Abstract

Several studies have observed higher plasma lactate concentrations ([La]p) in sprinters compared to endurance trained or untrained subjects in response to sprint exercise. However the majority of these studies did not take into account the plasma volume variations (∆VP) induced by supramaximal exercise which are found to be larger in sprinters. Consequently, we studied [La]p evolution in response to the Wingate test in sprinters (S), endurance trained (ET) and untrained subjects (UT) with regard to the changes in plasma volume (PV). 6 S (21 ± 0.9 yrs), 6 ET (21.2 ± 0.7 yrs) and 6 UT (21.5 ± 0.6 yrs) male subjects participated in this study. The hematocrit and [La]p were measured from venous blood at rest, at the end of the Wingate test and after 5, 10, 20 and 30 min of recovery. The ∆VP was determined by taking into account the hematocrit variations. [La]p were corrected with regard to the changes in PV. The Wingate test was accompanied by a significant decrease in PV, the maximal values were -19.97 ± 3.05 % in S, -9.45 ± 3.05 % in ET and -9.05 ± 3.31 % in UT. This decrease was significantly higher in S than in ET and UT at the end of the test and after 5 min induced an overestimation of the maximal values of measured [La]p in the three groups: +18.7 % in S (16.6 ± 0.9 vs. 13.5 ± 0.6 mmol·L-1), +18.8 % in ET (12.2 ± 0.9 vs. 9.9 ± 1.8 mmol·L-1) and +6.5 % in UT (12.3 ± 1 vs. 11.5 ± 1 mmol·L-1). In conclusion, these results underline the importance of taking into account the ∆VP to compare and to interpret [La]p and their evolution in response to supramaximal exercise between subjects with different training status. Verf.-Referat