Analysis of breathing in the crawl as a function of skill and stroke characteristics

The purpose of this study was to measure and compare the durations of exhalation (DE), inhalation (DI), and inhalatory apnea (DAI) expressed as percentage of stroke-cycle duration using two groups (more expert and less expert) of 6 front crawl swimmers each at near 100-m speed (high speed) and 800-m speed (low speed). Two breathing conditions were considered, breathing to the preferred side with and without a nose-clip. The relationships between stroking characteristics (swimming speed, stroke rate, and stroke length) and the three durations of breathing were examined as a function of skill and swimming speed. The data show that use of a nose-clip does not significantly change those measures. At high speed, the more expert group had a lower inhalation and a higher exhalation than the less expert group. The stroke rate correlated with speed .92 (p<.01) and was mainly associated with inhalation (r=-.78, p<.01). Inclusion of exhalation as a second variable improved significantly (p<.01) the accuracy of the regression up to .97. At low speed, the less expert had lower inhalatory apnea than the more expert. Stroke length correlated with speed .86 (p<.01) and was mainly associated with inhalatory apnea (r=.70, p<.05). At high speed, the more expert had a lower inhalation than at low speed, while durations of exhalation and inhalatory apnea did not vary significantly. On the contrary, the less expert had a lower exhalation and a higher inhalatory apnea, while duration of inhalation remained relatively unchanged. The present study shows that these durations and their relations to stroking characteristics could be considered significant indicators of skill in swimming.