Is backward stepping over obstacles achieved through a simple temporal reversal of forward stepping?

The main purpose of the study was to examine whether backward stepping over obstacles was a simple temporal reversal of kinematic and muscle activation patterns found in forward obstacle avoidance. Obstacle avoidance was used as a probe to represent one aspect of walking over variable terrain. Kinematics, trajectories and muscle activation profiles for forward versus backward stepping over obstacles revealed that the simple reversal of locomotor patterns observed for level walking cannot be applied to obstacle avoidance. However, key kinematic data and limb trajectories for backward leading limb stepping were found to be similar to existing forward trailing limb data. Therefore, it appears that stepping over obstacles requires a complex upper level reorganization of the basic locomotor pattern based on biomechanical and sensory feedback.