Relationship between trunk acceleration and arm stroke cycle coordination in competitive front crawl swimming

Abstract

In this study, the cyclic motion of front crawl was analyzed to determine the relationship between peak trunk acceleration and the arm stroke cycle. The data acquired in this study to quantify the timing of peak trunk acceleration, was recorded using triaxial accelerometers attached to the participants’ left and right wrist and one mounted on the swimmers’ lower back. Fifteen competitive national level front crawl swimmers were selected as participants (2 female, 13 male) to swim two trials of front crawl. For trial 1, the participants were instructed to swim at a preselected speed of their best time from competition, plus 50%. For trial 2, the swimmers were instructed to swim at their individual maximum velocity. The swimmers had 2 minutes of recovery between trials. Acceleration data were collected to determine the duration from the point where the hand enters the water, to the point of peak trunk acceleration (HaTD). To determine the peak trunk acceleration as a percentage of the stroke cycle (HaT%), the point of hand entry preceding the peak trunk acceleration was also determined. The results showed that trunk acceleration occurs earlier in the stroke cycle, meaning a smaller HaTD when swimming fast compared to when swimming slow (p < 0.05). The results also showed that the trunk acceleration occurs at the same percentage of the stroke cycle, meaning that HaT% was the same when swimming fast compared to when swimming slow (p > 0.05). Finally it was shown that varying degrees of bilateral asymmetry in HaTD and HaT% occur when swimming at both maximum and slow velocity.