A VIDEO-BASED TECHNIQUE FOR MEASURING ANKLE-SUBTALAR MOTION DURING STANCE

This study was designed to demonstrate that an accurate and reliable technique for measuring the rotational motion between rigid bodies can be developed from a video-based data collection system. Tests on the accuracy of the rotational measurements demonstrated that for each of five trials, under three test conditions, mean errors of less than 0.4° and standard deviations of less than 0.2° were found for all three joint axes. The reliability of the technique for evaluating ankle-subtalar motion during stance was also demonstrated, and the technique was then applied to evaluate ankle-subtalar motion during the stance phase of gait. The rotational motion of the combined ankle-subtalar joint was characterized by complexity and inter-subject variability. Two simplified models previously used to describe ankle-subtalar motion were tested using the current data and were proven to be inadequate for describing ankle-subtalar motion during stance. © 1990.