Trapezius muscle rest time during standardised computer work – A comparison of female computer users with and without self-reported neck/shoulder complaints

Abstract

Work related musculoskeletal disorders (WMSDs) in the shoulder/neck area are a common and increasing problem among European computer workers, especially women. Long-term low-level workloads with low degree of muscle rest are a potential risk factor for developing WMSDs. The purpose of the present study of female computer users (age 45-65 years) in Denmark and Sweden was to investigate if subjects with self-reported neck/shoulder complaints (cases, N = 35) show less trapezius muscle relative rest time (RRT) than controls (N = 44) when performing standardised short-term computer work tasks in controlled laboratory conditions. Surface electromyography (EMG) signals were recorded bilaterally from the upper trapezius muscles during a type, edit, precision and colour word stress task. Besides RRT, 10th percentile RMS values were calculated. On the average, 15 of the cases and 18 of the controls showed analysable EMG files per task. For the colour word stress task, the results showed lower RRT values and higher 10th percentile RMS amplitude levels among cases compared to controls. No such signs could be found for the other tasks performed. The present results indicate an increased motor response to a psychological stressor among subjects with self-reported neck/shoulder complaints.

The effect of work-related sustained trapezius muscle activity on the development of neck and shoulder pain among young adults

“…The proportion of time with muscle rest (43,44) and the total relative time with episodes of sustained muscle activity (45,46) both capture the temporal aspect of muscle activity. These methods, however, produce a description of the average time with sustained muscle activity while disregarding the duration of activity episodes.…”

Tailored Exercise with an Innovative Mechanical Device: Effects on Cervical-Dorsal Rachis

“…The sEMG clearly show that, during Phase 2, a sharp contraction of the LT corresponds to a large relaxation of the UT. Since altered trapezius activity has been linked to neck pain and previous studies have shown that individuals with neck pain display altered trapezius activation patterns [7,8], we hypothesize that this particular trapezius activity, obtained with the use of the Angel's Wings, results in neck, shoulder, and dorsal pain relief. The device indeed permits the discharge of the force developed from the weight lift from the UT to the LT, relaxing the former muscle.…”

“…Altered trapezius activity has been linked to neck pain, and previous studies have shown that individuals with neck pain display altered trapezius activation patterns [7,8]. In particular, the deleterious effect of sustained activity pattern in the upper trapezius (UT) muscle (which is the occurrence of continuous muscle activation without interruptions) has been proposed as a common mechanism for explaining neck and shoulder pain [4,7,8].…”

“…In particular, the deleterious effect of sustained activity pattern in the upper trapezius (UT) muscle (which is the occurrence of continuous muscle activation without interruptions) has been proposed as a common mechanism for explaining neck and shoulder pain [4,7,8].…”

Autonomic Regulation in Musculoskeletal Pain

“…Studies on chronic neck pain have shown a different pattern of muscle activity as determined from electromyography (EMG) recordings, manifested in reduced muscle rest and increased activation of the neck-shoulder muscles in response to various functional tasks (Lundberg et al 1999;Thorn et al 2007;Johnston et al 2008). We recently investigated autonomic and muscular responses, in subjects with chronic neck-shoulder pain and healthy controls, to sustained muscle contraction and a cold stimulation, known to provoke sympathetic activation .…”