Background: The use of notebook computers has increasedand become very popular among computer users due to their light weight, small size, portability, and battery power optionand become the main cause of increased muscle activities in the neck and shoulder region between computer users. Purposes: To investigate the isokinetic measurements of shoulder muscle performance in notebook computer users. Design: Two groups post-test design. Materials and Methods: Thirty healthy subjects were be selected from students and employees of the Faculty of Physical Therapy Cairo university. The subjects were assigned randomly into two equal groups Group (A)is fifteen subjects whoare computer users. Their mean age (22.33±1.11) years, weight (75.36±17.6) kg, height (170.13±8.5) cm and BMI (25.87±5.17) kg/m2.Group (B) is fifteen subjects who are non computer users. Their mean age (22.8±3.4) years, weight (68.26±16.9) kg, height (171.53±10.35) cm and BMI (23.58±4.11) kg/m2. All participants were tested for shoulder flexion from 90° to 180° and shoulder abduction from 15° to 135° at angular velocity 60°/ sec and 180°/ sec for both ranges to measure muscle work, torque and work fatigue of shoulder flexors and abductors using Biodex system 3 isokinetic dynamometer. Results: There were no significant differences between the two groups in shoulder flexors work, torque and work fatigue at angular velocity 60°/ sec, and at angular velocity 180°/ sec. There were no significant differences between two groups in shoulder abductors work, torque and work fatigueat angular velocity 60°/ sec, and at angular velocity 180°/ sec. Conclusion: Notebook computers proved to have no effect over shoulder flexors and abductors performance during shoulder movement.
