SAGITTAL PLANE MOTION OF THE HUMAN ARCH DURING GAIT - A VIDEOFLUOROSCOPIC ANALYSIS

Despite an abundance of literature investigating arch structure and mu sculoskeletal injury, there seems to be little consensus regarding the most appropriate technique of measuring dynamic arch motion. In this study, digitized videofluoroscopy was used to determine the sagittal p lane motion of the medial longitudinal arch during dynamic gait. Nine female subjects requiring diagnostic foot radiographs underwent videof luoroscopy during a normal gait cycle. The calcaneal inclination angle , calcaneal-first metatarsal angle (Cl-MT1) and height-to-length ratio of the arch, all reputed to measure arch alignment, were digitally an alyzed from static radiographic images. Both the calcaneal inclination angle (0.96) and Cl-MT1 (-0.98) angles were highly correlated with th e criterion measure of height-to-length ratio. Repeated measures analy sis of variance (ANOVA) identified a significant increase in the mean Cl-MT1 angle during stance, suggesting a continual lowering and elonga tion of the arch. This study questions the validity of characterizing foot motion based on static measures of arch shape and recommends that further research be conducted to establish whether the observed trend s reflect normal or pathological foot function.