Evaluating the maximal rate of lactate accumulation and estimated maximal lactate steady state in cycling.

This study examined the reliability of the maximal rate of blood lactate (BLa) accumulation (VLa) and the, thereof, derived calculated power output at maximal La steady state (cP-MLSS). Additionally, cP-MLSS was compared with the second La thresholds determined by experts (LT), being an accurate and often used threshold concept. 13 physically active male participants (length: 182 ± 4 cm; body mass: 76.3 ± 5.8 kg) completed a step incremental protocol to determine (60.5 ± 5.8 mL·min·kg) and LT. Additionally, a 15-s isokinetic sprint test was conducted on four separate occasions to determine VLa. cP-MLSS was calculated using a mathematical model based on VLa, and body mass. Intraclass correlation coefficients (ICC) and coefficients of variation (CV%) were used to assess reliability. A paired sample T test was used to compare cP-MLSS (mean value of the 4 test days) and LT. We found good reliability for VLa (ICC = 0.80) and excellent reliability for cP-MLSS (ICC = 0.99). Moreover, LT (277 ± 41 W) and cP-MLSS (282 ± 43 W) were not significantly different. However, comparison revealed relatively wide limits of agreement (-39 to 29 W). This study concludes that VLa and cP-MLSS are reliable measures but need further research and refinement to be used as valid parameters in training and performance contexts.