Validity of electrical impedance myography to estimate percent body fat: comparison to bio-electrical impedance and dual-energy X-ray absorptiometry.

Background: Assessment of percent body fat (%BF) is typically measured with bioelectrical impedance (BIA) as a proxy for dual-energy X-ray absorptiometry (DXA). Notably, poorer agreement between BIA and DXA among persons who are overweight or obese has been reported. The use of electrical impedance myography (EIM) as a proxy for DXA has not been validated.

Validity and reliability of Fitbit activity monitors compared to ActiGraph GT3X+ with female adults in a free-living environment.

Objectives: Inexpensive activity monitors have recently gained popularity with the general public. Researchers have evaluated these consumer-based monitors in laboratory-conditions. Given the current wide-spread consumer use of these devices, it is important to ensure users are attaining accurate information compared to previously validated measures.