Are Dynamic Phenomena Prior to Stepping Essential to Walking?

The aim of our research was to examine the function of the pre-gait weight shifts in generating the dynamic forces needed to start walking at different speeds. Five subjects participated in the experiment, and a total of 105 gait initiation movements, executed on a large force plate, for three speed conditions (slow, normal, and fast), were examined. Results, which related to durations of the anticipation and of the step execution phases and to biomechanical parameters (progression velocity of the center of gravity, backward shift of the center of foot pressure, and magnitude of propulsive forces at heel-off time), suggested that dynamic phenomena prior to stepping are essential to walking as far as they contribute to the creation of convenient conditions for progression. The configuration of the support basis prior to stepping limits the progression velocity reached at the end of the first step.