Effects of Vibration Resistance Exercises on EMG and Skeletal Muscle Hemodynamics

Objectives: Past studies show that vibration can stimulate muscle activity and improve muscle performance. However, further verification is needed on the effects of different vibration frequencies combined with different muscle strength exercise intensities on EMG activity and skeletal muscle hemodynamics. Methods: We recruited 27 male college athletes for 40%, 60%, and 80% maximum voluntary contraction (MVC) tests at the vibration frequencies of 0 Hz, 10 Hz, 20 Hz, and 30 Hz. We collected EMG activity signals using wireless EMGs and skeletal muscle hemodynamic parameters using a near-infrared spectrometer. Results: At an 80% MVC intensity of the rectus femoris, the mean, peak, and area of EMG at 30 Hz were significantly increased, compared with those at 0 Hz. At a 40% MVC intensity with vibration frequencies of 10 Hz, 20 Hz, and 30 Hz, the HHb of skeletal muscles was significantly increased, while the O2Hb and TSI were significantly decreased, compared with those at 0 Hz. Conclusions: We conclude that high frequency and strongly vibrated muscle strength exercise can improve EMG activity, while vibration and low-intensity muscle strength exercise could increase the oxygen consumption of skeletal muscles.