# Gait transition in swimming

## TL;DR

This paper investigates how swimmers transition between different arm coordination patterns as their speed increases, using a model to explain the shift from catch-up to superposition coordination and its implications for technique optimization.

## Contribution

It introduces a burst-and-coast model to explain the gait transition in swimming and identifies key parameters for optimizing swimmer technique.

## Key findings

- Swimmers switch from catch-up to superposition coordination with increased speed.
- The transition is explained by a burst-and-coast model based on propulsion timing and glide effectiveness.
- Parameters can be used to characterize and improve swimming technique.

## Abstract

The skill to swim fast results from the interplay between generating high thrust while minimizing drag. In front crawl, swimmers achieve this goal by adapting their inter-arm coordination according to the race pace. A transition has been observed from a catch-up pattern of coordination (i.e. lag time between the propulsion of the two arms) to a superposition pattern of coordination as the velocity increases. Expert swimmers choose a catch-up coordination pattern at low velocities with a constant relative lag time of glide during the cycle and switch to a maximum propulsion force strategy at higher velocities. This transition is explained using a burst-and-coast model. At low velocities, the choice of coordination can be understood through two parameters: the time of propulsion and the gliding effectiveness. These parameters can characterize a swimmer and help to optimize their technique.