Methods For Estimating Anaerobic Glycolytic Capacity (vLa Max ) In Trained Cyclists

Abstract

PURPOSE: The maximum rate of lactate production (vLaMax) can be used to estimate the maximum anaerobic energy contribution, which can be used to optimize endurance training. The aim of this study was to examine the reliability of a 20-sec vLaMax estimate using either a variable or standardized alactic time interval (talac). METHODS: 16 trained male cyclists and triathletes (35.3 + 8.9 yo, 1.80 + 0.05 m, and 73.3 + 11.2 kg, average 30-sec Wingate power of 9.0 +1.6 W.kg-1) were recruited. Subjects completed two familiarization trials on their own before completing two 20-sec maximal sprints on their own bikes which were attached to a Wahoo Kickr trainer. Each session began with a 10-min warm-up at 100 W before each sprint and were then followed by 12-min passive rest. A lactate (HLa) sample was taken from the finger at the end of the sprint and then every 2-min after that until HLa dropped > 1 mM. vLaMax was then calculated using (HLa post - pre)/(20-sec - alactic time), where talac was either time 0-sec to time where power drops 3.5%, or was set at 5-sec. RESULTS: Individual sprint sessions data were analyzed and no significant differences (p>0.05) nor were noted between session 1 and 2 data; all data were pooled and then vLaMax calculated using methods described above. Mean 20-sec sprint power was 9.8 + 1.0 W.kg-1 (~109% of Wingate) and a total work of 14.5 + 2.7. The talac was calculated to be 4.0 + 2.3-sec. There was no significant difference (p>0.05) between the calculated vLaMax 0.51 + 0.18 mM.L-1.sec-1 and vLaMax using the a standard 5-sec value, 0.54 + 0.15 mM.L-1.sec-1. Neither vLaMax value appears to be associated (r2 < 0.10, p>0.05) with absolute sprint performance. CONCLUSIONS: These results indicate that using a standard talac of 5-sec produced similar results as calculating it using a 3.5% drop in power. While vLaMax may ultimately influence HLa testing curves (i.e., lactate threshold) and endurance performance, it does not appear to be associated with actual sprint power output.