Abstract des Autors

Introduction: To determine endurance capacity and to give specific training recommendations, blood lactate (LA) concentrations are frequently used in performance diagnostics. In blood, LA is stored in red blood cells (RBC) and in plasma. Higher LA uptake by RBC might lead to delayed muscle fatigue since RBC serve as a dilution space for LA and more LA can be taken up by plasma which is released from the working muscle. Therefore, the aim of this study was to investigate the distribution of lactate in plasma and RBC in aerobically well-trained athletes (AA) in comparison to an untrained control group (CG). Materials and Methods: 13 AA and 13 CG participated in this study and conducted a high intensive treadmill test consisting of 2x4 minutes of running at 95% of the maximal running velocity with an active break of 4 minutes. Venous blood was drawn before and after the test. LA was measured in whole blood, plasma and RBC. Further, the ratio (LARatio) was calculated using the following formula: LA of RBC / LA of plasma. Results: AA exhibit significantly higher values in VO2peak and maximum running velocity. After the running test, LA in whole blood, RBC and plasma is increased significantly in both groups. No interaction effect (group X time point) was observed in any parameter. Values of LARatio did not show any significant differences. Conclusion: This study showed that the LA distribution in RBC and plasma after a high intensity running test is very similar in well trained endurance athletes and in untrained control subjects. Hence, LA uptake by RBC cannot or only in part be seen as a contributor to aerobic athletic performance.