Locomotion is a complex mechanism of propulsion and equilibrium control, and the analysis of ground reaction force(GRF) during locomotion can therefore give valuable information about basic mechanism of locomotion. Fourteen men with no history of neuro-musculoskeletal disorder were studied during walking with 5 different walking speeds(57.11∼99.09m/min). Vertical, anteroposterior and mediolateral force components were recorded with 2 force platforms. Elite DMA acquisition program(B.T.S., Italy) was used to calculate amplitude and duration of GRF.

The result was as follows;

1) Increased walking speed was accompanied by shorter stance and double support time with constant ratio of double support to stance time.

2) Timing of different events of GRF were earlier with increased walking speed without changing the ratio of each events to stance time at all walking speeds.

3) All peak forces were larger with increased speed except lateral force in late stance phase(Fx3).

4) The complex interactions between vertical, anteroposterior and mediolateral forces needed for propulsion and equilibrium during locomotion were different at different speeds.