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 (VO2max) and 40-km TT time were measured. Relationships between 40-km TT performance and (I) absolute PPO (W) and VO2max (l/min), (II) relative PPO (W/kg) and VO2max (ml/min/kg) and (III) PPO and VO2max 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 VO2max (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 VO2max. 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 VO2max 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 VO2max 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.