Author(s): MEIXNER, B., SPERLICH, B., Institution: JULIUS-MAXIMILIAN-UNIVERSITÄT WÜRZBURG , Country: GERMANY, Abstract-ID: 434

INTRODUCTION:
Recently, the testing procedure for the maximal rate of capillary blood lactate accumulation following an all-out sprint test of 10 - 30 s has gained popularity. The metabolic implications of this parameter are based on simulations of human muscle energy metabolism described by the mathematical equations of Mader. While there is still a scarcity in the literature on this matter, the reliability of the testing procedure has been well studied.
Most of the studies describing good to excellent reliability in many modalities of the procedure include 2 or 3 trials. In studies involving 2 trials, reliability of subsequent trials is unknown as only one exists. Meanhile, studies involving 3 trials have analyzed all three trials together. However, it is unknown if familiarization changes the results (i.e., what changes are caused by learning effects) and therefore the possible metabolic implications.
Therefore, the aim of this study was to determine differences in relevant variables (peak and mean power output, capillary lactate accumulation) between familiarization and subsequent trials.
METHODS:
50 cyclists performed a 15-s all-out sprint test in isokinetic mode at 130RPM on a Cyclus2 ergometer on three separate (T1, T2, T3) occasions. Capillary blood was sampled twice before and every minute (for 8 minutes) after the sprint to determine the difference between resting and peak post-exercise lactate values as maximal lactate accumulation.
Glycolytic contribution was calculated as the product of lactate accumulation, fat-free mass and the mechanical energy equivalent of lactate of 12J/kg FFM (Meixner et al. 2024). The fraction of glycolytic contribution to total work was also calculated. The One-way ANOVA was performed to determine differences in trials in peak and mean power output, capillary lactate accumulation, glycolytic contribution (Wgly) and percent of glycolytic contribution (%Wgly).
RESULTS:
Peak and mean power output was significantly lower in T1 compared to T2 and T3. Capillary blood lactate accumulation was significantly higher in T1 compared to T2 and T3. Accordingly, Wgly and %Wgly also significantly decreased in T2 and T3. No differences were found between T2 and T3.
CONCLUSION:
Several studies have shown that increased lactate accumulation and power output are intricately linked. Our results display a paradoxical behavior between T1 and subsequent trials: while lactate accumulation decreases, power output increases.
This is noteworthy as two relevant output components change in opposite directions and potentially obfuscate the relationship between power output and lactate accumulation. These findings highlight familiarization as a crucial element in this diagnostic procedure and we urge practitioners to include a familiarization trial in their practice.

Meixner B et al (2024) Relationship of peak capillary blood lactate accumulation and body composition in determining the mechanical energy equivalent of lactate during sprint cycling. Eur J Appl Physiol