Morning melatonin ingestion and diurnal variation of short-term maximal performances in soccer players.

ABSTRACT

Aim Very few studies have investigated the temporal specificity of melatonin (MEL) ingestion upon short-term maximal athletic performances. The aim of the present study was to explore the effect of morning MEL ingestion on cognitive and physical performances measured in the afternoon. Methods Twelve soccer players from a Tunisian squad (17.9 ± 1.3 years, 1.74 ± 0.06 m and 62.0 ± 8.8 kg) participated in the present study. They performed two testing sessions at 0800 h, 1200 h and 1600 h after either MEL (5mg) or placebo (PLA) ingestion, in a randomized order. During each period, the participants performed the following cognitive and physical tests reaction time and vigilance tests, medicine-ball throw (MBT), five jumps, handgrip strength (HG), and agility tests. Results cognitive and physical performances were significantly higher at 1600 h compared to 0800 h during the two conditions (p < 0.05). Moreover, performances of MBT and HG were lower in the morning with MEL in comparison to PLA (p < 0.05). However, MEL ingestion did not affect physical and cognitive performances measured at 1200 h and 1600 h. Conclusion morning MEL ingestion has no unfavourable effect on afternoon physical and cognitive performances in soccer players.