Body Composition

Question 1

Healthy body fat percentages

Answer 1

Males: 12-18%
Females: 18-23%

Question 2

Hydrostatic weighing

Answer 2

A type of densitometry.
Immerse a person in water and measure the amount of water displaced. Fat percentage can be calculated using Archimedes’ principle. Limitations include the need to account for residual lung volume.
Standard error is 2 to 2.5%

Question 3

Plethysmography

Answer 3

A type of densitometry.
Calculates density by measuring amount of air displaced in a closed chamber by looking at change in pressure. Body fat measured via equation.

Question 4

Anthropometry

Answer 4

Skinfold measurement: determines body fat by measuring nine standardized sites. All measurements taken on right side of body and taken multiple times at each site to ensure accuracy. Skinfold calipers should be positioned 1 cm away from the examiner’s fingers.
Accuracy of measurement is +/- 3%

Question 5

Bioelectrical Impedance Analysis (BIA)

Answer 5

Uses small electrical current and measures the resistance or opposition to the current flow. Resistance is inversely related to the composition of water. Formula height^2/resistance is used to calculate body fat %. No eating or drinking 4 hours before test, no vigorous physical activity within 12 hours of test, urinate within 30 min of test, no alcohol 48 hours before test.
Accuracy of measurement is +/- 3%.