Analysis of Breast, Back and Butterfly Strokes by the Swimming Human Simulation Model SWUM

In the preceding study, the swimming human simulation model “SWUM” has been developed by the authors, and the analysis of standard six beat crawl stroke has been conducted. In this paper, the analyses of three strokes, that is, breast, back and butterfly strokes were conducted. The swimming motion, velocity in the propulsive direction of the human body, and the fluid force in the propulsive direction acting on the upper and lower limbs were respectively shown for those three strokes. In addition, the stroke length and the propulsive efficiency of the four strokes were investigated by the simulation. It was found that the stroke lengths of the crawl, back and butterfly strokes in the simulation agree significantly with the actual values, and that of the breaststroke becomes relatively smaller. It was also found that the propulsive efficiency of the crawl, back and butterfly strokes becomes around 0.2, although that of the breaststroke becomes only 0.036.