Optimizing simulation suggests that maximizing swimming speed and minimizing undesirable body roll are contradicting for swimmers stroking with one upper limb

Abstract

How a swimmer stroking with one upper limb can minimize undesirable body roll by changing the forearm pronation/supination angle was investigated by physics-based optimizing simulation in this study. It was hypothesized that the undesirable body roll can be minimized by varying the pronation/supination angle during underwater stroke. It was also hypothesized that the time variation in pronation/supination angle minimizing the undesirable body roll is different from the time variation maximizing the swimming speed. To examine these hypotheses, three cases of maximizing swimming speed, balancing to maximize the swimming speed and to minimize the undesirable body roll, and minimizing the undesirable body roll, were virtually created in the simulation, and the results were compared. The result supported the first hypothesis that the reasonable pronation/supination angle and the resultant swimming movement were successfully obtained for the third case. The second hypothesis was also supported by the result that the swimming speed became lower according to the decrease in the undesirable body roll. It was suggested that there is a different mechanism to consider in underwater arm stroke for a swimmer stroking with one upper limb from that of an able-bodied swimmer.