POOL LENGTH ALTERS SWIMMING SKILLS AND PHYSIOLOGICAL FACTORS
Keskinen, K. L., Keskinen, O. P., & Mero, A. (1996). Effects of pool length on biomechanical performance in front crawl swimming. In J. P. Troup, A. P. Hollander, D. Strasse, S. W. Trappe, J. M. Cappaert, & T. A. Trappe (Eds.), Biomechanics and Medicine in Swimming VII (pp. 216-220). London: E & FN Spon.
Stroke rate, stroke length, and average swimming velocity, as well as several blood indices, were evaluated in five incremental (10 sec) 200 m swims in both 25 m and 50 m pools. Ss were male swimmers (N = 3), triathletes (N = 6), and fin-swimmers (N = 2).
Sub-maximum swimming speeds were similar in both pools but at maximum were 4.8% faster in the 25 m pool. Blood lactates were higher at the end of all 50 m swims. Heart rates were similar only at maximum speeds. Stroke rates were similar in both conditions. Stroke length was shorter in all conditions in 50 m swims, the diminution in length increasing as swimming speed increased. Stroke control was better maintained in 25 m pools. Stroke length shortened in both pools at anaerobic threshold.
Elite athletes demonstrated high levels of turning skills and used this skill to a greater advantage in short-course swimming than lesser-skilled swimmers.
The extra turns in short-course swimming have a direct effect on swimming stroke and metabolic economy. Long course swimming requires higher metabolic activity while stroke length is decreased. The rests for cyclic arm and shoulder activity afforded by the extra 25 m pool turns allows some recovery in energy capacity.
The faster an athlete swims in a 50 m pool the shorter will be stroke length relative to 25 m similar-velocity swims and the greater will be the metabolic cost.
Implication. For swimmers who train in 25 m pools, some 50 m pool training should also be provided. The dissimilar swimming patterns and metabolic rates require these exposures. Training in only one length pool will be a disadvantage for swimmers when they compete in the other length pool. Physiological tests conducted in one pool cannot be inferred as being valid for the other length pool.
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