The purpose of the study was to assess the accuracy of estimates of step frequency from
trunk acceleration data analyzed with commonly used algorithms and time window lengths, at a
wide range of gait speeds. Twenty healthy young subjects performed an incremental treadmill protocol from 1 km/h up to 6 km/h, with steps of 1 km/h. Each speed condition was maintained for two minutes. A waist
worn accelerometer recorded trunk accelerations, while video analysis provided the correct number
of steps taken during each gait speed condition. Accuracy of two commonly used signal analysis
methods was examined with several different time windows.