body composition. what is body composition? the ratio of lean body mass to body fat generally this...
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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?