Velocity fluctuations within a single stroke cycle in swimming are the result of accelerating and decelerating actions on the body exerted by propulsive movements and water resistance. Analysis of the relationship of the swimmer's acceleration and velocity versus time presents information about the way in which the different movements contribute to changes in swimming speed. Further, the magnitude of variation should indicate motion efficiency because less energy is wasted with a more uniform velocity. The precise nature of this relationship in swimming, however, has not been determined. Kornecki and Bober (1978) suggested that the deviation between extreme velocities and the mean velocity within a stroke cycle of a swimmer would be a useful measure of efficiency. The crucial problem has been to obtain data on single-stroke cycle kinematics in a way that makes more sophisticated analysis possible. Although time consuming and expensive, high speed cinematography is a classical method. Cavanagh (1976), however, has recently questioned the accuracy of acceleration data derived from such an analysis. Other instruments for recording velocity fluctuations have been presented (Karpovich and Karpovich, 1970; Kent and Atha, 1974). In the present study a linear accelerometer was used to determine the forward motion of the swimmer's body. The purpose was to develop a technique for reliable acceleration measurements and to analyze the data obtained for different swimmers and strokes.
© Copyright 1979 Swimming III. Proceedings of the Third International Symposium of Biomechanics in Swimming, University of Alberta, Edmonton, Canada. Published by University Park Press. All rights reserved.