Abstract
The purpose of this study was to investigate the effect of time of day and different modalities of recovery (active vs. passive recovery) after intermittent exercise in young soccer players. In randomized order, 16 boys participated in the study, divided into two groups: passive recovery (PRG, n = 8) and active recovery (ARG, n = 8). Both groups performed tests at 07:00 and 17:00 h. The results showed that performance in the Sargent jump test (SJT), 10-m sprint, and agility were higher in the evening (17:00 h), around the presumed peak of body temperature. SJT and agility performance decreased after the match. The better performance in SJT and agility were found in ARG rather than PRG (p < 0.01). The rating of perceived exertion (RPE) was lower in the morning (p < 0.05). Heart rate (HR) and blood pressure (DBP and SBP) increased immediately after the match. In addition, HR and SBP values differed between PRG and ARG (p < 0.01), with a greater recovery observed in the morning (p < 0.05). Muscle damage markers (lactate and creatine kinase) were significantly higher after the match (p < 0.05), and there was a significant decrease in lactate concentration after recovery in the ARG group compared to the PRG group (p < 0.05), even though neither lactate nor creatine kinase concentrations were affected by the time of day. In conclusion, the recovery process following exercise does not show time-of-day effects, even though active recovery appears to be an effective tool for accelerating the elimination of muscle damage markers and decreasing neuromuscular fatigue.