Upper extremity contraction moments and their relationship to swimming training

Abstract

A rationale is presented for relationships between the contraction moments at the shoulder and elbow joints and the forces acting on the adjacent body segments during the propulsive phase of front crawl swimming. It was hypothesised that the magnitude of the contraction moments necessary to sustain large hydrodynamic forces would be such that with swimming training the contraction moments would increase, and that the faster swimmers would have larger contraction moments. In order to reduce the complexity of the kinetic analysis it was assumed the contraction moments could be measured using a device which allowed for rotation without translation and provided an appropriate resistance moment. The contraction moment produced bending strain on a lever arm and the signal was integrated to give impulse and work output. Tests were carried out on a sample of 42 boys. Half of the group underwent a period of swim training and it was found that the medium ability swimmers did increase the initial segments of the impulse and work output curves. Tests on the remaining swimmers showed that the higher ability swimmers had impulse and work output curves which were significantly greater than for the lower ability swimmers.