Time-of-day effects on short-term exercise performances in 10- to 11-year-old boys.
The purpose of this study was to examine the time-of-day effects on short-term performances in boys. In a balanced and randomized study design, 20 boys performed four anaerobic tests of strength and power (grip strength, Squat-Jump, Five-jump and cycle Wingate tests) at 08:00, 14:00 and 18:00 hr on separate days. The results showed a time-of-day effect on oral temperature. Analysis of variance revealed a significant time-of-day effect for short-term performances for strength, cycle, and jump tests. The post hoc analysis revealed that performances improved significantly from morning to afternoon but no significant differences were noticed between 14:00 and 18:00 hr. The differences between the morning and the afternoon (the highest value measured either at 14:00 or at 18:00 hr) reached 5.9% for grip strength, 3.5% for the squat jump test, 5% for the five jump test, and 5.5% for P(peak) and 6% for P(mean) during the Wingate test. A significant positive correlation was found between temperature and short-term performances. In conclusion, a time-of-day effect in the child's maximal short-term exercise performances exists in relation with core temperature. Such variations would have pronounced effects when expressed in training programs and competitions.
Research Laboratory Sports Performance Optimization National Center of Medicine and Science in Sports (CNMSS), Tunis, Tunisia.
Hichem
H
Souissi
Anis
A
Chaouachi
Karim
K
Chamari
Mohamed
M
Dogui
Mohamed
M
Amri
Nizar
N
Souissi
D000704:Analysis of Variance; D001831:Body Temperature; D002648:Child; D002940:Circadian Rhythm; D005080:Exercise Test; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory; D053580:Muscle Strength / Q000502:physiology; D014416:Tunisia