Fernandes, R. J., Ribeiro, J. Sousa, A., Sousa, M., Abraldes, A., Ferragut, C., Figueiredo, P., & Vilas-Boas, J. P. (2012). Kinematic comparison of different step lengths in a swimming incremental protocol. Presentation 1908 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This study determined and compared the stroke rate, stroke length, arm coordination, and propelling efficiency during an intermittent incremental protocol with different step lengths. Long-distance swimmers (N = 25) performed 7 x 200, 7 x 300, and 7 x 400 m with 0.05m/s increments, 30 seconds rest between steps, and 24 hours between protocols in front crawl until exhaustion. The velocity of each step was common to the three protocols. Two arm-stroke cycles of the last 50 m lap of each step were digitized. Stroke length was assessed using the right hip point and stroke rate was calculated as the ratio of velocity to stroke length. Propelling efficiency was calculated. Arm coordination was determined by the lag time between propulsive inter-arm phases.

Stroke rate increased and stroke length decreased throughout the protocols, with a tendency for the smallest stroke lengths to occur in the last steps of the 400 m protocol. Arm coordination values indicated a catch-up coordination mode, being similar in all step lengths, and increasing at higher velocities. Propelling efficiency decreased throughout the steps of each protocol, without significant differences between protocols.

Implication. Different step lengths of progressive swimming steps do not significantly affect the swimming technique; reinforcing the use of the 7 x 200 m step test in training.

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