Body Composition. What is body composition? The ratio of lean body mass to body fat Generally this is a topic many physical educators try to avoid Although.

Body Composition

What is body composition? The ratio of lean body mass to body fat Generally this is a topic many physical

educators try to avoid Although “exact” figures for % fat may

not be necessary, it is important for students to understand the relationship of physical activity to body comp

Adolescent Body Fat Males: min. = 10%, max = 25% Females: min = 17%, max = 32%

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

20% over desirable body weight Severely overweight

40% over desirable body weightBurton, 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

Obesity 120 percent of ideal body weight or

greater

Overweight and Obesity: New Mexico

58% of New Mexico adults are overweight or obese. (CDC BRFSS, 2004)

18% of non-Hispanic white adults and 25% of Hispanic adults in New Mexico are obese. (CDC BRFSS, 2004)

Overweight and Obesity: New Mexico

24% of New Mexico high-school students are overweight or at risk of becoming overweight. (NM YRRS, 2003)

22% of low-income children between 2 and 5 years of age in New Mexico are overweight or at risk of becoming overweight. (CDC PedNSS, 2002)

Obesity Trends* Among U.S. AdultsBRFSS, 1990

No Data <10% 10%–14%

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

Obesity Trends* Among U.S. AdultsBRFSS, 1996

No Data <10% 10%–14% 15%–19%

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

Obesity Trends* Among U.S. AdultsBRFSS, 2001

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

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

Obesity Trends* Among U.S. AdultsBRFSS, 2004

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

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

Possible factors for overweight/obesity

Cultural differences

Eating disorders

Fast food

Inactivity

Contentment with body

weightTV time

Genetics

Relate to other HR components MS & E: muscles cells burn more calories at

rest than fat calories Aerobic: raise BMR and burns calories; more

effective than MS & E training Flexibility: less prone to injury when doing

aerobic activity and strength and endurance training

Aerobics + resistance= best management

Body Composition Assessment

Body Comp Tests Skinfold calipers

Tricep Calf

Body Mass Index Under 25 considered

safe =wt(kg)/ht2(m2)

Waist to hip ratio Above .86 females Above .95 men Indicate higher risks Apples rather than

pears Ht-wt charts

Skinfold TechniqueSubcutaneous

Fat

Skinfold Thickness

Skin

Skin

Subcutaneous Fat

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

Benefits of Skinfold Technique Fairly accurate Easy to perform Inexpensive Skinfold Sites for Children: tricep & calf

Not as “invasive” as adult sites

Body Composition AssessmentImplications of Results

Values are estimates (+/- 2-3% at best) Values are personal and confidential

Proper uses of results:- Serve as baseline data for repeated testing

- Provide motivation for goal setting

- Provide awareness about health risks

BMI BMI = weight in pounds

Ht in inches x ht in inches x 703

Advantages:

1. Takes little class time

Disadvantage:

1. BMI is age and gender specific

2. Over-simplifies body composition

BMI Chart for children

Underweight: BMI-for-age < 5th percentile  Less than 18.5

Normal: BMI-for-age 5th percentile to < 85th percentile

18.5-22At risk of overweight: BMI-for-age 85th percentile to < 95th percentile  

22-25Overweight: BMI-for-age > 95th percentile

25.1-29.9

Class Activity Since body composition is a private

matter, what would you want your students to know about this component of fitness and how would you teach it with sensitivity?