A common goal in swimming technique analysis is to improve swimming efficiency. Minimizing the total drag could increase the swimming velocity or improve efficiency for the same velocity, but it is also possible to improve efficiency without changing the drag. In the same drag condition, the velocity profile at the same mean velocity affects efficiency; the most obvious way to improve efficiency in this context is by reducing the intracycle velocity variation, which increases the mechanical efficiency due to the reduction of the velocity`s dynamical component (Fernandes et. al, 2023). Despite that, biological examples show that this is not the only possible strategy. Fishes are able to use intermittent locomotion to improve their efficiency, this strategy is known as burst-and-cost swimming and consists of a twophase periodical behavior, first an active propulsive phase followed by a passive gliding phase, the relative duration of each one of those phases, as well as the difference in the drag coefficient between than are determinants for the successful adoption of this strategy (Li et. al, 2023). In front crawl swimming the catch-up coordination mode presents some similarity with a burst-and-coast strategy, since there is a pseudo-gliding passive phase when the entry and catch phase of one arm occurs simultaneously with the recovery phase of the other one. However, even in the slow paces associated with a catch-up coordination mode, keeping a lower velocity variability is generally accepted as more efficient. To the best of our knowledge, it was never analyzed the possibility of deliberately adopting a burst-and-coast strategy to increase efficiency. To shed light on this issue, a Monte Carlo simulation in a very simple model was used to analyze the swimming mechanical economy during a burst-andcoast strategy, produced by the addition of a phase shift in one of the arms, generating a super-position propulsive active phase, followed by a more hydrodynamic pseudo-gliding passive phase. We hypothesized that human swimmers are not able to use the burst-and-coast strategy to increase their swimming economy due to the relatively short passive phase and the high drag factor associated with human swimming.
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