Abstract des Autors

The aim of this study was to determine whether the critical swimming velocity (Vcrit), employed in competitive swimming, corresponds to the exercise intensity at maximal lactate steady state. Vcrit is defined as the swimming velocity which could theoretically be maintained forever without exhaustion and expressed as the slope of a regression line between swimming distances and corresponding times. 8 swimmers were instructed to swim 2 distances (200 and 400 m) at maximal effort and the time taken to swim each distance was measured. In the present study, Vcrit is calculated as the slope of the line connecting the 2 times required to swim 200 m and 400 m. Vcrit determined by this new simple method was correlated significantly with swimming velocity at 4 mmol/l of blood lactate concentration and mean velocity in the 400 m freestyle. In the maximal lactate steady-state test, subjects were instructed to swim 1600 m (4x400 m) freestyle at 3 constant velocities (98, 100 and 102 of Vcrit). At 100 Vcrit blood lactate concentration showed a steady-state level of approximately 3.2 mmol/l from the first to the third stage and at 98 of Vcrit lactate concentration had a tendency to decrease significantly at the 4th stage. However, at 102 of Vcrit, blood lactate concentration increased progressively and those of the third and 4th stages were significantly higher than at 100 of Vcrit. The data suggest that Vcrit, calculated by swimming two timed, maximal effort tests, may correspond to exercise intensity at max. lactate steady state.