Association between working in awkward postures, in particular overhead work, and pain in the shoulder region in the context of the 2018 BIBB/BAuA Employment Survey

Impact of a passive upper-body exoskeleton on muscular activity and precision in overhead single and dual tasks: an explorative randomized crossover study

Introduction

Tasks performed at or above head height in industrial workplaces pose a significant challenge due to their association with musculoskeletal disorders. Upper-body exoskeletons have been identified as a potential solution for mitigating musculoskeletal loads and fighting against excessive muscular fatigue. However, the influence of such support on fine motor control, as well as on cognitive-motor interference, has received limited attention thus far. Therefore, this crossover randomized study aimed to investigate the impact of the use of a passive upper-body exoskeleton in the presence of muscular fatigue or not. Additionally, focusing on differences between single (ST) and dual (DT) industrial tasks consisting of overhead speed and accuracy exercises.

Methods

In both scenarios, N = 10 participants (5 male/5 female) engaged in an overhead precision task using a nail gun to precisely target specific areas on three differently sized regions, based on Fitts' law paradigm (speed-accuracy trade-off task). This was done with and without the passive upper-body exoskeleton, before and immediately after a fatiguing exercise of shoulder and leg muscles. In addition, a second task (dual-task, DT) was carried out in which the occurrence of an auditory signal had to be counted. The main outcomes were muscular activation of the shoulder girdle as well as the time to perform speed-accuracy tasks of different difficulty indexes (calculated by means of Fitts' law).

Results and discussion

In the absence of fatigue, the exoskeleton did not affect the speed-accuracy trade-off management of participants in the single task, but it did in the dual-task conditions. However, after muscle fatigue, the speed-accuracy trade-off was differently affected when comparing its execution with or without the exoskeleton. In general, the dual task resulted in longer times to perform the different tasks, whether it was with or without the exoskeleton. Furthermore, the use of the exoskeleton decreased muscle activity, which is associated with less physical effort, but only significantly for the M. deltoideus and M. trapezius when compared by tasks. Overall, these study findings highlight the potential supportive effects of using an upper-body exoskeleton for industrial overhead tasks.

Factors associated with frozen shoulder in adults: a retrospective study

OBJECTIVE

This study aims to explore the risk factors associated with frozen shoulder patients and further analyze the relationship between gender and diabetes with frozen shoulder.

METHOD

We have reviewed the data of 1205 frozen shoulder patients in China's Xinjiang region from 2018 to 2023. The collected information included patients' gender, occupation, place of origin, marital status, age, the season of disease onset, duration of illness, etiology, surgical history, hypertension, diabetes, respiratory diseases, knee joint disease, hyperlipidemia, cardiovascular diseases, cervical spondylosis, lumbar disc herniation, rheumatoid arthritis, hyperuricemia, sleep quality, smoking and alcohol consumption, and constipation. We have used multifactor logistic regression analysis to identify the risk factors for a frozen shoulder.

RESULTS

Single-factor logistic regression analysis showed that the number of females, patients with diabetes, knee joint disease, constipation, and patients with poor sleep quality in the observation group are higher than in the control group (P < 0.05). There were no statistically significant differences between the two groups in terms of occupation, place of origin, marital status, age, season of disease onset, duration of illness, etiology, surgical history, hypertension, respiratory diseases, hyperlipidemia, cardiovascular diseases, cervical spondylosis, lumbar disc herniation, rheumatoid arthritis, hyperuricemia, smoking, and alcohol consumption history (P > 0.05). Multivariate analysis showed that the final model included four variables: gender, diabetes history, sleep, and constipation. Among them, the OR values of gender and diabetes history were more significant than 1, indicating that they were independent risk factors for frozen shoulder, while the OR values of sleep and constipation were less than 1, suggesting that they were negatively associated with the occurrence of frozen shoulder.

CONCLUSION

The results of this study suggest that gender and diabetes are independent risk factors for frozen shoulder. Additionally, poor sleep quality and constipation also can be correlated with the occurrence of a frozen shoulder.

A Novel IMU-Based System for Work-Related Musculoskeletal Disorders Risk Assessment

This study introduces a novel wearable Inertial Measurement Unit (IMU)-based system for an objective and comprehensive assessment of Work-Related Musculoskeletal Disorders (WMSDs), thus enhancing workplace safety. The system integrates wearable technology with a user-friendly interface, providing magnetometer-free orientation estimation, joint angle measurements, and WMSDs risk evaluation. Tested in a cable manufacturing facility, the system was evaluated with ten female employees. The evaluation involved work cycle identification, inter-subject comparisons, and benchmarking against standard WMSD risk assessments like RULA, REBA, Strain Index, and Rodgers Muscle Fatigue Analysis. The evaluation demonstrated uniform joint patterns across participants (ICC=0.72±0.23) and revealed a higher occurrence of postures warranting further investigation, which is not easily detected by traditional methods such as RULA. The experimental results showed that the proposed system's risk assessments closely aligned with the established methods and enabled detailed and targeted risk assessments, pinpointing specific bodily areas for immediate ergonomic interventions. This approach not only enhances the detection of ergonomic risks but also supports the development of personalized intervention strategies, addressing common workplace issues such as tendinitis, low back pain, and carpal tunnel syndrome. The outcomes highlight the system's sensitivity and specificity in identifying ergonomic hazards. Future efforts should focus on broader validation and exploring the relative influence of various WMSDs risk factors to refine risk assessment and intervention strategies for improved applicability in occupational health.

Prevalence of shoulder pain and its correlates in Jeju agricultural population: A retrospective cross-sectional study

The aim of this study was to investigate the prevalence of shoulder pain and analyze its association with socio-demographic factors, agricultural work-related conditions, and biomechanical factors among farmers on Jeju Island. We utilized initial survey data from the Safety for Agricultural Injury of Farmers' cohort study involving adult farmers on Jeju Island. The presence and characteristics of shoulder pain, socio-demographics, agricultural work-related conditions, and biomechanical factors were assessed using semi-structured questionnaires. A total of 1206 participants were analyzed for prevalence and associated risk factors using frequency and multivariate logistic regression analyses. The overall prevalence of shoulder pain was 17%. Multivariate logistic regression analysis, adjusted for significant socio-demographic and agricultural work-related condition variables, revealed that stress level, type of farming, and experiencing an agricultural injury within the preceding year were significantly associated with shoulder pain (stress level: "occasional," adjusted odds ratio [aOR], 1.581; 95% confidence interval [CI], 1.079-2.318; "frequent," aOR, 1.964; 95% CI, 1.205-3.200; and "extreme," aOR, 2.999; 95% CI, 1.480-6.074 vs "rarely"; type of farming: "orchard," aOR, 0.82; 95% CI, 0.597-1.124; "livestock," aOR, 0.225; 95% CI, 0.079-0.641 vs "field"; and experienced an agricultural injury within the past year: "yes," aOR, 2.078; 95% CI, 1.269-3.405). In addition, 3 biomechanical factors significantly contributed to shoulder pain: activities requiring significant power such as shoveling, pickaxing, and hammering; repetitive use of a particular body part; and constant elevation of the arm above the head. The findings highlight the importance of postural education, injury prevention, and psychological support in managing shoulder pain among farmers.

Effect of passive shoulder exoskeleton support during working with arms over shoulder level

Musculoskeletal disorders have the highest prevalence of work-related health problems. Due to the aging population, the prevalence of shoulder pain in workers in physically demanding occupations is increasing, thereby causing rising costs to society and underlining the need for preventive technologies. Wearable support structures are designed to reduce the physical work load during physically demanding tasks. Here, we evaluate the physiological benefit of the DeltaSuit, a novel passive shoulder exoskeleton, using an assessment framework that conforms to the approach proposed in the literature. In this study, 32 healthy volunteers performed isometric, quasi-isometric, and dynamic tasks that represent typical overhead work to evaluate the DeltaSuit performance. Muscle activity of the arm, neck, shoulder, and back muscles, as well as cardiac cost, perceived exertion, and task-related discomfort during task execution with and without the exoskeleton were compared. When working with the DeltaSuit, muscle activity was reduced up to 56% (p < 0.001) in the Trapezius Descendens and up to 64% (p < 0.001) in the Deltoideusmedius. Furthermore, we observed no additional loading on the abdomen and back muscles. The use of the exoskeleton resulted in statistically significant reductions in cardiac cost (15%, p < 0.05), perceived exertion (21.5%, p < 0.001), and task-related discomfort in the shoulder (57%, p < 0.001). These results suggest that passive exoskeletons, such as the DeltaSuit, have the potential to meaningfully support users when performing tasks in overhead postures and offer a valuable solution to relieve the critical body parts of biomechanical strains for workers at high risk of musculoskeletal disorders.

Effects of back-support exoskeletons with different functional mechanisms on trunk muscle activity and kinematics

Musculoskeletal disorders constitute the leading work-related health issue. Mechanical loading of the lower back contributes as a major risk factor and is prevalent in many tasks performed in logistics. The study aimed to compare acute effects of exoskeletons with different functional mechanisms in a logistic task. Twelve young, healthy individuals participated in the study. Five exoskeletons with different functional mechanisms were tested in a logistic task, consisting of lifting, carrying, and lowering a 13 kg box. By using electromyography (EMG), mean muscle activities of four muscles in the trunk were analyzed. Additionally, kinematics by task completion time and range of motion (RoM) of the major joints and segments were investigated. A main effect was found for Musculus erector spinae, Musculus multifidus, and Musculus latissimus dorsi showing differences in muscle activity reductions between exoskeletons. Reduction in ES mean activity compared to baseline was primarily during lifting from ground level. The exoskeletons SoftExo Lift and Cray X also showed ES mean reduction during lowering the box. Prolonged task duration during the lifting phase was found for the exoskeletons BionicBack, SoftExo Lift, and Japet.W. Japet.W showed a trend in reducing hip RoM during that phase. SoftExo Lift caused a reduction in trunk flexion during the lifting phase. A stronger trunk inclination was only found during lifting from the table for the SoftExo Lift and the Cray X. In conclusion, muscle activity reductions by exoskeleton use should not be assessed without taking their designed force paths into account to correctly interpret the effects for long-term injury prevention.

Ergonomic Risk Factors for Musculoskeletal Disorders among Ethnic Lychee-Longan Harvesting Workers in Northern Thailand

Musculoskeletal disorders (MSDs) are one of the leading causes of occupational injuries and disabilities. The purpose of this study was to assess the prevalence of MSDs and occupational factors affecting MSDs among ethnic lychee-longan harvesting workers in northern Thailand. A cross-sectional study was conducted in the areas of three upper northern provinces of Thailand. The study areas are located in the highlands and rural plains, where many ethnic minority groups live, including Indigenous, Mien, Karen, and Lua. The majority of them work in a farm of perennial fruit trees, mainly lychee and longan. During the harvest season, 404 participants were recruited for the study using the convenience sampling technique. Data were collected using questionnaires that included general information, an ergonomic risk assessment, and a standardized Nordic questionnaire for assessing MSDs in 10 body parts. The average age of lychee-longan harvesting workers was 48.8 years. Almost all (99.5%) reported MSDs in one or more body regions in the previous seven days of work. The prevalence of MSDs was highest in the hands (82.9%), followed by the shoulders (82.2%) and the neck (79.7%). The total ergonomic risk scores, which included awkward posture, heavy carrying and lifting, repetitive activity, land slope, and equipment, were found to be significantly associated with MSDs in part of the neck (AOR = 1.17, 95%CI = 1.11-1.23), shoulder (AOR = 1.15, 95%CI = 1.10-1.21), elbow (AOR = 1.18, 95%CI = 1.12-1.24), hand (AOR = 1.12, 95%CI = 1.07-1.18), finger (AOR = 1.33, 95%CI = 1.24-1.44), upper back (AOR = 1.14, 95%CI = 1.09-1.20), lower back (AOR = 1.16, 95%CI = 1.11-1.22), hip (AOR = 1.11, 95%CI = 1.06-1.15), knee (AOR = 1.18, 95%CI = 1.12-1.24), and feet (AOR = 1.21, 95%CI = 1.15-1.28) when adjusting for ethnicity, sex, age, BMI, and work experience. Many parts of ethnic workers' bodies have been affected by occupational injuries, with a high risk of upper extremity injury. As a result, using an ergonomic approach to improving the working environment and appropriate posture movement is very beneficial in preventing MSDs among ethnic harvesting workers.

Manual handling of heavy loads and low back pain among different occupational groups: results of the 2018 BIBB/BAuA employment survey

Background

In Germany and other European countries, many occupations still involve manual handling of loads (MHL), an activity that puts the musculoskeletal system at risk of low back pain (LBP). This study aims to describe the current prevalence of MHL in different occupational groups stratified by gender in Germany, the association between MHL and LBP and the adjusted prevalence of LBP in different respond-categories of MHL.

Methods

Data was collected in telephone interviews conducted as part of the 2018 BIBB/BAuA Employment Survey, which covers work-related topics like working conditions, education, health status and job satisfaction. The analyses were limited to full-time workers (> 35 h/week) aged between 15 and 67. The frequency of MHL was analysed descriptively. BLOSSFELD classification was used to group the participants in occupational categories. The analysis of the association between MHL and the prevalence of LBP over the last 12 months was based on robust log-linear Poisson regression that results in prevalence ratios (PR). The main regression model was adjusted for gender, age, working hours, and working conditions. Adjusted estimates for the prevalence of LBP were calculated based on regression analysis.

Results

The sample consists of n = 14,331 participants (men: n = 8828, 61.6%; women: n = 5503, 38.4%; median age 49 years). Of these, 52.8% say they were exposed to MHL at work. MHL is most common in agricultural occupations, skilled and unskilled occupations. In the regression model, participants who said they were “often” exposed to MHL reported more frequently LBP than those participants who said they were “never” exposed to MHL. The PR as estimate for the association is 1.41 (95%CI [1.32; 1.49]). Postestimation of the prevalence of LBP began with 47.3% (95%CI [43.8%; 51.1%]) for participants who said they were “never” exposed to MHL and rose to 66.5% (95%CI [62.4%; 71.0%]) for participants who indicated they were “often” exposed to MHL.

Conclusions

The 2018 BIBB/BAuA Employment Survey emphasizes that MHL is still common in the German workforce and shows a significant association to LBP. Prevention policies for avoiding MHL remain vital.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04819-z.