Bilateral femoral rotations measured during walking: a new parameter to summarize and describe individual gait.

The aim of this study was to develop and assess a method of analysis of femoral rotations to describe and summarize an individual's gait. Twelve normal subjects underwent walking trials at both natural and slow speeds, controlled by a metronome. The three-dimensional rotations of each femur were measured, simultaneously, during walking using a 3SPACE Tracker. The phase lags between the three rotations for each leg, obtained by cross-correlations, provided the primary data. The device was found to be reliable and gave significant test--retest repeatability. The analyses provided summary parameters describing mathematically the patterns of rotations and showed there was repeatability within and between sessions. A strong systematic subject effect in all analyses indicated that these parameters provide a highly specific description of how an individual walks.