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The influence of external load configuration on trunk biomechanics and spinal loading during sudden loading
Sudden loading is a major risk factor for work-related lower back injuries among occupations involving manual material handling (MMH). The current study explored the effects of external weight configuration on trunk biomechanics and trunk rotational stiffness in the sagittal plane during sudden loading. Fifteen asymptomatic volunteers experienced sudden loadings using the same magnitude of weight (9 kg) with two different configurations (medially- or laterally-distributed) at three levels of height (low, middle and high). Results of this study showed that the medially distributed weight...
Surface electromyography for risk assessment in work activities designed using the “revised NIOSH lifting equation”
The aims of this study were: to identify surface electromyography (sEMG)-based indices of trunk muscles acquired during the execution of lifting tasks designed using the revised NIOSH lifting equation and featuring a progressively increasing lifting index (LI); to study changes of these indices in relation to the LI; to evaluate the relationship between the identified indices and forces (FL5−S1) and moments (ML5−S1) at the L5-S1 joint. sEMG, kinematic and kinetic data of 20 male workers were recorded in three conditions. We computed the average rectified value (ARV), root mean square...
How does the biomechanical exposure of the upper body in manual box handling differ from exposure in other tasks in the real industrial context?
The assessment of biomechanical exposure during handling tasks in relation to other activities that are performed in industrial settings can be crucial to understand the biomechanical demands of manual box handling for the upper limbs. This study aims to evaluate the representativeness of the handling task to the upper body in comparison with the other tasks in a real setting, compare the biomechanical exposure between tasks, and identify the differences in exposure during manual box handling from job exposure. Twelve workers had biomechanical exposure assessed through trapezius muscle activity...
Elongation of the surface of the spine during lifting and lowering, and implications for design of an upper body industrial exoskeleton
The aim of this study was to assess the elongation of the skin surface of the spine for simulated industrial lifting and lowering tasks to aid the design of industrial exoskeletons worn on the back. Eighteen male participants lifted and lowered a box of varying loads (5?kg, 10?kg, 15?kg) using three techniques (squat, semi-squat, stooped) from the ground to a table. Motion capture sensors attached to the spine from C7 to S1 measured movement. Stoop lifting involved significantly more elongation (mean 71.1?mm; margin of error ±6.9) than squat lifting (mean 36.8?mm; margin of error ±6...
Effectiveness of a vacuum lifting system in reducing spinal load during airline baggage handling
Information on spinal loading for using lift assist systems for airport baggage handling is lacking. We conducted a laboratory study to evaluate a vacuum lift system for reducing lumbar spinal loads during baggage loading/unloading tasks. Ten subjects performed the tasks using the industry average baggage weight of 14.5?kg on a typical two-shelved baggage cart with or without using the lift system (i.e. lifting technique). Repeated measures analysis of variance (2 tasks × 2 shelf heights x 2 techniques) was used. Spinal loads were estimated by an electromyography-driven biomechanical model...
NIOSH Lifting Equation App: NLE Calc
The National Institute for Occupational Safety and Health (NIOSH) Lifting Equation mobile application, NLE Calc, is a tool to calculate the overall risk index for single and multiple manual lifting tasks. This application provides risk estimates to help evaluate lifting tasks and reduce the incidence of low back injuries in workers. Source: https://www.cdc.gov/niosh/topics/ergonomics/nlecalc.html
Development and validation of an easy-to-use risk assessment tool for cumulative low back loading
The Lifting Fatigue Failure Tool (LiFFT) Recent evidence suggests that musculoskeletal disorders (MSDs) may be the result of a fatigue failure process in affected tissues. This paper describes a new low back exposure assessment tool (the Lifting Fatigue Failure Tool [LiFFT]), which estimates a “daily dose” of cumulative loading on the low back using fatigue failure principles. Only three variables are necessary to derive the cumulative load associated with a lifting task: the weight of the load, the maximum horizontal distance from the spine to the load, and the number of repetitions...
Neck posture during lifting and its effect on trunk muscle activation and lumbar spine posture
Neck and head posture have been found to have a significant influence on the posture of the lower spine region during lifting and both an extended/upward gaze and a flexed/downward gaze have been hypothesized to lead to increased pain and/or overuse of the neck musculature. As a result, strength training recommendations have turned to the use of a retracted neck posture as being the safer posture to assume during lifting. This study examined trunk and neck muscle activity and lumbar spine posture in seven participants while performing moderate load lifts using a retracted neck posture (chin drawn...
Pushing and pulling: An assessment tool for OHS practitioners
A tool has been developed for supporting practitioners when assessing manual pushing and pulling operations based on an initiative by two global companies in the manufacturing industry. The aim of the tool is to support occupational health and safety practitioners in risk assessment and risk management of pushing and pulling operations in the manufacturing and logistics industries. It is based on a nine-multiplier equation that includes a wide range of factors affecting an operator's health risk and capacity in pushing and pulling. These multipliers are based on psychophysical, physiological...
A multi-component patient-handling intervention improves attitudes and behaviors for safe patient handling and reduces aggression experienced by nursing staff
A controlled before-after study This study evaluated an intervention for patient-handling equipment aimed to improve nursing staffs' use of patient handling equipment and improve their general health, reduce musculoskeletal problems, aggressive episodes, days of absence and work-related accidents. As a controlled before-after study, questionnaire data were collected at baseline and 12-month follow-up among nursing staff at intervention and control wards at two hospitals. At 12-month follow-up, the intervention group had more positive attitudes towards patient-handling equipment and increased...
Association between occupational lifting and day-to-day change in low-back pain intensity based on company records and text messages
Most previous studies assessing the association between physical workload and development of low-back pain have used self-reports for exposure. Using company records for quantifying exposure, this study shows that consecutive working days and higher workload are associated with acutely increased low-back pain. Source: Andersen LL, Fallentin N, Ajslev JZN, Jakobsen MD, Sundstrup E. Scand J Work Environ Health , 2016. http://dx.doi.org/10.5271/sjweh.3592
Risk assessment of pushing and pulling (RAPP) tool
This tool is designed to help assess the key risks in manual pushing and pulling operations involving whole-body effort, eg moving loaded trolleys or roll cages, or dragging, hauling, sliding or rolling loads. It is intended to be used alongside the Manual handling assessment charts (the MAC tool)1 which helps assess lifting and carrying operations, and follows a similar approach to that tool. It is aimed at those responsible for health and safety in workplaces and will help you to identify high-risk pushing and pulling activities and check the effectiveness of any risk-reduction measures. Source...
Biomechanical risk assessment during field loading of hydraulic stretchers into ambulances
The process of loading a stretcher into an ambulance is known to cause a high incidence of back injuries among paramedics. This study aimed to assess the forces at L5/S1 during real-life stretcher loading activities and to determine the variables that contribute significantly to these forces. Analyses involved 58 paramedics (111 shifts) and 175 stretcher loading activities. Estimates of compression and shear forces at L5/S1 were calculated using the 3DSSPP program. Seventy-one percent of loading activities exceeded the safe loading level of 3.4 kN compression force at L5/S1 (mean: 3.9 kN, min–max...
Revised NIOSH Lifting Equation May generate spine loads exceeding recommended limits
The 1991 NIOSH Lifting Equation (NLE) is widely used to assess the risk of injury to spine by providing estimates of the recommended weight limit (RWL) in hands. The present study uses the predictive equations developed based on a detailed trunk musculoskeletal biomechanical model to verify whether the RWL generates L5-S1 loads within the limits (e.g., 3400 N for compression recommended by NIOSH and 1000 N for shear recommended in some studies). Fifty lifting activities are simulated here to evaluate the RWL by the NLE and the L5-S1 loads by the predictive equations. In lifting activities involving...
Validation of the HSE manual handling assessment charts as predictors of work-related low back pain
The aim of this research was to ascertain whether HSE's ‘Manual handling Assessment Charts' (MAC tool) could be used to predict workers losing time from work due to low back pain (LBP). Results from the study suggest that as the ‘Hand distance from the lower back' increased, the risk of lost time due to LBP increased. For each 10 cm increase, the rate of lost time increased by approximately 20%. No evidence of relationships between other risk factors in the MAC and lost time was found. There was no evidence that the rate of lost time due to LBP increased with either increasing...
Association Between Lifting and Use of Medication for Low Back Pain
Results From the Backworks Prospective Cohort Study Objective: To evaluate relationships between lifting and lowering of loads and risk of low back pain resulting in medication use (M-LBP). Methods: At baseline, worker demographics, psychosocial factors, hobbies, LBP history, and lifting and lowering (quantified using the Revised NIOSH Lifting Equation) were assessed. A cohort of 258 incident-eligible workers was followed up for 4.5 years to determine new M-LBP cases and changes in lifting/lowering requirements. Proportional hazards regression with time-varying covariates was used to model associations...
Prospective evaluation of the 1991 NIOSH Lifting Equation
An epidemiological prospective cohort study of the ability of the 1991 NIOSH Lifting Equation to predict loss of time from work due to low back pain (LBP) or to predict reports of LBP followed 515 industrial workers in jobs requiring manual handling for 18 months. Baseline measurements were made of their jobs, histories of musculoskeletal trouble and of psychosocial variables. Longitudinal analysis of tasks was based on 367 subject/job combinations. The strongest predictor of future LBP was a history of LBP. No relationship was found between the Composite Lifting Index (CLI) and either the incidence...
Practical Demonstrations of Ergonomic Principles
Musculoskeletal disorders (MSDs) often involve the back, wrist, elbow, and/or shoulder, and occur when workers are exposed over time to MSD risk factors, such as awkward postures, forceful exertions, or repetitive motions. These exposures sometimes occur due to poorly designed workstations, tasks, and/or hand tools [Chaffin et al. 2006; Sanders and McCormick 1993; Silverstein et al. 1996, 1997]. Workers must understand the nature of MSD risk factors and how to avoid exposure to them. In a classroom setting, trainers may discuss ergonomic principles and show examples of MSD risk factors with photographs...
Manutention - Comparaison des façons de faire entre les experts et les novices
Le succès mitigé des programmes de formation sur la prévention des blessures au dos en manutention s'explique peut-être par la faiblesse de nos connaissances pratiques sur ce que font les experts dans la réalisation de leur travail. Des études ont montré que des manutentionnaires d'expérience, reconnus par leurs collègues comme étant des experts, ont développé des façons de faire différentes des novices qui pourraient être à la fois sécuritaires et avantageuses en termes...
Comparaison de deux modèles biomécaniques articulaires dans l’évaluation du chargement lombaire
Les risques de blessures au dos lors d'activités au travail demeurent encore aujourd'hui très élevés. Ces risques semblent s'accroître lorsque la charge supportée par les tissus du dos augmente lors, par exemple, de travaux de manutention. Il n'existe pas de façon directe d'évaluer le chargement interne des tissus et le meilleur moyen consiste actuellement à utiliser des modèles biomécaniques articulaires. http://www.irsst.qc.ca/files/documents/PubIRSST/R-620.pdf

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