Chapter 13

Presentation Package for Presentation Package for Concepts of Physical Fitness 14eConcepts of Physical Fitness 14e

Section V: Concept 13Section V: Concept 13

Body Body CompositionComposition

Possessing an optimal amount of body fat Possessing an optimal amount of body fat contributes to health and wellness.contributes to health and wellness.

All rights reservedAll rights reserved

Concepts of Physical Fitness 14e2

Understanding & Interpreting Understanding & Interpreting Body Composition MeasuresBody Composition Measures

• Component of health-related fitness & a Component of health-related fitness & a component of metabolic fitness.component of metabolic fitness.

• Standards have been established for Standards have been established for healthy levels of body fatness healthy levels of body fatness (see next (see next slide)slide)

• Health standards have been established Health standards have been established for the Body Mass Index.for the Body Mass Index.

• Assessing body weight too frequently Assessing body weight too frequently can result in making false assumptions can result in making false assumptions about body composition changes.about body composition changes.



Methods Used to Assess Methods Used to Assess Body CompositionBody Composition

• DXADXA

• Underwater WeighingUnderwater Weighing

• Bod PodBod Pod

• Skinfold techniqueSkinfold technique

• OtherOther


Dual-energy Absorptiometry (DXA)

• ““Gold Standard” measure of Gold Standard” measure of body composition.body composition.

• Provides whole body Provides whole body measurements of body fatness measurements of body fatness as well as amounts stored in as well as amounts stored in different parts of the body.different parts of the body.

• Highly accurate measure of body Highly accurate measure of body composition for research and a composition for research and a criterion measure that has been criterion measure that has been used to validate other, more used to validate other, more practical measures of body practical measures of body composition.composition.


Underwater WeighingUnderwater Weighing

Click for Click for more infomore info

Web13-3 for info on underwater weighingWeb13-3 for info on underwater weighing

A person is weighed in A person is weighed in air and under water, and air and under water, and the difference in weight the difference in weight is used to assess the is used to assess the levels of body fatness.levels of body fatness.

Body fat provides more Body fat provides more buoyancy, so a fatter buoyancy, so a fatter person weighs less (on person weighs less (on a relative basis) than a a relative basis) than a lean person.lean person.


Bod PodBod Pod

• Uses the same principles as underwater Uses the same principles as underwater weighing, but relies on air displacement weighing, but relies on air displacement to assess body composition. to assess body composition.

• Evidence suggests that it provides an Evidence suggests that it provides an acceptable alternative to underwater acceptable alternative to underwater weighing and is particularly useful for weighing and is particularly useful for special populations (obese older people special populations (obese older people and the physically challenged).and the physically challenged).


Skinfold TechniqueSkinfold Technique

Layers of Layers of subcutaneous subcutaneous fat are measured at fat are measured at different sites of different sites of bodybodyto estimate total to estimate total body fat levelsbody fat levels

Cross sectional viewCross sectional view


Benefits of Skinfold Benefits of Skinfold TechniqueTechnique

• Skinfold measurements are the Skinfold measurements are the preferred, practical method of assessing preferred, practical method of assessing body fatness.body fatness.

• Fairly accurateFairly accurate

• Easy to performEasy to perform

• InexpensiveInexpensiveLab 13a infoLab 13a info


Common Skinfold SitesCommon Skinfold Sites

7 site procedure7 site procedure ChestChest

AxillaAxilla

TricepTricep

SubscapularSubscapular

AbdomenAbdomen

SuprailliumSupraillium

Thigh Thigh

Jackson and PollackJackson and Pollack

MalesMales FemaleFemaleChestChest TricepsTriceps

AbdomenAbdomen SuprailliumSupraillium

ThighThigh ThighThigh

Validation statistics on 3 site test: Validation statistics on 3 site test: - r = .97 with 7 site procedure- r = .97 with 7 site procedure- R- R22 = .80 with underwater weighing = .80 with underwater weighing

Alternative SitesAlternative Sites

(Males & Females)(Males & Females)TricepTricep

AbdomenAbdomen

CalfCalf

Web13-04Web13-04


Research Quality Research Quality Skinfold CalipersSkinfold Calipers

Harpenden CalipersHarpenden Calipers Lange CalipersLange Calipers


Other Body Composition Other Body Composition AssessmentsAssessments• Bioelectrical ImpedanceBioelectrical Impedance

• Infra-Red SpectroscopyInfra-Red Spectroscopy

• UltrasoundUltrasound

• Imaging TechniquesImaging TechniquesClick to seeClick to seemore info on all more info on all techniquestechniques


Anthropometric Anthropometric MeasurementsMeasurements

• Body Mass Index (BMI)Body Mass Index (BMI)

• Waist to Hip Ratio (WHR)Waist to Hip Ratio (WHR)

• Circumference measuresCircumference measures

More infoMore info

More infoMore info

More infoMore info

Lab 13bLab 13binfoinfo


Body Composition Body Composition AssessmentAssessmentImplications of ResultsImplications of Results

• Values are estimates (+/- 2-3% at best)Values are estimates (+/- 2-3% at best)

• Values are personal and confidentialValues are personal and confidential

Proper uses of results:Proper uses of results:

- Serve as baseline data for repeated testing- Serve as baseline data for repeated testing

- Provide motivation for goal setting- Provide motivation for goal setting

- Provide awareness about health risks- Provide awareness about health risks


Health Risks Associated Health Risks Associated with Being Overweightwith Being Overweight

• Coronary heart diseaseCoronary heart disease

• HypertensionHypertension

• HypercholesterolemiaHypercholesterolemia

• DiabetesDiabetes

• Premature deathPremature death

• Physical fitness provides protection Physical fitness provides protection from the health risks of obesity.from the health risks of obesity.

There are also health risks associated with being too thin!There are also health risks associated with being too thin!


Regional Fat DepositionRegional Fat Deposition• Abdominal body fat poses greater health Abdominal body fat poses greater health

risks than fat stored in other areasrisks than fat stored in other areas

• Males store more fat Males store more fat centrally and have centrally and have increased health increased health risks associated risks associated with body fatnesswith body fatness Higher health riskHigher health risk Lower health riskLower health risk

Male (apple)Male (apple) Female (pear)Female (pear)

Click for more Click for more info on fatinfo on fatdepositiondeposition


Health Risks Associated withExcessively Low Body Fatness

• Anorexia NervosaAnorexia Nervosa

• BulimiaBulimia

• Anorexia AthleticaAnorexia Athletica

• Female Athlete TriadFemale Athlete Triad

• Muscle Dysmorphia (males)Muscle Dysmorphia (males)

• Fear of ObesityFear of Obesity


The Origin of FatnessThe Origin of Fatness

• Obesity is a multifactorial disease that is Obesity is a multifactorial disease that is influenced by both genetics and the influenced by both genetics and the environment.environment.

• Body weight is regulated and maintained Body weight is regulated and maintained through complex regulatory processes.through complex regulatory processes.– Set-pointSet-point

• Fatness early in life leads to adult fatness.Fatness early in life leads to adult fatness.• Changes in basal metabolic rate can be the Changes in basal metabolic rate can be the

cause of obesity.cause of obesity.• ““Creeping Obesity” Creeping Obesity” (see next slide)(see next slide)

Lab 13c infoLab 13c info



Relationship Between PA & Relationship Between PA & Body CompositionBody Composition

• CombinationCombination of of regularregular PAPA andand dietarydietary restrictionrestriction is the is the mostmost effectiveeffective meansmeans of of losinglosing bodybody fatfat..

• PA that can be sustained for relatively long PA that can be sustained for relatively long periods is considered the most effective for periods is considered the most effective for losing body fat.losing body fat.

• Strength training can be effective in Strength training can be effective in maintaining a desirable body composition.maintaining a desirable body composition.

• Regular PA is critical for building and Regular PA is critical for building and maintaining bone health.maintaining bone health.


Target ZoneTarget Zone - Body Fat - Body Fat ReductionReduction

Table 3, p. 285Table 3, p. 285PhysicalPhysical ActivityActivity

Daily moderate PA; Daily moderate PA; 3-6 days/wk 3-6 days/wk vigorous PAvigorous PA

Slow, low-intensity Slow, low-intensity that results in ≤1-2 that results in ≤1-2 lbs/week of fat losslbs/week of fat loss

30-60 minutes30-60 minutes

DietDiet

Consistently Consistently and dailyand daily

Modest Modest caloric caloric restrictionrestriction

Moderate Moderate mealsmeals


19951995

Obesity Trends* Among U.S. AdultsObesity Trends* Among U.S. AdultsBRFSS,BRFSS, 1990, 1995, 20051990, 1995, 2005

(*BMI (*BMI 30, or about 30 lbs overweight for 5’4” person)30, or about 30 lbs overweight for 5’4” person)

20052005

19901990

No Data <10% 10%–14% 15%–19% 20%–24% 25%–29% ≥30%


Web LinksWeb Links

• Behavioral Risk Factor Surveillance Behavioral Risk Factor Surveillance System System (BRFSS)(BRFSS) Interactive Web Page Interactive Web Page

http://www.cdc.gov/brfss/http://www.cdc.gov/brfss/


SummarySummary

• Obesity is prevalent in society.Obesity is prevalent in society.

• Need to find ways to maintain optimal Need to find ways to maintain optimal body composition.body composition.

• Use assessments to determine body Use assessments to determine body composition and make the necessary composition and make the necessary healthy changes to physical activity healthy changes to physical activity and diet.and diet.


Web ResourcesWeb Resources

“On the Web” pages for ConceptOn the Web” pages for Concept

Online Learning CenterOnline Learning Center

Supplemental Supplemental GraphicsGraphics

•Lab InformationLab Information•Detail on BMI calculationsDetail on BMI calculations•Graphics on Obesity TrendsGraphics on Obesity Trends


Lab 13a InformationLab 13a InformationEvaluating Body Composition - SkinfoldsEvaluating Body Composition - Skinfolds

• The purpose of this lab is to The purpose of this lab is to evaluate body composition evaluate body composition with the skinfold assessment.with the skinfold assessment.

• Comparisons will be made Comparisons will be made between different procedures between different procedures and testers to learn about the and testers to learn about the accuracy of the tests.accuracy of the tests.


Lab 13a InformationLab 13a InformationSkinfold TechniqueSkinfold Technique

• Measurement Technique:Measurement Technique:– Mark site with markerMark site with marker– Pinch fold above and below Pinch fold above and below

mark with left and right handmark with left and right hand– Measure fold with caliper Measure fold with caliper

using the right handusing the right hand

• Scoring Procedure:Scoring Procedure:– Sum skinfolds from the 3 sitesSum skinfolds from the 3 sites– Look up percent body fat valueLook up percent body fat value

from chart in the bookfrom chart in the book

Return to Return to presentationpresentation


Lab 13b InformationLab 13b InformationEvaluating Body Composition – Height, Weight, and Evaluating Body Composition – Height, Weight, and Circumference MeasuresCircumference Measures

• The purpose of this lab is to The purpose of this lab is to evaluate body composition evaluate body composition with some anthropometric with some anthropometric assessmentsassessments– Height/WeightHeight/Weight– Body Mass IndexBody Mass Index– Waist to Hip RatioWaist to Hip Ratio


Lab 13b InformationLab 13b Information

BMI Measurement TechniqueBMI Measurement Technique

• Convert weight to kilograms (2.2 kg/lb.)Convert weight to kilograms (2.2 kg/lb.)

• Convert height to meters (.0254 m/in)Convert height to meters (.0254 m/in)

• Square the height in metersSquare the height in meters

• Divide the squared height value into the Divide the squared height value into the weight valueweight value

BMI = Wt (kg) / HtBMI = Wt (kg) / Ht22 (m) (m)


See Web13-06 for BMI calculatorsSee Web13-06 for BMI calculators


Lab 13b InformationLab 13b Information

WHR Measurement TechniqueWHR Measurement Technique

• Waist:Waist: Measure at the "natural waist" Measure at the "natural waist" (smallest circumference) or at the (smallest circumference) or at the level of the umbilicuslevel of the umbilicus

• Hip:Hip: Measure at the maximum Measure at the maximum circumference of the buttockscircumference of the buttocks

Divide the hip measurement into the Divide the hip measurement into the waist measurement to obtain the WHRwaist measurement to obtain the WHR



Sample BMI ValuesSample BMI Values

HT (in.)HT (in.) WT (lb.)WT (lb.) BMIBMI

7272 150150 21217272 180180 25257272 190190 26267272 200200 2828

This chart reveals how BMI values change for a This chart reveals how BMI values change for a hypothetical 6 foot tall person of different body weightshypothetical 6 foot tall person of different body weights

See Web13-See Web13-06 for BMI 06 for BMI calculatorscalculators



Definitions of OverweightDefinitions of Overweight

(Based on BMI values)(Based on BMI values)

• BMI accounts for differences in frame size BMI accounts for differences in frame size better than height weight tables. better than height weight tables. BMI = Wt (kg) / HtBMI = Wt (kg) / Ht22 (m) (m)

Standards:Standards:– Overweight:Overweight: > 25 > 25 – Obesity:Obesity: > 30> 30– Severe obesitySevere obesity > 40> 40

Problem:Problem: BMI does not take BMI does not take muscles mass into accountmuscles mass into account

Web13-1 for moreWeb13-1 for moreinformation on standardsinformation on standards



Lab 13c InformationLab 13c InformationDetermining Your Daily Energy ExpenditureDetermining Your Daily Energy Expenditure

• Estimate your basal metabolism.Estimate your basal metabolism.

• First determine the number of minutes you sleep.First determine the number of minutes you sleep.

• Monitor your activity expenditure for 1 day. Record Monitor your activity expenditure for 1 day. Record the number of 5-, 15-, and 30-minute blocks of time the number of 5-, 15-, and 30-minute blocks of time you perform each of the different types of physical you perform each of the different types of physical activities (e.g., if an activity lasted 20 minutes, you activities (e.g., if an activity lasted 20 minutes, you would use one 15-minute block and one 5-minute would use one 15-minute block and one 5-minute block). Be sure to distinguish between moderate block). Be sure to distinguish between moderate (Mod) and vigorous (Vig) intensity in your logging.(Mod) and vigorous (Vig) intensity in your logging.

• Discuss your daily caloric expenditure. In addition, Discuss your daily caloric expenditure. In addition, comment on whether you think you should modify comment on whether you think you should modify your daily caloric expenditure for any reason.your daily caloric expenditure for any reason.



Regional Fat DepositionRegional Fat DepositionVisceral FatVisceral Fat

• Visceral body fat poses greater health Visceral body fat poses greater health risks because this fat is more labile and risks because this fat is more labile and has greater access to the circulation.has greater access to the circulation.

• The accumulation of visceral body fat is The accumulation of visceral body fat is typical of the android (male) fat patterntypical of the android (male) fat pattern– males: visceral accounts for 10-35% of total fatmales: visceral accounts for 10-35% of total fat– females: visceral accounts for 8-13%of total fatfemales: visceral accounts for 8-13%of total fat


Abdominal Body FatAbdominal Body FatRelationships with CHD RisksRelationships with CHD Risks

• Abdominal obesity predicts CHD risk Abdominal obesity predicts CHD risk independent of BMI, smoking, cholesterol independent of BMI, smoking, cholesterol and hypertension.and hypertension.(Kannel et al., J. Clin Epid., 44, 183-190, 1991).(Kannel et al., J. Clin Epid., 44, 183-190, 1991).

• Abdominal obesity predicts CHD risk Abdominal obesity predicts CHD risk independent of total body fatness.independent of total body fatness. (Larsson et al. ,Appetite, 13, 37-44, 1989).(Larsson et al. ,Appetite, 13, 37-44, 1989).

• Abdominal obesity statisticallly accounts for Abdominal obesity statisticallly accounts for difference in CHD rates between men and difference in CHD rates between men and women.women. (Larsson et al., Am. J. Epi., 135: 266-273, 1992).(Larsson et al., Am. J. Epi., 135: 266-273, 1992).


Abdominal Body FatAbdominal Body FatRelationships with other risk factorsRelationships with other risk factors

• Abdominal obesity is strongly influenced by genetics - Abdominal obesity is strongly influenced by genetics - similar gain among twins (r=.72). similar gain among twins (r=.72). (Bouchard, NEJM, 322, 1477-1482, 1990).(Bouchard, NEJM, 322, 1477-1482, 1990).

• Abdominal obesity is greater in smokers than non-Abdominal obesity is greater in smokers than non-smokers due to the presence of androgens smokers due to the presence of androgens (Barrett-Conner, Ann. Int. Med. 111, 783-787, 1989).(Barrett-Conner, Ann. Int. Med. 111, 783-787, 1989).

• Abdominal body fat is preferentially lost during a Abdominal body fat is preferentially lost during a physical activity programphysical activity program(Kohrt, J. Gerontology, 47: M99-M105, 1992)(Kohrt, J. Gerontology, 47: M99-M105, 1992)


WOMENWOMENMENMEN

High RiskHigh Risk

Moderate RiskModerate Risk

Low RiskLow Risk

> 1.0> 1.0 > .85> .85

.90 -1.0.90 -1.0 .80-.85.80-.85

HEALTH RISKHEALTH RISK

< .90< .90 < .80< .80


Waist to Hip RatioWaist to Hip Ratio (WHR)(WHR)

• Waist to Hip Ratio is an effective way Waist to Hip Ratio is an effective way to examine regional fat distribution.to examine regional fat distribution.


Underwater WeighingUnderwater WeighingMeasurement issuesMeasurement issues

• Based on body density calculationsBased on body density calculations– Density of lean tissue = 1.1 g/ccDensity of lean tissue = 1.1 g/cc– Density of fat tissue = .9 g/ccDensity of fat tissue = .9 g/cc

• Sources of errorSources of error– Residual lung volumeResidual lung volume– Bone density varies by age, ethnicity and activity levelBone density varies by age, ethnicity and activity level

• General conclusionsGeneral conclusions– Gold standard measure (1-2% error)Gold standard measure (1-2% error)– Impractical for most applicationsImpractical for most applications



Bioelectric ImpedanceBioelectric Impedance(Measurement Issues)(Measurement Issues)

• Based on resistance to current flowBased on resistance to current flow– Lean tissue has more water - less resistanceLean tissue has more water - less resistance– Fat tissue has less water - more resistanceFat tissue has less water - more resistance

• Sources of errorSources of error– TemperatureTemperature– Hydration statusHydration status

• General conclusionsGeneral conclusions– Overestimates lean / underestimates obeseOverestimates lean / underestimates obese– Practical, but expensive, measure for general Practical, but expensive, measure for general

populationpopulation



Infrared SpectroscopyInfrared Spectroscopy(Measurement Issues)(Measurement Issues)

• Based on differential absorbance ratesBased on differential absorbance rates– Lean tissue has a different energy absorption Lean tissue has a different energy absorption

and reflectance pattern than fat tissueand reflectance pattern than fat tissue

• Sources of errorSources of error– Validity of absorbance readings is questionable!Validity of absorbance readings is questionable!

• General findingsGeneral findings– NOT a valid measure!NOT a valid measure!



UltrasoundUltrasound(Measurement Issues)(Measurement Issues)

• Based on reflection of soundBased on reflection of sound– Fat content increases the time is required Fat content increases the time is required

for sound to reflect off of bone and muscle. for sound to reflect off of bone and muscle.

• Sources of errorSources of error– Representative sites for measurementRepresentative sites for measurement– Measurement errorMeasurement error

• General conclusionsGeneral conclusions– Highly accurate measure of body fat - Highly accurate measure of body fat -

especially for obeseespecially for obese– Expensive and not practical for most Expensive and not practical for most

applicationsapplications



Imaging TechniquesImaging Techniques(Measurement Issues)(Measurement Issues)

• Based on imaging of body tissuesBased on imaging of body tissues– Based on cross sectional area measures Based on cross sectional area measures

calculated at different levels of the bodycalculated at different levels of the body

• Sources of errorSources of error– Representative sites for measurementRepresentative sites for measurement– Measurement errorMeasurement error

• General conclusionsGeneral conclusions– Very precise measure of body compositionVery precise measure of body composition– Expensive and not practical measure for most usesExpensive and not practical measure for most uses



CircumferencesCircumferences (Measurement Technique)(Measurement Technique)

• Based on circumference measuresBased on circumference measures– sample prediction equation:sample prediction equation:

% fat = - 47.372 + (.579 x abdomen) + (.252 x hip) + % fat = - 47.372 + (.579 x abdomen) + (.252 x hip) + (.214 x iliac) + (.356 x BW)(.214 x iliac) + (.356 x BW)

• Sources of errorSources of error– Location of sitesLocation of sites– Inability to distinguish fat and muscleInability to distinguish fat and muscle

• General conclusionsGeneral conclusions– Provides reasonable estimate of body fatProvides reasonable estimate of body fat– Not as accurate as skinfold and takes same timeNot as accurate as skinfold and takes same time


Chapter 13

Documents

body weight

body composition changes

desirable body composition

health risks of obesity

bone health

info lab

slide health standards

origin of fatness obesity