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Consistency of swimming performance within and between competitions


Medicine & Science in Sports & Exercise: May 2000 - Volume 32 - Issue 5 - pp 997-1001
APPLIED SCIENCES: Physical Fitness and Performance

STEWART, A. M., and W. G. HOPKINS. Consistency of swimming performance within and between competitions. Med. Sci. Sports Exerc., Vol. 32, No. 5, pp. 997–1001, 2000.

Purpose: The consistency of performance between events impacts how athletes should specialize in events, how competitions should be structured, and how changes in performance affect an athlete’s placing in an event. We have therefore determined the consistency of swimming performance in events within and between two national-level competitions.

Methods: We used mixed linear modeling to analyze official performance times of 149 male and 162 female swimmers at a junior national championship, and of 117 male and 104 female swimmers at an open national championship 20 d later. The events differed in stroke (backstroke, breaststroke, butterfly, freestyle, and individual medley) or distance (50–1500 m).

Results: Swimmers were most consistent in their performance for the same event between the two competitions (typical variation between competitions, 1.4%; 95% likely range of true value, 1.3–1.5%). They were less consistent between distances of a given stroke within each competition (1.7%; 1.5–1.9%) and least consistent between strokes for a given distance (2.7%; 2.3–3.1%). Variation in performance between the longest continuous freestyle distances (400, 800, and 1500 m) in the open competition was half that between widely spaced freestyle distances (50, 200, and 800 m). Faster swimmers were more consistent (1.1%; 0.9–1.4%) for the same event between competitions than slower swimmers (1.5%; 1.3–1.9%).

Conclusions: (a) Swimmers are stroke specialists rather than distance specialists; with the present set of events in competitions, they should concentrate training and competing on a particular stroke rather than a particular distance. (b) More swimmers would have a chance of winning a medal if events of a given stroke differed more widely in distance. (c) Factors that affect performance time by as little as 0.5% will affect the placing of a top junior swimmer.

In many sports athletes have the opportunity to compete in several events. In most cases, the events differ only in distance (e.g., running) or in technique (e.g., field athletics). Swimming is one of the few sports in which athletes compete in events differing both in distance and technique. Indeed, swimming competitions feature as many as 17 events drawn from five strokes (backstroke, breaststroke, butterfly, freestyle, and individual medley) and six distances (50, 100, 200, 400, 800, and 1500 m). Swimmers usually enter more than one event at a competition, but the consistency or reliability of their performance between events differing in distance or stroke is an issue researchers have not previously addressed. It has been our impression that swimmers tend to be consistently fast or slow in a given stroke over several distances, rather than consistently fast or slow over a given distance in several strokes. In the present study, we have addressed this issue by analyzing official competition results. Our findings could help swimmers make decisions about specializing in strokes or distances for training and competition. Our findings are also relevant to any consideration of the optimum distances in swimming competitions.

Talented swimmers usually enter several competitions in the course of a season, so it is also possible to estimate the reliability of performance in the same event between competitions. A recent analysis based on simulations of competitive events has shown that this reliability is the key factor in determining the extent to which a performance-enhancing strategy affects the chances of an athlete winning a medal (2). Briefly, an enhancement in performance has a substantial effect on medal prospects of a top athlete in an event only if the enhancement is at least 0.3, or more realistically 0.5, of the magnitude of the typical within-athlete variation in performance between events. Estimates of the variation in performance between events would therefore be useful to coaches and sport scientists who wish to enhance the performance of athletes. As yet, there are no published data on the reliability of competitive performance in any sport. In the present study, we have analyzed the results of two competitions to obtain estimates of this reliability for a group of talented young swimmers.

Scottish Institute of Sports Medicine and Sports Science, University of Strathclyde, Glasgow, SCOTLAND; and Department of Physiology, School of Medical Science, University of Otago, Dunedin, NEW ZEALAND

Submitted for publication June 1999.

Accepted for publication August 1999.

Address for correspondence: Will Hopkins, Department of Physiology, School of Medical Science, University of Otago, Box 913, Dunedin, New Zealand; E-mail:

©2000The American College of Sports Medicine