Journal of strength and conditioning research
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J Strength Cond Res · Mar 2010
Randomized Controlled Trial Comparative StudyAcute effects of Flexi-bar vs. Sham-bar exercise on muscle electromyography activity and performance.
This study was conducted to investigate whether the low-frequency (5-Hz) oscillatory vibration-like stimulus, purported to be delivered by exercising with Flexi-bar, acutely affects muscle activation and maximal voluntary contraction (MVC) force. Nine healthy men participated in 2 trials, separated by at least 1 week, during which 4 x 30-second sets of exercise were performed with either the Flexi bar or a Sham bar. Maximal voluntary contraction force for elbow flexion, elbow extension, and knee extension were measured before and after the exercise. ⋯ Knee extension MVC force significantly decreased after Flexi-bar exercise (-3 +/- 7%, p = 0.048) in parallel with reduced RF EMG amplitude (-8 +/- 5%, p = 0.04), but there were no acute residual effects on elbow flexion/extension MVC or arm and VL EMG muscle activity. Using Flexi bar during exercise provoked acute alterations in arm- and leg-muscle EMG parameters and maximum force-generating capacity, indicating greater fatigue development than when exercising with the Sham bar. The results of this study indicate that Flexi bar may therefore be used to impose a stronger training stimulus on the muscle during submaximal exercise.