We investigated the effect of time‐of‐day on both maximal sprint power and repeated‐sprint ability (RSA). Nine volunteers (22±4 yrs) performed a RSA test both in the morning (07:00 to 09:00 h) and evening (17:00 to 19:00 h) on different days in a random order. The RSA cycle test consisted of five, 6 sec maximal sprints interspersed by 24 sec of passive recovery. Both blood lactate concentration and heart rate were higher in the evening than morning RSA (lactate values post exercise: 13±3 versus 11±3 mmol/L -1, p , 0.05). The peak power developed during the
first sprint was higher in the evening than morning (958±112 vs. 915±133 W,
p , 0.05), but this difference was not apparent in subsequent sprints, leading to a
higher power decrement across the 5 x 6 sec test in the evening (11±2 vs. 7±3%,
p , 0.05). Both the total work during the RSA cycle test and the power developed
during bouts 2 to 5 failed to be influenced by time-of-day. This suggests that the
beneficial effect of time-of-day may be limited to a single expression of muscular
power and fails to advantage performance during repeated sprints.