1. Body Composition

2. Body frame-size (BFS) Female: 10.357*Ht. + (biacromial + bitrochanteric) Male: 8.239*Ht. + (biacromial + bitrochanteric)

3. Body frame-size (BFS)

4. BFS Limitations zUnvalidated estimates of body frame size zDeveloped primarily from white population zFocus on mortality data - not obesity related comorbidities zNo assessment of body composition

5. BMI Body mass (kg)  height (m 2 ) optimal range: 20 -25  or  from optimal range   of disease* * CAD, HTN, CVA, DM, CA, etc.

6. BMI Determine the BMI for: zMale zweight = 100 kg zheight = 2 m

7. BMI Limitations zfails to consider composition of body zfat

8. BMI zGenerally related to body composition zHighly correlated w/ relative body fat zprobably provides a better estimate of obesity

9. BMI Overweight (1998) zmales  27.8  25 zfemales  27.3  25 zobese: > 30

10. BMI

12. Population Overweight

13. 1976-80 z25% of all US adults  20 1988-91 z33.4% z47.2% Mexican-American women z48.6% African-American women

14. Leanness in Women Active low weight women are at risk of: zdelayed onset of menstruation zirregular menstrual cycle (oligomenorrhea) zcessation of menses (amenorrhea)

15. Leanness in Women Hypotheses: zExercise Stress (disruption of hypothalamic- pituitary-adrenal) zEnergy Availability yenergy reserve inadequate to sustain pregnancy y< 17% cessation / 22% normal cycle

16. Body Composition Models

17. Body Composition Total Body-Fat (Fat-Mass) = Essential Fat + Storage Fat Essential Fat (survival) zCNS zBone Marrow zOrgans (heart, liver, kidneys, spleen, etc.)

18. Fat-Free Mass vs. LBM LBM includes essential fat zLBM = Body Mass - Storage Fat FFM excludes essential fat zFFM = Body Mass - Total Body Fat

19. Behnke Model: Males

20. Behnke Model: Females

21. Body Composition 100 kg male w/ 20% body fat zBody mass: 100 kg zStorage Body Fat: 100 *.20 = 20 kg zLean Body Mass = 100 - 20 = 80 kg - includes 5% essential fat

22. Body Composition zFat Free Mass = Body Mass - Total Fat Mass zTotal Fat Mass = 20 kg + 4 kg (essential fats) zFat Free Mass = 100 - 24 = 76 kg

23. Importance of Body Fat DietExerciseCombination

24. Importance of Body Fat

25. Measuring Body Fat Direct zchemical analysis zdissection Indirect

26. Measuring Body Fat Hydrostatic Weighing / Densitometry zbody volume = loss of weight in H 2 0 (scale wt. - underH 2 O wt) z“gold standard” zbased on assumptions

27. Measuring Body Fat Skinfolds/Fatfolds Girth Measurements Bioelectrical Impedance Analysis (BIA) zconduction is better thru non-fat z  H 2 0   impedance   % body fat

28. Measuring Body Fat Near-Infrared Interactance (NIR) zFutrex-5000 zfiber optic zbiceps of dominant arm zvalidity????

29. Measuring Body Fat US Arm X-Ray (3 site) CT scan MRI DEXA (Dual-energy X-Ray Absorptiometry) - bony mineral content - r = 0.91 - 0.92

30. Desirable Body Mass Males zstrive for 15% z< 20% Females zstrive for 25% z< 30%

31. Desirable Body Mass z200 lbs. individual zWants to reduce % body fat from 20%  10% zWhat is this individual’s desirable weight?

32. Desirable Body Mass Desirable Body Mass (DSB) = fat-free body mass / (1.00 - desired % fat) Current fat-free body mass = 200 - (200 * 0.20) 160 lbs.

33. Desirable Body Mass Desirable Body Mass (DSB) = fat-free body mass / (1.00 - desired % fat) DSB = (160 / (1.00 - 0.10) 160 lbs. /.90 178 lbs.

34. Desirable Body Mass What is the loss in body weight? z 200 lbs. - 178 lbs. = 22 lbs.

35. General Guidelines for Weight Loss- Athlete z preserve FFM z200 - 500 kcal < daily energy expenditure z  resistance and endurance training