Chapter 8 (Assessing Body Composition)

Question 1

Body fat is essential for what?

Answer 1

• thermal insulation
• storage of metabolic fuel
• transport of fat-soluble vitamins

Question 2

Define body composition

Answer 2

• the measurement of fat mass versus fat-free mass

Question 3

Recommendations of body fat percentage for females

Answer 3

• 10% - 28%

Question 4

Recommendations of body fat percentage for males

Answer 4

• 3% - 22%

Question 5

What are the uses of body composition measurements?

Answer 5

• formulate nutritional recommendations
• disease risk
• monitoring risk
• assessing changes

Question 6

Multiple theoretical models estimate what?

Answer 6

• % body fat

Question 7

What are the two components of % body fat?

Answer 7

1. fat mass
2. fat-free mass

Question 8

What is the density of fat mass?

Answer 8

• 0.901 g/cc

Question 9

What is the density of fat-free mass?

Answer 9

• 1.100 g/cc

Question 10

Fat-free mass components

Answer 10

• 73.8% water
• 19% protein
• 6.8% mineral

Question 11

What aspects affect the components of fat-free mass?

Answer 11

• age
• sex
• ethnicity
• physical activity
• % body fat

Question 12

Most accurate body composition models

Answer 12

• multi compartment models

Question 13

What is densitometry?

Answer 13

• body density
  - Db = BM / BV
• body volume is obtained through hydrostatic weighing or air displacement

Question 14

What is an x-ray for body fat?

Answer 14

• dual energy x-ray absorptiometry (DEXA)
• CT

Question 15

What is hydrostatic weighing (hydro densitometry)?

Answer 15

• Body volume calculated by displacement of water
• body density calculated by weight above and below water

Question 16

What principle is hydrostatic weighing based on?

Answer 16

• Archimedes’ principle

Question 17

What law is the bod pod based on?

Answer 17

• Boyle’s law of pressure volume relationship

Question 18

What does the dual x-ray absorptiometry (DEXA) measure?

Answer 18

• densitometry
• bone mineral

Question 19

What Clinical method shows the distribution of fat?

Answer 19

• DEXA

Question 20

What clinical method best estimates mineral contribution to free-fat mass?

Answer 20

• DEXA

Question 21

What are examples of 3 component free-fat mass clinical tests?

Answer 21

• CT scan
• MRI

Question 22

What are manual field methods for testing for body fat?

Answer 22

• skinfold
• anthropometry

Question 23

What are electrical equipment field methods for testing for body fat?

Answer 23

• ultrasound
• bioelectrical impedance analysis

Question 24

An indirect measurement of subcutaneous body is the definition of what field method?

Answer 24

• Skinfold

Question 25

Skinfold are not great because of what?

Answer 25

- overestimates %BF in leaner clients - underestimates %BF in obese clients

Question 26

What are the major sources of error in a skinfold?

Answer 26

- technicians skill - SKF caliper - client factors

Question 27

What is a bioelectrical impedance analysis? (BIA)

Answer 27

- a combination of pairs of sending and receiving electrodes

Question 28

What is the impedance for fat and lean tissue?

Answer 28

- fat: electrodes flow slower (with resistance) - lean: electrodes flow faster/easier

Question 29

What is the main influential factor in BIA?

Answer 29

- hydration levels

Question 30

Potential disadvantage to BIA

Answer 30

- cannot distinguish intracellular and extracellular water

Question 31

Participates should do what before using the BIA?

Answer 31

- no eating/drinking before - no alcohol or caffeine - no exercise before - using the bathroom (women can not be on their period)

Question 32

What is the anthropometric method?

Answer 32

- measurement of the size and proportion of the human

Question 33

Downside to the anthropometric method

Answer 33

- does not separate fat and muscle

Question 34

What is circumference?

Answer 34

- measurement of the girth at prescribed landmarks

Question 35

Waist-to-hip ratio

Answer 35

- indirect measure of lower and upper body fat

Question 36

Waist- to-height rule of thumb?

Answer 36

- waist should be less then 50%