Evolution des nages et théorie des jeux

摘要

We used game theory to formalize a situation observed in competitive swimming, with a focus on European Championships thirty years apart. High-level swimmers move faster underwater than at the surface. In short-course (25 m pool) events, the 15-metre rule authorizes swimmers to swim further underwater than they do at the surface. However, competitive swimmers in 100 m backstroke, butterfly and freestyle events in short-course pools do not take advantage of this option and spend more time at the surface than underwater. By modelling a dilemma opposing a surface tactic (Surface+) and an underwater tactic (Underwater+), it was possible to predict the evolution of swimming techniques. Six situations appeared and were resolved by Nash equilibrium, a Maximin strategy and an Evolutionary Stable Strategy. In short-course events, underwater dolphin kicking (the “fifth stroke”) is a new “intruder” and is likely to become the dominant replicator – despite efforts from swimming institutions, which artificially trains swimmers to stay at the surface.