Prolonged writing task: comparison of electromyographic analysis of upper trapezius muscle in subjects with or without neck pain.

OBJECTIVES: Work related musculoskeletal disorders represent a serious public health problem as it is a leading cause for disability and absenteeism in workers. The main purpose of the present quasi-experimental study was to compare the muscle activity of the upper trapezius in subjects with neck pain and compare it to those of normal subjects.
MATERIALS AND METHODS: Fifty subjects were recruited for this study after prior screening for neck pain. A Standardized Nordic Musculoskeletal Questionnaire was used for analysis of neck pain in both symptomatic and asymptomatic groups. All the subjects were briefed about the study procedures and due consent was obtained prior to the start of the trial. The subjects were instructed to write for 30 minutes under standardized experimental conditions during which the activity of the upper trapezius was recorded using surface electromyography (EMG).
RESULTS: The comparison of the results in the symptomatic and asymptomatic group showed that the mean EMG activity of upper trapezius muscle was significantly higher in the former as compared to the later group (p < 0.05). The symptomatic group showed greater increase in muscle activity as compared to the asymptomatic group.
CONCLUSION: Our results depict that prolong and continuous writing tasks show overuse of upper trapezius and altered motor control pattern in symptomatic subjects as compared to the normal asymptomatic subjects.