Diurnal variation of psychomotor, cognitive and physical performances in schoolchildren: sex comparison

Abstract Background The present study investigated the effect of time of day (08h00 vs. 11h00 vs. 14h00 vs. 17h00) and sex (girls vs. boys) on physical (i.e., five jump test (5JT), push-ball test and 5 m shuttle run test (5mSRT)), cognitive (i.e., attention) and mental (i.e., mental flexibility) performances. Methods Thirty schoolchildren, equally divided in girls (n = 15; age: 9.60 ± 0.51 years) and boys (n = 15; age: 9.40 ± 0.51 years) performed the digit cancellation test, the trail making test, the 5JT, the 2 kg push-ball test and the 5mSRT in a counterbalanced and cross over study design at 08h00, 11h00, 14h00 and 17h00 with 48 h of rest in between. Additionally, rating of perceived exertion (RPE) was determined after each repetition of the 5mSRT and the average of the score (i.e., sum of RPE scores divided by 6) was determined. Results Results showed that RPE at the end of the test was significantly higher at 11h00 compared to 08h00 (p = 0.02) and 14h00 (p = 0.001) and average RPE was higher at 11h00 compared to 08h00 (p = 0.001). Likewise, attention was significantly higher at 08h00 compared to 17h00 (p = 0.001) before and after the 5mSRT test only in girls. However, 5JT performance was significantly lower at 17h00, both in girls and boys, compared to at 08h00 (p = 0.02 and p = 0.001 respectively), 11h00 (p = 0.004 and p = 0.001 respectively) and 14h00 (p = 0.001 and p = 0.001 respectively). However, push-ball (p = 0.086) and 5mSRT performances [best distance (p = 0.173), total distance (p = 0.306), mean distance (p = 0.29), fatigue index (p = 0.06)] were time of day independent. Mental flexibility was significantly higher at 08h00, 11h00 and 14h00 compared to 17h00 (p = 0.001). Conclusion Mental flexibility, attention and jump performances were time of day dependent and push-ball test and 5mSRT performances did not change according to the time of day. Also, no clear sex effect was found on the diurnal variation of mental, cognitive and physical performances.