Acute effects of antagonist muscle PNF stretching on neuromuscular fatigue, strength and electromyography of agonist muscle in knee joint of non-athlete peoples

Aim: the purpose of this study was to investigate the acute effects of antagonist muscle PNF stretching on
peak torque, rate of vertical jump height and fatigue of agonist muscle in knee joint of non-athlete subject.
Method: fifteen physical education male students (21/7±1/3 yrs, 180/9±7/02 cm, 75/2±9/8 kg) volunteered to
participate in current study. Subjects were tested for vertical jump height and isokinetic peak torque
production during knee extension at 600.s and 3000.s and also tested for isokinetic 25 repetition peak torque
production during knee extension at 600 for fatigue testing. Electromyographic data was recorded for the
vastus lateralis and biceps femoris muscles during fatigue testing. Paired samples t-tests way used for
analyzing data. Results: statistical results indicated that there was no significant differences between
stretching groups and non-stretching groups in isokinetic peak torque production during Knee extension at
600.s-1 (257 vs 257 N.m; p=0/945) and 3000.s-1 (145 vs 146 N.m; p=0/754). And also no significant
differences found between stretching groups and non-stretching groups in vertical jump height (54/3 vs 53/1
cm; p=0/358), also percentage of median frequency decrease of vastus lateralis muscle was not significant
(14/3 vs 4/8 per; p=0/161) and work fatigue of agonist muscles (49/6 vs 49/8 pre; p=0/891). Conclusion:
These results indicate that acute PNF stretching of antagonist muscles has no positive effects on peak torque,
rate of vertical jump height and fatigue of agonist muscle. Therefore possibly using this method before
exercise has no positive effects on increasing agonist muscles performance.