RESUMO
Recent studies have observed that stretching applied to antagonist muscles can promote improvement in agonist muscle performance. The purpose of this study was to investigate the effect of different numbers of interset proprioceptive neuromuscular facilitation (PNF) stretching for the antagonists on the total number of repetitions completed for the agonists (quadriceps) in the leg extension exercise. Fourteen physically active individuals (age: 29.35 ± 10.5 years; body mass: 79.1 ± 11.34 kg; height: 170.4 ± 8.7 cm) participated in this study. The following experimental protocols were performed: 1) Traditional protocol (Traditional) - without previous stretching; 2) PNF with lesser duration (PNF1-3 sets of 20 secs.); 3) PNF with greater duration (PNF2-3 sets of 30 secs.). Within the experimental protocols (PNF1 and PNF2), stretching exercises for the antagonists were performed before and between the four sets of the unilateral leg extension exercise. All tests were performed on the dominant limb only. The results showed that there was a significant difference in the total number of repetitions for the PNF2 protocol versus the Traditional protocol (p = 0.026). However, there was no significant difference between the PNF1 protocol versus the Traditional protocol (p = 0.577). In conclusion, in the leg extension exercise, an extended duration of interset PNF stretching for the hamstrings, promoted greater contractile performance for the quadriceps as demonstrated by significantly greater total repetitions over four sets.
RESUMO
Daily melatonin (10-50 mg/kg, i.p.) treatment at 08.30 h or 17.00 h for 1 week of female rats (2-months-old) increased the latency to the appearance of the first convulsion in the pilocarpine-induced seizure model. Other behavior parameters remained unaltered. The anticonvulsant effect of melatonin seemed to be more intense at the light-dark transition. Moreover, the effect of repeated melatonin treatment was also age-related, since it showed a lower threshold in 2-month-old than in 21-day-old rats, and the acute treatment was not efficient. [3H]N-methylscopolamine binding was unaltered in the hippocampus and striatum of adult rats after the association of melatonin and pilocarpine. While muscarinic binding was unaltered in adult rats, it increased in the hippocampus of young rats in the presence of melatonin (50 mg/kg) and pilocarpine, and did not change in the striatum. Melatonin partially recovered [3H]GABA binding in the hippocampus in the presence of pilocarpine-induced seizures, and intensified pilocarpine effects in the striatum of adult rats.
