Comparison of maximal lactate steady state with anaerobic threshold determined by various methods based on graded exercise test with 3-minute stages in elite cyclists

Abstract

Abstract Background The maximal lactate steady state (MLSS) is defined as the highest workload that can be maintained for a longer period of time without continued blood lactate (LA) accumulation. MLSS is one of the physiological indicators of aerobic performance. However, determination of MLSS requires the performance of a series of constant-intensity tests during multiple laboratory visits. Therefore, attempts are made to determine MLSS indirectly by means of anaerobic threshold (AT) evaluated during a single graded exercise test (GXT) until volitional exhaustion. The aim of our study was to verify whether AT determined by maximal deviation (D max ), modified maximal deviation (ModD max ), baseline LA concentration + 1 mmol/l (+ 1 mmol/l), individual anaerobic threshold (IAT), onset of blood lactate accumulation (OBLA 4mmol/l ) and V-slope methods based on GXT with 3-min stages provide valid estimates of MLSS in elite cyclists. Methods Twelve elite male cyclists (71.3 ± 3.6 ml/kg/min) completed GXT (the increase by 40 W every 3 min) to establish the AT (by D max , ModD max , + 1 mmol/l, IAT, OBLA 4mmol/l and V-slope methods). Next, a series of 30-min constant-load tests to determine MLSS was performed. Agreement between the MLSS and workload (WR) at AT was evaluated using the Bland–Altman method. Results The analysis revealed a very high (r s > 0.90, p < 0.001) correlation between WR MLSS and WR Dmax and WR IAT . The other AT methods were highly (r s > 0.70) correlated with MLSS except for OBLA 4mmol/l (r s = 0.67). The Bland-Altman analysis revealed the highest agreement with MLSS for the D max , IAT and + 1 mmol/l methods. Mean difference between WR MLSS and WR Dmax , WR IAT and WR +1mmol/l was 1.7 ± 3.9 W, 4.3 ± 7.9 W and 6.7 ± 17.2 W, respectively. Furthermore, the WR Dmax and WR IAT had the lowest limits of agreement with the WR MLSS. The ModD max and OBLA 4mmol/l methods overestimated MLSS by 31.7 ± 18.5 W and 43.3 ± 17.8 W, respectively. The V-slope method underestimated MLSS by 36.2 ± 10.9 W. Conclusions The AT determined by D max and IAT methods based on the cycling GXT with 3-min stages provides a high agreement with the MLSS in elite cyclists. Despite the high correlation with MLSS and low mean difference, the AT determined by + 1 mmol/l method may highly overestimate or underestimate MLSS in individual subjects. The individual MLSS cannot be properly estimated by V-slope, ModD max and OBLA 4mmol/l methods.

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