Lactate accumulation rate is associated with lactate turnpoints in cyclists and triathletes: a comparison of vLapeak and vLamaxblood.

PURPOSE: This study examined whether peak lactate accumulation rate (vLapeak) was associated with body-mass-normalised power at the first and second lactate turnpoints (LT1rel and LT2rel) beyond relative maximal oxygen uptake (relative V̇O2max) and gross efficiency in cyclists and triathletes. Parallel models using maximal blood lactate accumulation rate (vLamaxblood) assessed whether the findings depended on the calculation approach. METHODS: 182 cyclists and triathletes (107 men, 75 women) completed a 15-s sprint test, an incremental lactate profile, and a ramp test to exhaustion. Hierarchical linear regression models included relative V̇O2max and gross efficiency before adding either vLapeak or vLamaxblood. Sex and sex × predictor interactions were examined exploratorily. RESULTS: Models including relative V̇O2max, gross efficiency, and vLapeak explained 75.3% of the variance in LT1rel and 80.4% in LT2rel. Adding vLapeak increased explained variance by 4.9 and 5.0% points, respectively (both p < 0.001). Higher vLapeak was associated with lower LT1rel (B = - 0.803, 95% confidence interval - 1.070 to - 0.536) and LT2rel (B = - 0.900, 95% confidence interval - 1.165 to - 0.635), whereas relative V̇O2max and gross efficiency were positively associated with both outcomes. The vLamaxblood models showed the same direction and significance with similar fit. Sex and sex × predictor interactions did not improve the models. CONCLUSION: Body-mass-normalised lactate turnpoint power reflects variation in aerobic power and efficiency as well as in the sprint-induced lactate accumulation response. Comparable findings for vLapeak and vLamaxblood indicate that the associations were largely independent of whether the estimated alactic time interval was included in the calculation.