Body Composition

Question 1

what is body composition?

Answer 1

body’s relative amount of fat mass and fat-free mass (bone, water, muscle, connective and organ tissues, teeth)

Question 2

what is the difference between essential and non-essential fat?

Answer 2

1. essential fat → crucial for body function
   
   1. 3-5% of total body weight in males
   2. 8-12% of total body weight in females
   3. reducing essential fat below minimal amount can impair overall health
2. non-essential fat → adipose tissue
   
   1. storage fat accumulates mainly in adipose tissue

Question 3

list 3 theories that explain changes in body composition and weight

Answer 3

1. calorie in and out
2. hyperplasia fat cells
3. set point theory

Question 4

what is the hyperplasia fat cell theory?

Answer 4

1. if someone gains too much fat tissue and each fat cells size is maximized the individual will undergo hyperplasia, this can occur during any stage of life
2. when they lose weight, individuals lose fat but they are not reducing the number of fat cells just shrinking them
3. body may interpret shrunken fat cells as a sign of early starvation and send signals to trigger the body to slow metabolism in order to restore the fat cells to their normal size

Question 5

when does fat hyperplasia normally ocur?

Answer 5

1. last trimester prior to birth
2. first year of life
3. during adolescence

Question 6

what is the set point theory?

Answer 6

body has a comfortable body composition in which genetics play a role in determining

Question 7

list and describe 3 body classifications

Answer 7

1. ectomorph → tall and slim, with narrow shoulders and a low muscle mass percentage (“fast metabolism”)
2. endomorph → heavier and rounder, higher % body fat and less muscle mass
3. mesomorph → body types with a naturally high muscle-to-fat ratio

Question 8

list and describe 2 different body types

Answer 8

1. android → apple shaped
2. gynoid → pear shaped

Question 9

what are the health risks of too high body fat percentage?

Answer 9

1. heart disease and stroke
2. high BP
3. high cholesterol
4. diabetes
5. some cancers
6. gallbladder disease and gallstones
7. OA
8. Gout
9. breathing problems
10. early death

Question 10

what are the health risks of too low a body fat percentage?

Answer 10

1. malnutrition
2. vitamin deficiencies
3. anemia
4. osteoporosis
5. decreased immune function
6. increased risk for complications from surgery
7. fertility issues
8. growth and developmental issues

Question 11

what body comp assessment is the new gold standard?

Answer 11

DEXA

Question 12

list the advantages/disadvantages of underwater densitometry

Answer 12

1. Advantages
   
   1. proven to be valid and reliable
2. Disadvantages
   
   1. requires a lot of equipment and space
   2. equipment is expensive
   3. requires high skill level to administer and complete calculations
   4. time consuming and involved
   5. not everyone can tolerate being submerged underwater

Question 13

list the advantages/disadvantages of air densitometry

Answer 13

1. Advantages
   
   1. strong validity and reliability
   2. measurement time is short
   3. well suited for special populations
2. Disadvantages
   
   1. very expensive
   2. not everyone can tolerate d/t claustrophobia

Question 14

list the advantages/disadvantages of DEXA

Answer 14

1. Advantages
   
   1. quick
   2. do not have to wear bathing suit
   3. excellent precision
   4. excellent validity and reliability
   5. comfortable
2. Disadvantages
   
   1. costly
   2. radiation exposure (low)
   3. validity reduced in very lean and highly obese participants
   4. requires certification

Question 15

list the advantages and disadvantages of BIA (bioelectrical impedance assessment)

Answer 15

1. Advantages
   
   1. safe
   2. observer independent
   3. inexpensive
2. Disadvantages
   
   1. unreliable
   2. hydration status alters results
   3. affected by many factors

Question 16

list the advantages and disadvantages of MRI and CT for body comp assessment

Answer 16

1. Advantages
   
   1. highly specific as to tissue composition
   2. able to separate into regions
   3. highly valid and reliable
2. Disadvantages
   
   1. costly
   2. time consuming
   3. radiation exposure with CT
   4. difficulty comparing results

Question 17

list the advantages and disadvantages of skin fold/fatfold technique

Answer 17

1. Advantages
   
   1. easy to perform
   2. quick
   3. noninvasive
   4. inexpensive
   5. can be performed nearly anywhere
   6. valid with proper technique
2. Disadvantages
   
   1. technical source of error
   2. mostly measures subcutaneous fat
   3. not as accurate with highly obese and very lean populations

Question 18

list advantages and disadvantages of BMI

Answer 18

1. Advantages
   
   1. quick
   2. easy
   3. minimal equipment
   4. moderate validity
2. Disadvantages
   
   1. does not consider fat free mass vs fat mass
   2. can improperly categorize participant’s weight category

Question 19

list the advantages and disadvantages of circumference/anthropometric technique

Answer 19

1. Advantages
   
   1. cheap
   2. minimal equipment
   3. minimal training
   4. moderate validity
2. Disadvantages
   
   1. overestimates body fat on muscular participants
   2. underestimates body fat on lean participants

Question 20

T/F: approximately 20% of adults are classified in incorrect BMI category on basis of self-reported height and weight

Answer 20

TRUE

Question 21

list waist circumference values for high risk

Answer 21

males >102 cm (>40 inches)

females >88 cm (>35 inches)