Abstract
This study was designed to assess the effect of sport practice and warm-up duration on the morning-evening differences in muscle power and fatigue during performance of anaerobic exercise and perceptual responses to it. Twenty-two male physical education students - twelve trained (TG) (21.51 +/- 1.25years, 182.17 +/- 4.37cm and 82.88 +/- 11.23kg) and ten untrained (NTG) (23.89 +/- 3.17years, 176.8 +/- 2.2cm and 82.24 +/- 8.43kg) - participated in a crossover randomized study. They were asked to perform a 30-s Wingate test during six experimental sessions (three at 08:00 and three at 18:00h) after different active warm-up (AWU) durations (5min, 15min, or 20min). The AWU consisted of pedaling at a constant pace of 60rpm against 50% of maximal aerobic power. Rate of perceived exertion (RPE) was recorded after the AWU and again immediately after the Wingate test. Heart rate and temperature (T) were recorded during each session at rest, after AWU and immediately at the end of the Wingate test. During the Wingate test, peak power (PP), mean power (MP), and the fatigue index were recorded. While the RPE estimations were higher in NTG, no time-of-day effect was recorded in either experimental group (morning or evening). T, PP, and MP were higher in the afternoon than in the morning (ppT). Similarly, PP and MP during the Wingate test were significantly higher in the TG than in the NTG (p<0.001). The morning-evening difference of PP and MP was affected by AWU duration; AWU(15) was best in the morning for improving lower limb power for both the TG and NTG, whereas reducing this period to 5min in the evening was appropriate for TG only.