Races over 200 m for backstroke, breaststroke, and butterfly, and 400 in crawlstroke at the USA Long-course Championships were analyzed. Technique changes at various stages of the races were determined.

Crawlstroke. In 400 m races, hand forces decreased by 31% primarily as a result of a 20% decrease in angle of pitch, and a 10% decrease in hand velocity. These are significant declines. As a consequence, the time for each pull increased.

A drop in stroke rate during the last lap of a race probably indicates that technique changes and fatigue have interfered with performance. It then becomes a challenge for the coach to determine if the athlete was fully fit for the race, whether the individual's technique was correct, and/or if the mechanics of technique had been trained in a specific manner. [Non-specific training would not produce as much endurance for skill execution as would specific work].

Butterfly. In the men's 200 m, total and effective forces fell as the distance progressed. However, the angle of hand pitch improved at the same time increasing the efficiency of the pull.

[A possible explanation for this finding is that swimmers have been taught or practiced incorrect technique, that is, they have learned to override naturally effective movements. While in non-fatigued states, they are able to maintain the artificial mechanics. However, as fatigue increases, the natural tendency to optimize performance becomes increasingly more influential and better mechanics are adopted. This interpretation is not unfounded. In today's international swimming, butterfly is the worst performed stroke with times at the highest level being far slower than those which should be attained through the mechanical potential of the stroke. Times have changed little over the past decade. It should be vastly superior to backstroke but at Barcelona the times for 200 m races in butterfly and backstroke were quite close.]

The more successful butterfly swimmers had higher total and effective forces than less successful performers at all stages of the race. The better swimmers also displayed a greater improvement in effectiveness of pull as the race progressed than did lesser performers. This suggests that technique and specific training are important features of butterfly development.

Backstroke. The race winner in the women's backstroke displayed a significant improvement in both total and effective force as the race progressed. This was accompanied by an increase in hand velocity and a decrease in angle of hand pitch. These features had been trained by a high-intensity, stroke-specific program. The rest of the field did not display these features.

Breaststroke.In the men's 200 m race, the analysis was restricted to arm actions, although a significant amount of propulsion is derived from the legs.

The winner was Mike Barrowman. His pull was found to be nearly 20% more effective than any other performer. However, all swimmers showed similar performance trends. Forces decreased as the race progressed primarily as a result of a decrease in hand velocity, although the angle of pitch remained the same.

Implication. Hand velocity, distance per stroke, and angle of pitch are critical for the maintenance of technique. These features should be a major emphasis of training. The maintenance of these aspects during fatigue should result in better competitive resilience. It is not satisfactory to train swimmers in fatigue zones without stressing the maintenance of propelling efficiency. If that performance feature is allowed (trained) to become inefficient at practice, then that inefficiency will be displayed in a race. Thus, when swimmers are in training fatigue, rather than stressing working harder, the coach should stress working better (i.e., performing good stroke mechanics).

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