Espada, M. A., & Alves, F. B. (2010). Critical velocity and the velocity at maximal lactate steady state in swimming. A paper presented at the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, June 16–19, 2010.

This study compared critical velocity to the velocity associated with the maximal lactate steady state in male national and international competitive swimmers (N = 18). Ss performed a maximal 400-m front crawl swim in order to estimate maximal aerobic velocity (V400). Critical velocity was calculated from the slope of the regression analysis between the averaged velocity of the 400-m trial and a 200-m front crawl maximal trial. All Ss completed, in random order and on different days, 30-minute swims at constant intensity (85, 90, and 95% of V400) for the determination of the velocity, stroke parameters, and rating of perceived exertion associated with the maximal lactate steady state.

Only one S achieved MLSS at 85% of V400. Extreme values of 2.6 and 7.8 mmol/L were found associated with MLSS velocity. Critical velocity was significantly faster than MLSS and both expressed velocities were significantly different to V400. MLSS velocity and critical velocity were highly correlated (r = 0.94). Both were associated with V400 (r = 0.97, and r = 0.95, respectively). Stroke cycle parameters were unrelated to performance, MLSSv or CV.

Implication. Critical velocity in swimmers does not demarcate the transition from heavy to severe exercise and does not provide a direct non-invasive measure of MLSS velocity.

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