Allometric scaling of peak power output accurately predicts time trial performance and maximal oxygen consumption in trained cyclists.

OBJECTIVE: The purpose of this study was to determine if peak power output (PPO) adjusted for body mass(0.32) is able to accurately predict 40-km time trial (40-km TT) performance.

METHODS: 45 trained male cyclists completed after familiarisation, a PPO test including respiratory gas analysis, and a 40-km TT. PPO, maximal oxygen consumption (VO(2max)) and 40-km TT time were measured. Relationships between 40-km TT performance and (I) absolute PPO (W) and VO(2max) (l/min), (II) relative PPO (W/kg) and VO(2max) (ml/min/kg) and (III) PPO and VO(2max) adjusted for body mass (W/kg(0.32) and ml/min/kg(0.32), respectively) were studied.

RESULTS: The continuous ramp protocol resulted in a similar relationship between PPO and VO(2max) (r=0.96, p<0.0001) compared with a stepwise testing protocol but was associated with a lower standard error of the estimated when predicting VO(2max). PPO adjusted for body mass (W/kg(0.32)) had the strongest relationship with 40-km TT performance (s) (r=-0.96, p<0.0001). Although significant relationships were also found between absolute (W) and/or relative PPO (W/kg) and 40-km TT performance (s), these relationships were significantly weaker than the relationship between 40-km TT performance and PPO adjusted for body mass (W/kg(0.32)) (p<0.0001).

CONCLUSIONS: VO(2max) can be accurately predicted from PPO when using a continuous ramp protocol, possibly even more accurately than when using a stepwise testing protocol. 40-km TT performance (s) in trained cyclists can be predicted most accurately by PPO adjusted for body mass (W/kg(0.32)). As both VO(2max) and 40-km TT performance can be accurately predicted from a PPO test, this suggests that (well)-trained cyclists can possibly be monitored more frequently and with fewer tests.