A prospective study of musculoskeletal outcomes among manufacturing workers: I. Effects of physical risk factors

Exploring the influence of individual factors on the perception of mental workload and body postures

Studies have revealed that physical and mental demands, psychosocial factors, and individual factors can contribute to the development of WMSDs. Yet, much is still unknown regarding the effects of individual characteristics on WMSDs susceptibility. Previous studies discovered people assumed more awkward body postures to perform an activity when the perception of mental workload is higher. This research study explored if individual characteristics such as age, sex, personality, and anxiety help explain changes or differences in the perception of mental workload and body postures assume when performing activities. The study provided evidence that these individual characteristics have a modifying role on perceived mental workload and body postures. The results suggest that perceived mental workload is influenced to a higher extent by individual characteristics such as anxiety, sex, and personality traits. Women have a higher (18.7%) mental workload perception than men. Likewise, NASA-TLX scores are 22% higher for feelers than thinkers. In general, higher perceptions of mental workload were observed in participants with higher anxiety levels. On the other hand, body postures seem to be influenced by different individual factors depending on the nature of the activity. RULA scores increased on average by 13.1% between baseline and time constraint conditions. Larger differences were observed in certain individuals (e.g. introverts (19.7%) and intuitors (13.8%)) across conditions.

Robotization of Industrial Processes: Motivational Differences between Companies with and without Existing Robotic Processes

OCCUPATIONAL APPLICATIONSOur survey of 100 manufacturing facilities revealed statistically significant differences among company types in their perceptions of cost savings, productivity gains, and safety improvements as benefits of robotic implementation. Regardless of company type or size, indications of presence of cumulative, incidental, and static postural hazards were identified as primary perceived factors for injury potential. More than half of the surveyed companies reported being unaware of general safety standards utilized within their facilities, and most (70%) robotic companies were unaware of any robotic-specific standards utilized at their company. Our results indicate the importance of accounting for varying perspectives between company types regarding motivation for and safety impacts of robotics. With the advancement of technology and robotization of the manufacturing industry, there are also pressing needs for advancing robotic safety standards, implementing training programs, and continuous promotion of the general safety awareness.

Cardiovascular Disease Risk Factors Predict the Development and Numbers of Common Musculoskeletal Disorders in a Prospective Cohort

OBJECTIVE

The aim of the study is to assess risk of common musculoskeletal disorders (MSDs) based on cardiovascular disease (CVD) risk scores.

METHODS

Data from a 9-year prospective cohort of 1224 workers in three states were analyzed. Baseline data included questionnaires, structured interviews, physical examinations, anthropometric measurements, nerve conduction studies, and individualized measurement of job physical factors. Monthly follow-ups were conducted. Framingham risk scores were calculated. A priori case definitions were constructed for carpal tunnel syndrome, lateral epicondylopathy, medial epicondylopathy, and rotator cuff tendinopathy.

RESULTS

Adjusted RRs for one or more MSDs increased to 3.90 (95% confidence interval, 2.20-6.90) among those with 10-year cardiovascular disease risk scores greater than 15% and 17.4 (95% confidence interval, 3.85-78.62) among those with more than 4 disorders.

CONCLUSIONS

Cardiovascular disease factors are strongly associated with the subsequent development of common MSDs. Risks among those with multiple MSDs are considerably stronger.

Between Two Rocks and in a Hard Place: Reflecting on the Biomechanical Basis of Shoulder Occupational Musculoskeletal Disorders

OBJECTIVE

The aim was to review the biomechanical origins of occupational shoulder damage, while considering the complexity of shoulder mechanics and musculoskeletal consequences of diverse task demands.

BACKGROUND

Accessible measures of physical exposures are the primary focus of occupational shoulder assessments and analyses. This approach has led to guidelines and intervention strategies that are often inadequate for mitigating shoulder disorders amongst the complexity of modern workplace demands. Integration of complex shoulder mechanics into occupational assessments, analyses, and interventions is critical for reducing occupational shoulder injury risk.

METHOD

This narrative review describes shoulder biomechanics in the context of common injury mechanisms and consequent injuries, with a particular focus on subacromial impingement syndrome. Several modulators of shoulder injury risk are reviewed, including fatigue, overhead work, office ergonomics considerations, and pushing and pulling task configurations.

RESULTS

Relationships between work requirements, muscular demands, fatigue, and biomechanical tissue loads exist. This review highlights that consideration of specific workplace factors should be integrated with our knowledge of the intricate arrangement and interpersonal variability of the shoulder complex to proactively evaluate occupational shoulder demands and exposures.

CONCLUSION

A standard method for evaluating shoulder muscle exposures during workplace tasks does not exist. An integrated approach is critical for improved work design and prevention of shoulder tissue damage and accompanying disability.

APPLICATION

This review is particularly relevant for researchers and practitioners, providing guidance for work design and evaluation for shoulder injury prevention by understanding the importance of the unique and complex mechanics of the shoulder.

Changes in physical performance according to job demands across three cohorts of older workers in the Longitudinal Aging Study Amsterdam

This study set out to evaluate the association between job demands at baseline and physical performance over a six-year period across three cohorts of older Dutch workers examined 10 years apart. Data were drawn from three cohorts (1992-1999, 2002-2009 and 2012-2019) of the Longitudinal Aging Study Amsterdam. Individuals aged 55-65 years from each cohort who worked for pay were included (n = 274, n = 416, n = 618, respectively). Physical performance was measured using gait speed and chair stand performance. A population-based job exposure matrix was used to indicate levels of exposure probability of physical (use of force and repetitive movements) and psychosocial (cognitive demands and time pressure) job demands. We found that psychosocial job demands increased and physical demands decreased across the three cohorts. No between cohort differences were found for how job demands affected changes in physical performance over follow-up. For men, faster decline in gait speed was observed when comparing higher and lower use of force at baseline (β -0.012, 95% CI -0.021, -0.004). Greater use of force and repetitive movements were associated with faster decline in chair stand performance (β -0.012, 95% CI -0.020, -0.004 and β -0.009, 95% CI -0.017, -0.001, respectively). In women, no association of job demands on change in physical performance was observed. The study concluded that higher physical job demands were associated with stronger decline in physical performance across six years for men in all cohorts, while no associations were found among women.

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.

Assessing the artificially intelligent workplace: an ethical framework for evaluating experimental technologies in workplace settings

Experimental technologies, including AI and robots, are revolutionising many types of work. For example, the logistics warehouse sector is witnessing a wave of new technologies, such as automated picking tools, collaborative robots and exoskeletons, affecting jobs and employees. Notably, it is not always possible to predict the effects of such new technologies, since they have inherent uncertainties and unintended consequences. Hence, their introduction into workplaces can be conceived as a social experiment. This paper aims to sketch a set of ethical guidelines for introducing experimental technologies into workplaces. It builds on Van de Poel's general framework for assessing new experimental technologies and translates that framework into a more specific context of work. We discuss its five principles: non-maleficence, beneficence, responsibility, autonomy, and justice. Each of these principles is applied to workplaces in general, and specifically to the logistics warehouse setting as a case study. A particular focus in our discussion is put on the distinctive potential harms and goods of work.

Are Psychosocial Resources Buffering the Relation Between Physical Work Behaviors and Need for Recovery?

Objectives: We investigate whether job control and/or social support at work play a buffering role in the relation between various physical work behaviors and Need for Recovery (NFR) among employees with physically demanding jobs. Methods: Our findings are based on data from 332 workers. The Job Content Questionnaire was used to assess job control, social support and specific physically demanding tasks. General physical work behaviors were measured by two Axivity AX3 accelerometers. The NFR Scale (0-11) was used to assess NFR. We used multiple linear regression models. Results: Sitting at work turned out to be negatively associated with NFR, whereas physically demanding tasks were associated positively with NFR. Our results show a significant buffering role for job control on the correlation between sitting, physically demanding tasks and NFR, but not for social support. Conclusion: Our findings suggest that higher job control might be beneficial to reduce high NFR and eventually may help to reduce early drop-out and sickness absence. Further research is called for to confirm the buffering role of job control and to investigate the underlying mechanisms.

Assessing the relationship between domestic work experience and musculoskeletal health among rural Nigerian women

BACKGROUND

Women performing strenuous domestic tasks (especially those in developing countries) are at risk of experiencing musculoskeletal pain (MSP). Physical, psychosocial, and social conditions of work in rural environments contribute to women's domestic work experiences (DWEs) and the risk of MSP. The impact of DWEs on women's health is especially severe in water-insecure countries like Nigeria. This study examines the relationship between a recently developed measure of DWEs and self-reported pain in the lower back (LBP), neck/shoulder (NSP), and elbow/hand/wrist regions (EHWP) among rural Nigerian women.

METHODS

Interviewer-administered survey data were collected from 356 women in four rural communities of Ibadan, Nigeria. Binary and ordinal logistic regression models were used to examine the relationship between DWE factor scores, sociodemographic characteristics, and musculoskeletal pain symptoms and severity after controlling for sociodemographic covariates. Effect estimates of association were presented using the odds ratio (OR), and the corresponding 95% confidence interval (CI) at p-value of 0.05.

FINDINGS

Among 356 participants, the 2-month prevalence of LBP was 58%, NSP was 30%, and EWHP 30%. High DWE scores were significantly associated with higher odds of experiencing and having more severe LBP, NSP, and EHWP. Specifically, the odds of LBP [(OR = 2.88; 95% CI = 1.64-5.11), NSP (OR = 4.58; 95% CI = 2.29-9.40) and EHWP (OR = 1.88; 95% CI = 1.26-3.77)] were significantly higher among women who perceived their domestic work responsibilities as very stressful (i.e., 'high stress appraisal') compared to those with lower stress appraisal scores. Those who were time-pressured and had less autonomy over familial duties (i.e., 'high demand/low control') had significantly higher odds of LBP [(OR = 2.58; 95% CI = 1.64-4.09) and NSP (OR = 1.49; 95% CI = 1.24-2.58)]. Frequently fetching and carrying water over long distances and time (i.e., 'high water sourcing and carriage') was also associated with higher odds of LBP [(OR = 1.31; 95% CI = 1.09-1.79) and NSP (OR = 1.20; 95% CI = 1.08-1.76).

CONCLUSION

Strenuous and stressful DWEs were associated with MSP among rural Nigerian women. This study provides new evidence on how the physical, social, and psychosocial factors of domestic work can increase women's risk of MSP.

The problem with "ergonomics injuries": What can ergonomists do?

Effects of psychosocial hazards on risk of musculoskeletal disorders (MSDs) are often very substantial, but workplace risk management practices focus largely on biomechanical hazards, as do the risk assessment methods used by ergonomists. Translation of research evidence into more effective workplace practices demands a more holistic risk management framework that encompasses both types of hazard. In this context, we evaluate the validity of different MSD risk assessment methods for different purposes, focusing particularly on requirements for routine workplace risk management. These include choice of fit-for-purpose assessment methods, prioritisation of hazards that are most affecting risk, and control actions as high as possible in the risk control hierarchy. Ergonomists could facilitate more effective workplace risk management by promoting: awareness of the need for change; improvements to guidance from OHS regulators; research on MSD-related workplace management issues; and professional development programs on this topic for ergonomists and other OHS practitioners.

Workplace physical and psychosocial hazards: A systematic review of evidence informed hazard identification tools

Prevention of musculoskeletal disorders (MSDs) requires the identification of physical and psychosocial hazards. This systematic review aimed to identify accessible and validated tools, for the assessment of workplace physical and psychosocial hazards, and consolidate the results into a matrix for use by work health and safety (WHS) professionals. Web of Science, Medline, ProQuest Central, and PsychInfo electronic databases, along with grey literature, were searched (Jan 1990 to July 2020). Studies that included tools with evidence of validity for the identification of physical hazards, psychosocial hazards, or both were included. A total of 83 tools were identified and then reviewed to ensure the tools were accessible. The final matrix included a total of 26 tools (16 physical, 4 psychosocial, and 6 comprehensive [physical and psychosocial]). Evidence on best practice for MSD mitigation supports the need for a comprehensive approach; however, the current review identified limitations in the availability of such tools to support WHS professionals.

The impact of ergonomic-educational interventions on reduction of musculoskeletal symptoms among employees of oil and gas installations in Iran

BACKGROUND: Musculoskeletal disorders can cause increased absenteeism, costs, and injuries. OBJECTIVE: The present study was aimed to investigate the impact of ergonomic-educational interventions on the reduction of musculoskeletal symptoms among employees of oil and gas installations. METHODS: This interventional study was conducted on 1243 male workers of oil and gas installations in the south of Iran. The Nordic questionnaire and quick exposure check (QEC) method were used to evaluate the risk of developing musculoskeletal disorders in the participants. Then, the educational interventions via training sessions, designed educational booklets and leaflets, and prepared educational film were performed. Data were collected at the times of two months before and six months after the interventions. RESULTS: The prevalence of musculoskeletal symptoms, at least in one of the body areas, was equal to 71.28%. The results showed that the prevalence of these symptoms significantly decreased in all body areas after the educational interventions (P <0.028). The highest reduction rate occurred in the regions of wrists and hands (52.77%), knees (47.17%), and waist (47.13%), respectively. Moreover, the results indicated that the mean value of the total score of quick exposure check (QEC) had a meaningful decrease from 0.92 to 0.54 after the educational interventions (P <0.0001). CONCLUSION: The planned educational interventions efficiently reduced the prevalence of musculoskeletal symptoms and the ergonomic risk levels estimated by QEC in the research population.

Evidence for the Effectiveness of Feedback from Wearable Inertial Sensors during Work-Related Activities: A Scoping Review

Background: Wearable inertial sensor technology (WIST) systems provide feedback, aiming to modify aberrant postures and movements. The literature on the effects of feedback from WIST during work or work-related activities has not been previously summarised. This review examines the effectiveness of feedback on upper body kinematics during work or work-related activities, along with the wearability and a quantification of the kinematics of the related device. Methods: The Cinahl, Cochrane, Embase, Medline, Scopus, Sportdiscus and Google Scholar databases were searched, including reports from January 2005 to July 2021. The included studies were summarised descriptively and the evidence was assessed. Results: Fourteen included studies demonstrated a 'limited' level of evidence supporting posture and/or movement behaviour improvements using WIST feedback, with no improvements in pain. One study assessed wearability and another two investigated comfort. Studies used tri-axial accelerometers or IMU integration (n = 5 studies). Visual and/or vibrotactile feedback was mostly used. Most studies had a risk of bias, lacked detail for methodological reproducibility and displayed inconsistent reporting of sensor technology, with validation provided only in one study. Thus, we have proposed a minimum 'Technology and Design Checklist' for reporting. Conclusions: Our findings suggest that WIST may improve posture, though not pain; however, the quality of the studies limits the strength of this conclusion. Wearability evaluations are needed for the translation of WIST outcomes. Minimum reporting standards for WIST should be followed to ensure methodological reproducibility.

Predictors for Clinical Outcomes Related to Upper Extremity Musculoskeletal Disorders in a Healthy Working Population

A wide range of endpoints and methods of analysis can be observed in occupational health studies in the context of work-related musculoskeletal disorders (WMSDs). Comparison of study results is therefore difficult. We investigated the association between different clinical endpoints and the presence of upper extremity WMSDs in a healthy working population. Furthermore, the influence of socio-demographic, work-related, and individual predictors on different endpoints was examined. Two self-administered questionnaires were distributed to 70 workers and employees. In addition, a standardized physical examination and an industry test were performed in this cross-sectional study. Correlations between WMSDs and clinical endpoints were analyzed with the Spearman method and prediction ellipses. Multiple regression models were used to study the strength of associations with a pre-defined set of potential influencing factors. The prevalence of WMSDs was 56% (39/70). Disabilities of Arm, Shoulder, and Hand (DASH) score/pain under strain showed the strongest correlations with WMSDs. When analyzing the correlation between WMSDs and pre-selected predictors, none of the predictors could be identified as a risk factor. The DASH score remains a close candidate for best surrogate endpoint for WMSDs detection. Standardized analysis methods could improve the methodological quality of future occupational health studies.

Low back and neck pain: objective and subjective measures of workplace psychosocial and physical hazards

OBJECTIVE

This study explored the role of occupational physical activity (OPA), physical demands and psychosocial work-related factors on low back pain (LBP) and neck-shoulder pain (NSP) amongst workers with physically demanding professions.

METHODS

Data from 331 participants within the service and manufacturing sector in the Flemish Employees' Physical Activity (FEPA) study were used, with objective measures of OPA and subjective measures of physical and psychosocial work environment. A modified Nordic questionnaire collected data on LBP and NSP.

RESULTS

LBP (> 30 days over a year) was reported by 25% of participants, NSP (> 30 days over a year) by 30% and the composite measure of LBP/NSP simultaneously by 17%. Objective measures of OPA were not significantly associated with any pain groups. In the final model, self-reported physical demands were associated with NSP (OR 2.03, 95% CI 1.30-3.18) and LBP/NSP (OR 2.00, 95% CI 1.16-3.45) but not LBP. Job control was negatively associated with LBP (OR 0.59, 95% CI 0.35-0.99) and LBP/NSP (OR 0.54, 95% CI 0.3-0.98).

CONCLUSION

Objective measures were not associated with LBP or NSP. Self-reported measures provided insights into potential workplace hazards such as physical demands and job control which can be used to inform future strategies to prevent the development of LBP and NSP.

Comparing upper arm and trunk kinematics between manufacturing workers performing predominantly cyclic and non-cyclic work tasks

Musculoskeletal disorders (MSDs) are common among manufacturing workers. Exposure to non-neutral postures and high movement speeds associated with MSDs among manufacturing workers may depend on the extent of the variability in the work tasks performed (i.e., predominantly "cyclic" versus "non-cyclic" work). The objectives of this study were to (i) compare mean levels of full-shift exposure summary metrics based on both posture and movement speed between manufacturing workers performing predominantly cyclic (n = 18) and non-cyclic (n = 17) tasks, and (ii) explore patterns of between- and within-worker exposure variance and between-minute (within-shift) exposure level and variation within each group. Inertial sensors were used to measure exposures for up to 15 full shifts per participant. Results indicated (i) substantially higher upper arm and trunk movement speeds among workers performing predominantly cyclic tasks relative to workers performing non-cyclic tasks despite similar postures, and (ii) greater exposure variability both between and within workers in the non-cyclic group.

The impact of occupational and personal factors on musculoskeletal pain - a cohort study of female nurses, sonographers and teachers

Background

Musculoskeletal pain is common in the general population and constitutes a major public health problem. A large proportion of these conditions may be work related. The aim of this study was to explore the relative importance of physical, psychosocial and personal factors, in number of pain sites and in five specific pain sites, among women in common professions with a broad variety of occupational exposures.

Methods

A cohort of 1115 women responded to a questionnaire on ergonomic, psychosocial, personal and life-style factors, and the outcome measure of musculoskeletal pain (based on frequency and intensity of complaints at nine anatomical sites), at baseline and at follow-up. Sum scores of ergonomic and psychosocial factors were created. The importance of exposure at baseline for the number of pain sites at follow-up were estimated using ordinal regression. The importance of exposure at baseline for pain in the neck, shoulders, hands, lower back and feet at follow-up were estimated using multi-exposure Poisson regression models.

Results

High sum scores for ergonomic and psychosocial factors were of importance for a high number of pain sites, although the strongest risk factor was a high number of pain sites already at baseline. On the individual level, there was a large fluctuation in number of pain sites between the two time points. Eighteen percent reported persistent (or recurrent) ≥ four pain sites, while only 11 % did not report any pain at baseline or at follow-up. Among the specific pain sites, a high sum score of ergonomic factors was associated with pain in the neck, hands and feet. A high sum score of psychosocial factors was associated with neck and shoulder pain. The strongest risk factor was, however, pain at that specific anatomical site at baseline. Only a few of the personal and life-style factors were associated with pain.

Conclusions

An overwhelming majority of the women in common occupations were affected by musculoskeletal pain. Both ergonomic and psychosocial factors were predictive of a high number of pain sites and of specific pain sites. These findings indicate the need for preventive measures on the individual, organizational and societal level.

Preventive factors against work-related musculoskeletal disorders: narrative review

Musculoskeletal disorders (MSDs) are major causes of morbidity among workers. They comprise several signs and symptoms, as e.g. pain, paresthesia, fatigue and limited range of motion, which can be related to work tasks. Workplace-related factors include physical, psychological, social and biomechanical hazards. The main kinetic factors associated with MSDs include repetitive movements, exerting excessive force, awkward postures, compression and mechanical vibration. Accurate knowledge of epidemiological aspects, evaluation of ergonomic hazards and musculoskeletal symptoms, and workplace exercise may help reduce the occurrence of MSDs. The aim of the present review is to analyze the applicability of preventive strategies against MSDs among workers. We performed a narrative review based on a survey of databases PubMed and BIREME and included studies published in English, Spanish or Portuguese. We found that workplace exercise is beneficial for both employers and workers. Risk analysis of MSDs is essential for early identification of occupational hazards and to prevent health consequences and costs associated with absenteeism.

Is Repetitive Workload a Risk Factor for Upper Extremity Musculoskeletal Disorders in Surgical Device Mechanics? A Cross-Sectional Analysis

To assess the prevalence of upper extremity work-related musculoskeletal disorders (WMSDs) among surgical device mechanics compared to a control group, a total of 70 employees were included and assigned to three occupational groups (grinders, packers, and control). Personal factors, work exposure, manual skill, and complaints were assessed by two self-administered questionnaires and an industry test. WMSDs were diagnosed in a standardised clinical examination. The two-one-sided t-tests (TOST) procedure was used to test the clinical equivalence of the respective grinding and packaging groups vs. the control group in terms of the Disabilities of the Arm, Shoulder and Hand (DASH) score. Thirty-nine study participants (56%) experienced at least one WMSD at the elbow, forearm, and/or wrist, mainly with signs of epicondylitis and nerve entrapment at the medial elbow. The risk of grinders developing upper extremity WMSD was about 2.5-times higher and packers had an 8.6-fold higher risk of a clinically relevant DASH > 29 compared to the control group. However, these differences were not statistically significant. The groups were also proven to be clinically equivalent in terms of DASH score. Surgical device mechanics do not seem to have worse DASH values or be at higher risk of upper limb WMSDs compared to a control group. This is the first study to analyse and compare different workplaces in this industry that are also common in other industries.

Biomechanical factors during common agricultural activities: Results of on-farm exposure assessments using direct measurement methods

Agricultural work is associated with increased risk of adverse musculoskeletal health outcomes. The purpose of this study was to quantify exposure to biomechanical factors among a sample (n = 55) of farmers in the Midwest region of the U.S. while they performed a variety of routine agricultural activities, and to compare exposure levels between these activities. Surface electromyography was used to estimate activity levels of the erector spinae, upper trapezius, forearm flexor, and forearm extensor muscle groups. Simultaneously, inertial sensors were used to measure kinematics of the trunk, upper arm, and wrist. In general, lower muscle activity levels, less extreme postures, and slower movement speeds were observed during activities that involved primarily the use of agricultural machinery in comparison to manual activities, suggesting a potential advantage of mechanization relative to musculoskeletal health. Median wrist movement speeds exceeding recently proposed exposure thresholds were also observed during many manual activities, such as milking animals and repairing equipment. Upper arm postures and movement speeds did not appear to confer excessive risk for shoulder-related outcomes (on the whole), but interpretation of the results is limited by a sampling approach that may not have captured the full extent of exposure variation. Not surprisingly, substantial variation in exposure levels were observed within each agricultural activity, which is related to substantial variation in the equipment, tools, and work practices used by participants. Ultimately, the results of this study contribute to an emerging literature in which the physical demands of routine agricultural work have been described on the basis of sensor-based measurements rather than more common self-report or observation-based approaches.

Personal and occupational factors contributing to biomechanical risk of the distal upper limb among dairy workers in the Lombardy region of Italy

Biomechanical overload in the wrist flexor and extensor muscles, together with awkward hand positions during work activities, can result in occupational wrist and hand disorders. Dairy workers, specifically those that work in the milking parlor, are exposed to highly repetitive and forceful exertions of the upper limb throughout their work shift. There are very few studies that have investigated the determinants that contribute to the risk of distal upper limb musculoskeletal disorders among dairy workers. The purpose of the present study was to identify the variables affecting the biomechanical overload of the distal upper limb among milking parlor workers, define risk profiles, and propose possible interventions to reduce the high physical loads to the distal upper limb during milking activities. Forty male workers from the three most common milking parlor systems in Lombardy Italy were recruited to participate in this study. Multiple correspondence analysis of personal characteristics and occupational risk factors, followed by cluster analysis, led to the identification of three distinct groups of workers. Low, medium and high risk profiles were assigned to each group based on the risk assessments performed using the Strain Index and electromyography of the distal upper limb. The main risk determinants were workstation characteristics, work organization and milking routine. A well-organized milking routine, milking cluster weight below 2.4 kg or the use of supporting arms for the milking cluster may reduce the risk of biomechanical overload.

Objectively measured occupational physical activity in blue-collar workers: What is the role of job type, gender and psychosocial resources?

The aim was to describe occupational physical activity (OPA) and examine the role of psychosocial job resources among blue-collar workers. In a sample of 198 workers (57% male; mean age 44.9 (SD 9.9) year) from 7 companies in Denmark, two accelerometers (Actigraph) were placed on the thigh and trunk during 1-5 consecutive days, to determine working time spent standing, walking, on feet and in activity of moderate to vigorous intensity level (MVPA). The level of influence and social support at work were assessed by questionnaire. The exposure to OPA significantly varied by particular job type, especially in male predominant occupations. Overall, psychosocial job resources did not affect the exposure to OPA. These findings suggest that workplace interventions aiming to prevent adverse outcomes of OPA among blue-collars workers ought to focus on task redesign and target work organizational factors related to specific job type.

Effectiveness of Workplace-Based Muscle Resistance Training Exercise Program in Preventing Musculoskeletal Dysfunction of the Upper Limbs in Manufacturing Workers

Aims Given the high levels of absenteeism due to musculoskeletal disorders of the upper limbs, there is a need for preventive strategies to protect workers exposed to high risk levels. The purpose of this study was to determine the effect of a workplace-based muscle resistance training exercise program in the presence of pain and musculoskeletal dysfunction of the upper extremities in manufacturing workers exposed to repetitive movements and excessive effort in the workplace. Method Randomized controlled trial in manufacturing workers. A sample of 120 healthy workers was allocated at random to an experimental group, which received a resistance-based exercise program, and a control group, which performed stretching exercises. Results The muscle resistance training exercise had a protective effect on the intensity of pain perceived by workers in their upper limbs (RR: 0.62 95% CI 0.44-0.87) compared with the group of workers who performed stretching exercises. Conclusion A workplace-based muscle resistance training exercise program is an effective preventive strategy in factory workers exposed to risk; however, it is necessary for companies initially to adopt mechanisms to minimize exposure as a prevention strategy.

A Pilot Study of Five Types of Maximum Hand Strength among Manufacturing Industry Workers in Taiwan

Background: The purpose of this study is to collect five types of maximum hand strength among workers in the manufacturing industry in Taiwan. Methods: This study is a cross sectional study with a stratified and convenient sample of workers on the production line in manufacturing industries in Central Taiwan. In total, we recruited 198 healthy subjects to participate in this study. Five types of hand strength were measured in both hands three times with 3 min rests between trials. Results: The strength of females for these five types of hand exertions were 52.0% to 67.6% of the strength of males (p < 0.001). For both genders, there was a main effect for the types of hand strength for the right hand (p < 0.001) and the left hand (p < 0.001). In general, the hand strength in U.S. and EU countries was 1.2 to 1.7 times greater than the strength among the three types of hand exertions in this study. Conclusion: These results can be used to evaluate the musculoskeletal burdens on the upper extremities in the manufacturing industry and could also be used for tool and job design and job modifications.

Association between Occupational Injury and Subsequent Employment Termination among Newly Hired Manufacturing Workers

Few longitudinal studies have examined occupational injury as a predictor of employment termination, particularly during the earliest stages of employment when the risk of occupational injury may be greatest. Human resources (HR) records were used to establish a cohort of 3752 hourly employees newly hired by a large manufacturing facility from 2 January 2012, through 25 November 2016. The HR records were linked with records of employee visits to an on-site occupational health center (OHC) for reasons consistent with occupational injury. Cox regression methods were then used to estimate the risk of employment termination following a first-time visit to the OHC, with time to termination as the dependent variable. Analyses were restricted to the time period ending 60 calendar days from the date of hire. Of the 3752 employees, 1172 (31.2%) terminated employment prior to 60 days from date of hire. Of these, 345 terminated voluntarily and 793 were terminated involuntarily. The risk of termination for any reason was greater among those who visited the OHC during the first 60 days of employment than among those who did not visit the OHC during the first 60 days of employment (adjusted hazard ratio = 2.58, 95% CI = 2.12–3.15). The magnitude of effect was similar regardless of the nature of the injury or the body area affected, and the risk of involuntary termination was generally greater than the risk of voluntary termination. The results support activities to manage workplace safety and health hazards in an effort to reduce employee turnover rates.

Radio frequency identification to measure the duration of machine-paced assembly tasks: Agreement with self-reported task duration and application in variance components analyses of upper arm postures and movements recorded over multiple days

Technical advances in inertial measurement units (IMUs) with data logging functionality have enabled multi-day collection of fullshift upper arm postures and movements. Such data are useful for characterizing job-level exposures and, when coupled with task-level information, can inform interventions to mitigate high-exposure tasks. Previously reported methods for capturing task-level information, however, were limited primarily to self-report diaries or direct observation. In this study of machine-paced manufacturing workers (n=6), a low-cost radio frequency identification (RFID) system was used to collect information about when, and for how long, specific assembly tasks were performed during up to 14 consecutive work shifts (76 total work shifts across the six participants). The RFID data were compared to information collected with a self-report diary using Bland-Altman analyses. In addition, the RFID data were paired with IMU data to identify task-level exposures from within full-shift recordings of upper arm postures and movements. These data were then used to estimate the relative contributions of between- and within-worker sources of variance to overall variance in posture and movement summary measures using hierarchical random-effects analysis of variance (ANOVA) techniques. Average estimates of daily task duration based on RFID data were comparable to estimates obtained by self-report (mean bias < ±1 minute) but with substantial variability (limits of agreement > ±100 minutes). In addition, the ANOVA models containing task-level information suggested a substantial amount of the overall exposure variance was attributed to repeated observations of the same task within a work day. These findings (i) suggest that while the RFID system used in this study performed adequately, further refinement, validation, and/or alternative strategies may be needed and (ii) underscore the importance of repeated full-shift and task-based measurement approaches in characterizing physical exposures, even in machine-paced environments.

Work-Related Upper Limb Symptoms in Hand-Intensive Health Care Occupations: A Cross-Sectional Study With a Health and Safety Perspective

BACKGROUND

Research with physical therapists reveals high rates of work-related musculoskeletal injuries, especially low back pain, with early career onset. Less focus has been given to upper limb disorders (ULDs) in these professionals, who frequently perform repetitive arm/hand and precision finger motions during work.

OBJECTIVE

The objective was to estimate prevalence of body-site-specific upper limb (UL) symptoms and diagnosed ULDs in Irish chartered physical therapists, physiotherapists, and athletic therapists, with adjustment for leisure time injury, and document first onset of specific UL symptoms.

DESIGN

The design was a cross-sectional survey (N = 347) using random sampling (physiotherapists in private practice), proportionate cluster sampling (hospital-based physiotherapists), and all-population sampling (physical therapists and athletic therapists).

METHODS

The methods used were a postal questionnaire with annual, current, and incapacitating UL symptoms (neck, shoulders, elbows, wrists, fingers, thumbs) (Nordic Questionnaire); symptom onset; diagnosed UL disorders; and sociodemographics; prevalence with 95% CIs, and adjusted prevalence (general linear modeling).

RESULTS

Adjusted annual prevalence of UL symptoms in at least 1 body site was 78.1% (95% CI = 71.4-82.2), and of incapacitating symptoms was 21.0% (95% CI = 16.4-27.0). Shoulder (53.2%, 95% CI = 47.9-58.7), neck (49.4%, 95% CI = 44.2-55.0), and thumbs (46.1%, 95% CI = 40.7-51.5) were mostly affected. Hospital-based therapists had a significantly higher prevalence of incapacitating symptoms compared with others (35.7% vs 23.3%). Respondents totaling 28.2% had at least 1 lifetime diagnosis of ULD, most commonly shoulder tendonitis (12.5%, 95% CI = 8.4-15.3) and overuse syndrome (11.8%, 95% CI = 8.4-15.3). First onset was mostly after 5 years working as a therapist; however, this differed by anatomical site.

LIMITATIONS

A cross-sectional study design limited interpretation of symptoms as work-related causes.

CONCLUSIONS

The high prevalence of ULD and symptoms warrants attention from occupational health and safety personnel. Training in injury prevention and risk assessment should be provided during education and as part of continuing education.

Occupational health and safety management practices and musculoskeletal disorders in aged care

Purpose The purpose of this paper is to examine whether occupational health and safety (OHS) management used to manage musculoskeletal disorders (MSDs) in the aged care sector reflects contemporary research evidence of best practice to reduce the incidence of these disorders. Design/methodology/approach In total, 58 interviews were conducted with managers and supervisors in the aged care sector across four organisations in Australia. Policies and procedures relating to MSDs were reviewed for each organisation. Findings Policies and procedures for managing MSDs do not reflect contemporary evidence, which supports a complex aetiology, related to a range of physical and psychosocial workplace factors. Despite strong evidence that psychosocial factors contribute to MSD development, these were not included in the policies and procedures reviewed. Findings from the interviews management practices including leadership and various components of HRM were functioning well but fragmentation was evident due to the challenging nature of the aged care sector. Practical implications To address the significant burden of MSDs in the aged care sector, policies and procedures need to include coverage of psychosocial and physical workplace factors. The development of systematic and integrated OHS management at the workplace level may play an important role in the effective management of MSDs. Originality/value This study offers insights into the previously unexplored area of MSD risk management and the role of management practices such as HRM in the aged care sector.

Effect of Time Elapsed since Last Pruner Maintenance on Upper-Extremity Biomechanics during Manual Flower Cutting

OBJECTIVE

Manual flower cutting imposes large biomechanical demands on workers' upper extremities. Solutions are required to reduce these demands. This study investigated the effect of time elapsed since the last pruner maintenance on the biomechanical demands of the upper extremities during flower-cutting operations.

METHODS

Sixteen experienced workers were recruited. All workers performed flower cutting 1, 15, and 30 days after standard pruner maintenance, including cleaning, adjustment, and sharpening. The outcomes included kinematics of the wrist, elbow, and forearm; muscular activity of the extensor carpi radialis, extensor carpi ulnaris, flexor carpi radialis, flexor carpi ulnaris, biceps and medium deltoids of the dominant arm; and self-reported effort.

RESULTS

On average across muscles, a 15-day delay (from 1 to 15 and from 15 to 30 days) in the execution of pruner maintenance increased over 8% the median recorded muscular activity as measured by the percentage of the maximum voluntary contraction of the root mean square signal. An increase in time since last pruner maintenance resulted in an increase in the 90th percentile pronation-supination posture (larger excursion toward pronation); the median and the 90th percentile velocity of the wrist and elbow; and the 90th percentile acceleration in the pronation-supination direction. There was an increase in perceived effort as measured by a Borg scale as time since last maintenance increased from 1 to 15 days.

CONCLUSION

Increasing the frequency of pruner maintenance procedures can effectively reduce workers' mechanical exposures during manual flower-cutting operations. Companies should implement daily maintenance programs considering their implementation capacity and expected benefits.

Factor associated with self-reported work-related musculoskeletal disorders in Brazilian adults

OBJECTIVE

To describe the prevalence of work-related musculoskeletal disorder (WMSD) and analyze the factors associated with this outcome in the Brazilian population.

METHODS

In this cross-sectional, population-based study, we use data from the National Survey on Health (PNS) of 2013. The sample was composed of 60,202 Brazilians aged 18 years or older. The outcome variable was the occurrence of self-reported WMSD. Sociodemographic and occupational characteristics, personal resources, and health conditions were investigated as explanatory variables. Analyses were performed with the software Stata 12.0 and considered the weighting imposed by the sampling design of the study. Then, univariate and multivariate binary logistic models were carried out, considering a significance level of 5%.

RESULTS

The results obtained indicated that the prevalence of WMSD in the Brazilian population was of 2.5%, ranging from 0.2% (Acre) to 4.2% (Santa Catarina). The factors associated with a greater chance of occurrence of WMSD were: female sex (OR = 2.33; 95%CI 1.72–3.15); be temporarily away from work (OR = 2.44; 95%CI 1.41–4.23); be exposed to noise at the workplace (OR = 2.16; 95%CI 1.68–2.77); seniority equal to or greater than 4.5 years at the current job (OR = 1.37; 95%CI 1.09–1.72); participate in volunteer work (OR = 1.65; 95%CI 1.25–2.17); report medical diagnosis of arthritis or rheumatism (OR = 2.40; 95%CI 1.68–3.44); and depression (OR = 2.48; 95%CI 1.86–3.31). On the other hand, factors associated with less chance of WMSD were: not having a partner (OR = 0.73; 95%CI 0.37–0.71) and working in an open environment (OR = 0.51; 95%CI 0.37–0.71).

CONCLUSIONS

The associated factors and the prevalence found indicate regional and gender differences. Special attention to comorbidities and environmental noise monitoring would benefit the health of workers in the Country.

Work characteristics predict the development of multi-site musculoskeletal pain

PURPOSE

Musculoskeletal pain in more than one body region is common and a barrier to sustaining employment. We aimed to examine whether work characteristics predict the development of multi-site pain (MSP), and to determine differences in work-related predictors between age groups.

METHODS

This study is based on 5136 employees from the Study on Transitions in Employment, Ability and Motivation (STREAM) who reported no MSP at baseline. Measures included physical, emotional, mental, and psychological job demands, social support and autonomy. Predictors of MSP were studied by logistic regression analyses. Univariate and multivariate analyses with age stratification (45-49, 50-54, 55-59, and 60-64 years) were done to explore differences between age groups.

RESULTS

All work characteristics with the exception of autonomy were predictive of the development of MSP, with odds ratios varying from 1.21 (95% CI 1.04-1.40) for mental job demands to 1.63 (95% CI 1.43-1.86) for physical job demands. No clear pattern of age-related differences in the predictors of MSP emerged, with the exception of social support, which was predictive of MSP developing in all age groups except for the age group 60-64 years.

CONCLUSIONS

Adverse physical and psychosocial work characteristics are associated with MSP. Organisations need to comprehensively assess work environments to ensure that all relevant workplace hazards, physical and psychosocial, are identified and then controlled for across all age groups.

Investigation of musculoskeletal symptoms in a manufacturing company in Brazil: a cross-sectional study

•

Upper limb MSD were prevalent among manual manufacturing workers.

•

Shoulder was the body region with the highest prevalence of symptoms.

•

Repetitive work and lack of rest breaks are influential risk factors for MSD.

•

Performing work pause was identified as a significant variable.

•

MSD had a significant negative impact on workers’ general health.

Background

Musculoskeletal disorders are prevalent and represent the most common health problem among the working population in industrially-developing countries, with considerable costs and impact on quality of life. Despite the high incidence of disability insurance claims among Brazilian manufacturing-sector workers, only a few studies assessed musculoskeletal disorders prevalence.

Objective

To provide information on the prevalence of musculoskeletal disorders among manufacturing-sector workers and to explore the relationship between musculoskeletal disorders and sociodemographic and occupational characteristics in a medium metallurgical company located in Brazil.

Methods

A cross-sectional study was carried out. Data was collected through the use of a specifically-designed questionnaire and the items used to collect musculoskeletal disorders data were based on the Nordic Musculoskeletal Questionnaire. Descriptive statistics were used and multivariate logistic regression analysis (p < 0.02) was performed to explore the associations between musculoskeletal disorders and potential risk factors.

Results

The upper limb was the most frequently affected body region among manufacturing-sector workers: shoulder (24.8%), elbow and/or forearm (15.5%), wrist and/or hand (19.0%). Adjusted logistic regression analysis showed that company experience (p = 0.02), presence of sleep disorders (p = 0.00), self-reported general health state (p = 0.00) and perform work pause (p = 0.00) were significant risk factors for development of musculoskeletal disorders.

Conclusion

Sociodemographic and work-related aspects are influential risk factors for musculoskeletal disorders. These results add comprehension about musculoskeletal disorders prevalence and suggest a need for greater emphasis on prevention strategies.

A long-term evaluation of the stage of change approach and compensable injury outcomes - a cluster-randomised trial

This study investigated the long-term injury outcomes for workers in companies from a range of industries which had been randomly allocated to receive ergonomics interventions tailored according to the stage of change (SOC) approach or standard ergonomics advice. Differences in compensable injury outcomes between the groups were analysed using logistic regression models. Questionnaire results from face-to-face interviews to assess musculoskeletal pain and discomfort (MSPD), job satisfaction and other factors were also analysed. Although not significant at the 0.05 level, after adjusting for workgroup clustering, workers in receipt of tailored advice were 55% (OR = 0.45, 95% CI = 0.19-1.08) less likely to report a compensable injury than those in receipt of standard ergonomics advice. Workload, job satisfaction and MSPD were significantly correlated with injury outcomes. The observed outcomes support the potential value of the SOC approach, as well as highlighting the need to consider workload, job satisfaction and MSPD when planning injury prevention programmes. Practitioner Summary: This study investigated compensable injury outcomes for workers who had received ergonomics advice tailored according to the stage of change (SOC) approach compared with standard ergonomics advice. The results support the potential value of the SOC approach and highlight the need to consider workload, job satisfaction and musculoskeletal pain and discomfort when planning injury prevention interventions.

Work-related determinants of multi-site musculoskeletal pain among employees in the health care sector

BACKGROUND

Work-related musculoskeletal pain is a major occupational problem. Those with pain in multiple sites usually report worse health outcomes than those with pain in one site.

OBJECTIVE

This study explored prevalence and associated predictors of multi-site pain in health care sector employees.

METHOD

Survey responses from 1348 health care sector employees across three organisations (37% response rate) collected data on job satisfaction, work life balance, psychosocial and physical hazards, general health and work ability. Musculoskeletal discomfort was measured across 5 body regions with pain in ≥ 2 sites defined as multi-site pain. Generalized linear models were used to identify relationships between work-related factors and multi-site pain.

RESULTS

Over 52% of the employees reported pain in multiple body sites and 19% reported pain in one site. Poor work life balance (PRR = 2.33, 95% CI = 1.06-5.14). physical (PRR = 7.58, 95% CI = 4.89-11.77) and psychosocial (PRR = 1.59, 95% CI = 1.00-2.57) hazard variables were related to multi-site pain (after controlling for age, gender, health and work ability. Older employees and females were more likely to report multi-site pain.

CONCLUSION

Effective risk management of work related multi-site pain must include identification and control of psychosocial and physical hazards.

Fingertip forces and completion time for index finger and thumb touchscreen gestures

Users actuate touchscreen computers by applying forces with their fingers to the touchscreen, although the amount and direction of the force is unknown. Our aim was to characterize the magnitude, direction and impulse of the force applied during single finger (tapping and sliding in four directions) and two finger gestures (stretch and pinch). Thirteen subjects performed repeated trials of each gesture. Mean(±SD) resultant force was 0.50(0.09)N for tap, 0.79(0.32)N to 1.18(0.47)N for sliding gestures, 1.47(0.63)N for pinch and 2.05(1.13)N for stretch. Mean resultant force was significantly less (p<0.04) for tap than for all gestures except slide right. The direction of force application was more vertical for the two-finger gestures as compared to the single- finger gestures. Tap was the fastest gesture to complete at 133(83)ms, followed by slide right at 421(181)ms. On average, participants took the longest to complete the stretch gesture at 920(398)ms. Overall, there are differences in forces, force direction, and completion times among touchscreen gestures that could be used to estimate musculoskeletal exposure and help forge guidelines to reduce risk of musculoskeletal injury.

Effects of milking unit design on upper extremity muscle activity during attachment among U.S. large-herd parlor workers

BACKGROUND

Large-herd dairy parlor workers experience a high prevalence of musculoskeletal symptoms in the upper extremity. The purpose of this study was to evaluate the effect of milking unit design on upper extremity muscle activity during milking unit attachment.

METHODS

Upper extremity muscle activity was recorded among U.S. large-herd parlor workers (n=11) using surface electromyography. Participants performed several milking unit attachment cycles with each of six milking unit designs. Muscle activity levels were then compared between unit designs.

RESULTS

Mean muscle activity levels (in %MVE) across milking units ranged from 6.8 to 8.2 for the upper trapezius, 8.2 to 10.3 for the anterior deltoid, 13.8 to 17.2 for the forearm flexors, and 9.9 to 12.4 for the forearm extensors. Pairwise comparisons between milking units did not reveal statistically significant differences in muscle activity levels across milking unit designs. However, a general pattern of higher muscle activity was observed with specific milking units. Milking unit weight, milk tube spread, and teat cup shape may explain differences in muscle activity levels.

CONCLUSIONS

Milking unit design may influence muscle activity levels among parlor workers. Small reductions in muscle activity associated with milking unit design have the potential to delay the onset of fatigue or development of musculoskeletal health outcomes among parlor workers.

Validity and Reliability of the Upper Extremity Work Demands Scale

Purpose To evaluate validity and reliability of the upper extremity work demands (UEWD) scale. Methods Participants from different levels of physical work demands, based on the Dictionary of Occupational Titles categories, were included. A historical database of 74 workers was added for factor analysis. Criterion validity was evaluated by comparing observed and self-reported UEWD scores. To assess structural validity, a factor analysis was executed. For reliability, the difference between two self-reported UEWD scores, the smallest detectable change (SDC), test–retest reliability and internal consistency were determined. Results Fifty-four participants were observed at work and 51 of them filled in the UEWD twice with a mean interval of 16.6 days (SD 3.3, range = 10–25 days). Criterion validity of the UEWD scale was moderate (r = .44, p = .001). Factor analysis revealed that ‘force and posture’ and ‘repetition’ subscales could be distinguished with Cronbach’s alpha of .79 and .84, respectively. Reliability was good; there was no significant difference between repeated measurements. An SDC of 5.0 was found. Test–retest reliability was good (intraclass correlation coefficient for agreement = .84) and all item-total correlations were >.30. There were two pairs of highly related items. Conclusion Reliability of the UEWD scale was good, but criterion validity was moderate. Based on current results, a modified UEWD scale (2 items removed, 1 item reworded, divided into 2 subscales) was proposed. Since observation appeared to be an inappropriate gold standard, we advise to investigate other types of validity, such as construct validity, in further research.

Risk assessment of cheese processing tasks using the Strain Index and OCRA Checklist

The purpose of this study was to conduct and compare two ergonomic risk assessment methods often used in occupational health research and practice: the Strain Index (SI) and Occupational Repetitive Actions (OCRA) Checklist. Seven raters used the SI and OCRA Checklist to assess task-level physical exposures to the upper extremity of workers performing 21 cheese-manufacturing tasks. Of the total task exposures assessed with both methods, nearly half (49.1%) were classified as hazardous using the OCRA Checklist while 60.2% were classified as hazardous using the SI. Although the underlying injury risk characterization constructs of the SI and OCRA Checklist differ, the results indicated that the SI and OCRA Checklist often classified job tasks into similar risk categories. The differences in risk classifications determined by the SI and OCRA Checklist for job tasks were likely related to the definition of variables measured by these assessment methods as well as the complexity of tasks evaluated. By design, the SI is specific to the distal upper extremity while the OCRA Checklist accounts for the entire upper extremity including the shoulder. When conducting risk assessments of industrial work tasks, the choice of analysis tools should be based on the purpose of the assessment and the complexity of task functions. Both the SI and OCRA Checklist yield risk assessment ratings that are similar for cheese processing tasks.

Does age matter in predicting musculoskeletal disorder risk? An analysis of workplace predictors over 4 years

BACKGROUND

Musculoskeletal disorders (MSDs) are a major workplace issue. With increasing pressure to extend working lives, predictors of MSD risk across all age groups require accurate identification to inform risk reduction strategies.

METHODS

In 2005 and 2009, a survey was conducted in a Finnish food processing company (N = 734). Data on workplace physical and psychosocial hazards, work ability, job satisfaction and lifestyle-related variables were collected, and MSD risk was measured through assessment of work-related strain in four body areas. Predictors of MSD risk across three age groups (20-35, 36-49, 50+) were assessed with linear regression analysis.

RESULTS

Physical hazards and MSD risk were related differently for each age group. The relationship between psychosocial hazards and MSD risk was less clear. For younger workers, physical hazards were not associated with MSD risk. In contrast, for those aged 36-49, repetitive movements (B = 1.76, p < 0.001) and awkward postures (B = 1.30, p = 0.02) were associated with increased MSD risk. For older workers, environmental hazards were positively associated with MSD risk (B = 0.37, p = 0.04). Predictors of MSD risk changed differently for each age group during 4 years of follow-up. For younger workers, change in environment and repetitive movements, for middle age team support and for older workers change in awkward posture were significant predictors of MSD risk.

CONCLUSIONS

These results support the need for workplace-specific hazard surveillance data. This will ensure that all contributing factors to MSD risk can be accurately identified and controlled independent of age.

The occurrence of overload at work and musculoskeletal pain in young physiotherapists

BACKGROUND

A job requiring stooping, lifting, carrying loads and multiple repetitions of the same movement patterns leads to overloading the musculoskeletal system.

OBJECTIVE

The aim of the study was to assess the work-related load experienced by physiotherapists and the occurrence of the musculoskeletal system overload.

METHODS

The study included 108 young physiotherapists, 69 women and 39 men, aged from 25 to 35 years (mean 27.12 ± 3.72 years). The study used an anonymous questionnaire and Quick Exposure Check.

RESULTS

The most common musculoskeletal complaints were as follows: 70 physiotherapists (64.8%) reported low back pain, 60 (55.6%) cervical pain, and 34 (31.5%) pain in the wrists and fingers. Statistically significant positive correlations were revealed between the number of years worked in the profession and shoulder pain. The number of hours of work per week was positively correlated with the occurrence of pain in all analyzed body areas. Professional experience was negatively correlated with the level of stress felt. Physiotherapists dealing with manual therapy and exercise physiotherapy were particularly vulnerable to musculoskeletal overload.

CONCLUSIONS

Popularization of knowledge regarding ergonomics among physiotherapists could reduce the occurrence of musculoskeletal overload.

Exposure-response relationships between movements and postures of the wrist and carpal tunnel syndrome among male and female house painters: a retrospective cohort study

OBJECTIVES

To investigate exposure-response relationships between measured movements and postures of the wrist and the incidence of carpal tunnel syndrome (CTS), and any modifications by sex.

METHODS

In 2011, we established a historical cohort of 9364 members of the Painters' Union in Denmark. Self-reported task distributions were obtained by questionnaire (53% responded) and combined with sex-specific task exposure matrices to get individual estimates of exposure intensity, that is, velocity of wrist flexion/extension, mean power frequency (MPF) and non-neutral wrist postures. Exposure duration was assessed from yearly working proportions. Registered first-time hospital discharge CTS diagnoses and CTS surgery were collected as outcomes. The cohort was followed from 1994 to 2010. Log-linear Poisson regression was used.

RESULTS

For CTS diagnoses, the adjusted incidence rate ratios (IRRs) increased with increasing wrist velocity (IRR=1.37 (95% CI 1.10 to 1.71) per °/s) and MPF (IRR=1.53 (95% CI 1.21 to 1.91) per 0.01 Hz). For CTS surgery, the results were similar. The outcomes were not related to non-neutral postures or exposure duration. The adjusted IRRs for women were higher than those for men. There were no multiplicative interaction effects between exposure intensity, exposure duration and sex. However, the absolute incidence rates (IRs) increased at a steeper rate for women than for men, indicating an additive interaction.

CONCLUSIONS

The incidence of CTS increased with increasing velocity of wrist flexion/extension and MPF of wrist movements. The relative increase in incidence rates was the same for women and men, but the absolute incidence rates increased at a steeper rate for women than for men.

Requirements for more effective prevention of work-related musculoskeletal disorders

BACKGROUND

Exposures to occupational hazards substantially increase workers' risk of developing musculoskeletal disorders (MSDs) and can exacerbate pre-existing disorders. The effects on MSD risk of the physical requirements of work performance are well recognised, but there is now ample evidence that work-related psychosocial hazards can also have substantial effects; further, some hazards may be additive or interactive. This evidence is not reflected in current workplace risk management practices.

DISCUSSION

Barriers to more effective workplace management of MSD risk include: the widespread belief that risk arises largely or entirely from physical hazard exposures; regulatory and guidance documents targeting MSDs, most of which reflect this belief; risk assessment tools that focus narrowly on subsets of mainly physical hazards and yet generate outputs in the form of MSD risk indicators; and the conventional occupational health and safety (OHS) risk management paradigm, which is ill-suited to manage MSD risk. It is argued that improved workplace management of MSD risk requires a systems-based management framework and more holistic risk assessment and control procedures that address risk from all types of hazard together rather than in isolation from each other, and that support participation by workers themselves. New MSD risk management tools are needed to meet these requirements. Further, successful implementation of such changes is likely to require some restructuring of workplace responsibilities for MSD risk management. Line managers and supervisors often play key roles in generating hazards, both physical and psychosocial, so there is a need for their more active participation, along with OHS personnel and workers themselves, in routine risk assessment and control procedures. MSDs are one of our largest OHS problems, but workplace risk management procedures do not reflect current evidence concerning their work-related causes. Inadequate attention is given to assessing and controlling risk from psychosocial hazards, and the conventional risk management paradigm focuses too narrowly on risk from individual hazards rather than promoting the more holistic approach needed to manage the combined effects of all relevant hazards. Achievement of such changes requires new MSD risk management tools and better integration of the roles of OHS personnel with those of line managers.

Musculoskeletal pain among Midwest farmers and associations with agricultural activities

BACKGROUND

Although agricultural workers experience a high prevalence of musculoskeletal pain, associations between specific agricultural activities and musculoskeletal pain are not well characterized.

METHODS

Among 518 regional farmers, responses to a mailed questionnaire were used to estimate (i) the 2-week prevalence of low back, neck/shoulder, and elbow/wrist/hand pain, and (ii) associations between the average hours per week performing common agricultural activities and musculoskeletal pain.

RESULTS

The low back was the most common location of musculoskeletal pain (33.2%), followed by the neck/shoulder (30.8%) and elbow/wrist/hand (21.6%). Statistically significant adjusted associations were observed between performing equipment repair and maintenance and low back pain; milking animals and neck/shoulder pain; and manual material handling and elbow/wrist/hand pain, among others.

CONCLUSIONS

The observed prevalence estimates are consistent with previous literature, and the associations between agricultural activities and musculoskeletal pain provide an initial basis for targeted intervention research.

Risk factors of work-related upper extremity musculoskeletal disorders in male cameramen

OBJECTIVE

The aim of this study is to determine the risk factors related to upper extremities work-related musculoskeletal disorders (WRMSDs) in cameramen.

METHODS

A questionnaire survey was performed on 166 cameramen in a broadcasting station. The questionnaire consisted of questions on the general characteristics, the health behavior, work type and duration, physical burden, ergonomic posture, and musculoskeletal symptoms. Definition of musculoskeletal disorders was based on NIOSH criteria.

RESULTS

The positive rate of WRMSDs symptoms by parts of the body was turned out to be the highest in the shoulder (14.5%) and the lowest in arm and elbow (6%). Logistic regression analysis revealed that symptoms in the shoulders increased with BMI (OR = 3.62, 95% CI = 1.03-12.71), physical burden (OR = 9.29, 95% CI = 1.72-61.78 in the very hard group) and ergonomic factors (OR = 4.50, 95% CI = 1.03-19.68). Ergonomic factors were only related to the symptoms of hand and wrist (OR = 10.21, 95% CI = 1.02-102.20). WRMSDs symptoms, in the whole upper extremities, were higher in the 50 or older age group (OR = 5.86, 95% CI = 1.03-33.26), higher BMI group (OR = 3.26, 95% CI = 1.28-13.53), non-exercise group (OR = 2.37, 95% CI = 1.24-12.59), high physical burden group (OR = 7.6, 95% CI = 1.34-52.74), and high grade ergonomic risk group (OR = 4.82, 95% CI = 1.29-16.06).

CONCLUSION

The most serious musculoskeletal disorders of male cameramen were shoulder pain. Ergonomic factors and physical burden were the most significant factors affecting WRMSDs in cameramen in this study. Cameramen should be educated to be able to improve the ergonomic occupational environment and to set up preventive measures against the risk factors during work.

The accuracy of conventional 2D video for quantifying upper limb kinematics in repetitive motion occupational tasks

Marker-less 2D video tracking was studied as a practical means to measure upper limb kinematics for ergonomics evaluations. Hand activity level (HAL) can be estimated from speed and duty cycle. Accuracy was measured using a cross-correlation template-matching algorithm for tracking a region of interest on the upper extremities. Ten participants performed a paced load transfer task while varying HAL (2, 4, and 5) and load (2.2 N, 8.9 N and 17.8 N). Speed and acceleration measured from 2D video were compared against ground truth measurements using 3D infrared motion capture. The median absolute difference between 2D video and 3D motion capture was 86.5 mm/s for speed, and 591 mm/s(2) for acceleration, and less than 93 mm/s for speed and 656 mm/s(2) for acceleration when camera pan and tilt were within ± 30 degrees. Single-camera 2D video had sufficient accuracy (< 100 mm/s) for evaluating HAL. Practitioner Summary: This study demonstrated that 2D video tracking had sufficient accuracy to measure HAL for ascertaining the American Conference of Government Industrial Hygienists Threshold Limit Value(®) for repetitive motion when the camera is located within ± 30 degrees off the plane of motion when compared against 3D motion capture for a simulated repetitive motion task.

Evaluation of alternate category structures for the Strain Index: an empirical analysis

OBJECTIVE

The purpose of this study was to develop alternative Strain Index risk classification categories.

BACKGROUND

Strain Index scores are usually categorized into four Strain Index "risk categories." The "original" risk categories were developed in the meat-packing industry and may not be fully applicable to other industries.

METHOD

Daily Strain Index scores were estimated among 276 manufacturing workers participating in a cohort study of occupational risk factors for hand-arm musculoskeletal symptoms. Each score was categorized using the original method and a new method based on quartiles of Strain Index score values among symptomatic participants. Models examining associations between original Strain Index risk categories and incident hand-arm symptoms were compared to models examining associations between the alternative Strain Index risk categories and incident hand-arm symptoms.

RESULTS

Compared to the respective referent categories, a twofold or greater increase in the risk of incident hand-arm symptoms was observed for the highest original Strain Index risk category (HR = 2.06, 95% CI = [1.08-3.92]) and for the second highest alternate Strain Index risk exposure category (HR = 2.21, 95% CI = [1.26-3.85]). Although significant associations between Strain Index risk category and incident hand-arm symptoms were observed for both Strain Index categorization methods, model fit statistics favored the alternate approach.

CONCLUSION

Results from this study suggests that the Strain Index risk category structure may need to be tailored to specific populations.

APPLICATION

If verified, results from this study provide a better way to identify hazardous manufacturing jobs and target them for exposure reduction.