ABSTRACT
A few studies have reported that nighttime sleep and daytime napping are significantly associated with sleep disorders, memory, concentration, cognitive ability, and academic performance in children. Moreover, sleep is identified as an important factor that has a profound effect on children’s athletic performance. If a short daytime nap is shown to benefit children involved in sports activities, this evidence could be used to improve children’s athletic performance in the afternoon. In this study, we investigated whether a short daytime nap could reduce the decline in athletic performance observed in the afternoon in children involved in basketball games. We investigated 10 elementary school-age male basketball players. The study was performed under two conditions, with and without a 20-min nap during the lunch break, and evaluation was performed under both conditions for 3 days each. The reaction and 20-m sprint times were measured after morning practice, before afternoon practice, and at the end of practice on all days. At the beginning of afternoon practice, the 20-m sprint time was significantly shorter (p<0.05) in the no-nap group (4.18±0.27 s) than in the nap group (4.24±0.24 s). In conclusion, our results suggest that a short daytime nap in children may reduce the decline in exercise performance observed in the afternoon.
ABSTRACT
The present study was conducted to examine whether stretching was effective to control muscular atrophy.Subjects were eight male undergraduate students (height 171.4 ± 5.8 cm, body weight 72.2 ± 7.8 kg, and age 20.6 ± 1.1 years) and the muscle analyzed was the vastus lateralis.Firstly, the subjects were instructed to perform strength training for a period of 16 weeks, which was followed by a 12-week detraining period. During the detraining period, either the right or the left leg was stretched daily for 10 minutes (2 sets). The mass of the vastus lateralis muscle was estimated based on its cross-sectional area (CSA), as assessed by magnetic resonance imaging (MRI). Relative decreases in muscle mass were compared between the stretched and the non-stretched control leg.Muscle mass in the non-stretched leg showed significant decreases during detraining, while no significant decreases in muscle mass were detected in the stretched leg. This outcome indicates that stretching can influence muscle plasticity and, therefore, is effective for preventing decreases in muscle mass.In conclusion, this study suggests that, added to its known ability to improve flexibility, accelerate recovery from fatigue, and prevent injuries, static stretching is effective for controlling muscle atrophy.
ABSTRACT
The effects of stretching, sport massage, light exercise (80% of the subjects' anaerobic threshold), and hot pack on the recoveries of work capacity and blood lactate (La) after strenuous exercise were compared with the resting recovery conditions. In each experiment for the four recovery strategies, twelve male physical education students participated as subjects. The subjects performed 5-s maximal effort cycle ergometer exercise bouts, repeated 8 times with 20-s rests (W 1) . A 33-min rest period was given after W 1, and then the same exercise as W 1 was performed again (W 2) . During the rest period (from 9 to 19min after W 1), one of the recovery strategies was practiced for 10min. The subjects also participated in a control experiment (rest recovery) on another day. Blood samples were taken from the earlobe to determine La. The rate of work capacity recovery was significantly higher than the control when stretching was performed, but no significant difference was observed in the recovery rate of La. The same tendency was also observed in the case of sport massage. In the case of light exercise, on the other hand, the recovery rate of La was significantly higher than the control, whereas the recovery rate of work capacity was not significantly different. Many of the subjects complained that the intensity of light exercise was too hard. No significant differences were found in the recovery rates of both work capacity and La by application of a hot pack. These results suggest that stretching and sport massage are effective for accelerating recovery of work capacity. Light exercise was not effective in this study. However, considering previous investigations which showed light exercise to be effective, it might be effective if an abequate work intensity is given. A hot pack is suggested not to be effective. No significant correlation was observed between the recovery rate of La and that of work capacity. Thus it seems that the recovery of work capacity is regulated by factors other than La.