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Sex Differences

Males tend to swim faster than females. Women have higher percentage of body fat than men, whereas men have more muscle weight. This results in women floating better and showing a greater swimming economy, 30 % lower energy cost than men have been reported (McArdle, Katch and Katch 1996).


Swimming power and especially upper body strength have been demonstrated to be crucial to success in sprint swimming. 86% of one's performance in a 25-m front crawl sprint result from the swimmers' strength and the ability to develop power. For the competitive distance swimmer the strength component is less. At 100, 200, and 400m, the contribution of muscular strength drops to 74, 72 and 58%, respectively. During slow, low-intensity swimming most of the muscle force is generated by slow twitch fibers. As the muscle tension requirements increase, the fast twitch fibers are incorporated. In sprint events (50-200m) demanding maximal strength, the second group of fast twitch fibers sets in. The tendency is that swimmers have higher percentage of slow twitch muscle fibers in their shoulders and particularly musculus deltoideus. However, muscle fiber composition appears not to be a deciding factor in successful competition. Swimming is performed almost totally with concentric contractions (Costill, Maglischo and Richardson 1992).


The coach is an important person with his or her ability to observe and make subjective assessments of performance. But there is also a need to have objective measurements, being more valuable in giving some dimension to the result, e.g. time, distance, score (McLatchie 1993). The physiological tests are designed to follow the swimmer's physical capabilities, improvements achieved, and to assist in planning the training program (Costill, Maglischo and Richardson 1992). Total fitness consists of strength, speed, flexibility and endurance, and all of these aspects should be evaluated.

The following points should be considered before assessing fitness:

  • pre-test procedures
  • the purpose and intention of the test
  • the suitability of the test and the equipment used
  • the statistical criteria for the test
  • the use of the test results (McLatchie 1993).

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