Abstract des Autors

In this study we evaluated BLR in endurance athletes during a 40 km long lasting time trial. Main question in this study was whether BLR during this field test corresponded with two common used laboratory parameters to detect AT: the fixed 4 mmol/l lactate (AT4) and the lactate threshold defined as the point just before a curvilinear increase of lactate is observed. Plasma lactate levels were assessed in 19 elite triathletes (mean+/-sd; age 26.5+/-6.2 yr; HT 176.5+/-7.3 cm; WT 67.7+/-7.1 kg) during a 40 km long lasting time trial on a bicycle. Several weeks before the time trial a lactate heart rate curve was assessed in the laboratory using an incremental exercise test on a cycle ergometer. The most important observation in this study was that the mean lactate concentration during the time trial was 7.8+/-2.4 mmol/l. Four subjects maintained plasma lactate levels which exceeded 10 mmol/l or more for almost 1 hour. The high level of individual variability was conspicuous (range 3.8-14.6 mmol/l). These values exceeded all previous data from other investigations. A possible explanation may be that lactate is not a limiting factor but an important metabolizer during prolonged exercise. Verf.-Referat