Some mechanisms of voluntary control of walking in humans

Abstract

The electrical activities of some muscles of the lower extremities have been studied by the method of presentation of an acoustic signal for a change in walking speed. It has been established that the motor response to a signal has two stages, at which (1) the ratio of muscle activities facilitating acceleration or deceleration of walking is formed and (2) the muscle activity corresponding to the new rate of locomotion is set. The latent period of the first stage of the motor response depends on the temporal relationship of the signal and the phase of muscle activity: it is minimum if the signal coincides with the phase of activity and maximum if the signal is given in the phase of bioelectric silence. It may be supposed that the voluntary control of the locomotion rate is related to at least two types of cortical effects: cyclic and acyclic. The former determine the transition from one speed of walking to another through changing human body posture characteristics (probably, they influence interneurons and motoneurons of reflex arcs); the latter, the characteristics of the new mode of the locomotor cycle by affecting the functional state of the interneurons and motoneurons of the spinal generator of stepping movements.