DOES THE STEP LENGTH REQUIREMENT IN THE SUBSEQUENT STEP INFLUENCE THESTRATEGIES USED FOR STEP LENGTH REGULATION IN THE CURRENT STEP

A comprehensive description of the prospective gait adaptations used d uring transient step length adjustments was achieved by examining the kinematics, force plate kinetics and EMG simultaneously. To achieve a single lengthened step, the runner decreased braking and increased pus h-off during stance, and increased the reach of the swinging limb. Whe n foot placement was also constrained in the subsequent step, the gait parameters showed significantly different modifications in both stanc e and swing limbs during the first step. When a short step followed th e long step, the centre of mass was biased backwards in the first step , allowing greater time and/or distance to reduce the linear momentum to accomplish the subsequent short step safely. To achieve two long st eps, the take-off velocity was increased, while the landing velocity w as reduced because the subject was not free to compensate during the s ubsequent step. These adaptive strategies highlight the interaction of the task, stability and safety requirements during locomotion and ten d to support a malleable control of human locomotion.