The purpose of this study was to clarify the changes in the medial longitudinal arch (MLA) and plantar load distribution during the stance phase of walking at different speeds. Eight healthy male subjects participated in this study. Plantar pressure measurement plate (Novel GmbH®, 100Hz), motion capture system (Oxford, 100Hz) and force plate (Kistler, 1KHz) were synchronized. Using this system, subjects performed 3 walking trial at 0.8 (Slow), 1.2 (Normal), 1.7 (Fast) m/s. Plantar load distribution was divided into five sub-area based on anatomical measurement points. MLA angle was calculated as the angle between the distal first metatarsal, navicular tuberosity and calcaneus. In comparison with Slow, Fast showed no difference in the amount of change in MLA angle, despite the greater load applied to the medial forefoot at push-off phase. Increasing the plantar loads in medial foot as well as stiffening the MLA might be important roles during push-off phase in walking at fast speed
