Presentation Package for Concepts of Physical Fitness 12e Section V: Concept 15: Body Composition Created by: Gregory J. Welk Iowa State University

Presentation Package for Presentation Package for Concepts of Physical Fitness 12eConcepts of Physical Fitness 12e

Section V: Concept 15:Section V: Concept 15:

Body CompositionBody Composition

Created by:Gregory J. Welk

Iowa State University

2 Concepts of Physical Fitness 12e

Trends in the Prevalence of Trends in the Prevalence of Obesity in the U.S. 1991-98, Obesity in the U.S. 1991-98,

0

5

10

15

20

1991 1992 1993 1994 1995 1996 1997 1998

Women

Men

% Obese

Mokdad et al. JAMA 1999; 282:1519Web15-1

Click to see progression oftrends over time


Health Risks Associated with Health Risks Associated with Being OverweightBeing Overweight

Coronary heart diseaseCoronary heart disease HypertensionHypertension HypercholesterolemiaHypercholesterolemia DiabetesDiabetes

There are also health risks associated with being too thin!


Definitions of Overweight:Definitions of Overweight:((Based on ht /wt tables)Based on ht /wt tables)

Moderately OverweightModerately Overweight– 20% over desirable body weight20% over desirable body weight

Severely overweightSeverely overweight– 40% over desirable body weight40% over desirable body weight

Burton, Foster, Hirsch, and Van Itallie, Health implications of obesity: An NIH consensus development conference. Int J. Obesity, 9, 155-169, 1985.

Problem: Ht/Wt tables do not take muscles mass into account


Definitions of Overweight Definitions 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 BMI = Wt (kg) / Ht(kg) / Ht22 (m) (m)

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

Problem: BMI does not take muscles mass into account

Click for info on BMI

Web15-1 for moreinformation on standards


Levels of Body FatnessLevels of Body Fatness

MenMenWomenWomen

Essential fatEssential fat 5% 5% 10% 10%

BorderlineBorderline 5-9% 10-16%5-9% 10-16%

Good fitness Good fitness - health- health 10-20%10-20% 17-28%17-28%

Marginal fitnessMarginal fitness 21-25%21-25% 29-35%29-35%

OverfatnessOverfatness > 25% > 25% > 35% > 35%

Click for calculations of ideal wt based on % fat


Regional Fat DepositionRegional Fat Deposition

Abdominal body fat poses greater Abdominal body fat poses greater health risks than fat stored in other health risks than fat stored in other areasareas

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 risk Lower health risk Male (apple) Female (pear)

Click for more info on fatdeposition


Body Composition Body Composition Assessment TechniquesAssessment Techniques

Underwater weighingUnderwater weighing Technological assessmentsTechnological assessments Skinfold techniqueSkinfold technique Anthropometric measurementsAnthropometric measurements


Underwater Weighing Underwater Weighing TechniqueTechnique

Click for more info

Web15-2 for info on underwater weighing

Body fat provides Body fat provides more bouyancy so a more bouyancy so a fatter person weighs fatter person weighs less (on a relative less (on a relative basis) than a lean basis) than a lean personperson


Technological Assessments Technological Assessments of Body Compositionof Body Composition

Dual X-Ray Impedance Analysis (DXA)Dual X-Ray Impedance Analysis (DXA) Bioelectric impedance Infra-red spectroscopy Infra-red spectroscopy UltrasoundUltrasound Imaging techniques Imaging techniques (DEXA, MRI)

Click to seemore info on all techniques

Click individualtechnique to see more detail

Web15-2 for info on DXA


Skinfold TechniqueSkinfold Technique

Layers of subcutaneous fat are measured at different sites of bodyto estimate total body fat levels

Cross sectional view


Benefits of Skinfold Benefits of Skinfold TechniqueTechnique

Fairly accurateFairly accurate Easy to performEasy to perform InexpensiveInexpensive


Common Skinfold Sites Common Skinfold Sites

7 site procedure7 site procedure Chest

Axilla

Tricep

Subscapular

Abdomen

Supraillium

Thigh

Jackson and PollackJackson and Pollack

MalesMales FemaleFemaleChest Triceps

Abdomen Supraillium

Thigh Thigh

Lab 15a info

Validation statistics on 3 site test: - r = .97 with 7 site procedure- R2 = .80 with underwater weighing

Alternative SitesAlternative Sites

(Males & Females)(Males & Females)Tricep

Abdomen

Calf

Web15-3


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 info

More info

More info

Lab 15binfo


Body Composition AssessmentBody Composition AssessmentImplications 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


Sample BMI ValuesSample BMI Values

HT (in.) WT (lb.) BMI

72 150 2172 180 2572 190 2672 200 28

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

Return to presentation

See Web15-05 for BMI calculators


Body Composition Body Composition (2 compartment model)(2 compartment model)

FatFat Lean Body Mass (LBM): Lean Body Mass (LBM):

(bones, muscles, tissues, organs)(bones, muscles, tissues, organs)

70kg person with 20% body fat:Lean tissue: 70 kg x .80 = 56 kg

Fat tissue: 70 kg x .20 = 14 kg

Sample calculation:


Calculating Desired Calculating Desired Body WeightBody Weight

Desired Weight =Wt. - (fat weight)

(1 - desired %Fat)

See sample calculation

Desired Weight = Wt. - (Wt. x %Fat / 100)

(1 - desired %Fat)

Current Lean weight

Desired Lean %

=


Calculating Desired Calculating Desired Body Weight Body Weight (Example)(Example)

Current weight = 200 Current body fat% = 20% Desired body fat% = 15%

DesiredWeight =

200 - (200 x .20)

(1 - .15)

DesiredWeight =

200 - 40

(.85)=

160

.85= 188



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 independent of Abdominal obesity predicts CHD risk independent of BMI, smoking, cholesterol and hypertensionBMI, smoking, cholesterol 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 independent of Abdominal obesity predicts CHD risk independent of total body fatness.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 women difference in CHD rates between men and 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)


WOMENMEN

High Risk

Moderate Risk

Low Risk

> 1.0 > .85

.90 -1.0 .80-.85

HEALTH RISK

< .90 < .80


Waist to Hip Ratio (WHR)Waist to Hip Ratio (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.


Obesity Trends* Among U.S. Adults Proportion of Obese

Adults by StateBRFSS(*BMI 30, or ~ 30 lbs overweight for 5’4” woman)

Slides from the CDC


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

(*BMI 30, or ~ 30 lbs overweight for 5’4” woman)

No Data <10% 10%-14% 15-19% 20% Source: Mokdad

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Obesity Trends* Among U.S. Adults Obesity Trends* Among U.S. Adults BRFSS, 1991, 1995 and 2000BRFSS, 1991, 1995 and 2000

1991 1995

2000

Source: Mokdad A H, et al. J Am Med Assoc 1999;28216, 2001;286:10.


Web LinksWeb Links

BRFSS Interactive Web Page BRFSS Interactive Web Page http://www.cdc.gov/nccdphp/brfsshttp://www.cdc.gov/nccdphp/brfss/ /

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Presentation Package for Concepts of Physical Fitness 12e Section V: Concept 15: Body Composition Created by: Gregory J. Welk Iowa State University