A Two-test Protocol for the Precise Determination of the Maximal Lactate Steady State.

The purpose of this study was to determine the efficacy of a two-test method for precisely identifying the Maximal Lactate Steady State (MLSS). Eight male competitive cyclists performed two bouts on a cycle ergometer. Following a maximal oxygen consumption (V̇O) test (66.91 ± 5.29 mL·kg·min) we identified the lactate deflection point using the visual deflection (T), Log-Log (T), D (T), RER = 1.00 (T), ventilatory threshold (T), and the 1.0 mmol·L increase above baseline (T) methods. The second incremental test (SIT) consisted of 6-7 stages (5 min each) starting 20-30 W below to 20-30 W above the predetermined deflection point, in 10 W increments. Comparison of the two tests yielded different threshold estimates (range 11-46W) for all methods ( = 0.001-0.019) except the T ( = 0.194) and T ( = 0.100). The SIT resulted in significantly ( = 0.007) more narrow range of thresholds (27.5 ± 11.01W) compared to the V̇O test (70 ± 42.51W). The T from the SIT was identified as the MLSS and was verified using three 45-minute steady-state exercise bouts at 95%, 100%, and 105% of MLSS intensity (average increment 12.8 W). Blood lactate and V̇O were recorded every 5 minutes and differed between the three intensities at every time point ( < 0.001). V̇O increased from the 5 to the 45 minute by 7.02 mL·kg·min (100% MLSS), 3.63 mL·kg·min (95% MLSS) and 7.5 mL·kg·min (105% MLSS, to the 30 minute). These results indicate that the MLSS was identified correctly by the SIT, the single incremental test overestimated the MLSS intensity, and the T provides a very accurate determination of the lactate breakpoint. The use of a second submaximal test is required for a precise identification of MLSS.