Peak power predicts performance power during an outdoor 16.1-km cycling time trial

To assess i) the reproducibility of peak power output recorded during a maximal aerobic power test (MAP), and ii) its validity to predict endurance performance during a field based 16.1-km time trial (16.1-km TT). Two studies were completed: for part I, nine subjects performed three MAP tests; for part II, 16 subjects completed a MAP test and 16.1-km TT. Power output was recorded using an SRM power meter and was calculated as peak power output (PPO) recorded during 60 s of MAP and mean power output for the 16.1-km TT (16.1-km TT(PO)). There was no difference between PPO recorded during the three MAP trials, mean coefficient of variation for individual cyclists was 1.32% (95%CI = 0.97-2.03), and test-retest reliability expressed as an intraclass correlation coefficient was 0.99 (95%CI = 0.96-1.00). A highly significant relationship was found between PPO and 16.1-km TT(PO) (r = 0.99, P < 0.001) but not for PPO and 16.1-km TT time (r = 0.46. P > 0.05). The results show that PPO affords a valid and reliable measure of endurance performance which can be used to predict average power during a 16.1-km TT but not performance time.