Time-of-day effect on dart-throwing performance and the perception of the difficulty of the task in 9-10 year-old boys

The aim of this study was to examine the time-of-day effects on dart-throwing performance (at two distances from the dartboard) and the perception of the difficulty of the task in 9-10 year-old boys. In a randomized order, 12 healthy boys (age = 9.8 +/- 0.5 years, height = 144 +/- 6.2 cm, and body-mass = 32.7 +/- 3.4 kg) performed two test sessions, in the morning at 07: 00 h and in the evening at 17: 00 h. During each test session, performance during the dart-throwing test, oral temperature, and perceived difficulty (PD) of the task were recorded. Performance at throwing darts was scored by three methods: mean distance of the dart from the bulls-eye, number of times the target was missed (number of zeros), and variability of the scores from the darts thrown. Our results revealed that performance at throwing darts was significantly better in the afternoon than the morning, with lowest mean distance of the dart from the bulls-eye around the time of maximal values of oral temperature (p < 0.001). Also, the number of zeros and variability in the scores of the darts thrown at both short and long distances decreased at 17: 00 h in comparison with 07: 00 h (p < 0.05), again indicating a better performance in the afternoon. The PD of the task decreased significantly with time of day, with greater values at 07: 00 h in comparison with 17: 00 h (p < 0.05). Moreover, the PD of the task was higher with long than short distances (p < 0.001). In conclusion, this study demonstrates that psychomotor performance was better in the afternoon than the morning.