When running over obstacles of increasing height, heelstrike runners switch to a forefoot landing pattern once a critical obstacle height is reached. The primary purpose of this study was to determine whether ankle or knee joint kinetic variables trigger the gait change from a heelstrike to a forefoot striking pattern as obstacle height increases. Ten subjects were filmed from the sagittal plane as they ran at their preferred running speed over a force platform during six obstacle height conditions ranging from 10% to 22.5% of standing height, as well as an additional baseline condition with no obstacle (0%). An inverse dynamics approach was utilized to calculate ankle and knee joint kinetics at each condition. Although no variables were found which met all of the criteria necessary to be considered a determinant of the gait transition, there were variables which distinguished between a heelstrike and forefoot strike landing pattern as obstacle height increased. Differences in joint kinetics did not occur until a height was reached at which the landing strategy changed from a heelstrike to a forefoot landing pattern. Most differences occurred at the ankle joint, at which there was a greater maximum plantar flexor moment and a greater amount of energy absorbed when obstacles of sufficient height to require a forefoot landing pattern were negotiated.
Journal of Sports Medicine and Physical Fitness
Hreljac, Alan; Stergiou, Nicholas; and Scholten, Shane D., "Joint Kinetics of the Ankle and Knee When Running Over Obstacles" (2005). Journal Articles. 100.