The relationship between the raw acceleration signal from a commercially available accelerometer and ground reaction force

Accelerometers are increasingly employed to assess relationships between physical activity and health. Output is in proprietary counts, hindering between model comparisons, and translated into time spent at activity intensities based on energy expenditure. Bone mineral density (BMD) is improved by mechanical overload. Thus, in order to use accelerometers to assess activity beneficial to bone, accelerometer output needs to be calibrated against mechanical loading, e.g. ground reaction force (GRF). The purpose of this study was to examine the relationship between the raw acceleration signal (vertical and resultant over three axes) from a new commercially available accelerometer and mechanical loading.