The effects of daytime melatonin ingestion on arousal and vigilance vanish after sub-maximal exercise: a pilot study.

OBJECTIVE: Daytime melatonin ingestion is known to induce sleep at rest, which may affect arousal and vigilance. Physical exercise is known to produce an increase in core temperature and circulating cortisol which can enhance arousal and vigilance. The effect of submaximal exercise on vigilance and arousal following acute melatonin ingestion has not yet been studied. The present study aimed at investigating the effect of submaximal exercise on vigilance and arousal following daytime melatonin ingestion. PATIENTS AND METHODS: Eight physical education students undertook 45 min of submaximal exercise (at 60% of maximal aerobic speed) on a treadmill after melatonin-(6 mg) or placebo ingestion, in a randomized and counterbalanced order. RESULTS: Heart rate (HR), rectal temperature (Tre), felt arousal scale (FAS), and thermal sensations (TS) were recorded at baseline (pre-exercise), immediately after exercise (post-exercise), and after 30 min of recovery (30 min post-exercise). Blood was sampled for lactate and cortisol. At 30 min post-exercise, the Tre, HR, blood pressure, lactate, FAS, and TS were measured. The participants performed vigilance tests pre-exercise, post-exercise and 30 min post-exercise. Daytime melatonin ingestion affected arousal and vigilance in the pre-exercise period (p < 0.05) but had no effect on Tre, HR, blood pressure, lactate, TS, arousal, and vigilance measured 30 min post-exercise (p > 0.05). CONCLUSIONS: The negative effects of melatonin ingestion on vigilance and arousal vanished after a 45 min of submaximal exercise. The hypnotic effect of melatonin observed in the pre-exercise dissipated in the post-exercise period, possibly due to the significant elevation of Tre, HR, and cortisol at the end of submaximal exercise.

Postural profile of female basketball players and differences among playing positions.

OBJECTIVE: Basketball players often display poor balance and increased injury rates when compared to other athletic categories. Therefore, the relationship between postural control and injury risks in basketball athletes requires investigation. The purpose of this study was to: (a) establish a postural profile of elite women basketball players, (b) compare postural control of the different playing positions to detect the vulnerability of postural balance, and (c) attempt to understand the reasons underlying these differences. PATIENTS AND METHODS: 30 elite female basketball players (aged 21.4±2.3 years) were assigned to three groups according to their playing positions (n=10 guards; n=10 forwards; n=10 centers). A one-way analysis of variance was performed to determine differences between balance test variables under three conditions (static, dynamic antero-posterior and medio-lateral). When a significant main effect was observed, Tukey's post-hoc multiple comparisons tests were used to determine statistical significance. Associations between balance and morphological variables, muscle strength and power were assessed using Pearson's correlation coefficient. RESULTS: Results reveal that basketball players had better postural control than previously studied handball players and non-athletes, but they are more dependent on vision than other categories. When comparing postural controls of playing position, centers show greater vulnerability [Y mean (OE)] than forwards: p<0.001; or guards: p<0.01), due to morphological factors (body mass r=-0.80, height r=-0.68, and lower limb length r=-0.63, and specific power r=-0.40). CONCLUSIONS: Therefore, coaches and strength and conditioning specialists should give specific focus to improving lower limb strength and power in centers and taller basketball players to mitigate against injury risks related to postural control.

Effects of high-intensity interval training and plyometric exercise on the physical fitness of junior male handball players.

OBJECTIVE: This study analyzed the effects of high intensity interval training (HIIT) combined with plyometric exercise on the physical fitness of junior male handball players. PATIENTS AND METHODS: Subjects (age ~17 years) were randomly divided between experimental (n=17) and control (n=15) groups. During the 8-week intervention, the experimental group replaced a part of their regular regimen by HIIT, combined with plyometric exercise. Assessments in both groups before and after the intervention included: squat jump (SJ), countermovement jump (CMJ), sprint performance (5 m, 10 m, 20 m and 30 m), change of direction tests (Illinois modified test [Illinois-MT] and T-half test), 20-m shuttle run, and repeated sprint T-test. RESULTS: The two-way analyses of variance revealed significant group-time interactions (all p<0.05), favoring the intervention group in 5 m, 10 m, 20 m and 30 m sprint (d=0.33, 8.3%; d=0.52, 7.6%; d=0.57, 6.8%; and d=0.58, 8.8%, respectively), T-half (d=0.25, 5.1%), Illinois-MT (d=0.47, 4.2%), SJ and CMJ (d=0.34-0.39, 34-4-34.9%), repeated sprint T-test best time, mean time and total time (d=0.83, 6.9%; d=0.62, 7.4%; and d=0.61, 7.2%, respectively), 20 meter shuttle run test aerobic maximum speed and predicted maximal oxygen intake (d=0.36, 7.5%; d=0.19, 9.4%, respectively). CONCLUSIONS: HIIT combined with plyometrics can aid in the development of physical fitness abilities, which are extremely important to junior male handball players.