Developing VO2max prediction functions from the physical, motor performance and anthropometric components of a cohort of adolescents : the PAHL-study

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Developing

V

O

_2max

prediction functions

from the physical, motor performance and

anthropometric components of a cohort

of adolescents: The PAHL-Study

C Pienaar

12374695

Thesis submitted for the degree Doctor Philosophiae in Human

Movement Sciences the Potchefstroom Campus of the

North-West University

Promoter:

Dr B Coetzee

Assistant Promoter: Prof JWR Twisk

Co-Promoter:

Prof MA Monyeki

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This thesis was only possible through the Grace, Favour and Wisdom of my Saviour Lord Jesus Christ. I dedicate this entirely to my Creator and the King of Kings, “with whom

there is no variation or shadow of turning” - James 1:17

"In Christ Alone" – Owl City

In Christ alone, my hope is found  He is my light, my strength, my song 

This cornerstone, this solid ground  Firm through the fiercest drought and storm  What heights of love, what depths of peace  When fears are stilled, when strivings cease 

My Comforter, my All-in-All  Here in the love of Christ I stand There in the ground His body lay  Light of the World by darkness slain 

Then bursting forth in glorious day  Up from the grave He rose again!

And as He stands in victory  Sin’s curse has lost its grip on me

 For I am His and He is mine  Bought with the precious Blood of Christ

No guilt in life, no fear in death  This is the power of Christ in me 

From life’s first cry to final breath  Jesus commands my destiny  No power of hell, no scheme of man 

Can ever pluck me from His hand  Till He returns or calls me home  Here in the power of Christ I’ll stand

I truly am Greatly Blessed, Highly Favoured and Deeply Loved, just an ordinary girl Loved by an Extraordinary God.

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The co-authors of the three articles, which form part of this thesis, Dr. Ben Coetzee (Promoter), Prof Jos Twisk (Co-promoter) and Prof. Andries Monyeki (Assistant-promoter) hereby give permission to the candidate, Mrs. Cindy Pienaar to include the three articles as part of the PhD thesis. The contribution (advisory and supportive) of the co-authors was kept within reasonable limits, thereby enabling the candidate to submit this thesis for examination purposes. This thesis, therefore, serves as fulfillment of the requirements for the degree Doctor of Philosophy within the School of Biokinetics, Recreation and Sport Science in the Faculty of Health Sciences at the North-West University (Potchefstroom campus).

Dr. Ben Coetzee Prof. Jos Twisk

Promoter and co-author Co-promoter and co-author

Prof. Andries Monyeki

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Developing

V

O

_2max



prediction functions from the physical, motor performance and

anthropometric components of a cohort of adolescents: The PAHL-Study

The measurement of cardiorespiratory fitness has been extensively researched among adult populations, but very few researchers have focused their attention on the cardiorespiratory fitness of children and adolescents. Due to various constraints of direct V• O_2max testing, various indirect testing methods have been developed of which the 20-m Shuttle Run Test is the most widely used testing method. The influence of various anthropometric, physical and motor performance components as well as certain demographic factors such as gender, race, living area, and sport participation as well as physical activity level on the _2max

•

O

V value of participants seems to suggest that _2max

•

O

V can be predicted by including these components in prediction models. It is against this background that the objectives of this study are provided.

The following four objectives of the study were achieved through a literature review: Firstly, to name and describe the various direct and indirect methods for determining V• O_2max; secondly, to provide a review on the findings with regard to the aerobic performances or _2max

•

O

V values of children and adolescents; thirdly, to discuss the possible influence of various anthropometric, physical and motor-performance components on the aerobic performances or _2max

•

O

V values of the last-mentioned groups of subjects. As part of this objective, other literature-identified factors such as certain demographic factors (living area, race and gender), sport and physical activity participation level which may also influence the aerobic performances or _2max

•

O

V values

of the participants, were also discussed; fourthly, all literature identified models for the prediction of aerobic performances or _2max

•

O

V values in children, and in adolescents were mentioned and discussed. The next few objectives were achieved through a selected group, cross-sectional experimental research design; fifthly, to develop a valid _2max

•

O

V prediction function from several anthropometric measurements and demographic factors such as gender,

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Tlokwe Local Municipality (Potchefstroom area) of North West Province, South Africa; sixthly, to develop a _2max

•

O

V prediction function from the physical and motor-performance components as well as demographic variables such as gender, race and living area as well as sport participation level of a cohort of adolescents living in the Tlokwe Local Municipality (Potchefstroom area) of North West Province, South Africa; and finally, to determine the validity of the 20-m SRT to estimate the ₂

•

O

V _and _2max

•

O

V of a cohort of adolescent boys in the Tlokwe Local Municipality (Potchefstroom area) of North West Province, South Africa.

In order to fulfil the fifth and sixth objectives of the study, a total of 214 grade 8 adolescents (boys: 88 and girls: 126) (age: 15.82 ± 0.68 years) of high schools in the Tlokwe Local Municipality (Potchefstroom area) of the Dr Kenneth Kaunda District of the North West Province, South Africa were purposefully selected from pre-acquired class lists, from six secondary schools. Data was collected by means of various questionnaires, anthropometric measurements and physical and motor-performance tests, which also included the 20-metre SRT. For the fulfilment of the final objective of the study, 52 boys were purposefully selected from the above-mentioned group that completed various questionnaires as well as the 20-m SRT while they were fitted with a portable gas analyser apparatus.

With regard to the anthropometric and demographic variable prediction model, the forward stepwise regression analysis results showed that muscle mass percentage, sport participation level, stature, hip circumference and ectomorphy act as significant predictors (p ≤ 0.05) of the indirect, 20-m SRT _2max

•

O

V values of a cohort of adolescents. Muscle mass percentage emerged as the strongest predictor (59%) of adolescents’ V• O_2max values, followed by sport participation level (6%), ectomorphy (2%), stature (1%) and hip circumference (1%). The physical, motor-performance and demographic prediction model revealed that 10-metre speed, sit-up repetitions, sport participation level, handgrip strength, Vertical Jump Test (VJT) Tendo peak power, maximal heart rate (HRmax), living area, right shoulder external rotation flexibility

(RPSERT), horizontal jump test distance (HJT) and right Modified Thomas iliopsoas flexibility (RMTIT) served as significant predictors (p ≤ 0.05) of the indirect, 20m-SRT-derived _2max

•

O V

values of a cohort of adolescents. However, only 10-metre speed served as a major contributor (53.5%) to the indirect _2max

•

O

V values of the adolescents. The rest of the variables contributed

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variance in the _2max

•

O

V values of the adolescents. Cross-validations also revealed that both models are valid for predicting the 20-m SRT-derived indirect _2max

•

O

V values of this cohort of adolescents.

The 20-m SRT validity study showed that a significant difference (p ≤ 0.05) existed between the predicted indirect _2max

•

O

V results (42.06 ± 4.53 ml/kg/min) as obtained from the 20-m SRT booklet and the direct _2max

•

O

V results (50.62 ± 7.11 ml/kg/min) as obtained from the gas analysis. Furthermore, significant differences (p ≤ 0.05) were observed between the direct and indirectly predicted ₂

•

O

V values at levels 1-9 of the 20-m SRT compared to no significant

differences at levels 10 and 11 of the 20-m SRT.

In conclusion, to the researchers’ knowledge, this is the first study to develop valid V• O_2max prediction functions from the use of several anthropometric measurements, physical and motor-performance test results and demographic information for a group of South African adolescents. Furthermore, this is also the first study to reveal that the 20-m SRT is not a valid test for the accurate prediction of ₂ • O V and _2max • O

V of a cohort of adolescent South African boys. The results of this study may possibly allow practitioners in the field of Human Movement Science to more accurately screen the indirect _2max

•

O

V values of adolescents by making use of easily obtainable measures and information, instead of the predicted _2max

•

O

V _{values of the 20-m SRT.}

Keywords: adolescents, aerobic, _2max

•

O

V , 20-m SRT, anthropometric, physical, motor, direct, indirect, gender

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Die ontwikkeling van VO_2maks



-voorspellingsfunksies uit die fisiese, motoriese

prestasie-en antropometriese komponprestasie-ente van ŉ kohort adolessprestasie-ente: Die PAHL-studie

Die meting van kardiorespiratoriese fiksheid is al breedvoerig onder volwasse populasies nagevors, maar baie min navorsers het al hulle aandag geskenk aan die kardiorespiratoriese fiksheid van kinders en adolessente. Weens verskeie beperkings van direkte VO_2maks



-toetsing is verskeie indirekte toetsmetodes al ontwikkel waarvan die 20-m Heen en Weer Hardlooptoets (20-m Shuttle Run Test – SRT) die toetsmetode is wat die algemeenste gebruik word. Die invloed van verskeie antropometriese, fisieke en motorieseprestasie-komponente asook sekere demografiese faktore soos geslag, ras, woongebied en sportdeelname asook fisieke aktiwiteitsvlak op die VO_2maks



-waarde van deelnemers blyk daarop te dui dat VO_2maks 

voorspel kan word deur hierdie komponente by voorspellingsmodelle in te sluit. Dit is teen hierdie agtergrond dat die doelstellings van hierdie studie voorsien word.

Die volgende vier doelstellings van die studie is bereik deur ŉ literatuuroorsig: Eerstens om die verskeie direkte en indirekte metodes vir die bepaling van VO_2maks



aan te dui en te beskryf; tweedens om ŉ oorsig te verskaf van die bevindings rakende die aërobiese prestasies of

2maks

O V



-waardes van kinders en adolessente; derdens om die moontlike invloed van verskeie antropometriese, fisieke en motorieseprestasie-komponente op die aërobiese prestasies of

2maks

O V



-waardes van laasgenoemde groepe proefpersone te bespreek. Ander literatuurgeïdentifiseerde faktore soos sekere demografiese faktore (woongebied, ras en geslag), sportdeelname- en fisieke aktiwiteitsvlak wat moontlik ook die aërobiese prestasies of

2maks

O V



-waardes van die deelnemers kan beïnvloed, is ook bespreek as deel van hierdie doelstelling; vierdens is alle literatuurgeïdentifiseerde modelle vir die voorspelling van aërobiese prestasie of VO2maks



-waardes by kinders en by adolessente uitgewys en bespreek. Die volgende doelstellings is bereik deur van ŉ geselekteerde groep, dwars-deursnit eksperimentele

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navorsingsontwerp gebruik te maak; vyfdens om ŉ geldige VO_2maks-voorspellingsfunksie uit etlike antropometriese metings en demografiese faktore soos geslag, ras en woonarea asook sportdeelnamevlak van ŉ kohort adolessente woonagtig in die Tlokwe Plaaslike Munisipaliteit (Potchefstroomgebied) van die Noordwes Provinsie, Suid-Afrika te ontwikkel; in die sesde plek, om ŉ VO_2maks



-voorspellingsfunksie uit die fisieke en motorieseprestasie-komponente asook demografiese veranderlikes soos geslag, ras en woongebied en sportdeelnamevlak van ŉ kohort adolessente woonagtig in die Tlokwe Plaaslike Munisipaliteit (Potchefstroomgebied) van die Noordwes Provinsie, Suid-Afrika, te ontwikkel; en ten slotte, om die geldigheid van die 20-m SRT te bepaal om die ₂

•

O

V en VO_2maks 

van ŉ kohort adolessenteseuns in die Tlokwe Plaaslike Munisipaliteit (Potchefstroomgebied) van Noordwes Provinsie, Suid-Afrika te beraam.

Om die vyfde en sesde doelstelling van die studie te behaal is 214 graad 8-adolessente (seuns: 88 en dogters: 126) (ouderdom: 15.82 ± 0.68 jaar) van hoërskole in die Tlokwe Plaaslike Munisipaliteit (Potchefstroomgebied) van die Noordwes Provinsie, Suid-Afrika doelbewus geselekteer uit vooraf bekomde klaslyste van ses sekondêre skole. Data is deur middel van verskeie vraelyste, antropometriese metings en fisieke sowel as motorieseprestasie toetse wat ook die 20-meter SRT ingesluit het, ingesamel. Vir die bereiking van die finale doelstelling van die studie is 52 seuns doelbewus geselekteer uit bogenoemde groep wat verskeie vraelyste voltooi het asook die 20-m SRT terwyl hul toegerus is met ŉ draagbare gasanaliseerapparaat.

Met betrekking tot die voorspellingsmodel vir antropometriese en demografiese veranderlikes, het die resultate van die vorentoe stapsgewyse regressie-analise getoon dat spiermassa-persentasie, sportdeelnamevlak, liggaamslengte, heupomtrek en ektomorfie as betekenisvolle voorspellers (p ≤ 0.05) van die indirekte, 20-m SRT VO_2maks



-waardes van ŉ kohort adolessente dien. Spiermassa-persentasie het na vore gekom as die sterkste voorspeller (59%) van adolessente se VO_2maks



-waardes, gevolg deur sportdeelnamevlak (6%), ektomorfie (2%), liggaamslengte (1%) en heupomtrek (1%). Die fisieke, motorieseprestasie- en demografiese voorspellingsmodel het aan die lig gebring dat 10-meter-speed, opsit-herhalings, sportdeelnamevlak, handgreepkrag, Vertikalesprong-toets (Vertical Jump Test – VJT) Tendo piek-krag, maksimale harttempo (HRmaks), woongebied, regter eksterne-skouerrotasie-soepelheid (right shoulder external rotation flexibility – RPSERT), afstand vir die horisontalesprong-toets (Horizontal Jump Test – HJT) en Right Modified Thomas iliopsoas-soepelheidstoets (RMTIT) as betekenisvolle voorstellers (p ≤ 0.05) van die indirekte, 20m-SRT-

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egter gedien as ŉ belangrike bydraer (53.5%) tot die adolessente se indirekte VO_2maks 

-waardes. Die oorblywende veranderlikes het 17.4% tot die totale variansie in VO_2maks



-waardes bygedra. In die geheel was laasgenoemde antropometriese, fisieke, motoriese-prestasie- en demografiese veranderlikes vir 70.5% van die variansie in die VO_2maks



-waardes van die adolessente verantwoordelik. Kruisvalidasie het ook aan die lig gebring dat beide modelle geldig is vir die voorspelling van die 20-m SRT-afgeleide indirekte VO_2maks



-waardes van hierdie kohort adolessente.

Die 20-m SRT geldigheidstudie het getoon dat ŉ betekenisvolle verskil (p ≤ 0.05) bestaan tussen die voorspelde indirekteVO_2maks



-resultate (42.06 ± 4.53 ml/kg/min), soos verkry van die 20-m SRT-pamflet, en die direkte VO_2maks



-resultate (50.62 ± 7.11 ml/kg/min), soos verkry van die gasanalise. Voorts is betekenisvolle verskille (p ≤ 0.05) waargeneem tussen die direk- en indirekvoorspelde VO_2maks



-waardes op vlakke 1-9 van die 20-m SRT, teenoor geen betekenisvolle verskille op vlakke 10 en 11 van die 20-m SRT nie.

Ten slotte, na die navorsers se wete, is hierdie die eerste studie wat geldige VO_2maks 

-voorspellingsfunksies ontwikkel het vir ŉ groep Suid-Afrikaanse adolessente deur gebruikmaking van etlike antropometriese metings, fisieke, en motorieseprestasie toetsresultate en demografiese inligting. Hierbenewens is dit ook die eerste studie wat aan die lig gebring het dat die 20-m SRT nie ŉ geldige toets is vir die akkurate voorspelling van V• O₂_enVO_2maks



in ŉ kohort Suid-Afrikaanse adolessenteseuns nie. Die resultate van hierdie studie kan moontlik praktisyns op die gebied van Menslike Bewegingskunde in staat stel om die direkte VO_2maks



-waardes van adolessente meer akkuraat te sif deur gebruik te maak van maklik bekombare metings en inligting, in plaas daarvan om die voorspelde VO_2maks



-waardes van die 20-m SRT daarvoor aan te wend.

Sleutelwoorde: adolessente, aërobiese, VO_2maks 

, 20-m SRT, antropometriese, fisieke, motorieseprestasie, direkte, indirekte, geslag

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RAINING

H

ABITS

...

I

NFORMATION

W

ITH

R

EGARD TO

M

ATURATION

...

I

NFORMATION

W

ITH

R

EGARD TO

P

HYSICAL

A

CTIVITY

...

A

NTHROPOMETRIC

M

EASUREMENTS

...

M

ATURITY

...

P

HYSICAL AND

M

OTOR

P

ERFORMANCE

M

EASUREMENTS

...

D

ATA

A

NALYSIS

...

R

ESULTS

………...

D

ISCUSSION

………...

C

ONCLUSIONS

…………..………...

A

CKNOWLEDGEMENTS

...

D

ISCLAIMER

..……..………...

R

EFERENCES

..…………..………...

151

152

154

156

159

160

161

164

165

170

176

177

(14)

C

H

A

P

T

E

R

5

5 T

TH

H

E

V

A

L

I

D

I

T

Y

O

F

T

H

E

2

0

0 -M

-

M

SH

S

H

U

T

L

E

RU

R

U

N

TE

T

E

S

T

O

DE

D

E

T

E

R

M

I

N

E

T

H

E

V

O

2₂

A

N

D

V

O

22MMAAXX

O

F

A

CO

C

O

H

O

R

T

O

F

AD

A

D

O

L

E

S

C

E

N

T

BO

B

O

Y

S

:

TH

T

H

E

P

A

H

L

S

ST

T

U

D

Y. Y

.

T

ITLE

P

AGE

………...

B

LIND

T

ITLE

P

AGE

………...

A

BSTRACT

………...

I

NTRODUCTION

………...

M

ETHODS

………...

R

ESULTS

………...

D

ISCUSSION

………...

C

ONCLUSION

...

P

RACTICAL

I

MPLICATIONS

………..………...

A

CKNOWLEDGEMENTS

...

D

ISCLAIMER

...

R

EFERENCES

……..………...

184

185

186

188

189

191

193

198

201

202

202 C

C

H

A

P

T

E

R

6 S

SU

U

M

A

R

Y

,

C

O

N

C

L

U

S

I

O

N

S

,

LI

L

I

M

I

T

A

T

I

O

N

S

AN

A

N

D

R

E

C

O

M

E

N

D

A

T

I

O

N

S. S

.

T

ITLE

P

AGE

………...

S

UMMARY

..………...

C

ONCLUSIONS

………...

L

IMITATIONS AND

R

ECOMMENDATIONS

..………...

2

0

6

207

208

213

215

(15)

A

AP

P

E

N

D

I

X

…

.

T

ITLE

P

AGE

………...

A

PPENDIX

A:

E

THICAL

A

PPROVAL

...

A

PPENDIX

B:

D

EMOGRAPHIC

,

G

ENERAL

I

NFORMATION

Q

UESTIONNAIRES AND

I

NFORMED

C

ONSENT

F

ORMS

...

A

PPENDIX

C:

P

HYSICAL

A

CTIVITY

Q

UESTIONNAIRE

,

A

NTHROPOMETRIC

,

P

HYSICAL AND

M

OTOR

P

ERFORMANCE

D

ATA

C

OLLECTION

F

ORMS

…...

A

PPENDIX

D:

I

NSTRUCTIONS FOR

A

UTHORS

:

J

OURNAL OF

H

UMAN

M

OVEMENT

S

CIENCE

.…...

I

NSTRUCTIONS FOR

A

UTHORS

:

P

EDIATRIC

E

XERCISE

S

CIENCE

...

I

NSTRUCTIONS FOR

A

UTHORS

:

J

OURNAL OF

S

CIENCE AND

M

EDICINE IN

S

PORT

...

217

218

219

221

230

241

246

255

(16)

L

I

_I

S

_S

T

_T

O

_O

F

_F

T

_T

A

_A

B

_B

L

_L

E

_E

S

_S

C

H

A

P

T

E

R

2

2 :

:

TABLE 2.1

Directly or indirectly measured (predicted) aerobic performance

values (

V

O

_2max



)

of children and adolescents………...

50 C

C

H

A

P

T

E

R

3

3 :

:

TABLE 3.1

TABLE 3.2

TABLE 3.3

TABLE 3.4

TABLE 3.5

TABLE 3.6

TABLE 3.7

Descriptive statistics (mean ± SD), statistical significance of the

differences in the chronological, maturity age and aerobic

performance-related variables of the various groups of adolescents..

Descriptive statistics (mean ± SD), statistical significance of the

differences for the body mass, stature and body composition-related

variables of the various groups of adolescents...

Descriptive statistics (mean ± SD), statistical significance of the

differences for the skinfold-related variables of the various groups of

adolescents...

Descriptive statistics (mean ± SD), statistical significance of the

differences for the breadth-related variables of the various groups of

adolescents...

Descriptive statistics (mean ± SD), the statistical significance of the

differences for the girth-related variables of the various groups of

adolescents...

Descriptive statistics (mean ± SD), the statistical significance of

differences for the length-related variables of the various groups of

adolescents...

Results of the forward stepwise regression analysis based on the

adolescents’ demographic and anthropometric data...

133

134

135

136

137

138

139

(17)

C

H

A

P

T

E

R

4

4 :

:

TABLE 4.1

TABLE 4.2

TABLE 4.3

Descriptive statistics (mean ± SD) and statistical significance of the

differences for the age, stature, body mass, maturity and

flexibility-related variables of the adolescent participants…………...

Descriptive statistics (mean ± SD) and statistical significance of the

differences in the physical and motor performance-related variables

of the adolescent participants..……..………...

Results of the forward stepwise regression analysis based on the

adolescents’ demographic, physical and motor performance data...

166

167

170 C

C

H

A

P

T

E

R

5

5 :

:

TABLE 5.1

TABLE 5.2

Descriptive statistics for the 20-m SRT related variables of the

adolescent boys. Values are mean ± SD...

Maximal values that were obtained during the 20-m SRT. Values are

mean ± SD...

196

(18)

L

I

S

T

O

F

I

G

U

R

E

S

C

H

A

P

T

E

R

3

3 :

:

FIGURE 3.1

The percentage contribution of each of the independent variables

from the forward stepwise regression analysis to the prediction of

2max

O

V

 ...

....………...

140 C

C

H

A

P

T

E

R

4

4 :

:

FIGURE 4.1

The percentage contribution of each of the independent variables

from the forward stepwise regression analysis to the total prediction

of the indirect

V

O

_2max



...

171 C

C

H

A

P

T

E

R

5

5 :

:

FIGURE 5.1

The ratio of variation between the direct and indirect

V

O

₂



-values as

well as the SE of the m SRT plotted against the levels of the

(19)

L

I

S

T

O

F

A

B

R

E

V

I

A

T

I

O

N

S

20-m SRT

20-m Shuttle Run Test

ACSM

ASLRT

American Council of Sports Medicine

Active Straight Leg Raise Test

AST

Abdominal Strength Test

ATP-CP

ATT

Adenosine Triphosphate-Creatine Phosphate

Agility T-Test

BD

Body Density

BMI

Body Mass Index

bpm

beats per minute

CAFT

cm

CMJ

Canadian Aerobic Fitness Test

centimetre

Counter Movement Jump

ES

FFM

Effect Size

Fat Free Mass

g/cm3

gram per cubic centimetre

ISAK

International Society for the Advancement of Kinanthropometry

HJT

Horizontal Jump Test

HRR

HR

max

Heart Rate Reserve

Heart rate

Heart Rate max

HRr

est

J

Resting Heart rate

Joules

(20)

kg

kilogram

L/min

LL

LS

MBPT

Litre per minute

Last level

Last shuttle

Medicine Ball Put Test

mi/h

min

ml/kg/min

mm

MRC

miles per hour

minutes

millilitre per kilogram per minute

millimetre

Medical Research Council

MTIT

Modified Thomas Iliopsoas Test

MTQT

Modified Thomas Quadriceps Test

n

NRF

Number of subjects in each subgroup

National Research Foundation

NWU

O

2

/min

North-West University

Oxygen uptake per minute

p

statistical significance

PAHLS

PE

Physical Activity and Health Longitudinal Society

Physical Education

PHV

Peak Height Velocity

RPE

PSLRT

Rating of Perceived Exertion

Passive Straight Leg Raise Test

PWV

Peak Weight Velocity

r or R

2

correlation

R

correlation coefficients

REE

RER

Resting Energy Expenditure

Respiratory Exchange Ratio

rev/min

RPSERT

revolutions per minute

Right Passive Shoulder External Rotation Test

RPSIT

Right Passive Shoulder Internal Rotation Test

(21)

RM

RMTIT

Repetition Maximum

Right Modified Thomas Iliopsoas Test

RMTQT

Right Modified Thomas Quadriceps Test

s

seconds

SD

Standard Deviation

SEC

Series Elastic Component

SEE

SF

Standard Error of Estimate

Skinfold

SUM6SF

TEM

Sum of the 6 Skinfolds

Technical Error of Measurement

2

CO

V



_{Carbon Dioxide Production}

E

V



_{Minute Ventilation}

VJ

VJT

Vertical Jump

Vertical Jump Test

2

O

V



_{Oxygen Uptake}

2max

O

V



_{Maximal Oxygen Uptake}

2peak

O

V



_{Peak Oxygen Uptake}

W

max

Watt

Maximal power output

WHPR

Waist to hip ratio

WHTR

yr

Waist to height ratio

years

(22)

C

(23)

1

1 I

_I

N

_N

T

_T

R

_R

O

_O

D

_D

U

_U

C

_C

T

_T

I

_I

O

_O

N

_N

1. Problem Statement

2. Objectives

3. Hypotheses

4. Structure of the Dissertation