Differential effects of mental concentration and acute psychosocial stress on cervical muscle activity and posture. Risk factors in the onset of neck/shoulder pain in a prospective study of workers in industrial and service companies Shoulder muscle activity in young and older people during a computer mouse task. Differential effects of mental load on proximal and distal arm muscle activity Effect of two contrasting types of physical exercise on chronic neck muscle pain. Shoulder muscle co-ordination during chronic and acute experimental neck-shoulder pain. An occupational pain study Group-based exercise at workplace: short-term effects of neck and shoulder resistance training in video display unit workers with work-related chronic neck pain—a pilot randomized trial Impact of regular relaxation training and psychosocial working factors on neck-shoulder tension and absenteeism in hospital cleaners. Effects of the Workplace Health Promotion Activities Soccer and Zumba on Muscle Pain, Work Ability and Perceived Physical Exertion among Female Hospital Employees Follow-up of neck and shoulder pain among sewing machine operators: The Los Angeles garment study.
Physical and psychosocial stressors in the workplace have been independently associated with the development of  neck pain  , yet interactions among these risk factors remain unclear . The purpose of this study was to compare the effects of mentally challenging computer work performed with and without exposure to a psychosocial stressor on cervical muscle activity and posture . Changes in cervical posture and electromyography of upper trapezius , cervical extensor , and sternocleidomastoid muscles were compared between a resting seated posture at baseline , a low stress condition with mental concentration , and a high stress condition with mental concentration and psychosocial stress in sixty healthy office workers .  Forward head posture significantly increased with mental concentration compared to baseline , but did not change with further introduction of the stressor . Muscle activity significantly increased from the low stress to high stress condition for both the dominant and non-dominant upper trapezius , with no corresponding change in activity of the cervical extensors or flexors between stress conditions . These findings suggest that upper trapezius muscles are selectively activated by psychosocial stress independent of changes in concentration or posture , which may have implication s for the prevention of stress-related trapezius myalgia in the workplace Aims : To quantify the relative contribution of work related physical factors , psychosocial workplace factors , and individual factors and aspects of somatisation to the onset of neck/shoulder pain .  Methods : Four year prospect i ve cohort study of workers from industrial and service companies in Denmark . Participants were 3123 workers , previously enrolled in a cross sectional study , where objective measurement of physical workplace factors was used . Eligible participants were followed on three subsequent occasions with approximately one year intervals . Outcomes of interest were : new onset of neck/shoulder pain ( symptom cases ) ; and neck/shoulder pain with pressure tenderness in the muscles of the neck/shoulder region ( clinical cases ) . Results : During follow up , 636 ( 14.1 % ) participants reported neck/shoulder pain of new onset ; among these , 82 ( 1.7 % ) also had clinical signs of substantial muscle tenderness . High shoulder repetition was related to being a future symptom case , and a future clinical case . Repetition was strongly intercorrelated with other physical measures . High job dem and s were associated with future status as a symptom case , and as a clinical case . A high level of distress predicted subsequent neck/shoulder pain , and neck/shoulder pain with pressure tenderness . Conclusions : High levels of distress , and physical and psychosocial workplace factors are predictors of onset of pain in the neck and /or shoulders , particularly pain with pressure tenderness in the muscles OBJECTIVE Assessment of the age effect in relation to computer work . BACKGROUND Increasingly , more older people are using computers , while hardware and software are not design ed with special consideration of their needs . METHODS Eight young and nine older females performed different computer mouse tasks .  Shoulder muscle activity was recorded from the right deltoid muscle , right and left upper trapezius muscle , and the neck extensor muscles . RESULTS Mean trapezius muscle activity was significantly higher in the older people ( 2.8%/3.7 % EMG(max ) for R/L ) compared to the young ( 1.1%/1.2 % EMG(max ) ) . There was a tendency to a higher activity in the older people for the deltoid muscle and the neck extensor muscles . There were small differences in shoulder muscle activation levels between mouse actions , target directions , and between precision dem and s. CONCLUSIONS Shoulder muscle activity during computer work is affected by age , but only to a minor extent by the type of computer mouse task . The deltoid and the trapezius muscle activities are low during computer mouse use when there is efficient forearm support by the table . Relevance An increasing number of people use computers for hours every day . Intensive use of computers increases the risk of development of work-related musculoskeletal symptoms in the shoulder region 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 OBJECTIVE The prevalence of neck muscle pain has steadily increased and especially pain from the descending part of the trapezius muscle has been associated with monotonous work tasks such as computer work . Physical exercise is generally recommended as treatment , but it is unclear which type of training is most effective . Our objective was to determine the effectiveness of specific strength training of the painful muscle versus general fitness training without direct involvement of the painful muscle ( leg bicycling ) on work-related neck muscle pain . METHODS We conducted a r and omized controlled trial and recruited subjects from 7 workplaces characterized by monotonous jobs ( e.g. , computer-intensive work ) . Forty-eight employed women with chronic neck muscle pain ( defined as a clinical diagnosis of trapezius myalgia ) were r and omly assigned to 10 weeks of specific strength training locally for the affected muscle , general fitness training performed as leg bicycling with relaxed shoulders , or a reference intervention without physical activity . The main outcome measure was an acute and prolonged change in intensity of neck muscle pain ( 100-mm visual analog scale [ VAS ] ) . RESULTS A decrease of 35 mm ( approximately 79 % ; P<0.001 ) in the worst VAS pain score over a 10-week period was seen with specific strength training , whereas an acute and transient decrease in pain ( 5 mm ; P<0.05 ) was found with general fitness training . CONCLUSION Specific strength training had high clinical relevance and led to marked prolonged relief in neck muscle pain .  General fitness training showed only a small yet statistically significant acute pain reduction Abstract Little is known about the mechanisms leading to chronic neck-shoulder musculoskeletal disorders  ( MSD ) . The aim of the present study was to investigate and compare motor function during controlled , low load , repetitive work together with chronic or acute experimental neck-shoulder pain . The clinical study was performed on workers with ( n = 12 ) and without ( n = 6 ) chronic neck-shoulder pain . In the experimental study , experimental muscle pain was induced in healthy subjects by intra-muscular injection of hypertonic saline into the trapezius muscle ( n = 10 ) . The assessed parameters related to motor performance were : work task event duration , cutting forces , surface electromyogram ( EMG ) activity in four shoulder muscles , displacement of the centre of pressure , and arm and trunk 3D movements . For controlled cutting force levels , chronic and acute experimental pain provoked a series of changes : a decreased working rhythm and a protective reorganisation of muscle synergy ( experimental study ) , higher EMG frequency contents which may indicate altered motor unit recruitment , and greater postural activity and a tendency towards increased arm and trunk movements . These pain-related changes can play a role in the development of MSD . The present clinical and experimental study demonstrated similar interactions between motor co-ordination and neck-shoulder pain in occupational setting s. We therefore suggest that this experimental model can be used to study mechanisms related to MSD . Information on such modulatory processes may help in the design of new strategies aim ed at reducing the development of MSD Effectiveness of exercise therapy in video display unit ( VDU ) workers with work-related chronic neck pain ( W-RCNP ) is unclear . The aim of the study was to assess the efficacy of group-based neck-shoulder resistance exercises on symptoms and muscular function in VDU workers with W-RCNP . Thirty-five employees with CNP were r and omly assigned to neck-shoulder resistance exercise ( NSRE ) group or to conventional stretching and postural exercise ( SPE ) group . Participants trained 45 min , twice a week for 7 weeks . Primary outcomes were pain intensity ( 0–10 numeric rating scale , NRS ) and pain-related disability ( Vernon Neck Disability Index , NDI ) . Secondary outcomes were cervical active range of motion ( AROM ) , endurance of neck flexors , strength of shoulder abductors , and health-related quality of life ( SF-36 ) . Post-treatment , pain and disability decreased 2.5 and 5 points in NSRE ( p = 0.001 ) and 5 and 8 points in SPE ( p = 0.002 ) , with no significant differences between groups . AROM improved significantly in both groups ; between-group differences were not significant . Neck flexors endurance and shoulder abductors strength improved by 59.6 and 34.2 % ( p = 0.001 ) in the NSRE group and by 27.6 % ( p = 0.009 ) and 2.3 % ( p = 0.002 ) in the SPE group ; between-group differences were significant ( p = 0.016 and p < 0.001 , respectively ) . SF-36 score remained unchanged . NSRE and SPE are feasible and equally effective in reducing pain and pain-related disability as group exercises in W-RCNP . NSRE may provide some advantage in improving strength and endurance in neck muscles . Further , larger studies should confirm these findings and assess whether a better muscle function confers long-term clinical advantages Occupational stress in hospital cleaners ( n = 50 ) , and the effect of relaxation training ( n = 25 , age matched , r and omized ) , were studied by recording the electrical activity of the upper trapezius muscle at rest and during working conditions at the beginning , middle , and end of a 6-month follow-up period . A short ( 15-minute ) relaxation program was practice d daily at the workplace to provide stress management . The amount of sick leave was counted , and the extent of depression and some psychosocial working factors were screened . Intercorrelations were found between the neck-shoulder tension , psychosocial factors , depression , and the absentee rate . The relaxation training  diminished tension in the neck-shoulder region efficiently ; nevertheless , the decrease in absenteeism might have been related mainly to the social support offered by the research maneuver itself Objectives This 40-week workplace physical training RCT investigated the effect of soccer and Zumba , respectively , on muscle pain intensity and duration , work ability , and rating of perceived exertion ( RPE ) during work among female hospital employees . Methods 107 hospital employees were cluster-r and omized into two training groups , and a control group . The training was conducted outside working hours as two-three 1-h sessions per week for the first 12 weeks , and continued as one-two 1-h sessions per week for the last 28 weeks . Muscle pain intensity and duration , work ability , and RPE during work were measured at baseline and after 12 and 40 weeks . Results After 12 weeks , both the soccer ( −1.9 , 95 % CI , −3.0 , −0.8 , P = 0.001 ) and the Zumba group ( −1.3 , 95 % CI , −2.3 , −0.3 , P = 0.01 ) reduced the pain intensity ( on a scale from 0 to 10 ) in the neck-shoulder region ( eta squared = 0.109 ) , whereas only the soccer group ( −1.9 , 95 % CI , −3.2 , −0.7 , P = 0.002 , eta squared = 0.092 ) showed a reduction after 40 weeks referencing the control group . After 40 weeks , both the soccer ( -16.4 days , 95 % CI , −29.6 , −3.2 , P<0.02 ) and the Zumba group ( -16.6 days , 95 % CI , −28.9 , −4.2 , P<0.01 ) reduced the pain duration during the past 3 months in the neck-shoulder region ( eta squared = 0.077 ) . No significant effects on intensity or duration of pain in the lower back , RPE during work or work ability were found . Conclusions The present study indicates that workplace initiated soccer and Zumba training improve neck-shoulder pain intensity as well as duration among female hospital employees . Trial Registration International St and ard R and omized Controlled Trial Number Register IS RCT N 61986892 BACKGROUND The aim of the present study is to explore factors affecting or modifying self-reported neck/shoulder pain in sewing machine operators . METHODS We investigated self-report neck/shoulder pain in 247 workers who participated in a 4-month prospect i ve intervention study for musculoskeletal disorders . All participants were immigrants . We examine the influence of individual and work-related factors on changes in neck/shoulder pain during follow-up employing linear mixed models with time-spline functions . RESULTS We observed a dramatic decline ( 72 % ) in self-reported pain intensity in the first month of follow-up , followed by a small increase from the first to fourth month ( 4 % per month ) . Workers who perceived and reported their physical workload as high or worked overtime experienced less overall pain reduction . Higher baseline pain intensity , being of Hispanic ethnicity ( vs. Asian ) , and taking cumulative daily rest time during work of 35 min or more allowing for muscles to rest were associated with a larger pain reduction in the first month , but not thereafter . CONCLUSION Our findings indicate that some work-related factors may be of clinical relevance for reducing neck/shoulder pain . Having lower physical workloads and less overtime work should be considered when treating patients or planning workplace interventions for managing work-related musculoskeletal disorders in this underserved immigrant population
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 .