Time-of-Day Effects on Short-Term Exercise Performances in 10- to 11-Year-Old Boys

Abstract

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.

Time of Day Effect on Soccer—Specific Field Tests in Tunisian Boy Players

“…Body temperature as a marker of circadian rhythms, shows a diurnal variation with higher values recorded at 17:00 h (Figure 1) the gains observed in our experimental population (around 0.68˚C) are in accordance with the amplitude (peak-to-trough variation) demonstrated on boys which showed an amplitude ranging from 0.5˚C to 1˚C (Melhim et al, 1993;Souissi et al, 2010;Zarrouk et al, 2012). The results of the present investigation, focused on the diurnal fluctuations of boy's footballers, showed that agility and dribbling fluctuate with time-of-day, with morning nadirs, evening highest values and an amplitude equal to 8% ± 6.7% and 4.5% ± 5.9%, respectively.…”

“…It can, thus, be concluded that there is a circadian rhythm in some specific skills performance in boy's footballer. Indeed, the association between the diurnal temperature variation and the different aspects of physical (Souissi et al, 2010;Winget et al, 1985), mental , perceptual, sensory motor, psychomotor (Weipeng et al, 2011) and cognitive performances (Winget et al, 1985) were found on many studies in adults Winget et al, 1985) and in children ( (Souissi et al, 2010) performances. Usually, peak performances were found to occur in the early evening and correspond to the maximum body (Aloui et al, 2012;Reilly et al, 2007, Bernard et al, 1998Melhim et al, 1993;Souissi et al, 2010).…”

“…Indeed, the association between the diurnal temperature variation and the different aspects of physical (Souissi et al, 2010;Winget et al, 1985), mental , perceptual, sensory motor, psychomotor (Weipeng et al, 2011) and cognitive performances (Winget et al, 1985) were found on many studies in adults Winget et al, 1985) and in children ( (Souissi et al, 2010) performances. Usually, peak performances were found to occur in the early evening and correspond to the maximum body (Aloui et al, 2012;Reilly et al, 2007, Bernard et al, 1998Melhim et al, 1993;Souissi et al, 2010). Although the exact mechanisms explaining this relationship remain unclear, it has been suggested that the increase in body temperature allows an increase in energy metabolism, improved muscle compliance, facilitate actin-myosin crossbridging (Weipeng et al, 2011), enhance metabolic reactions, increase the extensibility of connective tissue, reduce muscle viscosity and increase conduction velocity of action potentials (Sedliak et al, 2007).…”

Time-of-day effects on postural control and attentional capacities in children

“…However, it was reported that the postural control of young adults reaches a most important peak at 18:00 h [6]. Thus, despite the fact that the temperature and the muscular power were reported to be better at the end of the day [45,17], 5-6-year-old children controlled their balance at the middle morning similarly to the late afternoon. This finding may be related to the important attentional capacities indicating probably better sensory integration ability and to the better contribution of vision to maintaining posture revealed at 10:00 h in the present study' participants.…”

“…Similarly, the optimum of the reaction time was observed at the early evening near the peak of the body temperature [9,10,38,39]. It has been found that performances for strength and power in children improved significantly from morning to the afternoon [45]. It was generally accepted that the diurnal increase in central body temperature could act as a passive warm-up that may increase nerve conduction velocity, joint suppleness, and muscle strength [41].…”