Ratio of Propelling Force Generated by a Palm and by a Forearm in Freestyle Swimming

Abstract

The propelling force in swimming is mainly generated by hands and arms rather than by legs. However, the ratio of the thrust force by a hand to that by the whole forearm with hand has not been experimented. Replicas of a hand and a forearm with hand were made from an excellent swimmer's. Those characteristic data of the lift-drag forces and the propelling force ratio were taken by wind tunnel tests based on the angle of attack and the sweepback angle. The following results were found. As for the S-shaped pull stroke, the thrust force by the whole forearm with hand was 3 to 4 times larger than that by the hand itself in the catch and the finish phases while about 1.8 times larger in the pull phase. In the drag pull type stroke, the I-shaped pull, the thrust force by the whole forearm with hand was 1.8 times larger than that by the hand itself throughout all the three phases. Furthermore, the fluid characteristic of the whole forearm with the hand showed similar to that of the hand itself.