Fig. 2

The perturbation treadmill system used a Photo of the perturbation system during balance training. The system is compose of a motor-driven treadmill, mounted on a moving platform, motion controller, safety harness and an operator station; b the perturbations velocity control diagram during training delivered unpredictably in forward, backward, left, and right directions. Note those are actual measurements taken during perturbation training. c Example of the perturbation applied during the treadmill walking training (c1–c12). The perturbation applied unpredictably (c5) by horizontal movement of the platform towards the left side during the right foot initial contact-loading response phases of gait cycle. The participant right foot was slipped unpredictably to the left while walking in the center of the platform. The participants performed a cross over stepping response by his left foot (c6–c9), than additional side step was performed by the right foot stepping outside the treadmill (c10–c12)