Critical aerobic power during simulated 20 km bicycle racing

The main purpose of the study was to investigate the relationships between the Lactate Threshold (LT), maximal oxygen uptake (KO2max), performance time, and Critical Aerobic Power (CAP) during a simulated 20 km cycling time trial (20 kmTT). CAP was operationally defined as the average oxygen uptake sustained during the 20 kmTT. The subjects were 11 experienced male cyclists (mean±SD age: 29±7.2 yr; VO2max: 4.51±0.11 (L · min−1). Each subject completed two 20 kmTT using their own racing bicycle on a custom designed, computerized roller system. Elapsed time for the best trial averaged 34.58 ±3.29 min. Test‐retest reliability estimates for elapsed time, average heart rate and VO2 during the two trials were 0.92, 0.98 and 0.98, respectively. Oxygen uptake during the 20 kmTT averaged 115% of VO2 at LT and 86% of FO2max· A significant correlation was found between CAP and performance time (r= —0.81, p ≤ 0.01). Significant correlations were found between CAP and VO2 at LT (r = 0.62, p ≤ 0.05) and CAP and VO2max (r = 0.97, p ≤ 0.05). Using stepwise regression, VO2max was the strongest predictor of CAP with no further contribution from VO2 at LT. It was concluded that CAP is a strong determinant of cycling performance for 30–40 min duration. In this study, CAP was dependent more on VO2max than on the LT.