Body composition analysis

Lecture of Body Composition Analysis for Physiotherapy students

1. Body Composition Analysis

2. What is body composition? Body composition describes the relative proportions of fat, bone and muscles mass in the human body . Body composition = the body’s relative amounts of fat mass and fat-free mass (bone, water, muscle, connective and organ tissues, teeth)

3. Total body fat = Essential Fat + Storage fat Essential fat – in bone marrow, nervous tissue, organs(Young men – 3-5 % of body mass, Young female – 08 - 12% of body mass) Storage fat – accumulates in adipose tissue(Young Men- 3% of body mass, Young female – 12% of body mass ) Fat free mass(FFM) = body mass – fat mass

4. Essential fat = crucial for normal body functioning 3–5% of total body weight in males 8–12% of total body weight in females Nonessential fat = adipose tissue

5. Essential fat All fat is not bad!! We need fat for padding of organs, insulation, energy source There is a minimum amount that we need to function daily = essential fat Consists of fat stored in major organs, muscles, and central nervous system Required for normal physiological functioning: reducing essential fat below some minimal amount can impair overall health. Extremes in dieting (and exercise) can reduce essential fat stores)

6. Essential fat constitutes about 3% of the total weight in men and 12% in women

7. Fat-Free Body Mass (FFM) Defined as body mass devoid of all extractable fat Fat mass = Body mass * % body fat Body mass = 75.1 kg Body fat = 23.6% FFM = Body mass - fat mass What is the FFM for this person? Answer: 57.4 kg

8. Why we need body composition analysis? Body Compo s i t io n and analy s is prov i des i nfor mati o n ( l ik e % of body fa t , fat dist ri b ution , body segm e n t girth etc.)which are per t inent t o at hle t ic per f or m ance and fo r reducin g ri s k fa ctor s ass ocia te d wit h musculosk el e tal inj ur y and dis e as e . how much fat to lose versus how much muscle to gain? Health Implications there is an ideal % fat for health reasons (prevent onset of diabetes, CHD, BP, etc…)

9. Consequences of too much increased body fat Increased risk of chronic disease and premature death; associated health problems include Unhealthy blood fat levels Impaired heart function Heart disease and hypertension Cancer Impaired immune function Gallbladder disease Kidney disease Skin problems Sleeping problems

10. Obese people are more than three times as likely as nonobese people to develop diabetes Excess body fat is a key risk factor for the most common type of diabetes Excess body fat decreases the ability to perform physical activities

11. Problems Associated with Very Low Levels of Body Fat Too little body fat is associated with reproductive, circulatory, and immune system disorders Less than 10–12% for women Less than 5% for men

12. Different Levels of BC Measurement

13. Body Compo s itio n M o de l Categorized as direct, i n direct or doubly in d irect meth o ds Direct me th o d(chemical ana l ysi s of whole bod y or cadaver) is n o t su itable in th e liv i ng body. I n di r ect meth o d(h y dr o stat i c weig h i n g etc.) - Compone n t and pro p erty ba s ed model Dou b ly indirect me th o d(skinfol d s etc.)

14. Assessing Body Composition Height, Weight, BMI W a ist and hip circumfe r e nce H ydrod e ns i tometry (hydrostatic weighing) Air displacement method Sk i nfold assessm e nt Bioelectrical Impedence C T , PET MRI and spec troscop y Dual energy X-ray absorptiometry ( DEXA ) Thr e e d im ens ion a l scanning

15. Factors to consider while choosing the technique. Nee d of t h e i ndividu a l Purpose of evalu a tion C ost of m eas u re m ent Eq u ipme n t needed Ava i l a bil i t y of t h e a s sessme n t t o ols T r a i ning Advantages vs. disadv a n t a g es Accur a cy , rel i abil i t y and valid i ty

16. Height   Stadi o me ter  Subject removes sh o es  Stan d s straig h t u p and heels together  Takes a deep br e ath and h o ld it  Sta n ds with head level a nd lo o k s strai g ht  Consi d er standard tim e and moni t ori n g pr e activi t y level Me a sured in c m s and inches

17. Body Mass  Best meas u red on a calibrated scale Removes exce s s layer of cloth i ng and shoes Empty pockets , remove jew elery and mobiles Co n sider a sta n dard time B o dy w eight ( po u nds) and mass(k ilograms) are different ter m inologies

18. Body Mass Index  A rough assessment based on the concept that a person’s weight should be proportional to height Body weight in kilograms is divided by the square of height in meters Elevated BMI is linked to increased risk of disease, especially if associated with large waist circumference Poor predictor of body fat Not useful for resistance-trained population

19. Waist to Hip Ratio Indication of the pattern of body fat distribution. The waist circumference should be measured at the midpoint between the lower margin of the last palpable ribs and the top of the iliac crest, using a stretch‐resistant tape S hould stand with feet close together, arms at the side,should be relaxed, and the measurements should be taken at the end of a normal respiration

20. The WHO states that abdominal obesity is defined as a waist-hip ratio above 0.90 for males and above 0.85 for females

21. Skinfold Thickness Based on the principle that approximately half of the body’s fatty tissue is directly beneath skin Reliable measurements of this tissue give a good indication of percent body fat Skinfold test is done with pressure calipers Several sites are measured and percent fat is estimated from the sum of the three sites using Tables All measurements should be taken on the right side of the body

22. Men Women

23. Hydrostatic Weighing Underwater weighing Most common technique used for decades A person’s “regular” weight is compared with underwater weight Fat is more buoyant than lean tissue Almost all other indirect techniques have been validated against hydrostatic weighing

24. D b ody = M body / V body Involves measuring the density of the athlete’s body V o lu m e of b ody can b e determined b y hy d rostat i c weigh i n g . Arc h i medes pri n ciple - an object (or human ) imm e rsed in flu id, l oses an amount of we ig h t equivale n t t o th e weight of t h e flu id t h at is disp l aced

25. Density body = Mass/Vo l u m e corrected Re lat i ve fat = 495/ Density bo d y - 450 Fa t mass = ( m ass × relative fat) /100 Fa t free m ass = mass – fat m ass V o lu m e = Mass – underwate r mass V o lume corrected for water densi t y : I n testi n al ga s and RV

26. Variables needs to known to Use Hydrodensitometry Residual volume Density of water Amount of gas trapped in the gastrointestinal system Dry body weight Body weight fully submerged in water

27. Hydrostatic Weighing Drawbacks Time consuming Not feasible to test large number of people Requires measurement of residual lung volume (if unknown, can be estimated) Difficult to perform on the aquaphobic

28. Air Displacement Method Individual sits inside small chamber Computerized pressure sensors determine the amount of air displaced by the person Body volume is calculated by subtracting the air volume with the person inside the chamber from the volume of the empty chamber (air in the lungs is taken into consideration) Body density and percent body fat are then calculated BOD –POD device used.

29. it’s important to wear minimal, form-fitting clothing such as a lycra or swimsuit for accurate result.

30. Bioelectrical Impedance Analysis (BIA) BIA is a rapid, non invasive and relatively inexpensive method for evaluating body composition Sensors are applied to the skin and a weak electrical current is run through the body to estimate body fat, lean body mass, and body water Based on the principle that fatty tissue is a less-efficient conductor of an electrical current The easier the conductance, the leaner the individual Body weight scales with special sensors on the surface may also be used to perform this procedure