Surface EMG and psychophysiological stress reactions in women during repetitive work

In order to understand the high prevalence of musculoskeletal disorders ass ociated with stressful work, it is important to explore the relationship be tween muscle activity and psychophysiological stress responses. The present real-life study examines surface trapezius electromyographic (sEMG) activi ty, heart rate, blood pressure, and levels of urinary catecholamines and sa livary cortisol among 31 female employees working at supermarkets, where th e prevalence of neck and shoulder disorders is high (60 70%). As expected, the results show that psychophysiological arousal was high during work. Sig nificant correlations were found between self-reports indicating negative s tress (stressed, exhausted, tense) and sEMG activity during work. No signif icant correlations were found between self-reports of positive reactions (s timulated, concentrated, happy) and sEMG activity. No associations were fou nd between sEMG activity and pain or between negative stress ratings and pa in. Objectively measured workload and physiological stress responses did no t correlate significantly with sEMG activity. Thus, our data indicate that perceived negative stress may have a specific influence on muscle activity, which may be of importance for musculoskeletal disorders in jobs with low- to-moderate physical load and negative psychosocial factors.