Abstract des Autors

The purpose of this study was to identify the parameters that distinguish swimmers of different skill levels in a 100m front crawl swum at maximal speed. Seventy-five non-expert subjects were divided into 3 groups of 25 (more expert: ME, intermediate: I, less expert: LE) on the basis of their time performance on the 100m front crawl. The first aim was to measure and compare the swimming speed (S), stroke length (L), stroke rate (R), starting time (ST), turning time (TT) and breathing frequency (B) of these three groups. The second aim was to determinate which variables can be considered to contribute significantly to the 100m mean swimming speed (S 100) and B variability. A stepwise regression between S 100 and all other variables showed that S 100 was mainly related to L, R, and TT (r=0.99, p < 0.01). The regression equation showed that the increase in S 100 resulted from a large increase in L with a small increase in R and a decrease in TT. This result indicates that TT is a more significant determinant of performance than ST for a 100m swim. This seems to be due to a skill-related increase in the degree of specificity of the sensorimotor systems used for turning. An analysis of variance was used to compare the means obtained by the three groups on each of the dependent variables and the values of the different variables on the four consecutive 25m parts of the swim, as a function of skill level and lap. The reults showed that an increase in skill elevl was reflected by greater stability of S, L, R and TT and an increase in B over the 100m (p<0.05). B was lower (p<0.05) for MEs (28.41+/-5.66 breaths.min) and Is (30.50+/-5.80) than for LEs (38.82+/-6.59) and mainly asociated with L (r=-.55, p<.01). It was assumed that the rapid exhaustion of anaerobic energy production and the more superficial breathing by LEs would require an earlier increase in B avoid too strong an oxygen deficit at the end of the race. The mean number of arm cycles between two breaths was higher (p<0.05) for MEs (1.69+/-0.30) and Is (1.51+/-0.30) than for LEs (1.27+/-0.32) who may choose to take fewer breaths so as to maintain a state of equilibrium and therby increase propulsion. Verf.-Referat