Validity and reliability of Japanese version of MAPO index for assessing manual patient handling in nursing homes

OBJECTIVES

Low back pain (LBP) among caregivers in Japanese nursing homes has long been considered an occupational health issue. This study aims to verify the reliability and validity of our developed Japanese version of the Movement and Assistance for Hospitalized Patients (J-MAPO) index, a risk assessment tool for LBP, in nursing homes.

METHODS

Two inspectors assessed 15 nursing homes using J-MAPO, and deduced three LBP risk levels as follows: low, moderate, and high risk. Caregivers in nursing homes responded to a self-administered questionnaire on LBP over the past 12 months. Data from 296 caregivers with no missing data were used. We further used logistic regression models to analyze the association between LBP as a dependent variable, and J-MAPO risk level as an independent variable. We used Cohen's kappa coefficient to assess inter-rater reliability to further assess the agreement between the two inspectors.

RESULTS

The multivariate logistic regression analysis showed that the adjusted odds ratio and 95% confidence intervals for LBP increased progressively with J-MAPO risk level (Low-risk: 1.00; Moderate-risk: 1.70 [0.74-3.91]; High-risk: 2.67 [1.28-5.56]). Furthermore, the J-MAPO risk levels assessed by the two inspectors were in perfect agreement (κ = 1) observed for inter-rater reliability using Cohen's kappa coefficient.

CONCLUSIONS

High inter-rater reliability and J-MAPO risk levels were associated with LBP. Therefore, our results suggest that the J-MAPO is a useful risk assessment tool for LBP in Japanese nursing homes.

The highs and lows of lifting loads: SPM analysis of multi-segmental spine angles in healthy adults during manual handling with increased load

Introduction: Manual handling personnel and those performing manual handling tasks in non-traditional manual handling industries continue to suffer debilitating and costly workplace injuries. Smart assistive devices are one solution to reducing musculoskeletal back injuries. Devices that provide targeted assistance need to be able to predict when and where to provide augmentation via predictive algorithms trained on functional datasets. The aim of this study was to describe how an increase in load impacts spine kinematics during a ground-to-platform manual handling task. Methods: Twenty-nine participants performed ground-to-platform lifts for six standardised loading conditions (50%, 60%, 70%, 80%, 90%, and 100% of maximum lift capacity). Six thoracic and lumbar spine segments were measured using inertial measurement units that were processed using an attitude-heading-reference filter and normalised to the duration of the lift. The lift was divided into four phases weight-acceptance, standing, lift-to-height and place-on-platform. Statistical significance of sagittal angles from the six spine segments were identified through statistical parametric mapping one-way analysis of variance with repeated measures and post hoc paired t-tests. Results: Two regions of interest were identified during a period of peak flexion and a period of peak extension. There was a significant increase in spine range of motion and peak extension angle for all spine segments when the load conditions were increased (p < 0.001). There was a decrease in spine angles (more flexion) during the weight acceptance to standing phase at the upper thoracic to upper lumbar spine segments for some condition comparisons. A significant increase in spine angles (more extension) during the place-on-platform phase was seen in all spine segments when comparing heavy loads (>80% maximum lift capacity, inclusive) to light loads (<80% maximum lift capacity) (p < 0.001). Discussion: The 50%-70% maximum lift capacity conditions being significantly different from heavier load conditions is representative that the kinematics of a lift do change consistently when a participant's load is increased. The understanding of how changes in loading are reflected in spine angles could inform the design of targeted assistance devices that can predict where and when in a task assistance may be needed, possibly reducing instances of back injuries in manual handling personnel.

The Three-Dimensional Body Center of Mass at the Workplace under Hypogravity

The center of mass dynamics of the seated posture of humans in a work environment under hypogravity (0 < g < 1) have rarely been investigated, and such research is yet to be carried out. The present study determined the difference in the body system of 32 participants working under simulated 1/6 g (Moon) and 1 g (Earth) for comparison using static and dynamic task measurements. This was based on a markerless motion capture method that analyzed participants' center of mass at the start, middle and end of the task when they began to get fatigued. According to this analysis, there is a positive relationship (p < 0.01) with a positive coefficient of correlation between the downward center of mass body shift along the proximodistal axis and gravity level for males and females. At the same time, the same positive relationship (p < 0.01) between the tilt of the body backward along the anterior-posterior axis and the level of gravity was found only in females. This offers fresh perspectives for comprehending hypogravity in a broader framework regarding its impact on musculoskeletal disorders. It can also improve workplace ergonomics, body stability, equipment design, and biomechanics.

Effects of Slide Sheet Use and Bed Position on Muscle Activities in the Low Back and Extremities: A Pilot Experimental Simulation Study

BACKGROUND

Low-friction slide sheets (SS) are designed to reduce compression loads on the body during manual handling tasks, such as boosting patients. Using SS has been shown to decrease muscle activity in the lower back and upper extremities. However, it is unclear if this effect varies with different bed positions. To investigate this, we studied the effects of SS use, bed height, and their combination on muscle activity during a simulated patient boost.

METHODS

Thirty-three Japanese undergraduate students (age 21.0 ± 1.1 years; 14 men, 19 women) participated. Participants were asked to boost a dummy figure on the bed three times each using four conditions. During the repositioning task, electromyography of eight muscles of the lower back and upper and lower extremities, hip and knee joint flexion angles, pelvic forward tilt angle, and position of the center of mass based on the posterior superior iliac spine were evaluated.

FINDINGS

Electrophysiological activities of muscles of lower back and upper extremities were significantly lower with SS than without it in both bed positions (30% and 40% of body height); the reduction in muscle activities with SS use was 20% to 40%. Lowering the bed did not affect the SS effect magnitude on reducing muscle activities, although postural changes, including hip and knee joint flexion, were observed.

CONCLUSIONS/APPLICATION TO PRACTICE

SS reduced muscle activities in the back, upper, and lower extremities when the bed was in the low position, and this effect persisted at a bed height of ≥30% of the participant's height.

An Exploration of the Influence of Non-Biomechanical Factors on Lifting-Related LBP

Objective: The primary objective was to compare non-biomechanical factors between manual workers with and without a history of LBP related to lifting. A secondary objective was to investigate associations between the change in pain intensity during repeated lifting (termed pain ramp) and non-biomechanical factors tested in the LBP group. Methods: Manual workers currently in lifting occupations with and without a history of lifting-related LBP were recruited (21 LBP and 20 noLBP) and took part in a repeated (100) lift task. A series of non-biomechanical factors, including psychological, work-related, lifestyle, whole health and psychophysical factors, were collected. Psychophysical factors (pressure pain thresholds (PPTs) and fatigue) were also measured at different time points. Associations between pain ramp during lifting and non-biomechanical factors were investigated with linear regression. Results: The LBP group reported worse perceived sleep quality, more musculoskeletal pain sites other than LBP and greater symptoms related to gastrointestinal complaints and pseudo-neurology compared to the group with no history of LBP. The group with LBP were also slightly more worried about the lifting task and felt more fatigued at the end of the lifting task. The feeling of fatigue during lifting was positively associated with pain ramp in the LBP group. Anxiety and gastrointestinal complaints were weakly negatively associated with pain ramp during lifting. Conclusions: The group differences of poorer perceived sleep, greater non-specific health complaints, slightly more worry about the lifting task and more perceived fatigue in the LBP group highlight the complex and multi-factorial nature of LBP related to lifting. The feeling of fatigue was positively associated with pain ramp in the LBP group, suggesting a close relationship with pain and fatigue during lifting that requires further exploration.

A systematic literature review of evidence for the use of assistive exoskeletons in defence and security use cases

Advances in assistive exoskeleton technology, and a boom in related scientific literature, prompted a need to review the potential use of exoskeletons in defence and security. A systematic review examined the evidence for successful augmentation of human performance in activities deemed most relevant to military tasks. Categories of activities were determined a priori through literature scoping and Human Factors workshops with military stakeholders. Workshops identified promising opportunities and risks for integration of exoskeletons into military use cases. The review revealed promising evidence for exoskeletons' capacity to assist with load carriage, manual lifting, and working with tools. However, the review also revealed significant gaps in exoskeleton capabilities and likely performance levels required in the use case scenarios. Consequently, it was recommended that a future roadmap for introducing exoskeletons to military environments requires development of performance criteria for exoskeletons that can be used to implement a human-centred approach to research and development.

Optimizing aged care environments to promote resident functional mobility and reduce staff injury risk

Introduction: This study aimed to evaluate the suitability and usability of the Pro-Mobility patient/person handling assessment tool (ProMob) within residential aged care. Physiological changes associated with ageing influence an older person's ability to perform functional mobility tasks such as transferring from furniture and walking. Strategies that improve capability and/or reduce the physical demands of the task have the potential to promote an older person's mobility, independence and wellbeing. Environment-related strategies in Manual Handling of People (MHP), such as optimum seated heights, in part address this challenge, as they can promote resident functional mobility while also protecting staff from injury. The ProMob tool was developed to address this issue through systematic evaluation of these environmental factors. Methods: The participants in this study were seven (7) residential aged care facilities (RACFs) operated by a not-for-profit aged care organization. A qualified assessor evaluated MHP risk management with the ProMob tool at each RACF through collection of data for a random sample of residents (n = 67) regarding their living environments and available mobility information. Data was transferred to an SPSS-22 statistical software database for analysis which involved descriptive statistics and cross tabulations. Results: Application of the ProMob tool provided effective quantification of the nature and extent of environment-related MHP interventions that may influence resident mobility. Areas for improvement with MHP risk management were identified, with variation evident across RACF's within the same organisation, which was not consistent with levels of care (e.g., lack of clear space to facilitate mobility). Low level care facilities were observed to have fewer adaptive environmental features that could potentially slow decline in independence. Discussion: Features of the aged care environment can be used to facilitate the functional mobility of aged care residents, and simultaneously reduce injury risk for staff in MHP interactions. The ProMob tool can be used for auditing care facilities, planning re-development, and continual improvement in provision of care and management of staff injury risk exposure.

Does intra-lumbar flexion during lifting differ in manual workers with and without a history of low back pain? A cross-sectional laboratory study

Advice to limit or avoid a flexed lumbar curvature during lifting is widely promoted to reduce the risk of low back pain (LBP), yet there is very limited evidence to support this relationship. To provide higher quality evidence this study compared intra-lumbar flexion in manual workers with (n = 21) and without a history of LBP (n = 21) during a repeated lifting task. In contrast to common expectations, the LBP group demonstrated less peak absolute intra-lumbar flexion during lifting than the noLBP group [adjusted difference -3.7° (95%CI -6.9 to -0.6)]. The LBP group was also further from the end of range intra-lumbar flexion and did not use more intra-lumbar range of motion during any lift condition (both symmetrical and asymmetrical lifts and different box loads). Peak absolute intra-lumbar flexion was more variable in the LBP group during lifting and both groups increased their peak absolute intra-lumbar flexion over the lift repetitions. This high-quality capture of intra-lumbar spine flexion during repeated lifting in a clinically relevant cohort questions dominant safe lifting advice.Practitioner summary: Lifting remains a common trigger for low back pain (LBP). This study demonstrated that people with LBP, lift with less intra-lumbar flexion than those without LBP. Providing the best quality in-vivo laboratory evidence, that greater intra-lumbar flexion is not associated with LBP in manual workers, raising questions about lifting advice.

Healthcare worker choice and low back force between self-chosen and highest bed height when boosting a patient up in bed

Healthcare workers have a high rate of low back injury due to patient handling tasks. These workers receive training in patient handling methods such as adjusting bed height, but often ignore them. In this study, 35 healthcare workers completed patient boosts at a self-chosen bed height and again with the bed in a higher standardised position. Motion capture and force data were collected for analysis. Given the choice, less than half of participants adjusted the bed at all and none of them moved the bed to the highest position (99.1 cm). The self-chosen bed position yielded significantly higher low back force than the higher position at L4-L5 and L5-S1 (p = 0.02, p = 0.01 respectively). Low back forces can be reduced by raising the bed prior to engaging in patient handling tasks, which is a simple step that can reduce forces placed on healthcare workers' low backs. Practitioner summary: Healthcare workers experience high rates of low back pain secondary to patient handling tasks. In this cross-sectional crossover study, healthcare workers consistently chose a low bed height when boosting a patient, which resulted in higher low back loads compared to the highest bed height.

Biomechanical Analysis of Stoop and Free-Style Squat Lifting and Lowering with a Generic Back-Support Exoskeleton Model

Musculoskeletal disorders (MSDs) induced by industrial manual handling tasks are a major issue for workers and companies. As flexible ergonomic solutions, occupational exoskeletons can decrease critically high body stress in situations of awkward postures and motions. Biomechanical models with detailed anthropometrics and motions help us to acquire a comprehension of person- and application-specifics by considering the intended and unintended effects, which is crucial for effective implementation. In the present model-based analysis, a generic back-support exoskeleton model was introduced and applied to the motion data of one male subject performing symmetric and asymmetric dynamic manual handling tasks. Different support modes were implemented with this model, including support profiles typical of passive and active systems and an unconstrained optimal support mode used for reference to compare and quantify their biomechanical effects. The conducted simulations indicate that there is a high potential to decrease the peak compression forces in L4/L5 during the investigated heavy loaded tasks for all motion sequences and exoskeleton support modes (mean reduction of 16.0% without the optimal support mode). In particular, asymmetric motions (mean reduction of 11.9%) can be relieved more than symmetric ones (mean reduction of 8.9%) by the exoskeleton support modes without the optimal assistance. The analysis of metabolic energy consumption indicates a high dependency on lifting techniques for the effectiveness of the exoskeleton support. While the exoskeleton support substantially reduces the metabolic cost for the free-squat motions, a slightly higher energy consumption was found for the symmetric stoop motion technique with the active and optimal support mode.

Care after death in children's hospices: recommendations for moving and handling, and for managing physiological deterioration

BACKGROUND

Children's hospices provide a range of services for babies, children and young people who have a life-limiting or life-threatening condition, including care after death in specialist 'cool bedrooms'. Care after death is a challenging but important element of hospice care.

AIM

The aims of the study were to identify the practices of staff providing care after death in UK children's hospices, notably their moving and handling practices and their management of physiological deterioration, and to produce recommendations that promote safe and consistent practice in moving and handling and in managing physiological deterioration after death in UK children's hospices.

METHOD

An electronic survey was sent to all 54 UK children's hospices. Free-text responses were analysed using deductive content analysis and used to add depth to the quantitative findings.

FINDINGS

Out of 54 children's hospices, 33 responded to the survey. There were great variations in the way hospices delivered care after death, notably in length of stay, interventions and equipment. The lack of consistent practice grounded in evidence-based policy and training may mean that some staff experience higher levels of stress and anxiety than others and that some staff take risks when providing care after death, particularly to express empathy towards bereaved families.

CONCLUSION

Recommendations are made about moving and handling a child's body after death and managing its physiological deterioration. Hospices can use these recommendations to develop policy and training, standardise what is expected of staff and support practitioners in adequately caring for children after death.

Ergonomics in the anaesthetic workplace: Guideline from the Association of Anaesthetists

Ergonomics in relation to anaesthesia is the scientific study of the interaction between anaesthetists and their workspace environment in order to promote safety, performance and well-being. The foundation for avoiding pain or discomfort at work is to adopt and maintain a good posture, whether sitting or standing. Anaesthetists should aim to keep their posture as natural and neutral as possible. The successful practice of anaesthesia relies on optimisation of ergonomics and lack of attention to detail in this area is associated with impaired performance. The anaesthetic team should wear comfortable clothing, including appropriately-sized personal protective equipment where necessary. Temperature, humidity and light should be adequate at all times. The team should comply with infection prevention and control guidelines and monitoring as recommended by the Association of Anaesthetists. Any equipment or machinery that is mobile should be positioned where it is easy to view or reach without having to change the body or head position significantly when interacting with it. Patients who are supine should, whenever possible, be raised upwards to limit the need to lean towards them. Any item required during a procedure should be positioned on trays or trolleys that are close to the dominant hand. Pregnancy affects the requirements for standing, manually handling, applying force when operating equipment or moving machines and the period over which the individual might have to work without a break. Employers have a duty to make reasonable adjustments to accommodate disability in the workplace. Any member of staff with a physical impairment needs to be accommodated and this includes making provision for a wheelchair user who needs to enter the operating theatre and perform their work.

Effects of industrial back-support exoskeletons on body loading and user experience: an updated systematic review

This study is an updated systematic review of papers published in the last 5 years on industrial back-support exoskeletons. The research questions were aimed at addressing the recent findings regarding objective (e.g. body loading, user performance) and subjective evaluations (e.g. user satisfaction), potential side effects, and methodological aspects of usability testing. Thirteen studies of active and twenty of passive exoskeletons were identified. The exoskeletons were tested during lifting and bending tasks, predominantly in laboratory settings and among healthy young men. In general, decreases in participants' back-muscle activity, peak L5/S1 moments and spinal compression forces were reported. User endurance during lifting and static bending improved, but performance declined during tasks that required increased agility. The overall user satisfaction was moderate. Some side effects were observed, including increased abdominal/lower-limb muscle activity and changes in joint angles. A need was identified for further field studies, involving industrial workers, and reflecting actual work situations. Practitioner summary: Due to increased research activity in the field, a systematic review was performed of recent studies on industrial back-support exoskeletons, addressing objective and subjective evaluations, side effects, and methodological aspects of usability testing. The results indicate the efficiency of exoskeletons in back-load reduction and a need for further studies in real work situations. Abbrevaitions: BB: biceps brachii; BF: biceps femoris; CoM: centre of mass; DA: deltoideus anterior; EMG: electromyography; ES: erector spinae; ES-C: erector spinae-cervical; ESI: erector spinae iliocostalis; ESI-L: erector spinae iliocostalis-lumborum; ESL: erector spinae longissimus; ES-L: erector spinae-lumbar; ESL-L: erector spinae longissimus-lumborum; ESL-T: erector spinae longissimus-thoracis; ES-T: erector spinae-thoracic; GM: glutaeus maximus; LBP: low back pain; LD: latissimus dorsi; LPD: local perceived discomfort scale; LPP: local perceived pressure scale; MS: multifidus spinae; MSD: musculoskeletal disorder; M-SFS: modified spinal function sort; NMV: no mean value provided; OA: obliquus abdominis (internus and externus); OEA: obliquus externus abdominis; OIA : obliquus internus abdominis; RA: rectus abdominis; RF: rectus femoris; RoM: range of motion; SUS: system usability scale; T: trapezius (pars Ascendens and Descendens); TA: trapezius pars ascendens; TC: mid-cervical trapezius; TD: trapezius pars descendens; VAS: visual analog scale; VL: vastus lateralis; VM: vastus medialis.

To Flex or Not to Flex? Is There a Relationship Between Lumbar Spine Flexion During Lifting and Low Back Pain? A Systematic Review With Meta-analysis

OBJECTIVE

To evaluate whether lumbar spine flexion during lifting is a risk factor for low back pain (LBP) onset/persistence or a differentiator of people with and without LBP.

DESIGN

Etiology systematic review with meta-analysis.

LITERATURE SEARCH

Database search of ProQuest, CINAHL, MEDLINE, and Embase up to August 21, 2018.

STUDY SELECTION CRITERIA

We included peer-reviewed articles that investigated whether lumbar spine position during lifting was a risk factor for LBP onset or persistence or a differentiator of people with and without LBP.

DATA SYNTHESIS

Lifting-task comparison data were tabulated and summarized. The meta-analysis calculated an n-weighted pooled mean ± SD of the results in the LBP and no-LBP groups. If a study contained multiple comparisons (ie, different lifting tasks that used various weights or directions), then only 1 result from that study was included in the meta-analysis.

RESULTS

Four studies (1 longitudinal study and 3 cross-sectional studies across 5 articles) included in meta-analysis measured lumbar flexion with intralumbar angles and found no difference in peak lumbar spine flexion when lifting (1.5°; 95% confidence interval [CI]: -0.7°, 3.7°; P = .19 for the longitudinal study and -0.9°; 95% CI: -2.5°, 0.7°; P = .29 for the cross-sectional studies). Seven cross-sectional studies measured lumbar flexion with thoracopelvic angles and found that people with LBP lifted with 6.0° less lumbar flexion than people without LBP (95% CI: -11.2°, -0.9°; P = .02). Most (9/11) studies reported no significant between-group differences in lumbar flexion during lifting. The included studies were of low quality.

CONCLUSION

There was low-quality evidence that greater lumbar spine flexion during lifting was not a risk factor for LBP onset/persistence or a differentiator of people with and without LBP. J Orthop Sports Phys Ther 2020;50(3):121-130. Epub 28 Nov 2019. doi:10.2519/jospt.2020.9218.

Ergonomic principles in patient handling: Knowledge and practice of physiotherapists in Nigeria

BACKGROUND

Physiotherapists are advocates of workplace health and safety. Despite the high prevalence of work-related musculoskeletal disorders (WMSDs), there is limited knowledge of ergonomic principles have been successfully applied in the workplace by Nigerian physiotherapists.

OBJECTIVES

This study evaluates the knowledge and practice of ergonomic principles in patient handling among physiotherapists in Nigeria.

METHOD

A cross-sectional survey design was used to sample 360 physiotherapists practicing in Nigeria. Participants responded to a three-part structured questionnaire that had a reliability coefficient of 0.77. Data was analyzed using descriptive statistics and Chi-Square.

RESULTS

The majority (95.9%) of the participants had good knowledge of the ergonomic principles in patient handling while only 48.6% reported practicing them. Poor practice was mainly due to a lack of patient handling equipment. There was no significant association between knowledge and practice of ergonomic principles among study participants. Specific areas of physiotherapy practice showed a significant association with ergonomic knowledge and practice. Years of physiotherapy practice and highest educational qualifications showed a significant association with the levels of practice and knowledge respectively.

CONCLUSION

Physiotherapists in Nigeria reported a good level of knowledge of ergonomic principles, but a poor practice level. Perhaps this non-adherence contributed to the high prevalence of WMSDs among physiotherapists in Nigeria.

Influencing lumbar posture through real-time biofeedback and its effects on the kinematics and kinetics of a repetitive lifting task

BACKGROUND

Repetitive, flexed lumbar postures are a risk factor associated with low back injuries. Young, novice workers involved in manual handling also appear at increased risk of injury. The evidence for the effectiveness of postural biofeedback as an intervention approach is lacking, particularly for repetitive, fatiguing tasks.

RESEARCH QUESTION

How does real-time lumbosacral (LS) postural biofeedback modify the kinematics and kinetics of repetitive lifting and the risk of low back injury?

METHODS

Thirty-four participants were randomly allocated to two groups: biofeedback (BF) and non-biofeedback (NBF). Participants repetitively lifted a 13 kg box at 10 lifts per minute for up to 20 min. Real-time biofeedback of LS posture occurred when flexion exceeded 80% maximum. Three-dimensional motion analysis and ground reaction forces enabled estimates of joint kinematics and kinetics. Rating of perceived exertion (RPE) was measured throughout.

RESULTS

The BF group adopted significantly less peak lumbosacral flexion (LSF) over the 20 min when compared to the NBF group, which resulted in a significant reduction in LS passive resistance forces. This was accompanied by increased peak hip and knee joint angular velocities in the BF group. Lower limb moments did not significantly differ between groups. Feedback provided to participants diminished beyond 10 min and subjective perceptions of physical exertion were lower in the BF group.

SIGNIFICANCE

Biofeedback of lumbosacral posture enabled participants to make changes in LSF that appear beneficial in reducing the risk of low back injury during repetitive lifting. Accompanying behavioural adaptations did not negatively impact on physical exertion or lower limb joint moments. Biofeedback of LS posture offers a potential preventative and treatment adjunct to educate handlers about their lifting posture. This could be particularly important for young, inexperienced workers employed in repetitive manual handling who appear at increased risk of back injury.

Task rotation in an underground coal mine: A pilot study

BACKGROUND

Task rotation is used to decrease the risk of workplace injuries and improve work satisfaction.

OBJECTIVE

To investigate the feasibility, benefits and challenges of implementing a task rotation schedule within an underground coalmine in NSW, Australia.

METHODS

A mixed method case control pilot study with the development and implementation of a task rotation schedule for 6 months with two work crews. A questionnaire including The Nordic Musculoskeletal Questionnaire, The Need for Recovery after Work Scale, and The Australian WHOQOL- BREF Australian Edition was used to survey workers at baseline, 3 and 6 months. A focus group was completed with the intervention crew and management at the completion of the study.

RESULTS

In total, twenty-seven participants completed the survey. Significant improvements in the psychological and environmental domains of the WHOQOL-BREF questionnaire were found in the intervention crew. Musculoskeletal pain was highest in the elbow, lower back and knee, and fatigue scores improved, across both groups. The intervention crew felt 'mentally fresher', 'didn't do the same task twice in a row', and 'had more task variety which made the shift go quickly'.

CONCLUSION

Task rotation was positively regarded, with psychological benefits identified. Three rotations during a 9-hour shift were feasible and practical in this environment.

Daily Shoulder Pain Among Flight Baggage Handlers and its Association With Work Tasks and Upper Arm Postures on the Same Day

Objectives

This study of flight baggage handlers aimed at examining the extent to which shoulder pain developed during single work shifts, and whether a possible development was associated with biomechanical exposures and psychosocial factors during the same shift.

Methods

Data were collected during, in total, 82 work shifts in 44 workers. Right and left shoulder pain intensity was rated just before and just after the shift (VAS scale 0–100 mm). Objective data on ‘time in extreme’ and ‘time in neutral’ upper arm postures were obtained for the full shift using accelerometers, and the baggage handlers registered the number of ‘aircrafts handled’ in a diary. During half of the shift, workers were recorded on video for subsequent task analysis of baggage handling. ‘Influence’ at work and ‘support’ from colleagues were measured by use of Copenhagen Psychosocial Questionnaire (COPSOQ). Associations between exposures and the increase in pain intensity during the shift (‘daily pain’) were analysed for the right and left shoulder separately using Generalized Estimating Equations (GEE).

Results

‘Daily pain’ was observed in approximately one third of all shifts. It was significantly associated with the number of ‘aircrafts handled’ for both the right and left shoulder. In multivariate models including both biomechanical exposures and the psychosocial factors ‘influence’ at work and ‘support’ from colleagues, ‘aircrafts handled’ was still significantly associated with ‘daily pain’ in both shoulders, and so was ‘influence’ and ‘support’, however in opposite directions.

Conclusions

‘Daily pain’ was, in general, associated with biomechanical exposures during the same shift and with general ‘influence’ and ‘support’ in the job. In an effort to reduce pain among flight baggage handlers, it may therefore be justified to consider a reduction of biomechanical exposures during handling of aircrafts, combined with due attention to psychosocial factors at work.

Shoulder torques resulting from luggage handling tasks in non-inertial frames

BACKGROUND

This paper reports on the torques developed in the shoulder joint experienced by occupants of moving vehicles during manual handling tasks. Handling heavy weights can cause musculoskeletal injuries, especially if handling is done with arms extended or at high levels.

OBJECTIVE

The aim of the study was to measure the longitudinal and lateral accelerations in a variety of passenger vehicles together with the postures of subjects lifting luggage onto storage shelves. This data enabled the application of inverse dynamics methods in a non-inertial reference frame to calculate the shoulder joint torques.

METHODS

The subjects lifted 3 pieces of luggage of masses of 5 kg, 10 kg and 14 kg onto shelving which were at heights of 1.2 m, 1.6 m and 1.8 m. The movement of subjects was measured using a 12 camera, 3-dimensional optical tracking system. The subjects stood on force plates to measure the ground reaction forces.

RESULTS

Sixty-three trials were completed, although 9 trials were aborted because subjects felt unable to complete the task. It was found that the shoulder torques exceeded the levels recommend by the UK Health and Safety Executive for manual handling. A lift assistance device is suggested to reduce the shoulder torques required for luggage handling.

The Effect of Occupational Lifting on Hypertension Risk: Protocol for a Project Using Data From the Copenhagen City Heart Study

BACKGROUND

Hypertension is a major risk factor for cardiovascular disease and is responsible for 14% of all annual deaths globally. The prevalence of hypertension varies across occupational groups, possibly affected by differences in the working environment. One work-related factor that might impose a risk for hypertension is lifting due to the acute large increases in blood pressure (BP) during lifting.

OBJECTIVE

The aim of this study is to explore associations between heavy occupational lifting and hypertension in the Copenhagen City Heart Study.

METHODS

This study will use data from the third, fourth, and fifth examination of the Copenhagen City Heart Study. The dataset contains person-based information on health as well as a large variety of biological, environmental, and lifestyle-related factors. Using a cross-sectional design, we will investigate the association between heavy occupational lifting and hypertension, defined as using antihypertensive drugs or having a measured systolic BP (SBP) ≥140 mm Hg or diastolic BP (DBP) ≥90 mm Hg. Furthermore, in a prospective design, we will investigate the association between heavy occupational lifting and risk of becoming an SBP case, defined as the shift from not using antihypertensive drugs in examination n to use of antihypertensive drugs in examination n+1 or an above median delta value of SBP (SBP in examination n+1−SBP in examination n).

RESULTS

In the third examination in 1991-1994, 10,135 out of 16,560 participants attended (61.20%), in the fourth examination in 2001-2003, 6237 out of 12,599 participants attended (49.50%), and in the fifth examination in 2011-2015, 4550 out of 9765 participants attended (46.59%). On the basis of the inclusion criteria of answering to the level of occupational physical activity, 5031 observations were excluded from examination 3, 2600 from examination 4, and 1621 from examination 5. Hence, the final populations for the cross-sectional and prospective analysis are assumed to include less than 7166 participants in the cross-sectional analysis and less than 1850 participants in the prospective analysis due to the additional inclusion criteria of measured BP and use of antihypertensive drugs.

CONCLUSIONS

One-third of the workforce in Europe reports to carry or move heavy loads regularly during working hours (6th survey in Eurofound). Thus, if this study shows occupational lifting to increase the risk for hypertension, the prevention for hypertension can be improved.

Pulling force prediction using neural networks

PURPOSE

In ergonomics and human factors investigations, pulling force (PF) estimation has usually been achieved using various types of biomechanical models, and independent approximation of PF was done with the help of upper extremity joints. Recently, multiple regression methods have gained importance for task-relevant inputs in predicting PF. Artificial neural networks (ANNs) also play a vital role in fitting the data; however, their use in work-related biomechanics and ergonomics is inadequate. Therefore, the current research aimed to accomplish comparative investigation of ANN and regression models by assessing their capacity to predict PF values.

METHODS

Multipositional PF data were acquired from 200 subjects at three different handle heights and body locations. ANN and regression models were formed using a random sample of three subsets (75% training, 15% selection, 10% validation) for proving the outcomes.

RESULTS

The comparison of ANN and regression models shows that the predictions of ANN models had a profoundly explained variance and lower root mean square difference values for the PF data at three handle heights.

CONCLUSIONS

These outcomes advise that ANNs offer a precise and robust substitute for regression methods, and should be considered a useful method in biomechanics and ergonomics task assessments.

Older females in the workforce - the effects of age on psychophysical estimates of maximum acceptable lifting loads

The number of older workers in the workforce is increasing substantially, and advanced age is associated with factors that could influence musculoskeletal injury risk and work capacity. This study's goals were to test whether psychophysical estimates of maximum acceptable weight of lift (lift_max) differed between younger and older workers, and to examine potential explanatory factors. Twenty-four female workers (half 50 + years; half 20-32 years) self-adjusted a box's mass to their perceived lift_max during four lifting tasks. Older workers' lift_max values were significantly lower (by approximately 24%) than their younger counterparts. There were no age-related differences in resting heart rate, or peak joint angles and final heart rate during the lifting trials. However, the older group demonstrated lower grip strength (by 24%), and lower heart rate reserve during the trials (by 18%). These results question whether current maximum acceptable lifting weights based on psychophysical information are appropriately protective for female workers greater than 50 years of age. Practitioner Summary: This psychophysical study demonstrated that older female workers (aged 50-63 years) selected maximum acceptable lift masses that were (on average) 24% lower than younger workers (aged 20-32 years), which corresponded with lower grip strength and heart rate reserve. Current maximum acceptable lifting weights based on psychophysical information may not protect female workers greater than 50 years of age.

An Ergonomic Assessment of Hospital Linen Bag Handling

The Joint Commission provides accreditation standards for staging hospital waste, but there are no federal lifting safety standards for linen bags. We evaluated hospital laundry bag lifting using the Revised National Institute for Occupational Safety and Health (NIOSH) Lifting Equation. We hypothesized that the permitted 32-gallon linen container capacity might allow filling to weights above our calculated Recommended Weight Limit (RWL) for some lifting positions and contents. We found that 30- and 40-gallon bags filled with loose dry linen had predicted weights within estimated RWLs only for lifts close to the body. Thirty- and 40-gallon bags filled more than halfway with dry compact linen had predicted weights above estimated RWLs for all lifting positions. Thirty- and 40-gallon bags filled with wet compact linen exceeded estimated RWLs for all positions when less than one-quarter full. Bag volume and filling controls may be considered to ensure linen bags are not excessively heavy.

Work-related back discomfort and associated factors among automotive maintenance mechanics in Eastern Nigeria: A cross sectional study

BACKGROUND

Back pain has been identified as a common cause of disability in the working population. Automotive mechanics habitually use awkward back posture in their course of manual activity and hence may be at risk of work-related back pain.

OBJECTIVE

To investigate the prevalence, pattern and severity of back pain among automotive maintenance mechanics, as well as the personal and job variables associated with or predicting occurrence of back pain.

METHOD

Using a cross-sectional design, information about self-reported back pain and the associated variables were collected among 684 randomly recruited automotive mechanics.

RESULT

Prevalence of back pain was 76.02%; with the majority experiencing low back pain. 63.3% of the workers reported they limited their activity due to the back pain. Older workers (>50 years), daily work lasting ≥5 hours duration, no more than primary education, being normal weight, frequent use of kneeling and sustained postures, and lack of knowledge of ergonomic postures were associated with increased prevalence of back pain. Lack of job autonomy, inadequate task clarity, heavy physical work load, manual material handling, strenuous posture, noisy environment, vibrations, work schedule and inadequate auxiliary support were also associated with increased prevalence of back pain among the mechanics.

CONCLUSION

Work-related back pain is prevalent among automotive maintenance mechanics. Work-related back pain is high among automotive maintenance mechanics. Workstation policy and legislation on reduction of risks with combined health literacy and ergonomic education programs in this occupational group are imperative.

Estimation of lumbar spinal loading and trunk muscle forces during asymmetric lifting tasks: application of whole-body musculoskeletal modelling in OpenSim

Large spinal compressive force combined with axial torsional shear force during asymmetric lifting tasks is highly associated with lower back injury (LBI). The aim of this study was to estimate lumbar spinal loading and muscle forces during symmetric lifting (SL) and asymmetric lifting (AL) tasks using a whole-body musculoskeletal modelling approach. Thirteen healthy males lifted loads of 7 and 12 kg under two lifting conditions (SL and AL). Kinematic data and ground reaction force data were collected and then processed by a whole-body musculoskeletal model. The results show AL produced a significantly higher peak lateral shear force as well as greater peak force of psoas major, quadratus lumborum, multifidus, iliocostalis lumborum pars lumborum, longissimus thoracis pars lumborum and external oblique than SL. The greater lateral shear forces combined with higher muscle force and asymmetrical muscle contractions may have the biomechanical mechanism responsible for the increased risk of LBI during AL. Practitioner Summary: Estimating lumbar spinal loading and muscle forces during free-dynamic asymmetric lifting tasks with a whole-body musculoskeletal modelling in OpenSim is the core value of this research. The results show that certain muscle groups are fundamentally responsible for asymmetric movement, thereby producing high lumbar spinal loading and muscle forces, which may increase risks of LBI during asymmetric lifting tasks.

Guidance for community-based caregivers in assisting people with moderate to severe traumatic brain injury with transfers and manual handling: evidence and key stakeholder perspectives

Adults with moderate to severe traumatic brain injury (TBI) rely on assistance from paid and unpaid caregivers upon return to the community. An inability to move independently makes these adults highly dependent on caregivers for transfers and manual handling tasks. Evidence-based guidelines are therefore important to ensure that caregivers and people in the community are protected and that practices are standard and consistent. This study commenced with a rapid review of evidence-based recommendations between 2000 and 2015 pertaining to transfers and manual handling in people with TBI; and ended with a structured stakeholder dialogue that reflected upon this evidence and gathered perspectives on how to address key issues in community-based manual handling following TBI. Three relevant guidelines were identified, providing nine recommendations encompassing assessment of the person's ability to assist caregivers, manual handling and appropriate equipment use. Due to the low number of recommendations and low level of supporting evidence, these recommendations alone could not provide comprehensive guidance. Three systematic reviews and two primary studies were also identified, and these suggest that comprehensive training programmes in transfers and manual handling tasks are effective. Further to this, a structured stakeholder dialogue was conducted, which revealed six major themes - (i) comprehensive risk assessment, (ii) presence of two caregivers, (iii) provision of training, (iv) home environment modification, (v) equipment, and (vi) policy implementation context. Recommendations for health professionals include providing information packs to caregivers, risk assessment and mitigation for those at high risk, and strategies to prevent and minimise injury in caregivers. Development of comprehensive guidance for caregivers in transfers and manual handling in people with moderate to severe TBI living in the community is a hidden but important priority.

Practices and risks associated with operation of tie-down lashings in the vehicle transport industry

Load restraint systems in automobile transport utilise tie-down lashings placed over the car's tyres, which are tensioned manually by the operator using a ratchet assembly. This process has been identified as a significant manual handling injury risk. The aim of this study was to gain insight on the current practices associated with tie-down lashings operation, and identify the gaps between current and optimal practice. We approached this with qualitative and quantitative assessments and one numerical simulation to establish: (i) insight into the factors involved in ratcheting; (ii) the required tension to hold the car on the trailer; and (iii) the tension achieved by drivers in practice and associated joint loads. We identified that the method recommended to the drivers was not used in practice. Drivers instead tensioned the straps to the maximum of their capability, leading to over-tensioning and mechanical overload at the shoulder and elbow. We identified the postures and strategies that resulted in the lowest loads on the upper body during ratcheting (using both hands and performing the task with their full body). This research marks the first step towards the development of a training programme aiming at changing practice to reduce injury risks associated with the operation of tie-down lashings in the automobile transport industry. Practitioner Summary: The study investigated current practice associated with the operation of tie-down lashings through qualitative (interviews) and quantitative (biomechanical analysis) methods. Operators tended to systematically over-tension the lashings and consequently overexert, increasing injury risks.

Lift performance and lumbar loading in standing and seated lifts

This study investigated the effect of posture on lifting performance. Twenty-three male soldiers lifted a loaded box onto a platform in standing and seated postures to determine their maximum lift capacity and maximum acceptable lift. Lift performance, trunk kinematics, lumbar loads, anthropometric and strength data were recorded. There was a significant main effect for lift effort but not for posture or the interaction. Effect sizes showed that lumbar compression forces did not differ between postures at lift initiation (Standing 5566.2 ± 627.8 N; Seated 5584.0 ± 16.0) but were higher in the standing posture (4045.7 ± 408.3 N) when compared with the seated posture (3655.8 ± 225.7 N) at lift completion. Anterior shear forces were higher in the standing posture at both lift initiation (Standing 519.4 ± 104.4 N; Seated 224.2 ± 9.4 N) and completion (Standing 183.3 ± 62.5 N; Seated 71.0 ± 24.2 N) and may have been a result of increased trunk flexion and a larger horizontal distance of the mass from the L5-S1 joint. Practitioner Summary: Differences between lift performance and lumbar forces in standing and seated lifts are unclear. Using a with-in subjects repeated measures design, we found no difference in lifted mass or lumbar compression force at lift initiation between standing and seated lifts.

Human Body Mechanics of Pushing and Pulling: Analyzing the Factors of Task-related Strain on the Musculoskeletal System

The purpose of this review is to name and describe the important factors of musculoskeletal strain originating from pushing and pulling tasks such as cart handling that are commonly found in industrial contexts. A literature database search was performed using the research platform Web of Science. For a study to be included in this review differences in measured or calculated strain had to be investigated with regard to: (1) cart weight/ load; (2) handle position and design; (3) exerted forces; (4) handling task (push and pull); or (5) task experience. Thirteen studies met the inclusion criteria and proved to be of adequate methodological quality by the standards of the Alberta Heritage Foundation for Medical Research. External load or cart weight proved to be the most influential factor of strain. The ideal handle positions ranged from hip to shoulder height and were dependent on the strain factor that was focused on as well as the handling task. Furthermore, task experience and subsequently handling technique were also key to reducing strain. Workplace settings that regularly involve pushing and pulling should be checked for potential improvements with regards to lower weight of the loaded handling device, handle design, and good practice guidelines to further reduce musculoskeletal disease prevalence.

Moving and handling: reducing risk through assessment

Manual handling injuries can occur almost anywhere in a healthcare environment, and most staff perform a variety of moving and handling tasks every day. Heavy lifting, awkward posture, and previous or existing injury can increase the risk of musculoskeletal disorders. A healthcare professional's involvement in moving and handling is more widespread than it might appear, and their actions and understanding of techniques, legislation and guidelines have a direct effect on patient care. Every situation that involves the handling, or partial handling, of a person presents varying levels of risk to the patient and the carer. Maintaining a good level of patient mobility and independence is an essential part of care delivery and can reduce the risk of long-term physical and psychological effects. Delivery of care should focus on the individual's capacity, not their incapacity, to ensure that they are treated with dignity and respect.

An integrated practice approach to mobility care for older people

Mobility is important to older people in nursing homes and residential facilities since it contributes to their health and quality of life. Many residents in such facilities require some form of assistance to move and accomplish activities of daily living. Therefore, nurses and healthcare assistants should have the knowledge and skills to provide effective mobility care. This article discusses three important aspects of mobility care: safety, mobility optimisation and person-centred approaches to care. Safety is important as residents and staff are at risk of injury during mobility care. Mobility optimisation is essential to ensure residents maintain their independence. Person-centred approaches to care are central to providing an integrated approach to mobility care.

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.

Lower extremity kinematics that correlate with success in lateral load transfers over a low friction surface

We previously studied balance during lateral load transfers, but were left without explanation of why some individuals were successful in novel low friction conditions and others were not. Here, we retrospectively examined lower extremity kinematics between successful (SL) and unsuccessful (UL) groups to determine what characteristics may improve low friction performance. Success versus failure over a novel slippery surface was used to dichotomise 35 healthy working-age individuals into the two groups (SL and UL). Participants performed lateral load transfers over three sequential surface conditions: high friction, novel low friction, and practiced low friction. The UL group used a wide stance with rotation mostly at the hips during the high and novel low friction conditions. To successfully complete the practiced low friction task, they narrowed their stance and pivoted both feet and torso towards the direction of the load, similar to the SL group in all conditions. This successful kinematic method potentially results in reduced muscle demand throughout the task. Practitioner Summary: The reason for this paper is to retrospectively examine the different load transfer strategies that are used in a low friction lateral load transfer. We found stance width to be the major source of success, while sagittal plane motion was altered to potentially maintain balance.

An analysis of patient safety incident reports describing injuries to staff working in critical care in the North West of England between 2009 and 2013

BACKGROUND

Critical care environments are potentially high-risk areas for staff harm due to procedural demand and increased incidence of delirium/dependence. The principal types of harm and temporal trends have not yet been quantified.

METHODS

Retrospective analysis of a multicentre dataset prospectively collected over a five-year period. All patient safety incidents reported to a regional network project were analysed; those recorded as staff harm were extracted, quantified and assessed by thematic analysis to identify key areas of harm, temporal trends and incident rates.

RESULTS

Staff harm accounted for 7% of all reported patient safety incidents over the study period. Incident rates remained static, ranging annually from 2.6 to 3.7 episodes/1000 patient days. Assaults on staff accounted for the highest proportional contribution on thematic analysis, which was a consistent annual finding. Sharps injuries and manual handling incidents were also notable contributions. Temporal trends for each theme remained static over the study period implying limited reduction in staff harm despite implementation of national guidance and local initiatives.

CONCLUSION

Staff harm is a consistent issue for those working in critical care. Assaults on staff appear to be the highest contributor on thematic analysis. These data imply significant reduction in harm can still be achieved and can be used to design and implement interventional measures.

Safe moving and handling of patients: an interprofessional approach

A gap in the medical undergraduate curriculum on safe moving and handling of patients was identified, and a project to enhance moving and handling education for undergraduates in various healthcare disciplines was undertaken. A team of nurses, doctors, physiotherapists and e-learning professionals developed a cross-discipline e-learning resource, piloted with medical and nursing students at Queen's University Belfast. One outcome of the project was the development of a deeper recognition of the common curriculum across healthcare disciplines.

Physiological and biomechanical responses to a prolonged repetitive asymmetric lifting activity

This study investigated the effects of a prolonged repetitive asymmetric lifting task on behavioural adaptations during repetitive lifting activity, measures of tissue oxygenation and spine kinematics. Seventeen volunteers repeatedly lifted a box, normalised to 15% of the participant's maximum lifting strength, at the rate of 10 lifts/min for a period of 60 min. The lifts originated in front of the participants at ankle level and terminated on their left side at waist level. Overall, perceived workload increased during the repetitive lifting task. Erector spinae oxygenation levels, assessed using near-infrared spectroscopy, decreased significantly over time. Behavioural changes observed during the repetitive lifting task included increases in the amount of forward bending, the extension velocity and the lateral bending velocity, and a reduced lateral bending moment on the spine. These changes, with the exception of the reduced lateral bending moment, are associated with increased risk of low back disorder.

A new pre-employment functional capacity evaluation predicts longer-term risk of musculoskeletal injury in healthy workers: a prospective cohort study

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To determine if a job-specific pre-employment functional assessment (PEFA) predicts musculoskeletal injury risk in healthy mineworkers.

SUMMARY OF BACKGROUND DATA

Traditional methods of pre-employment screening, including radiography and medical screenings, are not valid predictors of occupational musculoskeletal injury risk. Short-form job-specific functional capacity evaluations are increasing in popularity, despite limited evidence of their ability to predict injury risk in healthy workers.

METHODS

Participants were recruited from an Australian coal mine between 2002 and 2009 as part of the hiring process. At baseline, participants were screened with the JobFit System PEFA, and classified as PEFA 1 if they met job demands and PEFA>1, if not. Males who completed the PEFA and were employed were included. Injury data from company records were coded for body part, mechanism, and severity. The relationship between PEFA classification and time to first injury was analyzed using Cox proportional hazards regression with adjustments for department and post hoc stratification for time (0-1.3 yr, 1.3-6 yr).

RESULTS

Of the 600 participants (median age, 37 yr, range, 17.0-62.6 yr), 427 scored PEFA 1. One hundred ninety-six sprain/strain injuries were reported by 121 workers, including 35 back injuries from manual handling. Significant differences between PEFA groups were found in time to first injury for all injury types during the long term (any injury: adjusted hazard ratio [HR] = 2.3, 95% confidence interval [CI] = 1.4-3.9; manual handling injury: HR = 3.3, CI = 1.6-7.2; any back injury: HR = 3.3, CI = 1.6-6.6; back injuries from manual handling HR = 5.8, CI = 2.0-16.7), but not during the short term. An area under the receiver operator curve value of 0.73 (CI = 0.61-0.86) demonstrated acceptable predictive ability for back injuries from manual handling during the long term.

CONCLUSION

JobFit System PEFAs predict musculoskeletal injury risk in healthy mineworkers after 1.3 years of employment. Future research should assess whether use of these assessments as part of a holistic risk management program can decrease workplace musculoskeletal injuries.

Effects of Manual Handling, Posture, and Whole Body Vibrations on Low-Back Pain

To determine the effect of occupational stress on low-back pain (LBP), a cross-sectional study has been carried out, by interviews, on workers exposed to 3 stresses: manual handling (MH, 82 women and 264 men), whole body vibrations (WBV, 274 men), and static postures (278 women). Anthropometric data, occupational stress, LBP severity and frequency, and a psychological evaluation of these groups were compared to those of a control population of 208 workers (104 men and 104 women). The results show that 30% of the population had never suffered from LBP. Age and the body mass index of the workers were the parameters most closely associated with LBP. Women involved in MH had higher frequency and severity of LBP than their reference population. Men involved in MH or exposed to WBV had higher frequency of painful episodes than their reference population. Workers exposed to one of the stresses were on sick leave for LBP more often, and for longer periods, than workers in the reference group. The results show that individual factors are often decisive in the onset of LBP. Nevertheless, in the more serious LBP cases, occupational stress is an aggravating factor for LBP and its consequences.

Workplace Design for Manual Assembly Tasks: Effect of Spatial Arrangement on Work-Cycle Time

This article reports the results of an experimental study undertaken to investigate the effect of spatial arrangement of assembly board and parts bin in the normal work area on work-cycle time in manual assembly tasks. Operator performance was measured in terms of average work-cycle time taken to complete a laboratory-simulated manual assembly task. Results showed that both location and distance factors had significant effects on work-cycle time. Effect of the size of parts was also investigated in the study. Average observed work-cycle times were compared with the methods-time measurement (MTM) values. Repetitive manual assembly tasks are common in industry and are thought to lead to musculoskeletal disorders. The results of this research are important for ergonomic design of the workplace for assembly tasks, which would help to enhance operators' efficiency.

Predictive Models of Lumbar Loadings When Handling Boxes

Back problems resulting from the compression forces on the intervertebral disks during manual material-handling tasks are an important problem affecting workers in various industries. The quantification of these forces using intradiscal pressure or biomechanical modeling is complex, time consuming, and costly, and these methods cannot be readily used in the workplace to estimate loadings on the lower back. The objective of this study was to develop a predictive model that would allow the estimation of lumbar loadings for lifting and lowering boxes using easily measured anthropometric variables and variables related to the task. A dynamic and planar segmental model and a model of internal forces at L5/S1 were used to determine the compression forces on the lower back. Two predictive models, a field model and a laboratory model, were developed to estimate the compression forces when lifting or lowering 3.3 kg to 22.0 kg boxes between heights of 15 cm and 185 cm. Both models were validated by an examination of the residuals. Their predictive performance was also compared, with the laboratory model offering a slightly better prediction than the field model. Thus, these equations represent a practical tool for a better planning of handling tasks in the working environment with the purpose of reducing the back injuries of workers.