AN EXPLOSIVE PUSH-OFF IN THE TURNING MOVEMENT IS VERY IMPORTANT FOR FEMALE SWIMMERS
Puel, F., Morlier, J., Cid, M., Chollet, D., & Hellard, P. (2010). Biomechanical factors influencing tumble turn performance of elite female swimmers. A paper presented at the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, June 16–19, 2010.
The freestyle tumble turn can be divided into the approach, rotation, wall contact, glide, underwater propulsion, and stroke resumption phases. This study analyzed the relationships between both kinematic and dynamic factors of the phases and the three meters in and out of the wall (turning performance). Elite female swimmers (N = 8) were monitored during a crawl stroke tumble turn at maximum speed. Five stationary video cameras were located underwater in a semi-elliptical arc centered on the calibrated turn place. An underwater 3D force platform was mounted on the turning wall. The important kinematic data were horizontal velocities of the head and the duration of each phase. The major dynamic data were the time between the beginning of the push-off and the maximum horizontal force peak. The tumble-turn performance criterion was the time taken to swim from three meters in to three meters out of the wall.
High correlation coefficients values were observed between the turn performance and maximum horizontal force (r = 0.84), the time to achieve the maximum horizontal force (r = 0.82), and glide duration (r = 0.79). Maximum horizontal force explained 80% of turning-performance, glide duration explained 12%, and velocity at the end of the glide accounted for 3%.
Implication. The best female swimmers were able to develop maximal horizontal force very quickly during the push-off phase (a high degree of explosiveness). The turning performance is characterized by very fast approach swimming, and very fast rotation in addition to an explosive push-off.
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