A total of 80 voluntaries are planned to include in this study. Vibration will be applied the right forearm. Muscle electrical activity will be measured on ipsilateral and contralateral flexor carpi radialis (FCR) muscle at rest as EMGrms by surface electromyography (EMG). The rest-EMGrms will be measured at before and during vibration. An increase in muscle electrical activity at rest indicates an increase in motor neuron pool activation. The right distal radius bone mineral content (BMC) and density will be measured by dual energy X-ray absorptiometry (DXA).