Hip velocity and arm coordination in front crawl swimming

The hip intracyclic velocity variability and the index of coordination in front crawl swimming were examined in relation to performance level. 22 swimmers were assigned to either an elite or a recreational swimming group and performed 4 swim trials at different paces relative to their individual maximum velocity. A velocity meter system was set to determine intracyclic velocity variability and video analysis allowed the determination of the index of coordination. Mean intracyclic velocity variability was lower in the elite swimmers than the recreational swimmers (14.39 ± 1.97 vs. 17.80 ± 4.23%, p<0.05), and remained stable with swim pace (i. e., the relative velocity) for the elite group, whereas it increased for the recreational group (p<0.05). The elite swimmers were characterized by a lower mean index of coordination than the recreational swimmers (-9.6 ± 7.1 vs. -6.9 ± 5.0%, p<0.05), but it increased with swim velocity in the elite group and showed only a tendency in the recreational group (p=0.07). These findings suggest that low intracyclic velocity variability and its stability over a range of swimming paces, which result from optimized inter-arm coordination, are characteristic of skilled performance. Thus, the examination of intracyclic velocity variability and index of coordination variability with different swim paces could provide new insight into skilled performance in swimming.