[Analysis of the fore-aft and lateral components of the floor reaction force in normal gait].

Floor reaction force on walking was studied in normal subjects using a large force plate (80 x 400 cm). Relationships between the horizontal components of the floor reaction force and step length and width were analyzed at different walking velocities. The impulses of fore-aft force were closely correlated with step length. Especially, the impulse per unit body weight per unit duration of force in both the restrictive and propulsive period showed a high positive relationship with step length. The differences in impulse observed among the subjects were reduced upon standardization of step length with body height. The impulse of lateral force also showed a positive relationship with step length, but the correlation coefficients were lower than those for fore-aft force and step length. The influence of restraint due to the measuring system on lateral force during walking as revealed by a large force plate should be considered.