In subgroup analyses , we found an equal effect of different stressor types ( i.e. cognitive/emotional stress , work pace , and precision ) on muscle activity in both body regions .
In conclusion , simulated workplace stressors result in an increase in neck-shoulder and forearm muscle activity .
No indications were found that different types of stressors affect these body regions differently .
Workplace stressors have been indicated to play a role in the development of neck and upper extremity pain possibly through an increase of sustained ( low-level ) muscle activity .
The aim of this review was to study the effects of workplace stressors on muscle activity in the neck-shoulder and forearm muscles .
An additional aim was to find out whether the muscles of the neck-shoulder and the forearm are affected differently by different types of workplace stressors .
Differential effects of mental load on proximal and distal arm muscle activity
Work-related upper extremity disorders ( WRUEDs ) that result from keyboarding  tasks are prevalent and costly . Although the precise mechanisms causing the disorder are not yet fully understood , several risk factors have been proposed . These include the repetitive nature of the motor task and the associated sustained static working postures , but also more psychological factors such as mental load . Epidemiological surveys have shown that WRUEDs are more prone to develop in the postural muscles of the neck/shoulder area than in the executive muscles controlling the h and . The present study investigated whether the activation patterns of these two muscle types are differentially affected by an additional mental load during the performance of a repetitive tapping task .  Participants tapped various keying patterns with their dominant index finger at two prescribed tempi . Mental load was manipulated by means of an auditory short-term memory task . We recorded the  EMG activity of two neck/shoulder muscles ( trapezius and deltoid ) , two upper arm muscles ( biceps and triceps ) , and four forearm muscles ( flexor digitorum superficialis , extensor digitorum , extensor carpi radialis longus and extensor carpi ulnaris ) and analyzed the kinematics and impact forces of the index finger . The results confirmed that the upper limb has two functions . Specifically , activity of the executive distal musculature was increased during tapping at the higher pace , while the activity of the postural upper limb musculature was elevated due to the memory task . We argue that continuously increased muscular activity can lead to fatigue and thus eventually cause musculoskeletal complaints . The results are discussed with respect to biomechanical adaptation strategies that deal with the consequences of increased noise in the neuromotor system due to enhanced mental processing
In subgroup analyses , we found an equal effect of different stressor types ( i.e. cognitive/emotional stress , work pace , and precision ) on muscle activity in both body regions .
In conclusion , simulated workplace stressors result in an increase in neck-shoulder and forearm muscle activity .
No indications were found that different types of stressors affect these body regions differently .
Workplace stressors have been indicated to play a role in the development of neck and upper extremity pain possibly through an increase of sustained ( low-level ) muscle activity .
The aim of this review was to study the effects of workplace stressors on muscle activity in the neck-shoulder and forearm muscles .
An additional aim was to find out whether the muscles of the neck-shoulder and the forearm are affected differently by different types of workplace stressors .