A model of kinematic variables determining height achieved in water polo boosts

A boost is a skill used in water polo to raise the body for the purpose of shooting for goal or passing, or defending against these. The purpose of th is study was to investigate kinematic variables contributing to height achi eved in a boost. The kinematics of the vertex, shoulders, and lower limbs o f 16 players ranging in ability from novice to elite were quantified using three-dimensional videographic techniques. Maximum height of the vertex wit h respect to water level ranged from 0.50 m to 0.90 m. A multiple regressio n model comprising the squared maximum resultant foot speed, range of knee joint extension, and initial trunk angle with respect to the horizontal acc ounted for 74% of the variance in height achieved. Anteroposterior and medi olateral motions assisted in maintaining foot speed throughout the period o f knee extension. The foot orientations and direction of foot motion of the elite players suggested that effective technique involves the use of both drag and lift forces.