A modified formula using energy system contributions to calculate pure maximal rate of lactate accumulation during a...

Purpose: This study aimed at comparing previous calculating formulas of maximal lactate accumulation rate ( _La.max) and a modified formula of pure _La.max (P _La.max) during a 15-s all-out sprint cycling test (ASCT) to analyze their relationships. Methods: Thirty male national-level track cyclists participated in this study (n = 30) and performed a 15-s ASCT. The anaerobic power output (W_peak and W_mean), oxygen uptake, and blood lactate concentrations (La^-) were measured. These parameters were used for different calculations of _La.max and three energy contributions (phosphagen, W _PCr; glycolytic, W _Gly; and oxidative, W _Oxi). The P _La.max calculation considered delta La^-, time until W_peak (t_PCr-peak), and the time contributed by the oxidative system (t_Oxi). Other _La.max levels without t_Oxi were calculated using decreasing time by 3.5% from W_peak (t_{PCr -3.5%}) and t_PCr-peak. Results: The absolute and relative W _PCr were higher than W _Gly and W _Oxi (p < 0.0001, respectively), and the absolute and relative W _Gly were significantly higher than W _Oxi (p < 0.0001, respectively); _La.max (t_{PCr -3.5%}) was significantly higher than P _La.max and _La.max (t_PCr-peak), while _La.max (t_PCr-peak) was lower than P _La.max (p < 0.0001, respectively). P _La.max and _La.max (t_PCr-peak) were highly correlated (r = 0.99; R = 0.98). This correlation was higher than the relationship between P _La.max and _La.max (t_{PCr -3.5%}) (r = 0.87; R = 0.77). _La.max (t_PCr-peak), P _La.max, and _La.max (t_{PCr -3.5%}) were found to correlate with absolute W_mean and W _Gly. Conclusion: P _La.max as a modified calculation of _La.max provides more detailed insights into the inter-individual differences in energy and glycolytic metabolism than _La.max (t_PCr-peak) and _La.max (t_{PCr -3.5%}). Because W _Oxi and W _PCr can differ remarkably between athletes, implementing their values in P _La.max can establish more optimized individual profiling for elite track cyclists.