How do elite artistic swimmers generate fluid forces by hand during sculling motions?

The purpose of this study was to clarify how elite artistic (synchronised) swimmers generate fluid forces with their hands during two kinds of sculling motions: flat sculling in the back-layout position and support sculling in the vertical position. We used the pressure-distribution measuring method to estimate unsteady fluid forces acting on the hand during sculling motions performed by seven elite artistic swimmers. In addition, we simultaneously analysed sculling motions using three dimensional-direct linear transformation methods. We found that sculling motions continuously generated fluid forces that are large during the stroke phase and small during the transition phase. Lift force was efficiently generated, and a large upward propulsive force was obtained during the stroke phase in both flat and support sculling. During the outside transition from out- to in-sculling, the net vertical load (= gravitational force-buoyant force) was supported by the drag force. In both flat and support sculling, artistic swimmers generated an even fluid force in the upward direction during the in-sculling and out-sculling phases to maintain a stable position.