Body composition analysis

Question 1

What effect body composition?

Answer 1

Proportion of FM and FFM in the body
Genetics
Growth and development
Exercise
Diet

Question 2

What can body composition assessments tell us?

Answer 2

FFM
FM
Bone mass
Muscle mass

Question 3

Why do we measure body composition?

Answer 3

Health implications

Improve performance

Question 4

What are the essential fat for males and females?

Answer 4

3%

12%

Question 5

What does body composition measure?

Answer 5

Molecular and tissue level

Question 6

What does the two compartmental divide the body into?

Answer 6

Fat and Fat-free mass

Question 7

What does the FFM consist of?

Answer 7

Bone
Muscle
Organs
Connective tissue

Question 8

What does fat mass consist of?

Answer 8

All of the body’s fat including essential fat.

Question 9

Where is essential fat stored?

Answer 9

Major organs
Muscles
Central nervous system

Question 10

How is non-essential fat stored?

Answer 10

In adipose tissues

Question 11

Where is non-essential fat stored?

Answer 11

Visceral fatty tissue
Subcutaneous
Intermuscular
Intramuscular

Question 12

What factor affect storage fat?

Answer 12

Gender
Age
Genetics
Metabolism
Diet
Activity level

Question 13

How do men distribute fat?

Answer 13

Android fat distribution

Question 14

How do women distribute fat?

Answer 14

Gynoid fat distribution

Question 15

What are the assumptions of the two component model?

Answer 15

Fat density is 0.9g/ml
FFM density is 1.1g/ml
Fat and FFM is the same for everyone
The densities of the various components of FFM are constant within an individual
The individual being measured differs from a reference body only in the amount of fat

Question 16

What does the three compartmental model consist of?

Answer 16

FM
Total body water
FF dry mass

Question 17

What does the four compartmental model consist of?

Answer 17

FM
Total body water
Bone minerals
Residuals

Question 18

Can we distinguish between fats?

Answer 18

No

Question 19

What is the range of body density?

Answer 19

0.9 and 1.1

Question 20

How does Bioelectrical Impedance Analysis (BIA) work?

Answer 20

Measures impedance by body tissues to the flow of a small alternating electrical current.

Question 21

What premise if BIA based on?

Answer 21

FF tissue is a better conductor of electrical current

Question 22

What does BIA assume?

Answer 22

That FFM has a constant proportion of water (about 75%)

Question 23

What factors can influence the result of the BIA?

Answer 23

Change in hydration levels
Sensitive to body temperature, caffeine, exercise, fed/fasted
Sensitive to placement of electrodes

Question 24

What are the assumptions of BIA?

Answer 24

The human body is a perfect cylinder
The impedance to a current is directly related the length of the conductor and inversely related to it’s cross-sectional area
Biological tissues act as conductors or insulators, and the flow will follow the path of least resistance
Impedance is a function of resistance and reactance

Question 25

What are the advantages of BIA?

Answer 25

``` Convenient Fast test time ~ 5 mins Comfortable Privacy not compromised Reproducible Cheap (£250-£1000) ```

Question 26

What are the disadvantages of BIA?

Answer 26

Testing conditions need to be carefully controlled Does not account for race Tends to overestimate body fat in very lean muscular people and underestimate in % fat in obese

Question 27

Is DEXA multicompartmental?

Answer 27

Yes

Question 28

How does DEXA work?

Answer 28

2 low energy x-ray beams are used it measure the amount of radiation absorbed Soft tissues absorb the rays

Question 29

What does the DEXA scan measure?

Answer 29

``` Total body bone mineral Total body bone density Bone free lean tissue mass FM FFM soft tissue mass ```

Question 30

What is considered the gold standard of measuring body composition?

Answer 30

DEXA

Question 31

What are the advantages of the DEXA scan?

Answer 31

``` Accurate Measurement of bone content (osteoporosis) Safe Rapid Minimal subject cooperation ```

Question 32

What are the disadvantages of DEXA?

Answer 32

Costly | Limited access

Question 33

What are the uses for MRI?

Answer 33

Can measure liver, skeletal muscle and abdominal adiposity. | Skeletal muscle mass and volume

Question 34

Disadvantages of the MRI?

Answer 34

Inaccessible and expensive

Question 35

What is the range off the true value you can expect using hydrodensitometry?

Answer 35

+2.5% if done with experienced subjects

Question 36

Is hydrodensitometry considered a three compartmental model?

Answer 36

No it's considered a two | FM and FFM

Question 37

How does underwater weighing work?

Answer 37

Water density is ~1.0g/ml | Therefore fat will float and more muscle will sink

Question 38

In underwater weighing if someone has high body volume and low body density, what will their fat levels be?

Answer 38

Higher

Question 39

In underwater weighing if someone has low body volume and high body density, what will their fat levels be?

Answer 39

Lower

Question 40

What are the advantages of underwater weighing?

Answer 40

Accurate is done correctly | Many equations that are specific to each group

Question 41

What are the disadvantages of underwater weighing?

Answer 41

Most subjects not comfortable blowing all their air out Ambulatory problems Some people just don't like water

Question 42

What can cause error in underwater weighing?

Answer 42

Not getting all air out Reading scale wrong Not using the correct equation Estimation of residual volume (RV)