• J. Santos Silva
  • J. Vilas-Boas


INTRODUCTION-Swimming velocity is the product of the stroke rate (SR) times the stroke length (SL), which can be' described as the distance travelled by the swimmer during a single stroke cycle The urgency of performance analysis, the easy assessment of this variables, and their intrinsic importance, imposed a proliferation of research in this domain. Among available studies, some of them pointed out the difficulty to establish a profile to the SR variation along a specific swimming event (Craig et al., 1985: Keskinen and Komi, 1993). Nevertheless, those studies were based on a single competition. The purpose of this study was to evaluate the variations of the stroke rate, in the 100 m events, during a complete competitive season. METHODS-Five female elite swimmers (aged 16.6±2.9yrs, 60.2:t6.6Kg weigh and 173.0:t6.9cm high) were studied' during a complete short course season All 100 meters events were studied (freestyle, backstroke, breaststroke and butterfly). The video tape records of the events were observed and the mean SR for each lap was determined using Seiko S1 01 A watch with a frequency measuring function each 3 arm strokes. RESULTS-Main results of the are present d in Table 1. Despite none statistical significant difference were found between laps, SR values consistently decreased during the race for all events in the different styles. despite a slight increase in the final lap of the breaststroke event. This evidence is in accordance with Ungerechts and Thiesmann (1995) results. As SR values could be taken as an indicator of physiological background (Ungerechts and Thiesmann, 1995), the degree of the decrease of SR values during the race, can be used to analyse the preparation status of swimmers. CONC USION-SR values consistently decrease during 100 m events for all the competitive swimming techniques REFERENCES Craig, A.B.; Skehan, P,L; Pawelczyk, JA: Boomer, W.L (1985). Velocity, strake rate. and distance per stroke during elite swimming competition. Medicine and Seienee in Sports and bereise, 6 (17). 625-634 Kesklnen, K.L.: Komi, P.V. (1993). Stroking Characteristics of front rawl swimming during exercise. J. of Applied Biomechanics, 9, 219-226 Ung rechts, B. E.; Thiesmann. M. (1995) Changes of stroke rate during swimming races Abstracts of XVth Congress of the International Society of Biomechanics, Jyvaskyla