Visual control of locomotion: Strategies for changing direction and for going over obstacles.

TLDR

Planning direction change in the preceding step is required to keep the body‑center‑of‑mass acceleration toward the landing foot at zero, because muscles cannot rotate or translate the body mediolaterally during the step cycle. Ground‑reaction forces, muscle activity, and kinematics were measured while systematically varying obstacle height, position, cue lights, and the time available within the step cycle to assess gait adjustments for obstacle avoidance and direction change. The study found that locomotor control involves greater supraspinal involvement.

Abstract

Dynamics of gait adjustments required to go over obstacles and to alter direction of locomotion when cued visually were assessed through the measurement of ground reaction forces, muscle activity, and kinematics. The time of appearance of obstacles of varying heights, their position within the step cycle, and cue lights for direction change were varied. Direction change must be planned in the previous step to reduce the acceleration of the body center of mass toward the landing foot to 0. The inability of steering within the step cycle is due to the incapacity of muscles to rotate the body and translate it along the mediolateral axes. For obstacle avoidance, Ss systematically manipulated the gait patterns as a function of obstacle height and position and the time available within the ongoing step. Greater supraspinal involvement in control of locomotion is found.