An increasingly popular method for measuring body composition is the BOD POD. The BOD POD (BP) uses air-displacement plethysmography, a pressure sensing diaphragm, to estimate body volume. As part of the manufacturer’s protocol, body mass is measured on a digital scale and stored into the BP system. Using Boyles’s Law, an estimation of body volume is calculated based on pressure changes inside the BP. This volume estimate is combined with body mass to measure body density. The body density is then used to estimate percent body fat (%BF) by using a population specific equation [2, 7]. Using a two-compartment model, the BP is able to accurately measure body composition.