200 m IS AN ADEQUATE STEP DURATION FOR ASSESSING PHYSIOLOGICAL PARAMETERS
De Jesus, K., Baldari, C., de Jesus, K., Guidetti, L., Ribeiro, J., Vilas-Boas, J. P., & Fernandes, R. J. (2013). Are incremental 200m swimming step lengths proper for assessing relevant ventilatory parameters? Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 528.
"The intermittent incremental protocol of 2-3-minute step durations (i.e., 200m) conducted in ecological swimming conditions has been an important method for assessing relevant physiological parameters. However, some researchers suggest steps of, at least four minutes duration to accurately determine the ventilatory response during the N x 200m protocol."
This study determined if 200m steps gave similar information regarding ventilation parameters when compared to longer step lengths (e.g., 300 and 400m). National level swimmers (N = 6) performed 7 x 200, 7 x 300, and 7 x 400m front crawl protocol variants until exhaustion (with 48 hour intervals between each test). The speed of each step was common to the three trials. The increments were 0.05m/s with 30s intervals. VO2 was averaged every 10 seconds using a portable gas analyzer connected to a respiratory snorkel. Relevant ventilation parameters were assessed: maximal oxygen uptake, maximal carbon dioxide production, maximal ventilation, and maximal tidal volume.
Median and interquartile ranges for maximal oxygen uptake, maximal carbon dioxide production, maximal ventilation, and maximal ventilation values were similar for the three step-duration variations.
Implication. Short step durations (i.e., 200 m) yield similar results to longer durations when determining physiological parameters in swimming. The savings in time and ease of implementation warrant 200 m being retained as the normal step duration.
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