Swimming in certain positions relative to other swimmers can offer an advantage
Shutterstock/Jacob Lund
Swimming with other swimmers can be more efficient than swimming alone. Open water swimmers, such as those in marathon swimming events at the Olympic games, can significantly reduce the drag between themselves and the water by positioning themselves strategically relative to other swimmers.
In a similar manner, birds can fly longer distances when in formation, fish can increase their endurance when swimming in schools, and cyclists can save energy when cycling in groups. Researchers at École des Ponts ParisTech in France, led by Remi Carmigniani, sought to investigate whether swimmers can also tap into the advantages of swimming in groups. Their work is aimed at supporting French athletes in their training for the Paris 2024 Olympic and Paralympic Games.
The research team utilized an 80-meter water channel and two plastic mannequins that mimicked the posture of swimmers with their arms held close to their bodies. Each mannequin was equipped with sensors to measure drag forces, or the friction forces between the mannequin and the water. The researchers placed the two mannequins in different configurations, including one behind the other and side by side, and then conducted water flow experiments at various speeds to collect drag data.
Through the measurements and computer simulations of the experiments, the researchers discovered that a swimmer can reduce drag on their body by up to 40 percent by swimming behind another swimmer. If a swimmer is forced to swim side by side with a competitor, swimming at the level of the other swimmer’s hip can reduce drag by about 30 percent. Carmigniani explains that the latter effect is a result of swimmers “surfing” the waves created by their neighboring swimmers.
Athletes interviewed by the researchers confirmed that swimming exactly parallel to or passing another person at their side is both tiring and difficult, which aligns with the study’s findings, says Baptiste Bolon, a member of the research team. Jean-Claude Chatard from Jean Monnet University in France, who was not involved in the experiment, considers the study complementary to past research that measured the physiological responses of human swimmers, such as oxygen uptake and heart rate, across different swimming configurations. While mannequins are not identical to swimmers as they are more passive, Chatard believes that some of the experiment’s precise findings, such as the optimal distance to leave while swimming behind another swimmer in a lane, could be valuable for athletes.
The researchers plan to further investigate the most efficient and least tiring route for one swimmer to overtake another by passing from the side. They also intend to explore configurations involving more than two swimmers, reflecting actual race scenarios.
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