Biomechanical analysis of two change-of-direction maneuvers while running.

Many research efforts focus on unidirectional gait. However, few functional activities are exclusively linear: people regularly change directions to evade obstructions. Directional changes have been identified as particularly hazardous, but rarely studied. The purpose of this study was to examine the kinetics of abrupt changes of direction while running. Twelve adult volunteers performed 10 trials each for 45 degrees and 90 degrees change-of-direction conditions. Orthogonal force and moment (torque) records were obtained using a computer-interfaced force platform system. Vertical, braking, and propulsive force and applied torque variables were extracted for statistical analysis. Significant force differences (p < .01) were identified between conditions. Applied torques were highly variable and not significantly different. Functionally, these data suggest that applied forces serve as the principal impetus of directional change.