Alterations in cervical muscle activity in functional and stressful tasks in female office workers with neck pain

Abstract

This study determined differences between computer workers with varying levels of neck pain in terms of work stressors, employee strain, electromyography (EMG) amplitude and heart rate response to various tasks. Participants included 85 workers (33, no pain; 38, mild pain; 14, moderate pain) and 22 non-working controls. Work stressors evaluated were job demands, decision authority, and social support. Heart rate was recorded during three tasks: copy-typing, typing with superimposed stress and a colour word task. Measures included electromyography signals from the sternocleidomastoid (SCM), anterior scalene (AS), cervical extensor (CE) and upper trapezius (UT) muscles bilaterally. Results showed no difference between groups in work stressors or employee strain measures. Workers with and without pain had higher measured levels of EMG amplitude in SCM, AS and CE muscles during the tasks than controls (all P < 0.02). In workers with neck pain, the UT had difficulty in switching off on completion of tasks compared with controls and workers without pain. There was an increase in heart rate, perceived tension and pain and decrease in accuracy for all groups during the stressful tasks with symptomatic workers producing more typing errors than controls and workers without pain. These findings suggest an altered muscle recruitment pattern in the neck flexor and extensor muscles. Whether this is a consequence or source of the musculoskeletal disorder cannot be determined from this study. It is possible that workers currently without symptoms may be at risk of developing a musculoskeletal disorder.

The effect of psychosocial stress on muscle activity during computer work: Comparative study between desktop computer and mobile computing products

“…Many previous studies used plain copying as a baseline for muscle activity [1,14,20,27,28]. The participants need to copy some text at their own comfortable pace and condition.…”

“…Different tasks may produce different levels of stress, hence lead to different effects on the muscle activity. Based on our literature review, stress induced by a stressful environment (including noise, verbal provocation, calling out any mistakes and evaluation by a supervisor) has the largest effect on trapezius muscle activity (but not on other muscle activity) followed by skill and intelligence tasks, time pressure tasks, arithmetic task and color-word tasks [1,8,12,14,18,19,28,30]. Therefore, we believed that psychosocial stress would increase trapezius muscle activity (First Hypothesis).…”

A comparative investigation of flexion relaxation phenomenon in healthy and chronic neck pain subjects

“…During full flexion, this supporting role transfers from the superficial extensor musculature to other stabilisation systems [7,[9][10][11][12]. The relationship between pain and altered muscle activation patterns is also complex, and researchers use experimental pain models to explain how pain can change the motor control and load transfer between tissues [7,32]. Altered motor control strategies may be seen as compensatory mechanisms, such as reorganisation of activity among agonist, synergists and antagonist muscles to allow the movement in painful and painless conditions.…”

Dysfonctionnements musculaires douloureux de l’appareil manducateur et dysfonctionnements cervicaux et linguaux connexes (3e partie)

“…Cependant, chez ces patients algiques, un stress psychique augmente l'activité posturale des muscles cervicaux. De plus, à l'arrêt d'une tâche stressante, les muscles se mettent difficilement au repos (retard à l'inactivation) [28] (voir ci-après).…”

“…Chez les patients présentant des myalgies cervicales, lors d'une tâche mentale (stress psychologique), l'activité du muscle trapèze supérieur est accrue [16], et particulièrement durant une tâche stressante [28], et chez ces personnes myalgiques travaillant sur ordinateur, ce muscle se met difficilement au repos au moment de l'arrêt d'une tâche expérimentale stressante [28].…”