Comparing data over time is important for determining whether you;
- eat enough and eat right
- maintains muscle mass
- gain or lose weight
Measurement methods
Calipers
- Measures only subcutaneous fat
- Margin of error: -/+ 1–3%
- Enables comparison of subcutaneous fat over time
BIA – Bioelectrical Impedance Scale
- Measures and calculates body composition
- Enables individual follow-up
- Calculates fat mass = TBW (total body weight) – FFM (fat-free mass (bones, water, muscles, blood))
BodPod
- Measures body fat using air pressure
- Margin of error: +/- 0.5–1%
- An expensive method that requires trained staff
Underwater surveying
- Fat and muscle have different densities relative to their volume. This is determined by measuring how much water is displaced. It is based on Archimedes' principle.
- Margin of error: +/- 0.5–1%
- An expensive method that requires trained staff
- Most commonly found in research laboratories and universities
DEXA – Dual-energy X-ray absorptiometer
- Measures body fat using X-ray energy
- Margin of error: +/- 0.5–1%
- An expensive method that requires trained staff
- Most commonly found in research laboratories and universities