and purpose: Handgrip strength is an objective measure of muscular function in the upper extremity and has been used as a marker of frailty in adults. Muscle electromyography (EMG) is an indirect and non-invasive method to evaluate muscle function and activity and predict hand grip force. Subjects: Fifty normal male university students volunteered to participate in this study. They were selected from the students of Faculty of Physical Therapy, Cairo University. Those subjects were collected in

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... one group. Procedures: Hand grip strength was assessed using Hand held dynamometer and Root mean square of wrist flexors was assessed by using Noraxon MyoSystem 1400A Instrument. Three dependent variables; Root mean square (RMS) of flexor carpi radials (FCR), RMS of flexor carpi ulnaris (FCU), and handgrip strength were measured and one independent variable which was the (elbow positions); within subject factor which had three levels (0° elbow flexion, 90° elbow flexion, and full elbow flexion). Results: For hand grip strength, RMS of FCR and RMS of FCU, the results showed that there was significant increase in the value of three values index in favor to 90° elbow flexion position than all other elbow flexion position. Conclusion: it was concluded that there were significant effects of the tested elbow positions (the independent variable) on the three tested dependent variables; RMS of flexor carpi radials,RMS of flexor carpi ulnaris, and handgrip strength (F=143.4, P=0.0001*).