FATIGUE IN A 100-m SWIM INCREASES PROGRESSIVELY THROUGHOUT THE TASK

Stirn, I., Jarm, T., Kapus, V, & Strojnik, V. (2010). Fatigue analysis of 100 meters all-out front crawl using surface EMG. A paper presented at the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, June 1619, 2010.

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This study estimated the fatigue of selected propulsive muscles by analyzing EMG signals for amplitude and frequency during a short-course 100 m all-out front crawl swim in male competitive swimmers (N = 11). EMG signals from the pectoralis major, latissimus dorsi, and triceps brachii muscles were recorded. Amplitude and mean power frequency were calculated. Lactate concentration was measured and stroke length, stroke rate, and swimming velocity were extracted from the video recordings.

The highest blood lactate values were measured five minutes after the swim. Stroke length and stroke rate decreased from the first to the last lap. Swimming velocity decreased with each successive lap, with the last lap ~15% slower than the first. The EMG amplitude increased throughout the swim for the latissimus dorsi and the triceps brachii. The mean power frequency indicated by the EMG decreased significantly and similarly in all observed muscles by the end of the swim when compared to the beginning.

Implication. The work of major propulsive muscles in a short-course 100-m swim becomes less effective as the task progresses. That is despite the activation in two of the muscles (latissimus dorsi and the triceps brachii) increasing throughout the swim. "Trying-harder" as a sprint swim progresses does not translate into better swimming or any improvement in swimming velocity.

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