Further studies of shoulder and neck pain and exposures in customer service work with low biomechanical demands

Biomechanical Assessments of the Upper Limb for Determining Fatigue, Strain and Effort from the Laboratory to the Industrial Working Place: A Systematic Review

Recent human-centered developments in the industrial field (Industry 5.0) lead companies and stakeholders to ensure the wellbeing of their workers with assessments of upper limb performance in the workplace, with the aim of reducing work-related diseases and improving awareness of the physical status of workers, by assessing motor performance, fatigue, strain and effort. Such approaches are usually developed in laboratories and only at times they are translated to on-field applications; few studies summarized common practices for the assessments. Therefore, our aim is to review the current state-of-the-art approaches used for the assessment of fatigue, strain and effort in working scenarios and to analyze in detail the differences between studies that take place in the laboratory and in the workplace, in order to give insights on future trends and directions. A systematic review of the studies aimed at evaluating the motor performance, fatigue, strain and effort of the upper limb targeting working scenarios is presented. A total of 1375 articles were found in scientific databases and 288 were analyzed. About half of the scientific articles are focused on laboratory pilot studies investigating effort and fatigue in laboratories, while the other half are set in working places. Our results showed that assessing upper limb biomechanics is quite common in the field, but it is mostly performed with instrumental assessments in laboratory studies, while questionnaires and scales are preferred in working places. Future directions may be oriented towards multi-domain approaches able to exploit the potential of combined analyses, exploitation of instrumental approaches in workplace, targeting a wider range of people and implementing more structured trials to translate pilot studies to real practice.

Is Injury an Occupational Hazard for Horseracing Staff?

Occupational health is a key priority for the horseracing industry, yet little research on occupational injuries exists. This study investigated the prevalence and the effect of injury in British horseracing staff during a 12-month period. An online retrospective survey was answered by 352 participants, identifying self-reported injury prevalence, injury management practices and attitudes towards workplace injury reporting. Chi Squared tests for independence were undertaken. A total of 310 (88.1%) staff reported injuries; risk factors for injury type included self-perceived job security, working hours, and perceived job control. Physical limitations, loss of confidence, workplace changes, and lifestyle implications were reported as consequences of injury. A total of 75.3% (n = 134) of staff were likely to seek time-off following fractures, but only 48.6% (n = 86) would take time-off for concussion. Attitudes towards injury management were influenced by financial circumstances, perceived staff shortages, previous injury experiences, and perceived employer expectations. The high self-reported injury prevalence could result in decreased workforce efficiency, poor physical health, and negative implications on retention and career longevity. The perception of invisible injuries, i.e., concussion, and subsequent management, should be of immediate concern to racing organizations. This paper identifies recommendations to enhance the safety and wellbeing of horseracing staff.

Motor neurone disease-associated neck pain misdiagnosed as cervical spondylosis: A case report and literature review

BACKGROUND

Motor neurone disease (MND) is a chronic, progressive and currently incurable neurodegenerative disorder. Although pain as a symptom appears in many patients with MND, it is often misdiagnosed as other diseases when occurs before the onset of weakness. Patients are often assigned to non-neurological departments due to the atypical symptoms, which can lead to diagnostic delay and inappropriate treatment.

OBJECTIVE

To analyze the causes of misdiagnosis and improve the clinician's understanding of neck pain in patients with MND.

METHODS

We reviewed relevant literature and retrospectively reported a misdiagnosis case of MND-associated neck pain.

RESULTS

A case of MND presenting prominently as neck pain was suspected of suffering from cervical spondylosis and wrongly assigned to orthopedic clinic. When eventually being diagnosed as MND, his neck pain was found to be caused by intracranial hypertension (ICH) resulting from hypoxia via insidious respiratory failure through ventilator insufficiency.

CONCLUSION

Careful evaluation of the clinical progression of the symptoms, extensive EMG and nerve conduction study, as well as the establishment of better clinical approach to the diagnosis and higher public awareness allow a reduction of misdiagnosis.

Work demands and health consequences of organizational and technological measures introduced to enhance the quality of home care services--A subgroup analysis

This study of home care workers in a Norwegian municipality aimed to examine the effect of two measures involving organizational (job checklists) and technological (personal digital assistants) job aids on perceived work demands and musculoskeletal health. Questionnaire data was collected in 2009 (n = 138, response rate 76.2%) and 2011 (n = 80, response rate 54%). Forty-six home care workers responded at both waves. Respondents were assigned into 'high', 'moderate' and 'low' strain groups based on their responses to open and closed survey questions regarding impact of the two measures. One-way ANOVA with post-hoc t-tests and regression analyses investigated group differences and examined development in variables. Perceived work demands and health effects over the two-year study period were unchanged overall, yet significant differences between subgroups were highlighted. Work demands and shoulder-neck pain remained high for high-strain workers, but were reduced for low and moderate strain workers. Management should be aware of diversity in worker responses to rationalizations and give priority to supplementary, targeted measures to counteract adverse effects.

The influence of mental load on muscle tension

We examined the differences in muscle tension and in physiological measures depending on the type of mental task. Fifteen participants performed tests for sustained attention, vigilance and maintaining posture only. We analysed electromyogram (EMG) measures of extensor digitorum (ED), flexor carpi ulnaris (FU), deltoideus (DE) and trapezius (TR), and heart rate (HR) and respiratory frequency (RF). Measures indicated higher values for mental tasks than for maintained posture only with significant differences in all measures. The following relationships were also significant: between DE and physiological measures (HR and RF), between ED and the amplitude of EMG of the other three muscles, between FU and TR and between HR and RF. The results of this study showed that the relationship between mental demands and muscle tension was mostly reflected by tension in the arm and shoulder girdle muscles and, to a lesser degree, in forearm muscles.

PRACTITIONER SUMMARY

We focused on physiological and muscle tension measures differentiating work according to the level of mental demands. Differences in sustained attention, vigilance and maintaining posture only proved that mental demands were mostly reflected by tension in arm and shoulder girdle muscles and, to a lesser degree, in forearm muscles.

Are there health effects of harassment in the workplace? A gender-sensitive study of the relationships between work and neck pain

The aim of this study was to identify workplace physical and psychosocial risk factors for neck pain among male and female workers and, in particular, to study the relationship between neck pain and intimidation and sexual harassment in the workplace in a representative sample of the Quebec working population. The study sample included 5405 men and 3987 women. In multiple logistic regression analyses, when taking into account individual and other workplace factors, neck pain was significantly associated with intimidation at work among both male (odds ratio (OR) 1.4 (1.01-1.8)) and female workers (OR 1.3 (1.01-1.8)). Among female workers, neck pain was alsosignificantly associated with unwanted sexual attention (OR 1.6 (1.1-2.4)). If confirmed in prospective studies, these results suggest that interventions to prevent harassment in the workplace may help reduce musculoskeletal disorders in the workplace and that workplace programmes to reduce harassment in the workplace should include prevention of sexual harassment.

PRACTITIONER SUMMARY

While taking into account relevant personal factors and previously identified workplace physical and psychosocial risk factors, this gender-based study identifies new work exposures associated with neck pain that have not previously been studied, including unwanted sexual attention, intimidation and difficult or tense situations with the public.

Occupational musculoskeletal and mental health: Significance of rationalization and opportunities to create sustainable production systems - A systematic review

This literature review aims to identify occupational musculoskeletal and mental health effects of production system rationalization as well as organizational-level measures that may improve health outcome ("modifiers" in this review). A short review of the effect of ergonomic interventions is included as background and rationalization is discussed as a theoretical concept. Indicator variables for occupational musculoskeletal and mental health and related risk factors are presented. Variables with a generalized format were allowed in the literature searches (e.g., job satisfaction and absenteeism were accepted as risk factor and health indicator, respectively), suitable for the research fields of work sociology, organization science, human resource management (HRM) and economics research. One hundred and sixty-two studies of rationalization effects on health and risk factors and 72 organization-level modifier results were accepted into the final database. Entries were sorted by rationalization strategy and work life sector, and trends in outcome (positive, mixed, no effect, or negative effect on health and risk factors) were determined. Rationalizations have a dominant negative effect on health and risk factors (57% negative, 19% positive); the most negative effects were found for downsizing and restructuring rationalizations in general (71 studies negative, 13 positive) and for the health care sector in particular (36 studies negative, 2 positive). The rationalization strategy High Performance Work System (HPWS) was associated with the highest fraction positive outcome studies (6 of 10 studies). Other rationalization strategies (lean practices, parallel vs. serial production and mechanization level) reported intermediate results, in part dependent on work life sector, but also on the year when studies were carried out. Worker participation, resonant management style, information, support, group autonomy and procedural justice were modifiers with favourable influence on outcome. It is concluded that production system rationalization represents a pervasive work life intervention without a primary occupational health focus. It has considerable and mostly negative influence on worker health, but this can be reduced by attention to modifiers. The results create a basis for new priorities in ergonomic intervention research.

Experimental manipulation of psychosocial exposure and questionnaire sensitivity in a simulated manufacturing setting

PURPOSE

The objectives of this study were to determine the efficacy of experimental manipulations of psychosocial exposures and to evaluate the sensitivity of a psychosocial questionnaire by determining the factors perceived.

METHODS

A 50-item questionnaire was developed from the job content questionnaire (JCQ) and the quality of worklife survey (QWL). The experiment involved simulated work at different physical and psychosocial levels. Forty-eight participants were exposed to two levels of one psychosocial manipulation (job control, job demands, social support, or time pressure).

RESULTS

Significantly different questionnaire responses supported the effectiveness of psychosocial manipulations. Exploratory factor analysis revealed five factors: skill discretion and decision authority, stress level and supervisor support, physical demands, quality of coworker support, and decision-making support.

CONCLUSIONS

These results suggest that psychosocial factors can be manipulated experimentally, and that questionnaires can distinguish perceptions of these factors. These questionnaires may be used to assess perceptions of psychosocial factors in experimental settings.

Autonomic and muscular responses and recovery to one-hour laboratory mental stress in healthy subjects

BACKGROUND

Stress is a risk factor for musculoskeletal pain. We wanted to explore stress related physiology in healthy subjects in order to gain insight into mechanisms of pain development which may relate to the pathophysiology of musculoskeletal pain disorders.

METHODS

Continuous blood pressure, heart rate, finger skin blood flow, respiration, surface electromyography together with perception of pain, fatigue and tension were recorded on 35 healthy women and 9 healthy men before, during a 60 minute period with task-related low-grade mental stress, and in the following 30 minute rest period.

RESULTS

Subjects responded physiologically to the stressful task with an increase in trapezius and frontalis muscle activity, increased blood pressure, respiration frequency and heart rate together with reduced finger skin blood flow. The blood pressure response and the finger skin blood flow response did not recover to baseline values during the 30-minute rest period, whereas respiration frequency, heart rate, and surface electromyography of the trapezius and frontalis muscles recovered to baseline within 10 minutes after the stressful task. Sixty-eight percent responded subjectively with pain development and 64% reported at least 30% increase in pain. Reduced recovery of the blood pressure was weakly correlated to fatigue development during stress, but was not correlated to pain or tension.

CONCLUSION

Based on a lack of recovery of the blood pressure and the acral finger skin blood flow response to mental stress we conclude that these responses are more protracted than other physiological stress responses.

The influence of body posture, arm movement, and work stress on trapezius activity during computer work

The study aimed to determine the influence of arm posture and movement on trapezius activity of computer workers, considering the full workday. A second aim was to investigate if work periods perceived as stressful were associated with elevated or more sustained muscle activity pattern. Twenty-six computer workers performing call-center (n=11), help desk (n=7), or secretarial (n=8) work tasks participated. Bilateral trapezius surface electromyographic (sEMG) activity and heart rate was recorded throughout the workday. Simultaneous inclinometer recordings from left thigh and upper arms identified periods with sitting, standing, and walking, as well as arm posture and movement. Perceived work stress and tension were recorded on visual analog scales (VAS) every hour. Trapezius sEMG activity was low in seated posture [group median 1.8 and 0.9% of activity at maximal voluntary contraction (%EMGmax) for dominant and non-dominant side] and was elevated in standing (3.0 and 2.5% EMGmax) and walking (3.9 and 3.4% EMGmax). In seated posture (mean duration 79% of workday) arm movement consistently influenced trapezius activity, accounting for approximately 20% of intra-individual variation in trapezius activity. Arm elevation was on average not associated with trapezius activity when seated; however, considerable individual variation was observed. There was no indication of increase in trapezius activity or more sustained activity pattern, nor in heart rate, in high-stress versus low-stress periods, comparing periods with seated posture for the subjects reporting contrasts of at least two VAS units in stress (n=16) or tension (n=14) score.

Respiratory and stress-induced activation of low-threshold motor units in the human trapezius muscle

The study aimed to characterize trapezius motor unit firing pattern in low-amplitude contractions, with emphasis on respiratory modulated activity. Constant-amplitude contractions with shoulder elevation, controlled by feedback of the root mean square detected surface electromyographic (SEMG) signal, typing with arm movement and tasks with mental stress were performed. Single motor unit activity was recorded by a quadrifilar fine-wire electrode. A surface electrode simultaneously recorded SEMG activity. Contraction amplitudes ranged from 1 to 10% of the SEMG signal at maximum voluntary contraction (1-10% EMG(max)). The majority ( approximately 80%) of motor units recorded during constant-amplitude contractions showed firing rate modulation at the respiratory frequency. Respiratory firing rate modulation was clear for low amplitude contractions (< 3% EMG(max)), but was reduced at higher amplitudes (3-5.9% EMG(max)). Most motor units had peak firing rate at the transition from inspiration to expiration, but peak firing rate at the transition from expiration to inspiration or at the first harmonic frequency was also observed. The SEMG signal showed little or no respiratory modulation, possibly because respiratory phase varied between motor units. Respiratory modulation of firing rates was significantly reduced in experiments with mental stress and was rarely observed in typing experiments. Both central respiratory drive and peripheral afferent input may contribute to respiratory modulation of firing rates; however, animal studies indicate a central source of the respiratory modulated input. We speculate that the reduction in respiratory modulation of motor activity with mental stress is due to activation of alternative pathways providing excitatory input to trapezius motoneurons.

Low-amplitude trapezius activity in work and leisure and the relation to shoulder and neck pain

The aim of this study is to obtain evidence supporting or negating the hypothesis that muscle pain is associated with sustained activation of low-threshold motor units. Long-term surface electromyographic (EMG) recordings of trapezius activity pattern were related to subjectively reported shoulder and neck pain in work and leisure. Recordings from 118 female subjects (73 recorded both during work and leisure) were analyzed. Computer operators, secretaries, and health care and retail workers were represented in the material. The recordings were calibrated by the root-mean-square-detected response at maximal voluntary contraction (%maximum EMG). The analysis was performed by quantifying duration and amplitude of surface EMG activity exceeding 2% maximum EMG (“EMG bursts”). Three response categories were defined by duration of the burst periods during work: low- (<50%), intermediate- (50–70%), and high-response (>70%) groups. Shoulder and neck pain was assessed by hourly visual analog score throughout work and leisure and by pain score for the last 6 mo. Shoulder and neck pain was higher at work than leisure for subjects with long-term pain in both the high- and the low-response groups. Persistent pain, defined by the 6-mo score, was more prevalent in the high- than the low- and intermediate-response groups (73 vs. 37%); relative risk was 2.0. Trapezius activity was reduced from work to leisure for the high- but not the low-response group. The activity pattern is consistent with low-threshold motor unit overexertion for the high- but not the low-response group. We speculate that different mechanisms of muscle pain causation, dependent and independent of motor activity pattern, coexist.

Perceived muscular tension, job strain, physical exposure, and associations with neck pain among VDU users; a prospective cohort study

AIMS

To determine whether perceived muscular tension, job strain, or physical exposure are associated with increased risk of developing neck pain among VDU users.

METHODS

A baseline questionnaire was answered by 1283 respondents, of whom 671 were free from neck pain at baseline. Perceived muscular tension, job strain, and physical exposure were assessed at baseline. Information about newly developed neck pain was collected in 10 follow up questionnaires and the case definition was the first report of such pain in any of the follow up questionnaires. Median follow up time was 10.9 months.

RESULTS

Both men and women who perceived muscular tension at least a few times per week, compared to those who had not perceived muscular tension the preceding month, had an incidence rate ratio (IRR) of 1.9 (95% CI 1.25 to 2.93) for developing neck pain, when stratifying for sex. High perceived muscular tension was associated with an increased risk (IRR 1.6, 95% CI 1.02 to 1.91), even when controlling for job strain, physical exposure, and age in the model stratified by sex.

CONCLUSIONS

Perceived muscular tension was associated with an increased risk of developing neck pain among VDU users. The combination of high job strain and high perceived muscular tension was associated with higher risk of developing neck pain than the combination of high physical exposure and high perceived muscular tension. There was an indication of an excess risk due to interaction between high physical exposure and high job strain.