Courtesy of WOWSA, Huntington Beach, California.
Daniel Marinho, Joao Ribeiro, Narenda Manthripragada, Leandro Machado, J. Paulo Vilas-Boas, Ricardo Fernandes, Tiago Barbosa, Abel Rouboa and Antonio Silva conducted a fascinating experiment and research that was announced at the 57th annual American College of Sports Medicine in Baltimore, Maryland.
The research team analyzed the effect of depth on the hydrodynamic drag forces during the starts and turns of pool swimmers.
The research compared the drag coefficient and hydrodynamic drag force at three different locations under the surface of the water: at 0.20 meters, 0.75 meters and 1.30 meters, using computational fluid dynamics when the swimmer was two seconds off the wall.
They concluded that the hydrodynamic drag values decreased with the increase in depth and that gliding at 0.75 meters or deeper under the water surface seemed to be the optimal gliding depth for minimizing drag and improving swimming speed off the wall. They found that the decrease of drag values with depth can be due to the reduction of the wave drag effect which is an important contribution to total drag near the water surface.
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