LIFTING PERFORMANCE IN AQUATIC SPORTS

Abstract

Performance in aquatic sports is limited by the ability to maximize propulsive forces and minimize resistive forces. Propulsive forces may be generated by moving body parts or paddles in a direction opposite the direction of desired travel, that is, by using ‘drag’ forces. ‘Lift’ forces are perpendicular to the motion. Thus, if lateral motions are used, lift forces may contribute to propulsive force. Direct quantification of drag forces and lift forces in realistic settings is problematic. Therefore, scientists have relied on indirect evidence to assess the relative importance of drag forces and lift forces to propulsion in aquatic sports. The purpose of this presentation is to review the evidence relating to the use of drag forces and lift forces in three aquatic skills. These skills are freestyle swimming, flatwater kayak paddling, and the water polo ‘eggbeater’ kick. The implications for technique are discussed. Given the lack of definitive findings, the presenter seeks to stimulate further investigation into aquatic sports rather than to draw conclusions. Since the early 1970s, the view that good technique in freestyle swimming involves sculling actions of the hands to use lift forces in preference to drag forces has predominated. Recent three-dimensional studies have contradicted this view and indicate a need for further investigation. Flatwater kayak technique has changed greatly during the last 15 years following the introduction of the ‘wing’ blade. The wing blade, shaped like an airfoil to generate lift forces by the Bernoulli Principle, has resulted in improved performances. However, based on the small amount of evidence available, it is not yet clear whether lift forces contribute to propulsion more than drag forces. Some possible reasons for the improved performances in flatwater kayaking since the introduction of the wing blade are discussed. Despite its importance in water polo, the eggbeater kick has received scant attention by sports scientists. Recent indirect evidence suggests that lift forces play an important role in the eggbeater kick. It appears that players improve by modifying their motions to use lift forces in preference to drag forces.