1995 11/30/2005 10.83 88 33 10 4 47 37 4/20/1995 11/30/2005 10.61 91 23 23 14 55 43 3/16/1995 1/20/2006 10.85 110 20 17 13 37 50 5/9/1995 11/23/2005 10.54 79 31 0 0 27 7 3/3/1996 11/16/2005 9.71 101 36 22 0 42 56 3/14/1995 1/20/2006 10.86 81 26 20 8 37 25 4/8/1995 11/9/2005 10.59 107 25 16 12 35 35 ? 11/30/2005 10.92 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 6/11/1995 11/9/2005 10.41 86 41 21 1 31 31 3/29/1996 12/7/2005 9.69 91 29 9 4 40 40 5/4/1995 11/30/2005 10.58 60 17 3 0 41 13 6/17/1996 11/16/2005 9.42 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 12/20/1996 12/7/2005 8.96 115 12 42 1 40 24 5/10/1996 11/16/2005 9.52 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 8/27/1996 12/7/2005 9.28 79 24 13 8 41 15 9/14/1995 1/11/2006 10.33 90 22 10 5 37 16 4/15/1996 1/20/2006 9.77 83 13 6 0 26 10 8/28/1995 1/11/2006 10.37 91 25 0 20 39 33 7/2/1996 1/20/2006 9.55 102 21 83 25 42 4 7 ? 11/23/2005 ##### 71 16 0 0 43 20 5/30/1996 1/20/2006 9.64 115 23 11 0 23 11 4/11/1996 2/8/2006 9.83 81 35 6 12 31 38 10/5/1995 1/20/2006 10.29 91 30 4 0 46 31 7/24/1996 1/20/2006 9.49 #NULL! 13 0 7 22 5 7/24/1996 11/16/2005 9.31 83 34 25 4 31 18 1/26/1995 11/30/2005 10.84 107 44 2 4 32 20 11/2/1995 11/30/2005 10.08 127 35 3 7 29 21 3/28/1996 11/23/2005 9.66 89 26 19 8 28 14 7/25/1996 11/2/2005 9.27 102 36 4 1 37 24 6/17/1995 12/7/2005 10.48 #NULL! #NULL! #NULL! #NULL! #NULL! #NULL! 11/8/1996 12/7/2005 9.08 #NULL! 28 18 8 39 31 1/21/1996 1/20/2006 10.00 75 16 0 0 21 16 9/14/1996 11/9/2005 9.15 97 24 8 11 36 22 4/25/1995 1/20/2006 10.74 88 31 16 10 43 17 9/19/1995 11/30/2005 10.20 82 23 17 20 38 61 8/2/1995 11/2/2005 10.25 83 19 5 6 30 17 10/18/1995 11/9/2005 10.06 75 32 26 9 36 54 7/10/1996 1/20/2006 9.53 106 21 10 0 28 9 5/31/1996 11/30/2005 9.50 121 Raw Data 97 40 6 5 28 18 1/12/1996 11/30/2005 9.88 91 31 30 0 46 35 1/26/1996 1/20/2006 9.98 100 25 8 7 25 43 12/19/1996 12/7/2005 8.97 107 19 9 4 28 22 6/19/1995 11/23/2005 10.43 8 1 18 0 1 37 27 4/4/1995 11/23/2005 10.64 122 R a w Data Teacher School Ethnicity Code Wear Weather Avg Wear Total ID ID Code Days Code Hours Counts 235 13413 1 2 0.2 13.03038162 1844871 740 13441 1 1 0.4 14.20742638 2061594 653 13413 2 2 0.8 12.615788 1401196 235 13413 2 0 0.2 12.38531455 1418570 856 13755 1 0 1 14.19519746 1809042 521 13755 1 0 1 11.46798538 1144636 220 13394 2 0 0.8 14.87826159 1414068 220 13394 2 0 0.8 13.34169478 1560389 650 13441 1 0 0.4 13.82560032 1809262 653 13413 1 2 0.8 12.99116054 842437 740 13441 1 0 0.4 14.54383806 2673140 350 13441 2 0 0.4 14.52882417 1911797 546 13755 1 0 0.8 14.02849772 1970807 146 13392 2 2 0.8 14.67736167 2331735 856 13755 1 1 1 11.41135496 1475926 748 13413 1 0 0.2 12.14050407 1481188 653 13413 2 2 0.8 13.46826855 1475721 330 13394 2 0 0.8 13.19309387 1891861 730 13394 2 0 0.2 13.53792419 1017709 435 13413 2 0 0.8 11.5962859 1366065 650 13441 1 2 0.4 12.9605748 1814363 730 13394 2 2 0.8 11.38985161 1149876 521 13755 1 0 1 13.15086502 1150977 730 13394 2 2 0.2 12.58724001 749521 650 13441 1 0 0.4 11.5798037 1882124 140 13392 1 0 0.8 12.33339121 1756141 152 13413 1 2 0.8 12.75257199 1511791 235 13413 1 0 0.2 13.95453999 2102450 886 13413 1 2 0.8 12.40630538 1323842 426 13413 1 0 0.2 13.85650976 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168 13413 1 #NULL! #NULL! #NULL! #NULL! 521 13755 1 #NULL! #NULL! #NULL! #NULL! 320 13412 2 #NULL! #NULL! #NULL! #NULL! 574 13443 1 #NULL! #NULL! #NULL! #NULL! 653 13413 1 #NULL! #NULL! #NULL! #NULL! 886 13413 2 #NULL! #NULL! #NULL! #NULL! 127 13443 1 #NULL! #NULL! #NULL! #NULL! 163 13413 1 #NULL! #NULL! #NULL! #NULL! 210 13753 1 #NULL! #NULL! #NULL! #NULL! 810 13753 #NULL! #NULL! #NULL! #NULL! #NULL!

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