Optimizing freestyle flip-turn technique

Abstract

The purpose of this study was to examine the effect of three variables on the push-off velocity of the freestyle flip-turn. These variables are: (l)The distance from the wall a swimmer's hips are at foot contact (tuck index); (2) The depth of the foot plant on the wall during push-off (foot plant index); and (3) The percentage of wall-contact time spent in an active push-off phase (%WCT active). The flip-turns of twenty-three University (Division I) swimmers performed at race pace were captured using underwater videography and analyzed for kinematic data. Simultaneous regression analysis was conducted using the push-off velocity as a dependent variable to determine the overall predictive characteristics of the variables. The mean push-off velocity was 2.47 ms-1. The minimum velocity was 1.3 ms-1 and the maximum push-off velocity was 3.29 ms-1. The mean tuck index of all turns was 0.57 +0.14, indicating that the hips were a mean distance from the wall that was approximately 57% of the length of the swimmer's legs . The study found a significant, negative correlation between push-off velocity and tuck index, indicating that the more tucked position (lower tuck index) predicted higher push- off velocity. By using a curvilinear model, a tuck index of.46 was suggested to produce the maximum push-off velocity. Neither foot plant index nor %WCT active was found to significantly predict push-off velocity.