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 Composition and analysis provides information (like %
of body fat, fat distribution, body segment girth etc.)which
are pertinent to athletic performance and for reducing risk
factors associated with musculoskeletal injury and disease.
 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 Composition Model
 Categorized as direct, indirect or doubly indirect
methods
 Direct method(chemical analysis of whole body
or cadaver) is not suitable in the living body.
 Indirect method(hydrostatic weighing etc.)
 - Component and property based model
 Doubly indirect method(skinfolds etc.)

14. Assessing Body Composition
 Height, Weight, BMI
 Waist and hip circumference
 Hydrodensitometry (hydrostatic weighing)
 Air displacement method
 Skinfold assessment
 Bioelectrical Impedence
 CT, PET
 MRI and spectroscopy
 Dual energy X-ray absorptiometry (DEXA)
 Three dimensional scanning

15. Factors to consider while
choosing the technique.
 Need of the individual
 Purpose of evaluation
 Cost of measurement
 Equipment needed
 Availability of the assessment tools
 Training
 Advantages vs. disadvantages
 Accuracy, reliability and validity

16. Height

 Stadiometer
 Subject removes shoes
 Stands straight up and heels together
 Takes a deep breath and hold it
 Stands with head level and looks straight
 Consider standard time and monitoring pre activity
level
• Measured in cms and inches

17. Body Mass
 Best measured on a calibrated scale
 Removes excess layer of clothing and shoes
 Empty pockets, remove jewelery and mobiles
 Consider a standard time
 Body weight(pounds) and
mass(kilograms) are different
terminologies

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

20. 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
 Should 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

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

22. 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

24. Men Women

25. 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

26. Dbody = Mbody / Vbody
• Involves measuring the density of the athlete’s
body
• Volume of body can be determined by hydrostatic
weighing.
• Archimedes principle - an object (or human)
immersed in fluid, loses an amount of weight
equivalent to the weight of the fluid that is
displaced

27. Density body = Mass/Volume corrected
Relative fat = 495/ Density body- 450
Fat mass = (mass × relative fat)/100
Fat free mass = mass – fat mass
Volume = Mass – underwater mass
Volume corrected for water density :
Intestinal gas and RV

29. 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

30. 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

31. 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.

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

33. 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