Arellano, R., Dominguez-Castells, R., & Perez-Infantes, E. (2010). Effect of stroke drills on intra-cycle hip velocity in front crawl. A paper presented at the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, June 16–19, 2010.

This study evaluated the differences in intra-cycle hip velocity between formal front crawl and four other front crawl swimming coordination drills. National and regional level swimmers (M = 5; F = 8) participated in the study. The various stroke drills were: a) No-breathing formal freestyle swimming (the reference technique); b) crawl catch-up stroke, kicking some seconds after each stroke; c) one-arm front crawl with the resting arm extended in front, breathing on the arm-moving side; d) one-arm front crawl with the resting arm close to the body, breathing on the no-moving side; e) controlled two-arm freestyle, kicking some seconds after each stroke, with one arm resting close to the body and the second one resting extended in front.

The velocities of all drills were significantly slower than the reference technique. The percent of the drill/stroke underwater phases at which peak hip velocity of the drills and the reference technique occurred were not significantly different. As would be expected, the absolute velocities of the hips in the drills were significantly slower than the reference technique.

Implication. When compared to free crawl stroke swimming, hip velocities in drills are slower but occur at similar relative times throughout the underwater phases of the actions.

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