Fernandes, R. J., Ribeiro, J., Sousa, A., Monteiro, J., Guidetti, L., Baldari, C., Vilas-Boas, P. J. (2013). Oxygen uptake kinetics at extreme swimming intensity. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 2479.

This study characterized the VO2 kinetics of the 50 m freestyle swimming event. Trained swimmers (N = 6) performed 50 m maximal front crawl. VO2 was measured by a K4b2 portable gas analyzer connected to an AquaTrainer snorkel. VO2 data was fitted using the following mono-exponential model: VO2=VO2Basal*exp(time/time constant).

Task duration was 31.27±3.96 seconds. An instantaneous and sudden increase in VO2 occurred from the beginning of the effort (see following Figure 1), with 47.37±9.10 ml/kg/min for VO2peak and 23.53±6.30 seconds of time constant.

Implication. Despite the short duration of the 50 m front crawl event, swimmers are able to attain high values of VO2peak when inhalation is made possible. The high time constant value reflects the extreme intensity in which the effort occurred. VO2 stabilization did not occur, as reported for moderate and heavy exercise.

[Editor's note: Breathing during 50 m crawl stroke and butterfly stroke events generally does not occur. Swimmers rely on stored oxygen resources to energize a competitive effort. Consequently, the relevance of this study to actual competitive performances is minimal. Suffice it to say, 50-m crawl stroke races require as much stored oxygen as can be developed through training. Such training needs to be particularly high in intensity and as close to the race stroke mechanics as possible. It is likely that Ultra-short Race-pace Training for 100-m events will have some carry-over effects for 50-m events. The common observation that training for 100-m events is also accompanied by performance improvements in 50-m events supports that conjecture. Hypoxic training is likely to promote only a small improvement in the volume of stored oxygen and should not be considered a major training activity for physiological improvements. An emphasis on the surface-swimming technique and skills associated with a 50-m race are probably all the hypoxic work that needs to be done because they should be performed without breathing. Individuals with high capacities for stored oxygen will have an advantage over lesser-endowed individuals in 50-m races.

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