The purpose was to compute the instantaneous contributions of anatomical rotations of the trunk, upper arm, forearm, and hand to ball speed and to quantify the three-dimensional angular kinematics of the trunk and throwing arm during water polo penalty throws. The largest contributors to predicted ball speed |(vB)'| at release were forearm extension and a counterclockwise twisting rotation of the trunk. Upper arm internal rotation contribution to |(vB)'| at release was highly variable and exhibited a significant inverse relationship with the upper arm horizontal adduction contribution to |(vB)'| at release (r = −.70). Subjects with large internal rotation contributions to |(vB)'| tended to have the upper arm in positions of less external rotation, but internally rotating at a faster rate, at release. Subjects with large upper arm horizontal adduction contributions to |(vB)'| exhibited a trend for faster rates of upper arm horizontal adduction and positions of increased forearm pronation at release. Findings suggest that a continuum of technique styles are used by water polo players to produce ball speed at release.
The authors are with the Department of Sports Medicine and Physical Education, Pepperdine University, Malibu, CA 90263.