Effects of Mechanical Vibration Applied at Same Direction of Muscle Shortening on Superior Limbs Fatigue

Mechanical vibration has been used in sports training to increase strength performance and as preventive treatment for such diseases as osteoporosis and Parkinson’s disease. The use of vibration is based on fact that exposure of skeletal muscular system to mechanical vibrations may create a muscle contraction reflex called tonical vibration reflex (TVR). The aim of the present study was to verify the effects of mechanical vibrations applied in the same direction of muscle shortening on superior limbs fatigue. Sixteen volunteers, males, age 26,1 ± 4,9 perfomed on a random way two MVCs of elbow flexors muscles. Each contration was perfomed for six seconds, with rest of 30 minutes. During one of contractions four seconds of mechanical vibration (frequency of 20 Hz and amplitude of 6 mm) was added at the same direction of muscle shortening. A significant difference (p < 0.01) was observed between values of two MVCs. There was a significant decrease on muscle strength produced at the end of MVC without vibration. However, there was no difference on values of maximal strength on both contrations. Conclusion: mechanical vibration applied in the same direction of muscle shortening on superior limbs was able to decrease muscular fadigue produced during maximal voluntary contraction.