Is human gait initiation program affected by a reduction of the postural basis?

The aim of this study was to access the adaptability of the gait initiation program by imposing before and during gait a posture that partially preven ts the backward shift of the center of foot pressure. Six healthy subjects performed normal gait in the control situation (CS) and gait in the absence of heel ground contact in the test situation (TS) on a force platform at t hree different speed conditions. It is shown that an increase in the du rat ion of the anticipation phase in TS is necessary to create conditions for p rogression which allow the subjects to reach a gait velocity similar to the one obtained in CS at the end of the anticipatory movements and also at th e end of the first step. Modifications of the gait initiation program occur in order to fulfil the performance in terms of gait velocity. (C) 2000 Els evier Science Ireland Ltd. All rights reserved.