Aerobic and anaerobic power characteristics of off-road cyclists

Purpose: The purpose of this study was to describe the relationship between anaerobic power at different pedaling frequencies (including the optimal cadence) and aerobic power in off-road cyclists (CYC N = 25) and sports students, who did not perform specific cycle exercise more than two times per week (CON; N = 60). Methods: To describe the aerobic power, we measured the maximal power output (W-max) and the power output at the fixed lactate threshold at 4 mmol.L-1 (W-L4) obtained during a maximal aerobic power cycling test. To describe anaerobic power output, we measured the average power output (IsoW(mean)) over a range from 50 to 140 rpm by using a 10-s sprint on an isokinetic cycle ergometer. Results: For the 10-s anaerobic test, CON and CYC showed a peak power output (IsoW(peak)) Of 13.3 +/- 1.4 and 14.9 +/- 1.1 W.kg(-1), respectively. IsoW(peak) corresponded to an optimal cadence of 100 +/- 9.3 rpm for CON and 100 +/- 8.7 rpm for CYC. There was a significant difference (P < 0.001) in the W-max:IsoW(peak) (W-aerobic:W-anaerobic) ratio between CON (32 +/- 4.5%) and CYC (38 +/- 3.9%). Significant differences among group means were identified using an ANOVA test and a post hoc analysis. The off-road cyclists showed a significantly higher IsoW(mean) at all pedaling frequencies and at the optimal cadence (P < 0.01), There was a modest relationship between W-max and IsoW(peak) in both groups (CON r = 0.53; CYC r = 0.64: P < 0.01). Conclusion: Anaerobic power values are important components associated with cycle performance in both noncyclists and off-road cyclists. However, the results of the present study demonstrated the usefulness of the power index in the physiological evaluation of off-road cyclists, as it gives information on the proportion of aerobic to anaerobic energy contribution.