Angular momentum in the men's 110-m and women's 100-m hurdles races.

Twenty-three male and nine female hurdlers were filmed using three-dimensional methods at the 1988 United States Olympic Trials. With respect to the athletes, the X, Y, and Z axes pointed to the right, forward, and upward, respectively. During hurdle clearance, the X component of angular momentum was negative (clockwise rotation in a view from the right). Early in the airborne phase, it was associated with the motion of the trail leg. The downward motion of the lead leg was produced mainly by transfer of angular momentum from the trail leg, rather than by the lifting of the head-trunk. The Y component of angular momentum was negative (counterclockwise in a back view of a hurdler taking off from the right foot). It was necessary for the abduction of the trail leg. When this abduction slowed down, the angular momentum was taken up by the lowering (and slight adduction) of the left leg and elevation of the right elbow. The hurdle clearance required a positive Z component of angular momentum (counterclockwise in an overhead view): The clockwise angular momentum of the right arm as it swept backward was not enough to compensate for the larger counterclockwise angular momentum required for the forward motion of the trail leg. Our improved understanding of the rotations involved in hurdling will be useful for the correction of technique defects in individual athletes.