Factors associated with high physical exertion during manual lifting: Cross-sectional study among 200 blue-collar workers

Revised NIOSH lifting equation: a critical evaluation

The revised NIOSH lifting equation (RNLE) aims to manage lifting-related lower back pain (LBP), by determining safe load limits. Many researchers have studied the multiplier development criteria, the universal applicability of the equation and its ability to identify an increased risk of LBP in lifting tasks. Although a number of strengths of the equation have been highlighted, many limitations have also been identified. The need for new multipliers, such as worker and environmental characteristics, was highlighted in order to make the equation more adaptable. The RNLE was designed to protect 75% of female workers and is therefore inherently conservative. Additionally, as all multipliers have values less than or equal to 1, the recommended weight limits (RWLs) can be further reduced. Thus, new multipliers may be defined, by combining two or more existing multipliers, to make the RWLs more realistic.

Occupational discomfort and injuries among automotive technicians in Jeddah, Saudi Arabia: A cross-sectional study

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) are one of the major causes of disability and early retirement. Consequently, WMSDs cost businesses billions of dollars annually due to compensation claims and productivity loss. Automotive technicians are vulnerable to WMSDs due to the nature of their work, which exposes them to numerous WMSDs risk factors. OBJECTIVE: This cross-sectional study aimed to evaluate the WMSD cases among technicians and evaluate their postures while working in small automotive repair shops in Jeddah, Saudi Arabia (SA). METHODS: The study employed a cross-sectional design. A self-administrated questionnaire and body parts discomfort survey were filled by thirty automotive technicians. A postural analysis technique was performed to assess the body postures that technicians adopt while performing the tasks, in order to estimate the associated risk of WMSD discomfort. RESULTS: Most automotive technicians suffer severe pain in the lower back, shoulders, neck, hands or wrists, and knees. The technicians related the pain to awkward body postures, heavy lifting, and sustained forceful movements. CONCLUSION: Automotive technicians are advised to level the height of the work surface as feasible, to work as close as possible to said work surface, and to avoid working with awkward body postures as much as possible.

Investigation of precision task demands on workers’ muscular activities, heart rate, and perceived exertion rating

BACKGROUND: Manual material handling (MMH) tasks significantly contribute to musculoskeletal disorders in manual workers. OBJECTIVES: In this study, we assessed the physical factors of precision lifting tasks that affect muscular activities (electromyography, EMGs), heart rate, and perceived exertion rating in ten healthy male workers aged 25–35 years, while considering the safety aspect of the common types of safety footwear. METHODS: The independent variables that were assessed are as follows: 1) lifting method (precise and inexact), 2) lifting frequency (one and four liftings/min), and 3) type of safety footwear worn by the worker (light, medium, or heavy). The response variables data, represented by EMG signals, for four muscular activities (biceps brachii, deltoid, trapezius, and erector spinae), heart rate, and perceived exertion were analyzed using a three-factor within-subjects design. RESULTS: The results showed that wearing heavy safety shoes increases the effort used with precise lifting methods in trapezius and erector spinae muscular activities. We also observed that the heart rate and perceived exertion increased rapidly at four lifts/min compared to one lift/min, regardless of the lifting method. CONCLUSIONS: The advantages of choosing appropriate safety footwear must be carefully assessed before replacing the conventional working safety shoes.

Predicting load constant of RNLE based on demographics

Manual material handling (MMH) and lifting activities have been identified as risk factors for low back pain (LBP). Of the many tools available to analyse and design lifting tasks, the Revised NIOSH Lifting Equation (RNLE) is perhaps the most widely used. However, the equation is based on data primarily from the west. To make it universally applicable, the effect of worker characteristics like age, gender, weight, and anthropometry on MAWL was studied. A psychophysical methodology was adopted to arrive at the maximum acceptable weight limits (MAWLs). 58 industrial workers (30 men and 28 women) participated in the study. Based on the observations of the study, an equation was developed that would allow the RNLE load constant to be modified for different populations based on simple anthropometric data. The load constant for the Indian population was found to be comparable to the RNLE recommendations.

Factors associated with high physical exertion during healthcare work: Cross-sectional study among healthcare workers

BACKGROUND: High physical exertion during healthcare work is a documented risk factor for musculoskeletal pain, long term sickness absence and disability pension. Understanding the underlying factors of physical exertion is important to make the necessary preventive efforts in the working environment. OBJECTIVE: This study investigates factors associated with high physical exertion during healthcare work. METHODS: A total of 2047 Danish health care workers replied to a questionnaire about work and health. Associations (odds ratios; OR) of physical exertion (outcome variable) with the number of patients and self-reliant patients, frequency and type of assistive device use, BMI, leisure time activity, smoking, and age were modelled using mutually adjusted binary logistic regression. RESULTS: Factors associated with high physical exertion (OR and 95% CI) were high frequency of daily patient transfers 1.35 (1.23 – 1.48), less self-reliant patients 0.74 (0.62 – 0.89), less frequent use of necessary assistive devices 1.82 (1.50 – 2.21), as well as more frequent use of sliding pieces 1.23 (1.04 – 1.46), wheelchairs 1.23 (1.02 – 1.49), bed adjustments 0.88 (0.77 – 1.00) and intelligent beds 0.83 (0.71 – 0.95) during patient transfer. Age and lifestyle factors (BMI, smoking, and leisure time physical activity) were not associated with high physical exertion. CONCLUSIONS: The character of patient transfer specific healthcare work is associated with increased odds for high physical exertion whereas life-style factors are not. Thus, proper use of specific assistive devices and avoiding uneven distribution of difficult patients through appropriate planning may be protective strategies for lowering physical exertion during healthcare work.

Kinematic and perceptual responses in heavy lifting and pulling: Are there differences between males and females?

This study investigated kinematic and perceptual differences between the sexes in a heavy lifting and pulling task. A 20 kg box was lifted from floor to chest height, and a 70 kg mannequin pulled across 20m. The effect of height, mass and average grip strength on kinematics and perceived workload was examined in 42 (19 females, 23 males) healthy individuals. A univariate linear regression analysis found females lifted with greater lumbar extension compared to males (p < 0.001), and adopted more hip (p = 0.006) and knee flexion (p = 0.036) in the pulling task. Females reported a greater perceived workload in both tasks (p < 0.001). After the multivariable analysis, only grip strength remained significant for perceived workload in the lift (p = 0.04), and height for knee flexion in the pull (p = 0.009). This highlights that height and strength are important factors driving kinematics and perceived workload. Clinicians may consider these factors in heavy manual tasks, more so than sex.

Assessing ergonomic risk factors using combined data envelopment analysis and conventional methods for an auto parts manufacturer

BACKGROUND

Occupational injuries are currently a major contributor to job loss around the world and are also costly for businesses. The absence of rational analysis is felt in this area, so mathematical analysis is needed to obtain the logical results of these injuries in order to find gaps or loss points of the industry.

OBJECTIVE

This paper assesses the effects of five demographic factors on ergonomic risk and occupational injuries using an integrated mathematical programming approach. The obtained results will help managers to carry out any required corrective actions or establish benchmarks.

METHODS

Two typical ergonomic risk assessment methods, the Quick Exposure Check (QEC) and Rapid Entire Body Assessment (REBA), are applied to assess musculoskeletal disorders in workers. Then, considering the five demographic factors as input variables and risks computed by the QEC and REBA methods as outputs, final risk rates for each decision-making unit (DMU) are calculated using data envelopment analysis (DEA). The importance and weight of each risk factor is analyzed using statistical techniques and analysis of variance (ANOVA). To demonstrate the applicability of the methodology, it is applied to a large auto parts manufacturer.

RESULTS

The results revealed that the information obtained by DEA is consistent with those for REBA and QEC, which shows that education, experience and weight are factors that could help reduce ergonomic risks.

CONCLUSION

It is shown that demographic variables such as age, height, weight, education and work experience play an important and effective role in the explanation of ergonomic risk factors.