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Flashcards in Body composition Deck (33)
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1
Q

What is body composition?

A

=The body’s relative amounts of fat and lean body tissue (fat free mass)

2
Q

What are the components of fat free mass?

A

-Muscle
-Bone
-Water
-Organ tissues

3
Q

Formula to calc total body fat?

A

Essential fat + storage fat

4
Q

What is the purpose of essential fat and where is it located

A

-required for normal physiological function
-Is fat within major organs, muscle and CNS

5
Q

Difference in essential fat between male and females

A

-Women have more essential fat (12%) compared to males (3%)

6
Q

What is storage fat?

A

-Nonessential fat stored as adipose tissue near the body’s surface

7
Q

What is % body fat?

A

-% of total body weight that is fat
-is primary way to evaluate body composition

8
Q

How to calc fat free mass?

A

Body mass- fat mass

9
Q

Why is body composition measured?

A

-to help assess health risks and determine needed behaviour changes for optimal health
-to help athletes determine the best body composition for performance in their sport

10
Q

Effects of too little body fat?

A

-reproductive disorders
-circulatory disorders
-immune disorders

11
Q

Effects of too much body fat?

A

-cardiovascular disease
-hypertension
-type 2 diabetes
-cancer

12
Q

What is a 2 compartmental model of body comp

A

-splits body into fat free mass and fat mass and suggests one of these components is determined and the other is estimated from the result

13
Q

What is a 3 compartmental model of body comp

A

Includes bone mineral content in addition to fat free and fat mass

14
Q

What is a 4 compartmental model of body comp

A

Also includes total body water

15
Q

What are the different methods used to assess body composition?

A

-height; weight and BMI
-waist to hip ratio
-hydrostatic weighing
-skin fold measurements
-air displacement plethysmography
- dual x ray absorptiometry (DEXA)
-bio electrical impedance analysis (BIA)

16
Q

How to measure height?

A

-use stadiometer
-ensure participant removes shoes, stands up straight with heels together and holds deep breath during measurement

17
Q

How to measure weight?

A

-measure on calibrated scale
-ensure subject removes shoes and wears minimal clothing (nude if possible)

18
Q

BMI formula/ healthy ranges

A

=weight (kg) / height (m2)
-underweight <18.5
-normal 18.5- 24.9
-overweight 25-29.9
-obese 30-34.9
Extremely obese 35<

19
Q

How to measure wait to hip ratio

A

-waist circumference- measured at narrowest point below ribs
-hip circumference- measured at widest point

20
Q

How to measure using skin fold tests

A

-multiple sights are measured and % BF is calculated using some of sites
-measurements should be taken on right side of body

21
Q

What is used when performing skin folds and in what 2 ways can they be used?

A

-used callipers to measure thickness of double layer of skin
-used to track changes in individuals or sum of the skin folds or sum of multiple skin fold sites can be used with equation to calc % body fat

22
Q

Limitations of skin fold tests

A

-possible technician error
-skinfold thickbess can be affected by factors other than amount of fat: excercise increases skin thickness, dehydration reduces it, dermatitis increases it

23
Q

What are the 2 2 compartmental models?

A

-air displacement plethysmography
-BIA

24
Q

How does air displacement plethysmography work

A

-calculated %BF from body density and uses computerised air pressure sensors to determine amount of air displaced while participant is in bod pod

25
Q

How does BIA work

A

-rapid, non invasive and inexpensive
-sends electrical current thru body to estimate body fat (based on idea that fat is less conductive than lean tissue)

26
Q

Describe how DEXA works

A
  • is a 3 compartmental model
    -used a series of low dose radiation scans providing high accuracy
    -provided measurements of bone mineral, fat and non bone lean tissue
27
Q

Hydro-densitometry method?

A

-2 compartmental and indirect

28
Q

Hydro-densitometry method pros and cons

A

+can be accurate when carried out by qualified person
-assumption of specific tissue densities (differ in
elite athletic populations)
- residual lung volume can be a source of error
- Claustrophobia/fear whilst underwater
- Expensive equipment. Needs maintenance,
sterilisation and cleaning
- cannot measure distribution of FFM or FM
- air can be contained within an individual’s
swimsuit, skin, head, body hair, digestive
tract…leads to false estimations
- air temperature, barometric pressure, nitrogen
analyser and force sensor calibrations all can lead
to measurement error
- is time consuming and needs expertise.

29
Q

Air displacement plethysmography pros and cons?

A

+Overcomes several of the aforementioned
limitations of hydro-densitometry
+ Reliable
- Not sensitive enough for changes in elite
athletic body composition
-Too sensitive to clothing, body hair, air
movement, moisture, pressure and
temperature changes
-expensive to buy equipment.
-Overestimates BF% compared with hydro-
densitometry
- Body fat measures diverge at the extremes of
the BMI spectrum (concern in certain athletic
populations)
- cannot measure distribution of FFM or FM

30
Q

BIAS pros and cons?

A

+ Speed
+ minimal expertise required
+ portability
+ cost (compared to other methods)
-Can be affected by temperature and hydration
status
-sensitivity to conductive surface of electrodes and
electrode placement
- Assumptions on the composition of the body in
formula and calculations, irrespective of population group
-the limbs contribute a large proportion to whole-
body impedance, despite the relatively low
contribution to overall BM [31].
- Limited validation in athletic populations
-Some under and overestimation of FFM
-There is also large variability between devices

31
Q

Ultrasound pros and cons

A

-is multi compartmental
+ Reliable and accurate measure of subcutaneous
adipose tissue thickness
+ MAY be portable*
- Affected by the chosen frequency, pressure
and orientation of the probe causing
measurement error
-Requires technician expertise
-Can be expensive and impractical within the
applied setting, even with improved
portability

32
Q

DEXA pros and cons

A

-is multi compartmental
+ Reliable measure of body composition
+Measures Bone Mineral Content (low energy
availability etc)
+ Limb-specific estimations of FM and FFM which
can be useful when tracking injured athletes
-Uses radiation: legal and ethical constraints
(approval by doctor /national ethics committee)
- Requires trained and certified technician
- Variations between manufacturers (energy levels
emitted, pixel size, software algorithms etc)
-Expensive equipment
-Not portable
-Time consuming
-Not reliable at extremes of size (very large people)
- Affected by water and glycogen levels

33
Q
A