Relationship between static mobility of the first ray and first ray, midfoot, and hindfoot motion during gait.

The relationship between a static measure of dorsal first ray mobility and dynamic motion of the first ray, midfoot, and hindfoot during the stance phase of walking was investigated in healthy, asymptomatic subjects who represented the spectrum of static flexibility. Static first ray mobility of 15 subjects was measured by a load cell device and ranged from stiff (3.1 mm) to lax (8.0 mm). Using three-dimensional motion analysis, mean first ray dorsiflexion/eversion and mid-/hindfoot eversion peak motion, time-to-peak, and eversion excursion were evaluated. Subjects with greater static dorsal mobility of the first ray demonstrated significantly greater time-to-peak hindfoot eversion and eversion excursion (p <.01), and midfoot peak eversion and eversion excursion (p <.01). No significant association was found between static first ray mobility and first ray motion during gait. This research provides evidence that the dynamic response of the foot may modulate the consequences of first ray mobility and that compensory strategies are most effective when static measures of dorsal mobility are most extreme.