For Prolonged Computer Users: Laptop Screen Position and Sitting Style cause more Cervical Musculoskeletal Dysfunction Compared to Desktop,Ergonomic Evaluation

Abstract

and space saving, enabling the users to work anywhere and at anytime. But most laptops are designed with the screen joined to the keyboard, making it impossible to adjust separately in terms of screen height & distance, and keyboard height & distance. We proposed that computer type and user sitting style affect differently the craniocervical angle and the load over specific muscles in the back and neck. Subjects and methods: Thirty volunteer computer workers were studied at the Basic Sciences Department, Faculty of Physiotherapy, Cairo University from November 2012 to April, 2013. They first assumed the desktop then laptop sitting styles each for 20 minutes. Electromyography was done for the semispinalis cervicis, capitis and upper trapezius muscles, and subject’s posture was captured by an infrared camera. Results: There was a statistically significant increase in the craniocervical angle in desktop than in laptop sitting styles at p = 0.0001. There was significant decrease in semispinalis cervicis and capitis activities for desktop than for laptop on both sides at p = 0.0002. Conclusion: Contrary to laptop, sitting in front of desktop computer increases the craniocervical angle and lessens the muscular load on the semispinalis cervicis and capitis of both arms. Upper trapezius muscles are not affected. Keywords: