Does team lifting increase the variability in peak lumbar compression in ironworkers?

Ironworkers frequently perform heavy lifting tasks in teams of two or four workers. Team lifting could potentially lead to a higher variation in peak lumbar compression forces than lifts performed by one worker, resulting in higher maximal peak lumbar compression forces. This study compared single-worker lifts (25-kg, iron bar) to two-worker lifts (50-kg, two iron bars) and to four-worker lifts (100-kg, iron lattice). Inverse dynamics was used to calculate peak lumbar compression forces. To assess the variability in peak lumbar loading, all three lifting tasks were performed six times. Results showed that the variability in peak lumbar loading was somewhat higher in the team lifts compared to the single-worker lifts. However, despite this increased variability, team lifts did not result in larger maximum peak lumbar compression forces. Therefore, it was concluded that, from a biomechanical point of view, team lifting does not result in an additional risk for low back complaints in ironworkers.     

The evaluation of team lifting on physical work demands and workload in ironworkers

Lifting and carrying heavy loads occur frequently among ironworkers and result in high prevalence and incidence rates of low back complaints, injuries and work-disability. From a health perspective, little information is available on the effect of team lifting on work demands and workload. Therefore, the objective of this study was to compare the effects of team lifting of maximally 50 kg by two ironworkers (T50) with team lifting of maximally 100 kg by four ironworkers (T100). This study combined a field and laboratory study with the following outcome measures: duration and frequency of tasks and activities, energetic workload, perceived discomfort and maximal compression forces (Fc peak) on the low back. The physical work demands and workload of an individual iron worker during manual handling of rebar materials of 100 kg with four workers did not differ from the manual handling of rebar materials of 50 kg with two workers, with the exception of low back discomfort and Fc peak. The biomechanical workload of the low back exceeded for both T50 and T100 the NIOSH threshold limit of 3400N. Therefore, mechanical transport or other effective design solutions should be considered to reduce the biomechanical workload of the low back and the accompanying health risks among iron workers.     

Psychosocial indicators among aircraft maintenance workers with and without neck and shoulder musculoskeletal symptoms

In the aircraft maintenance industry, most of workers performs manual handling tasks of different materials, varying from small objects up to large pieces of the aircraft. It can increase the occurrence of work-related musculoskeletal disorders (WMSDs), which are strongly associated with high physical demands required by the task. Moreover, psychosocial demands are considered as risk factors for musculoskeletal disorders in both the upper limbs and lumbar spine. Thus, the objective of this study was to assess psychosocial indicators among aircraft maintenance workers according to the presence of neck and shoulder musculoskeletal symptoms. Eighty workers of an aircraft maintenance company were evaluated (32.69 ± 8.25 years, 79.8 ± 13.4 kg, 175 ± 7 cm). According to physical examination, 50 workers were classified as asymptomatic (AS - 4.1 ± 3.17 positive signs) whilst 30 workers were classified as symptomatic (SS - 26.72 ± 11.44 positive signs). AS and SS have shown similar profile of demand (p = 0.62), control (p = 0.66) and social support (p = 0.74) according to the Job Content Questionnaire. However, the groups are different when considering work engagement variables. In general, SS have higher scores than AS (p < 0.05).     

Low back pain disability and stay at work: contradiction or necessity?

The incidence of occupational diseases in the population is high and factors such as long working hours, poor posture, psychological and physical stress can contribute to its development. Among work-related musculoskeletal disorders, back pain has a high prevalence. The aim of the present study was to quantify and characterize pain complaints and to identify individuals with low back pain, in order to assess the degree of disability. Participated 226 employees of an institution of higher education. They answered a general questionnaire about location and quantification of pain complaints visual analog scale for pain and the Quebec Disability Questionnaire. Of all the workers, 69.60% had some type of musculoskeletal complaint; of those, 15.41% had low back pain. Considering workers who had back pain, 54.9% were female, 52.94% are under 30 years old and 43.14% between 1 and 5 years of work. As for the final score for the degree of disability, 41.17% had minimal disability and 37.25% moderate disability. The present study found large number of pain complaints and high prevalence of low back pain, resulting in individual's inability and difficulties in performing work activities.     

Biomechanical analysis of loading/unloading a ladder on a truck

Loading/unloading a ladder on vehicles are frequent tasks and involve overhead handling that may expose workers to risk factors of shoulder musculoskeletal disorders. The objective of the present study was to evaluate posture, forces required and perceived exertion when loading and unloading the ladder on a utility truck. Thirteen male overhead line workers from an electric utility in Brazil participated in this study. Shoulder elevation angle was measured using inclinometers. The required force to load/unload the ladder was measured by dynamometer. Subjective assessment of the perceived exertion was recorded to compare the exertion reported during the test conditions to the field conditions. The task of loading/unloading the ladder presented risks of shoulder musculoskeletal disorders (MSDs) to workers because it requires high levels of force (approximately 60% of the maximal force) combined with overhead posture of the shoulders (more than 100° from the neutral posture). Age and height presented to interfere in biomechanical risks presented in load/unload task. There was no significant difference between the subjective exertion during the test conditions and handling the ladder in the field. Ergonomic intervention is recommended to reduce these risks for shoulder MSDs.     

A polynomial equation to predict low back compression force: accounting for the effects of load height on instability

The purpose of this study was to develop a regression equation that, incorporating the potential energy of the load in the hands, was capable of improved predictions of spinal compression forces. A stepwise polynomial equation was developed from EMG profiles of 15 muscles, and its spinal joint loading predictions at L4/L5 were compared to current methods of calculating spinal compression. Absolute muscle activation was shown to increase with increased loading height, indicating that the central nervous system responds to changes in spinal stability. The inclusion of potential energy into the calculation of spinal disc compression at L4/L5 improved estimates of the compressive forces acting on the spine. This is the first model to incorporate potential energy into a predictive model for lumbar spine compression without the use of electromyography. It was concluded that potential energy plays a vital role in dictating the recruitment patterns of the trunk.     

Biomechanical and organizational risk and prevalence of low back pain in the old adults caregivers of a nursing home in Joao Pessoa/PB

The objective present study was to investigate the presence of low back pain in caregivers of a nursing home, related with the labored activities executed by these workers. 16 subjects were investigated, 15 female and one male, with 40,8 age average all being caregivers as their profession. It consisted of three phases, where the first concerns the analysis of the collective work, assessed in a perspective of caregivers, Second, a postural assessment to verify the retractions in such workers and the third stage was used Diagram of Corllet to identify the presence of signs and symptoms in caregivers. The study demonstrated that organizational and biomechanical factors are responsible for the high level of physical fatigue and presence of pain in 93,75% of the caregivers in some region of the body. 50% referred pain in the lumbar region. The results of the postural evaluation confirmed that the caregivers had alterations in the postural alignment, presenting retractions of the anterior and posterior chain. The suggestions are to minimize the risk factors of this productive process and the symptoms and signals presented from these workers by adoption ergonomic measures and the realization of a physical program with stretching and muscular strengthening of the muscles of the anterior and posterior body chain based on the method of Reorganization Postural Sensoperceptive.     

Musculoskeletal disorders and psychosocial risk factors among workers of the aircraft maintenance industry

During the recent decades Brazil has experienced an exponential growth in the aviation sector resulting in an increasing workforce. The aircraft maintenance industry stands out, where the workers have to handle different kind of objects. The aim of this study was to evaluate psychosocial indicators as well as musculoskeletal symptoms and disorders among aircraft maintenance workers. One hundred and one employees were evaluated (32.69 ± 8.25 yr, 79.8 ± 13.4 kg, and 1.75 ± 0.07 m). Musculoskeletal symptoms and disorders were assessed through the Nordic Musculoskeletal Questionnaire (NMQ) and a standardized physical examination. The Job Content Questionnaire (JCQ) and the Utrecht Work Engagement Scale (UWES) were applied to evaluate psychosocial indicators. Results of the NMQ indicate the lower back as the most affected body region. On the other hand, the physical examination has shown clinical diagnosis of shoulder disorders. Neck, upper back and ankle/foot were also reported as painful sites. Most of workers have active work-demand profile and high work engagement levels. We suggest that musculoskeletal symptoms may be related to high biomechanical demand of the tasks performed by workers, what must be further investigated.     

Comparison of a simulated versus work environment lifting task on L5/S1 compression forces

Since a patient's ability to perform simulated work activities guides return-to-work decisions, a significant question to address is whether the simulated work environment accurately reflects the actual work environment. Work hardening programs have been used extensively as a method of rehabilitating workers to return to their pre-injury functioning levels. Re-training workers to lift boxes is a common method used to simulate the work environment. Although very few boxes used in the real work environment have handles, boxes with handles are often used in the simulated work environment. The difference in compression forces at the L5/S1 joint while lifting boxes with and without handles was investigated. The Lift Trak Motion Analysis system was used to estimate lumbar isometric compression forces exerted while lifting a 20-pound (9.07-kg) box. The results indicated that estimates of compression forces when lifting a box without handles were significantly different (p < 0.01) than when lifting the same box with handles. Based on these results, it is recommended that work hardening professionals carefully re-evaluate the simulated work environments currently being used for treatment.     

Loads on the lumbar spine during a work capacity assessment test

Many clinicians and employers utilise work-related assessment tools for the purposes of identifying whether or not the performance of a specific job exposes an individual to a heightened risk of developing a low back injury. However, research has shown that some of these tools have not been assessed for validity or reliability, and thus may not accurately assess the risk associated with a particular activity. An example of a test employed by some Australian private industries is the Work Capacity Assessment Test, which is a procedure that is commonly used to screen potential employees and evaluate those workers returning to the workplace following injury. This research was designed to simulate the lifting component of the Work Capacity Assessment Test and involved a series of lifts ranging from 2.5 kg to 22.5 kg. Six subjects performed this task, whilst being assessed using two-dimensional videography and surface electromyography. The two-dimensional kinematic data were input into the 4D WATBAK software to quantify the compression forces acting between L4 and L5 during each performance. Results of this study showed that spinal compression and paraspinal muscle activity increased incrementally from the 2.5 kg lift to the 22.5 kg lift, whilst abdominal muscle activity also increased across the lifts. This study demonstrated that lifting masses of 22.5 kg or more can produce loads on the spine that are considered potentially hazardous, when compared to safe lifting guidelines, and indicated that there is a clear concern for the use of such lifting tasks in the evaluation of workers following injury.     

Cut-points to prevent low back injury due to force exertion at work

Force exertion is related to low back injuries (LBI). This paper critically reviews the literature concerning cut-points for back force exertion, presents available guidelines in a concise manner, and identifies areas that need further research. The studies reviewed were grouped according to the criteria used to set the cut-point values. Most often cut-points differ than concur. The approach considering physiological, psychophysical, epidemiological, and biomechanical aspects of back force exertion meets the most known criteria and presents the lowest common denominator of instantaneous load for lifting tasks. Further experimental and epidemiological studies in peak load and cumulative exposure are necessary. Compound indices should also be developed for pushing, pulling, and carrying. Future indices should consider electromyographically determined fatigue, differential viscoelastic properties of tissues, aging, and the cross sectional area of back muscles. We hope that this paper contributes to a more systematic appraisal of back force exertion at work.     

Evaluation of a personal device in reducing the risk of low back disorders during stooped work

Adoption of the stooped posture in the workplace is widespread throughout the world in agriculture, construction, and mining. This type of posture has been established as a risk factor for developing low back disorders (LBDs). The purpose of this study is to evaluate a personal weight transfer device as a possible intervention to reduce the load on the lumbar spine, thereby reducing the risk of developing LBDs. Eighteen healthy subjects performed stooped posture tasks in a laboratory study designed to simulate harvesting of low-growing crops. Results showed that when wearing the device in the static stooped posture, biceps femoris activity was reduced by 17%, lumbar flexion was reduced by 12%, ankle plantar-flexion increased by 5%, and the lumbar erector spinae of those subjects who did not experience flexion-relaxation of the erector spinae was reduced by 26%. Hip and knee flexion were not significantly altered. Therefore, the device may be beneficial for those with existing LBDs, and who use the stooped posture routinely.     

Biomechanical modelling and evaluation of construction jobs for performance improvement

Occupational risk factors, such as awkward posture, repetition, lack of rest, insufficient illumination and heavy workload related to construction-related MMH activities may cause musculoskeletal disorders and poor performance of the workers, ergonomic design of construction worksystems was a critical need for improving their health and safety wherein a dynamic biomechanical models were required to be empirically developed and tested at a construction site of Tata Steel, the largest steel making company of India in private sector. In this study, a comprehensive framework is proposed for biomechanical evaluation of shovelling and grinding under diverse work environments. The benefit of such an analysis lies in its usefulness in setting guidelines for designing such jobs with minimization of risks of musculoskeletal disorders (MSDs) and enhancing correct methods of carrying out the jobs leading to reduced fatigue and physical stress. Data based on direct observations and videography were collected for the shovellers and grinders over a number of workcycles. Compressive forces and moments for a number of segments and joints are computed with respect to joint flexion and extension. The results indicate that moments and compressive forces at L5/S1 link are significant for shovellers while moments at elbow and wrist are significant for grinders.     

Mitigation of musculoskeletal problems and body discomfort of agricultural workers through educational intervention

Farming is a physically arduous occupation that places farm workers' at potential risk of musculoskeletal disorders, which has been observed to impose a greater impact on their health. Each activity in agriculture brings about certain stress and strain on bones and muscles leading to work-related musculoskeletal disorders which can lead to several permanent diseases and disabilities. The purpose of analyzing musculoskeletal problems among male and female workers engaged in agriculture was to know about the risk factors dangerous to health so that interventions can be planned for mitigating them thereby increasing the efficiency of work. Educational intervention included audio-visual aids as well as printed literature. It was hoped that awareness of these factors through dissemination of information would contribute at preventing hazards amongst farmers and their families. The results revealed that the workers reported very severe to severe pain in low back while performing agricultural activities. Weeding was the most strenuous activity for females and threshing crop for males. Training and education on MSDs through educational intervention proved that the knowledge of the farm workers could be enhanced and can help reduce risk of many musculoskeletal problems. It can be help in empowering the community and mitigate MSDs in agriculture.     

Family comes first or open all hours?: How low paid women working in food retailing manage webs of obligation at home and work

This paper draws on qualitative findings from a study exploring work-life balance issues amongst female employees within food retailing. Whilst female employment is fundamental to this sector, there is limited evidence on employees' experiences of reconciling relatively low-paid work and the particular demands of food retailing with domestic and caring responsibilities. Managing competing discourses and demands at home and work is a feature of many women's lives. For those in low-paid jobs, with fewer material resources to fall back on, such webs of obligation, often stretching over the lifecourse, may be particularly difficult to navigate or escape. In food retail work, as in caring/domestic emergencies, timeframes may be tight and demands made on workers at short notice and outwith the standard working day. The study showed that sustaining their moral identities both as good mothers/daughters/family members ('family comes first') and as good and reliable workers ('the store must be staffed') was, therefore, an everyday practical accomplishment for these food retail employees. We explore women's accounts against the backdrop of particular familial, workplace and socio-cultural expectations and constraints, identifying overlapping sets of values between home and work as well as points of contradiction and tension.     

Musculoskeletal symptoms among dentists in relation to work posture

OBJECTIVE: To determine the effect of work posture on musculosketal complaints in Israeli dentists. METHODS: The population included 60 male dentists mean age was 46.0 (+/- SD 8.66), 30 worked in sitting position and 30 were altering positions. Study population completed the standardized Nordic questionnaire and informative form concerning recipient's practice of dentistry, bio-demographic variables and questions about workloads. RESULTS: Musculoskeletal symptoms in the last 12 months were localized primarily in the lower back and in the neck (55% and 38.3% respectively). There was a significant correlation between the time spent sitting and the severity of low back pain (r = 0.41, p = 0.01). On the other hand there was no significant correlation between time spent sitting and other musculoskeletal complaints (r = - 0.16). CONCLUSIONS: Dentists who work in the sitting position have more severe low back pain than do those who alternate between sitting and standing despite the fact that those who sat at least 80% of the time worked less hours and had less of a workload during their working hours. This suggests that altering position should be recommended to dentists. An intervention study, however, is needed to demonstrate that changing posture will decrease the prevalence of low back pain in dentists.