Thrust vs. Endurance Trade-off Optimization in Swimming

In this paper we apply methods typically used in engineering applications to the optimization of human locomotion, more specifically a swimmer's underwater `dolphin kick'. This is a dual-objective problem where we search for the optimal trade-off between thrust (simulated using Lighthill's fish propulsion method) and the force in the muscles to produce this thrust (simulated using musculoskeletal modelling). The expense of the analyses leads us to use a surrogate modelling based optimization technique (multi-objective expected improvement using Kriging). Our results indicate that optimal human motion does, in many respects follow that of fish, with low frequency eel-like techniques suitable for endurance and a high frequency tuna-like kick for high thrust. Matlab code, including thrust and muscle activity models is included as supplementary material.