Abstract des Autors

The aim of this study was to assess the sensitivity of the lactate minimum speed test to changes in endurance fitness resulting from a 6 week training intervention. Sixteen participants (mean+/-s : age 23+/-4 years; body mass 69.7+/-9.1 kg) completed 6 weeks of endurance training. Another eight participants (age 23+/-4 years; body mass 72.7+/-12.5 kg) acted as non-training controls. Before and after the training intervention, all participants completed: 1) a standard multi-stage treadmill test for the assessment of VO2max, running speed at the lactate threshold and running speed at a reference blood lactate concentration of 3 mmol/l; and 2) the lactate minimum speed test, which involved two supramaximal exercise bouts and an 8 min walking recovery period to increase blood lactate concentration before the completion of an incremental treadmill test. Additionally, a subgroup of eight participants from the training intervention completed a series of constant-speed runs for determination of running speed at the maximal lactate steady state. The test protocols were identical before and after the 6 week intervention. The control group showed no significant changes in VO2max, running speed at the lactate threshold, running speed at a blood lactate concentration of 3 mmol/l or the lactate minimum speed. In the training group, there was a significant increase in VO2max (from 47.9+/-8.4 to 52.2+/-2.7 ml/kg/min), running speed at the maximal lactate steady state (from 13.3+/-1.7 to 13.9+/-1.6 km/h), running speed at the lactate threshold (from 11.2+/-1.8 to 11.9+/-1.8 km/h) and running speed at a blood lactate concentration of 3 mmol/l (from 12.5+/-2.2 to 13.2+/-2.1 km/h) (all P<0.05). Despite these clear improvement in aerobic fitness, there was no significant difference in lactate minimum speed after the training intervention (from 11.0+/-0.7 to 10.9+/-1.7 km/h). The results demonstrate that the lactate minimum speed, when assessed using the same exercise protocol before and after 6 weeks of aerobic exercise training, is not sensitive to changes in endurance capacity. Verf.-Referat