Manual Material Handling Research Articles

Redesign of stroller work tools at PT. Ika Bina Agro Wisesa

PT. Ika Bina Agro Wisesa (PT. IBAS) is one of the agro-industries that manages or produces palm oil with a production capacity of 30 tons / hour and a total of 420 tons / day. The raw material of Fresh Fruit Bunches (FFB) of this factory comes from the plantation land of the community around the factory. The activity of harvesting FFB in this oil palm plantation has many manual material handling activities, especially for workers who lift and push wheelbarrows (angkong). The angkong work tool used is relatively old and looks unergonomic which can be seen when pushing the angkong in a very bent position so it is assumed that there is a large amount of force expended by workers. This research begins with a survey of the company and the field, then distributing Nordic Body Map (NBM) questionnaires to workers, using the Rapid Entire Body Assessment (REBA) method used to determine the level of risk of work posture in workers before and after the design of the tool, for the redesign of the stroller, anthropometric measurements are taken then using the Biomechanics method to determine the amount of force generated when pushing. This stroller redesign was carried out using operator anthropometry with the 95th percentile. After using the proposed tool, the work posture assessment is categorized as moderate which means that action is needed. The final results of the redesign are the length of the cart 90 cm, the width of the cart 66 cm, the diameter of the tire 32 cm, the height of the cart from the ground 125 cm, the height of the handle 96 cm, the width of the handle 40 cm, and the diameter of the handle 3 cm and the final results of the biomechanical assessment after the design concluded that the operator was no longer dangerous when pushing.

A Video-based Lifting Action Recognition Using Rank-Altered Kinematic Feature Pairs

Low-back musculoskeletal disorders (MSDs) are the primary work-related injuries among manual material handling (MMH) workers, who are frequently exposed to repetitive lifting. To prevent low-back MSDs in the workplace, we present a video-based lifting action recognition method using rank-altered kinematic feature pairs, called top-scoring pairs (TSPs). We derive TSPs from a video dataset containing lifting and other activities commonly seen in MMH. These TSPs collectively classify each frame as lifting and non-lifting. The validation process involves evaluating classification performance. The proposed method minimizes computational and memory requirements while achieving performance comparable to more complex methods with greater computational demands. This makes it suitable for systems with limited hardware resources, thereby providing extensive feasibility across a variety of MMH environments to improve workplace safety.

Estimation of joint kinetics during manual material handling using inertial motion capture: a follow-up study.

Musculoskeletal models based on inertial motion capture and ground reaction force (GRF) prediction hold great potential for field-based risk assessment of manual material handling. However, previous evaluations have identified inaccuracies in the methodology?s estimation of spinal forces, while the accuracy of other key outcome variables is currently unclear. This study evaluated knee, shoulder, and L5-S1 joint reaction forces (JRFs) derived from a musculoskeletal model based on inertial motion capture and GRF prediction against a model based on simultaneously collected optical motion capture and force plate measurements. Data from 19 healthy subjects performing lifts with various horizontal locations, deposit heights and asymmetry angles were analyzed, and the consistency and absolute agreement of the model estimates statistically compared. Despite varying levels of agreement across tasks and variables, considerable absolute differences were identified for the L5-S1 axial compression (RMSE = 63.0-94.2%BW) and anteroposterior shear forces (RMSE = 40.9-80.6%BW) as well as the bilateral knee JRFs (RMSE = 78.9-117%BW). Glenohumeral JRFs and vertical GRFs exhibited the highest overall consistency (r = 0.33-0.91, median 0.78) and absolute agreement (RMSE = 7.63-34.9%BW), while the L5-S1 axial compression forces also showed decent consistency (r = 0.04-0.89, median 0.80). The findings generally align with prior evaluations, indicating persistent challenges with the accuracy of key outcome variables. While the modelling framework shows promise, further development of the methodology is encouraged to enhance its applicability in ergonomic evaluations.

How to stay healthy in a physically demanding workplace – Die retrospektive Beurteilung einer gezielten betrieblichen Gesundheitsförderungsmaßnahme für körperlich schwer arbeitende Mitarbeiter und Mitarbeiterinnen im Allgemeinen Krankenhaus Wien

How to stay healthy in a physically demanding workplace – The retrospective assessment of a targeted occupational health promotion measure for employees doing physically demanding work at Vienna General Hospital Aim: Heavy physical work is one of the key factors in the development of spinal overload syndromes. Workplace health promotion (WHP) measures aim to minimize the harmful effects of heavy physical work as much as possible through personal measures. If generalized WHP measures are not possible, they should be carried out in a way that is tailored to specific professional groups. This paper presents such a targeted WHP measure for the patient transport services at Vienna General Hospital and its retrospective assessment by the participants. Methods: After participation in the targeted WHP measure, a validated questionnaire, the Comprehensibility of Health Education Programs (COHEP), was used. Results: The COHEP dimensions “comprehension-fostering behaviour of program trainers” (mean 16,3 ± 5,9), “transferability to everyday life” (mean 12,5 ± 4,0) and “comprehensibility of medical information” (mean 7,6 ± 2,2) were rated as very good. The COHEP dimension “amount of information” (mean 12,6 ± 6,8) was rated as average. Conclusion: The WHP project presented here was rated very highly in terms of comprehension-fostering behaviour, transferability to everyday life and comprehensibility of medical information. The amount of information, however, was rated as tending to be too extensive. Keywords: workplace health promotion – back health – manual material handling – weightlifting

Criteria for Assessing Exposure to Biomechanical Risk Factors: A Research-to-Practice Guide—Part 1: General Issues and Manual Material Handling

Musculoskeletal disorders are the most prevalent occupational health problem all over the world and are often related to biomechanical risk factors; to control these risk factors, several assessment methods (mostly observational) have been proposed in the past 40 years. An in-depth knowledge of each method to evaluate biomechanical risk factors is needed to effectively employ them in the field, together with a robust understanding of their effective predictive value and limitations. In Part 1, some general issues relevant to biomechanical risk assessment are discussed, and the method for assessing manual material handling after receiving more robust validation data is reviewed (Revised NIOSH Lifting Equation), together with a discussion about variability of tasks. Similarly, for the assessment of the biomechanical exposure of the upper limb, the TLV for Hand activity (ACGIH®) is presented in Part 2 of this guide, together with criteria to proportion risk assessment to the working duration in part-time jobs.

Quantification of social metrics for use in optimization: An application to solid waste management

Solid waste management (SWM) is an interdisciplinary field which requires a range of metrics to make informed decisions. Social indicators are of high interest to decision-makers but are particularly difficult to integrate into optimization frameworks, largely due to challenges of quantification. This study presents a methodology for quantifying a social metric for integration into sustainability assessment of solid waste management (SWM) systems using optimization. To identify social indicators, waste managers were consulted in Columbia, Missouri, USA. Meetings were held prior to indicator creation and reviewed mid-project with stakeholders. A number of concerns that could be categorized as social were raised. For the two most pressing issues to managers, quantitative metrics were created. First, SWM experiences high employee turnover, largely due to low wages. Turnover leads to less efficiency in collection and treatment, gaps in service, and cost to citizens. Hence, the first social metric proposed represents turnover of employees including loss of productivity, hiring and replacement costs, and quit rate. Second, this work estimated the value of exposure risk associated with manual material handling activities. This second social metric considered a worker's physical exposure to risk via activities of lifting, carrying, placing, emptying, and sitting. These social metrics were used within a multi-criterion decision-making framework for SWM, extending the traditional focus on economic and environmental objective functions. Results illustrate the trade-offs among these conflicting criteria and provide managerial insights into the costs and benefits of different waste management strategies.

Ergonomic Risk Assessment for Manual Handling Activities in Automotive Workshop

Ergonomic risk assessment tools are tools that have been designed to solve the problem of ergonomics in the workplace from manual material handling activities. The objective of this study is to investigate Musculoskeletal Discomfort among workers related to manual handling activities using Cornell Musculoskeletal Discomfort Questionnaires (CMDQ); to assess an ergonomics risk factor among workers related to manual handling activities using Manual Handling Assessment Chart (MAC), NIOSH Lifting Equation(NLE), and Key Indicator Method for Manual Handling Operation (KIM-MHO) method and; to compare the results between CMDQ and assessment tools. This case study was conducted in Parit Raja, Johor, Malaysia involving 34 male mechanics workers. The tools used are as stated in the objective with the help of measurement tools such as a goniometer. The result of the CMDQ reveals that the body part with the highest discomfort level among the workers in the lower back, shoulder right and shoulder left with the percentage from the total discomfort score of 20.91%, 13.57%, and 13.36% respectively. From the result of the assessments, it is concluded that the highest risk factor contributing to the MSDs is the bad posture of the worker during the manual handling operation followed by the frequency of lifting and the weight of the load. By comparing assessment tools, the first comparison is made between the CMDQ versus KIM-MHO, MAC Tools and NLE. In this comparison that, it is highlighted the result type from CMDQ are different from the KIM-MHO, MAC Tools and NLE as its questionnaire result shows us the discomforts levels on the body of workers and the body parts affected on their body for the last seven days but the assessment tools results show us the risk factor that contributes to the MSDs. For the comparison between the three assessment tools, it can be said that the tools that have the highest correlation with CMDQ are MAC Tools. In conclusion, most workers suffer from MSDs in their lower back due to their bad posture during manual handling. KIM-MHO is the best assessment tool among the three as it has the highest significance value while being the easiest tool to be used.

The effects of soft vs. rigid back-support exoskeletons on trunk dynamic stability and trunk-pelvis coordination in young and old adults during repetitive lifting

While back-support exoskeletons are increasing in popularity as an ergonomic intervention for manual material handling, they may cause alterations to neuromuscular control required for maintaining spinal stability. This study evaluated the effects of soft and rigid passive exoskeletons on trunk local dynamic stability and trunk-pelvis coordination. Thiry-two young (18–30 years) and old (45–60 years) men and women completed repetitive lifting and lowering tasks using two different exoskeletons and in a control condition. Both exoskeletons significantly reduced the short-term maximum Lyapunov exponent (LyE) of the trunk (p < 0.01), suggesting improved local dynamic stability. There was also a significant main effect of age (p = 0.05): older adults exhibited lower short-term LyE that young adults. Use of the soft exoskeleton significantly increased, while the rigid exoskeleton significantly decreased, long-term LyE, and these changes were more pronounced in the young group compared to the old group. Additionally, exoskeleton use resulted in significant increase (p < 0.001) of mean absolute relative phase (MARP) and deviation phase (DP) by ∼30–60 %, with greater increases due to the rigid than the soft device. Thus, trunk-pelvic coordination and coordination variability were negatively impacted by exoskeleton use. Potential reasons for these findings may include exoskeleton-induced changes in lifting strategy, reduced peak trunk flexion velocity, and cycle-to-cycle variability of trunk velocity. Furthermore, although the soft and rigid devices caused comparable changes in trunk-extensor muscle activity, they exhibited differential effects on long-term maximum Lyapunov exponents as well as trunk-pelvic coordination, indicating that exoskeleton design features can have complex effects on trunk neuromuscular control.

Postural analysis and ergonomic intervention of unorganized workers in indian construction sectors.

In India's fast-growing economy, the construction sector offers significant developments with huge employment opportunities but poses risks due to poor working environments and uncomfortable postures. Traditional methods, such as manual material handling, can lead to health hazards and musculoskeletal disorders such as overexertion, low back pain, etc. The purpose of this study was to analyze the working postures of unorganized employees engaged in residential buildings using Ergofellow software and to recommend changes in their unsafe working postures. Participants' working positions were video recorded and the postures were analyzed using Rapid Upper Limb Assessment (RULA), Rapid Entire Body Assessment (REBA) and Ovako Working Posture Analysis (OWAS). Paired sample t-tests were used to analyze significant differences between the RULA and REBA scores after the ergonomic interventions were implemented. From the analysis of RULA, REBA and OWAS, the working postures showed a high risk of potential injury and required an immediate change in employees' working postures. The RULA and REBA scores were subsequently lower after the ergonomic interventions, which were based on ergonomic and safety principles. The paired sample t-tests with p-values of less than 0.05 demonstrated decreased risks after ergonomic interventions. Working postures of the construction workers exposed to musculoskeletal disorders were examined and the ergonomic interventions were implemented. According to the recommendations, working positions were changed, and employee well-being was enhanced by reduced operational risks.

Comparison of the Accuracy of Ground Reaction Force Component Estimation between Supervised Machine Learning and Deep Learning Methods Using Pressure Insoles.

The three Ground Reaction Force (GRF) components can be estimated using pressure insole sensors. In this paper, we compare the accuracy of estimating GRF components for both feet using six methods: three Deep Learning (DL) methods (Artificial Neural Network, Long Short-Term Memory, and Convolutional Neural Network) and three Supervised Machine Learning (SML) methods (Least Squares, Support Vector Regression, and Random Forest (RF)). Data were collected from nine subjects across six activities: normal and slow walking, static with and without carrying a load, and two Manual Material Handling activities. This study has two main contributions: first, the estimation of GRF components (Fx, Fy, and Fz) during the six activities, two of which have never been studied; second, the comparison of the accuracy of GRF component estimation between the six methods for each activity. RF provided the most accurate estimation for static situations, with mean RMSE values of RMSE_Fx = 1.65 N, RMSE_Fy = 1.35 N, and RMSE_Fz = 7.97 N for the mean absolute values measured by the force plate (reference) RMSE_Fx = 14.10 N, RMSE_Fy = 3.83 N, and RMSE_Fz = 397.45 N. In our study, we found that RF, an SML method, surpassed the experimented DL methods.

Ergonomics and health risk awareness of workers involved in manual material handling at Sabon Gari Market in Zaria, Nigeria

This study assessed the manual handling of materials in a local market environment and evaluated workers’ awareness of ergonomics and health risks. Of 315 workers surveyed, 308 responded. The findings revealed a high prevalence rate of 96.4% for injuries and musculoskeletal discomfort, attributed to a low ergonomics and health risk awareness rate of only 6.8%. Consequently, 75% of workers resorted to self-medication or drug abuse for relief. The study also explored barriers to using engineering equipment, finding that 26.3% of respondents cited cost as a barrier, while 51% believed that the introduction of engineering equipment would lead to job loss. This research is valuable for practitioners and researchers as it highlights the current state of ergonomics and health risk awareness among workers who handle heavy loads. The study also highlights the need for improved ergonomic practices and health risk awareness to reduce injury rates and promote safer work environments.

SYSTEMATIC LITERATURE REVIEW: LEAN ERGONOMICS ANALYSIS IN SMALL &amp; MEDIUM ENTERPRISES (SMEs) MANUFACTURING SECTOR

Ergonomics has emerged as a significant workplace issue, negatively impacting finances due to worker absence and reduced productivity. Small and Medium Enterprises (SMEs) are particularly prone to occupational accidents, contributing to over 80% of such incidents. This review delves into the perspective of lean ergonomics within SMEs. The study followed a structured review protocol,formulating research questions and systematically searching the Scopus and WoS databases. The findings reveal several key points: (1) SMEs commonly implement ergonomics principles addressing awkward postures, repetitive movements, manual material handling, hand-wrist postures, excessive reach, grip strength, and prolonged standing; (2) Lean principles such as SMED, 5S, standardized work,TPM, VSM, and kanban positively impact ergonomics; (3) Various ergonomics assessment methods, including REBA, RULA, HFE, JSI, KIM, OCRA, and Shoaf’s model, are recommended for future research and practical application; (4) Ergonomics can underpin lean transformation efforts, with Lean Manufacturing (LM) contributing to reduced ergonomics risks. However, the review identified alimitation in the scope of databases used (WoS and Scopus), suggesting that expanding the range of databases and research keywords could improve future article searches. The study's primary focus serves as a reference point for future researchers and manufacturers interested in lean ergonomics, emphasizing the need for comprehensive approaches to enhance worker safety and productivity through ergonomic and lean practices.

Evaluating the Efficacy of a Passive Exoskeleton for Enhancing Ergonomics in Manufacturing

Manual material handling (MMH) significantly impacts worker health and productivity, often leading to musculoskeletal disorders (MSDs) primarily in the lower back. As a novel assistive technology, exoskeletons may serve as ergonomic tools to mitigate these work-related MSDs. It is essential to examine exoskeletons from the users’ perspectives before their widespread implementation in occupational settings. This study investigates the effectiveness of a passive back-support exoskeleton (BExo) in reducing perceived physical exertion and improving ergonomic safety in a manufacturing context. Twenty-two college students were recruited to perform MMH tasks in a controlled lab environment, both with and without the BExo, followed by completing a survey questionnaire on various aspects of the BExo. Using ANOVA, the study analyzed biomechanical exertion across various body parts and tasks. The findings indicate that the BExo substantially alleviated discomfort and physical exertion in the low back, shoulders and knees, thereby enhancing an ergonomic posture and reducing fatigue. These results underscore the potential of passive exoskeletons to boost workers’ safety and efficiency, providing valuable insights for future ergonomic strategies in industrial settings.

In-Field Training of a Passive Back Exoskeleton Changes the Biomechanics of Logistic Workers

OCCUPATIONAL APPLICATIONS Occupational exoskeletons receive rising interest in industry as these devices diminish the biomechanical load during manual materials handling. Still, we have limited knowledge when it comes to in-field use. This gap often contributes to failure in the implementation of exoskeleton in industry. In this study, we investigated how a training protocol consisting of in-field use of a passive back exoskeleton affected the biomechanics of logistic workers. More specifically, we focused on how the variation of the muscular and kinematic patterns of the user was altered after exoskeleton training. We found that training had a positive effect on exoskeleton use, as a relative decrease of 6–9% in peak back muscle activity was observed post-training. Additionally, training decreased knee flexion by 6°–16°, indicating a more stoop lifting technique. The findings point at the potential benefits of applying a training approach when implementing a back-supporting exoskeleton in logistics.

A comparative study of biomechanical assessments in laboratory and field settings for manual material handling tasks using extractor tools and exoskeletons.

To enhance physical capabilities of workers who regularly perform physically demanding tasks involving heavy lifting and awkward postures, various tools and occupational exoskeletons can be used. Most of the studies aiming to explore the efficiency of these tools and exoskeletons have been performed in confined and controlled laboratory spaces, which do not represent the real-world work environment. This study aimed to compare the outcome of biomechanical assessment of using a back support exoskeleton and assistive tools (Lever and Jake) in the procedure of a high demanding manual material handling task versus the results found by performing the same task in a laboratory. Ten able-bodied participants and ten able-bodied utility workers performed the same manhole removal task in-lab and in-field, respectively, with the aid of an exoskeleton and Lever and Jake tools. Muscle activity and Rapid Entire Body Assessment (REBA) scores were recorded using surface electromyography and inertial measurement units, respectively and compared between in-lab and in-field trials. The field experiments indicated significant differences (p < 0.05) in normalized muscle activity across most muscles when compared to laboratory data. These results revealed how muscle activity is affected by the controlled lab setting compared to real-world field conditions. However, REBA scores indicate similar ergonomic implications regardless of the utilization of exoskeletons or tools. These findings underscore that real-world field assessments are crucial for evaluating ergonomic risks and effects of occupational exoskeletons and tools to account for environmental factors and workers' skills in ergonomic evaluations of this nature.

Effect of Warehousing Management on Supply Chain Performance: A Case of Inyange Industries Ltd

In local and globalized markets, warehouses are crucial supply chain nodes. This study aimed to investigate the effect of warehousing on supply chain performance: A case of Inyange Industries Ltd. The goals were to evaluate how inventory management, warehouse capacity building, and material handling affects supply chain performance in Inyange Industries Ltd. This research experimented with three different theories: Just-in-time, Lean, and Triple-A supply chain. The population of this study were 105 staff members of Inyange Industries Ltd. Therefore, census was conducted because the population size is affordable and the researcher can be able to contact all the respondents. Quantitative data were analyzed using inferential research methodology in this study. Questionnaires were used to gather primary data, which was then analyzed. Data analysis was carried out using the Statistical Package for the Social Sciences (SPSS), and descriptive and inferential statistics were used to show the study's results. According to the research, supply chain performance is positively and significantly affected by both automated and manual material handling. Mechanical material handling, on the other hand, improves supply chain performance, but not much. Inyange Industries' supply chain performance is influenced by the material handling systems to the tune of 19.3%, as shown by the modified R2 value of 0.193. According to the research, supply chain performance is positively and significantly affected by inventory counts, warehouse management systems, and inventory organization. A 0.967 adjusted R^2 value suggests that 96.7% of the variation in Inyange Industries' supply chain performance is explained by the inventory management techniques. According to the research, supply chain effectiveness is positively and significantly impacted by warehouse demand planning, design, and management. Warehouse capacity planning techniques at Inyange Industries account for 95.4% of the variation in supply chain performance, as shown by the modified R2 value of 0.954. The research concluded that material handling, inventory management, and warehouse capacity planning are all important warehouse management measures that significantly impact supply chain performance for the better. The methods used by Inyange Industries Ltd. for managing their warehouses have resulted in an improvement in supply chain performance of 87.2%. The regression coefficients, supported by their t-test values and Beta coefficients, highlight both the significance and strength of relationships between independent and dependent variables. Material Handling demonstrated the greatest impact (β1=0.532, t=8.556, p=0.000), followed by Inventory Management (β2=0.379, t=6.147, p=0.000), and Warehouse Capacity Planning (β3=0.172, t=3.268, p=0.002), emphasizing their respective contributions to Supply Chain Performance of Inyange Industries Ltd.'s supply chain. This proved that material handling in warehouse management has a major influence on supply chain performance. Because the p-value was lower than 5%, we may say that the association is statistically significant. The research concluded that both automated and human material handling should get additional funding. To maximize efficiency in stock-taking as well. Previous studies have looked at a variety of organizational factors that affect performance of supply chains. To further understand how warehouse management strategies affect overall performance, more research is needed.

Effectiveness Of Manual Material Handling Tools For Chicken Feed Transporting Rails And Online Marketing Websites

This research aims to solve problems in the process of feeding broiler chickens on increasing the skills of chicken farmers. The mentoring activities carried out include assisting chicken farmers in using production technology assistance and demonstrating if there is damage or errors in operating Manual Material Handling (MMH) tools or difficulties in managing the website. The results of this research are: 1) 90% respondents understand how to operate Manual Material Handling tools; 2) 90% respondents understand the components of Manual Material Handling; 3) 95% of respondents strongly agree with the material duration in operating manual material handling; 3) 95% participant evaluation results after participating in training for the category of using MMH to Help Broiler Chicken Production answered strongly agree.

Ergonomic risks in manual material handling activities and musculoskeletal disorders complaints in the animal feed industry production area in East Java, Indonesia

Introduction: Manual lifting and load transfer processes that are not carried out properly will result in over exertion-lifting and carrying, i.e. body tissue damage caused by excessive lifting. One of the work-related diseases caused by this activity is Musculoskeletal Disorders (MSDs), a disorder that occurs in the muscles, nerves, tendons, ligaments, joints, cartilages, or the intervertebral discs. The study aims to find out the picture of ergonomic risk in manual material handling activity and musculoskeletal complaints. Methods: Data was obtained from two respondents through accidental sampling. The measurement of the lifting index is done with meters and calculated using the formula of the calculation of the lifting index. The instrument for measuring musculoskeletal disorders was the GOTRAK SNI 9011:2021 Questionnaire. Results: Lifting activities performed by the Hand Add section (LI: 3.054-3.228) and Bagging Off (LI: 3.073-3.470) have a Lifting Index value that is in category &gt; 3 so the interpreted activity has a high risk of causing musculoskeletal complaints. Workers who perform manual material handling activities have high complaints of skeletal and muscle disorders in the upper limbs. Conclusion: Manual handling activities performed in the industry have a high risk of causing injury. Workers who perform manual material handling activities are known to have high complaints of muscle and muscle disorders in the upper limbs.

Biomechanical analysis of different back-supporting exoskeletons regarding musculoskeletal loading during lifting and holding

Industrial back support exoskeletons (BSEs) are a promising approach to addressing low back pain (LBP) which still affect a significant proportion of the workforce. They aim to reduce lumbar loading, the main biomechanical risk factor for LBP, by providing external support to the lumbar spine. The aim of this study was to determine the supporting effect of one active (A1) and two passive (P1 and P2) BSEs during different manual material handling tasks. Kinematic data and back muscle activity were collected from 12 subjects during dynamic lifting and static holding of 10 kg. Mean and peak L5/S1 extension moments, L5/S1 compression forces and muscle activation were included in the analysis. During dynamic lifting all BSEs reduced peak (12–26 %) and mean (4–17 %) extension moments and peak (10–22 %) and mean (4–15 %) compression forces in the lumbar spine. The peak (13–28 %) and mean (4–32 %) activity of the back extensor muscles was reduced accordingly. In the static holding task, analogous mean reductions for P1 and P2 of L5/S1 extension moments (12–20 %), compression forces (13–23 %) and muscular activity (16–23 %) were found. A1 showed a greater reduction during static holding for extension moments (46 %), compression forces (41 %) and muscular activity (54 %). This pronounced difference in the performance of the BSEs between tasks was attributed to the actuators used by the different BSEs.

Equivalent weight: Application of the assessment method on real task conducted by railway workers wearing a back support exoskeleton

Commonly used risk indexes, such as the NIOSH Lifting Index, do not capture the effect of exoskeletons. This makes it difficult for Health and Safety professionals to rigorously assess the benefit of such devices. The community requires a simple method to assess the effectiveness of back-support exoskeleton's (BSE) in possibly reducing ergonomic risk. The method introduced in this work is termed “Equivalent Weight” (EqW) and it proposes an interpretation of the effect built on the benefit delivered through reduced activation of the erector spinae (ES). This manifests itself as an apparent reduction of the lifted load perceived by the wearer. This work presents a pilot study where a practical application of the EqW method is used to assess the ergonomic risk in manual material handling (MMH) when using a back support exoskeleton (StreamEXO). The results are assessed by combining observational measurements from on-site testing with five different workers and quantitative measures of the muscle activity reduction achieved during laboratory evaluation with ten workers. These results will show that when lifting, lowering, and carrying a 19 kg load the StreamEXO can reduce risk by up to two levels (from “high” to “low”) in the target sub-tasks. The Lifting index (LI) was reduced up to 64% when examining specific sub-tasks and the worker's movement conduction.