AUTHOR=Yang Woo-Hwi , Park So-Young , Kim Taenam , Jeon Hyung-Jin , Heine Oliver , Gehlert Sebastian 

TITLE=A modified formula using energy system contributions to calculate pure maximal rate of lactate accumulation during a maximal sprint cycling test

JOURNAL=Frontiers in Physiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2023.1147321

DOI=10.3389/fphys.2023.1147321

ISSN=1664-042X

ABSTRACT=<p><bold>Purpose:</bold> This study aimed at comparing previous calculating formulas of maximal lactate accumulation rate (<sup><italic>ν</italic></sup><sub>La.max</sub>) and a modified formula of pure <sup><italic>ν</italic></sup><sub>La.max</sub> (P<sup><italic>ν</italic></sup><sub>La.max</sub>) during a 15-s all-out sprint cycling test (ASCT) to analyze their relationships.</p><p><bold>Methods:</bold> Thirty male national-level track cyclists participated in this study (<italic>n</italic> = 30) and performed a 15-s ASCT. The anaerobic power output (W<sub>peak</sub> and W<sub>mean</sub>), oxygen uptake, and blood lactate concentrations (La<sup>−</sup>) were measured. These parameters were used for different calculations of <sup><italic>ν</italic></sup><sub>La.max</sub> and three energy contributions (phosphagen, <italic>W</italic><sub>PCr</sub>; glycolytic, <italic>W</italic><sub>Gly</sub>; and oxidative, <italic>W</italic><sub>Oxi</sub>). The P<sup><italic>ν</italic></sup><sub>La.max</sub> calculation considered delta La<sup>−</sup>, time until W<sub>peak</sub> (t<sub>PCr−peak</sub>), and the time contributed by the oxidative system (t<sub>Oxi</sub>). Other <sup><italic>ν</italic></sup><sub>La.max</sub> levels without t<sub>Oxi</sub> were calculated using decreasing time by 3.5% from W<sub>peak</sub> (t<sub>PCr −3.5%</sub>) and t<sub>PCr−peak</sub>.</p><p><bold>Results:</bold> The absolute and relative <italic>W</italic><sub>PCr</sub> were higher than <italic>W</italic><sub>Gly</sub> and <italic>W</italic><sub>Oxi</sub> (<italic>p</italic> &lt; 0.0001, respectively), and the absolute and relative <italic>W</italic><sub>Gly</sub> were significantly higher than <italic>W</italic><sub>Oxi</sub> (<italic>p</italic> &lt; 0.0001, respectively); <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr −3.5%</sub>) was significantly higher than P<sup><italic>ν</italic></sup><sub>La.max</sub> and <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr−peak</sub>), while <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr−peak</sub>) was lower than P<sup><italic>ν</italic></sup><sub>La.max</sub> (<italic>p</italic> &lt; 0.0001, respectively). P<sup><italic>ν</italic></sup><sub>La.max</sub> and <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr−peak</sub>) were highly correlated (<italic>r</italic> = 0.99; <italic>R</italic><sup><italic>2</italic></sup> = 0.98). This correlation was higher than the relationship between P<sup><italic>ν</italic></sup><sub>La.max</sub> and <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr −3.5%</sub>) (<italic>r</italic> = 0.87; <italic>R</italic><sup><italic>2</italic></sup> = 0.77). <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr−peak</sub>), P<sup><italic>ν</italic></sup><sub>La.max</sub>, and <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr −3.5%</sub>) were found to correlate with absolute W<sub>mean</sub> and <italic>W</italic><sub>Gly</sub>.</p><p><bold>Conclusion:</bold> P<sup><italic>ν</italic></sup><sub>La.max</sub> as a modified calculation of <sup><italic>ν</italic></sup><sub>La.max</sub> provides more detailed insights into the inter-individual differences in energy and glycolytic metabolism than <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr−peak</sub>) and <sup><italic>ν</italic></sup><sub>La.max</sub> (t<sub>PCr −3.5%</sub>). Because <italic>W</italic><sub>Oxi</sub> and <italic>W</italic><sub>PCr</sub> can differ remarkably between athletes, implementing their values in P<sup><italic>ν</italic></sup><sub>La.max</sub> can establish more optimized individual profiling for elite track cyclists.</p>