Thrust Forces in Underwater Swimming

Abstract

Instantaneous and mean static thrust levels were measured for eight underwater swimmers restrained in a submerged force platform. Swimming was examined barefoot and with two types of fins. The main beneficial effect of the fins was to eliminate the substantial negative thrust component associated with barefoot swimming. Higher maximal thrust outputs were achieved with curved fins than with straight-bladed ones. There were also significant differences between barefoot and finned swimming in the relationship of instantaneous thrust to leg position during the kick cycle. Kick rate and foot acceleration were both proportional to thrust output, but the relationship depended on diver size and experience.