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Mathiassen SE, Waleh Åström A, Strömberg A, Heiden M. Cost and statistical efficiency of posture assessment by inclinometry and observation, exemplified by paper mill work. PLoS One 2023; 18:e0292261. [PMID: 37788296 PMCID: PMC10547196 DOI: 10.1371/journal.pone.0292261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/16/2023] [Indexed: 10/05/2023] Open
Abstract
Postures at work are paramount in ergonomics. They can be determined using observation and inclinometry in a variety of measurement scenarios that may differ both in costs associated with collecting and processing data, and in efficiency, i.e. the precision of the eventual outcome. The trade-off between cost and efficiency has rarely been addressed in research despite the obvious interest of obtaining precise data at low costs. Median trunk and upper arm inclination were determined for full shifts in 28 paper mill workers using both observation and inclinometry. Costs were estimated using comprehensive cost equations; and efficiency, i.e. the inverted standard deviation of the group mean, was assessed on basis of exposure variance components. Cost and efficiency were estimated in simulations of six sampling scenarios: two for inclinometry (sampling from one or three shifts) and four for observation (one or three observers rating one or three shifts). Each of the six scenarios was evaluated for 1 through 50 workers. Cost-efficiency relationships between the scenarios were intricate. As an example, inclinometry was always more cost-efficient than observation for trunk inclination, except for observation strategies involving only few workers; while for arm inclination, observation by three observers of one shift per worker outperformed inclinometry on three shifts up to a budget of €20000, after which inclinometry prevailed. At a budget of €10000, the best sampling scenario for arm inclination was 2.5 times more efficient than the worst. Arm inclination could be determined with better cost-efficiency than trunk inclination. Our study illustrates that the cost-efficiency of different posture measurement strategies can be assessed and compared using easily accessible diagrams. While the numeric examples in our study are specific to the investigated occupation, exposure variables, and sampling logistics, we believe that inclinometry will, in general, outperform observation. In any specific case, we recommend a thorough analysis, using the comparison procedure proposed in the present study, of feasible strategies for obtaining data, in order to arrive at an informed decision support.
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Affiliation(s)
- Svend Erik Mathiassen
- Centre for Musculoskeletal Research, Department of Occupational Health Science and Psychology, Faculty of Health and Occupational Studies, University of Gävle, Gävle, Sweden
| | - Amanda Waleh Åström
- Centre for Musculoskeletal Research, Department of Occupational Health Science and Psychology, Faculty of Health and Occupational Studies, University of Gävle, Gävle, Sweden
| | - Annika Strömberg
- Department of Business and Economic Studies, Faculty of Education and Business Studies, University of Gävle, Gävle, Sweden
| | - Marina Heiden
- Centre for Musculoskeletal Research, Department of Occupational Health Science and Psychology, Faculty of Health and Occupational Studies, University of Gävle, Gävle, Sweden
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Nyman T, Rhén IM, Johansson PJ, Eliasson K, Kjellberg K, Lindberg P, Fan X, Forsman M. Reliability and Validity of Six Selected Observational Methods for Risk Assessment of Hand Intensive and Repetitive Work. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:ijerph20085505. [PMID: 37107787 PMCID: PMC10138863 DOI: 10.3390/ijerph20085505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/11/2023]
Abstract
Risk assessments of hand-intensive and repetitive work are commonly done using observational methods, and it is important that the methods are reliable and valid. However, comparisons of the reliability and validity of methods are hampered by differences in studies, e.g., regarding the background and competence of the observers, the complexity of the observed work tasks and the statistical methodology. The purpose of the present study was to evaluate six risk assessment methods, concerning inter- and intra-observer reliability and concurrent validity, using the same methodological design and statistical parameters in the analyses. Twelve experienced ergonomists were recruited to perform risk assessments of ten video-recorded work tasks twice, and consensus assessments for the concurrent validity were carried out by three experts. All methods' total-risk linearly weighted kappa values for inter-observer reliability (when all tasks were set to the same duration) were lower than 0.5 (0.15-0.45). Moreover, the concurrent validity values were in the same range with regards to total-risk linearly weighted kappa (0.31-0.54). Although these levels are often considered as being fair to substantial, they denote agreements lower than 50% when the expected agreement by chance has been compensated for. Hence, the risk of misclassification is substantial. The intra-observer reliability was only somewhat higher (0.16-0.58). Regarding the methods ART (Assessment of repetitive tasks of the upper limbs) and HARM (Hand Arm Risk Assessment Method), it is worth noting that the work task duration has a high impact in the risk level calculation, which needs to be taken into account in studies of reliability. This study indicates that when experienced ergonomists use systematic methods, the reliability is low. As seen in other studies, especially assessments of hand/wrist postures were difficult to rate. In light of these results, complementing observational risk assessments with technical methods should be considered, especially when evaluating the effects of ergonomic interventions.
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Affiliation(s)
- Teresia Nyman
- Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, SE-751 85 Uppsala, Sweden; (P.J.J.); (K.E.)
- Department of Occupational and Environmental Medicine, Uppsala University Hospital, SE-751 85 Uppsala, Sweden
- Correspondence:
| | - Ida-Märta Rhén
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-141 57 Huddinge, Sweden; (I.-M.R.); (M.F.)
- Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65 Stockholm, Sweden;
- Unit of Occupational Medicine, Institute of Environmental Medicine (IMM), Karolinska Institutet, SE-171 77 Stockholm, Sweden;
| | - Peter J. Johansson
- Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, SE-751 85 Uppsala, Sweden; (P.J.J.); (K.E.)
- Department of Occupational and Environmental Medicine, Uppsala University Hospital, SE-751 85 Uppsala, Sweden
| | - Kristina Eliasson
- Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University, SE-751 85 Uppsala, Sweden; (P.J.J.); (K.E.)
- Department of Occupational and Environmental Medicine, Uppsala University Hospital, SE-751 85 Uppsala, Sweden
| | - Katarina Kjellberg
- Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65 Stockholm, Sweden;
- Unit of Occupational Medicine, Institute of Environmental Medicine (IMM), Karolinska Institutet, SE-171 77 Stockholm, Sweden;
| | - Per Lindberg
- Department of Occupational Health Science and Psychology, Faculty of Health and Occupational Studies, University of Gävle, SE-801 76 Gävle, Sweden;
| | - Xuelong Fan
- Unit of Occupational Medicine, Institute of Environmental Medicine (IMM), Karolinska Institutet, SE-171 77 Stockholm, Sweden;
| | - Mikael Forsman
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-141 57 Huddinge, Sweden; (I.-M.R.); (M.F.)
- Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65 Stockholm, Sweden;
- Unit of Occupational Medicine, Institute of Environmental Medicine (IMM), Karolinska Institutet, SE-171 77 Stockholm, Sweden;
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Lovén K, Gudmundsson A, Assarsson E, Kåredal M, Wierzbicka A, Dahlqvist C, Nordander C, Xu Y, Isaxon C. Effects of cleaning spray use on eyes, airways, and ergonomic load. BMC Public Health 2023; 23:99. [PMID: 36639638 PMCID: PMC9840290 DOI: 10.1186/s12889-022-14954-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/27/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Cleaning workers are exposed to chemicals and high physical workload, commonly resulting in airway problems and pain. In this study the response in the upper airways and the physical workload following airborne and ergonomic exposure of cleaning spray was investigated. METHODS A survey was answered by professional cleaning workers to investigate their use of cleaning sprays and the perceived effects on eyes, airways and musculoskeletal pain. A human chamber exposure study was then conducted with 11 professional cleaning workers and 8 non-professional cleaning workers to investigate the airborne exposure, acute effects on eyes and airways, and physical load during cleaning with sprays, foam application and microfiber cloths premoistened with water. All cleaning products used were bleach, chlorine, and ammonia free. The medical assessment included eye and airway parameters, inflammatory markers in blood and nasal lavage, as well as technical recordings of the physical workload. RESULTS A high frequency of spray use (77%) was found among the 225 professional cleaning workers that answered the survey. Based on the survey, there was an eight times higher risk (p < 0.001) of self-experienced symptoms (including symptoms in the nose, eyes and throat, coughing or difficulty breathing) when they used sprays compared to when they cleaned with other methods. During the chamber study, when switching from spray to foam, the airborne particle and volatile organic compound (VOC) concentrations showed a decrease by 7 and 2.5 times, respectively. For the whole group, the peak nasal inspiratory flow decreased (-10.9 L/min, p = 0.01) during spray use compared to using only water-premoistened microfiber cloths. These effects were lower during foam use (-4.7 L/min, p = 0.19). The technical recordings showed a high physical workload regardless of cleaning with spray or with water. CONCLUSION Switching from a spraying to a foaming nozzle decreases the exposure of both airborne particles and VOCs, and thereby reduces eye and airway effects, and does not increase the ergonomic load. If the use of cleaning products tested in this study, i.e. bleach, chlorine, and ammonia free, cannot be avoided, foam application is preferable to spray application to improve the occupational environment.
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Affiliation(s)
- Karin Lovén
- grid.4514.40000 0001 0930 2361Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
| | - Anders Gudmundsson
- grid.4514.40000 0001 0930 2361Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
| | - Eva Assarsson
- grid.4514.40000 0001 0930 2361Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Monica Kåredal
- grid.4514.40000 0001 0930 2361Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Aneta Wierzbicka
- grid.4514.40000 0001 0930 2361Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
| | - Camilla Dahlqvist
- grid.4514.40000 0001 0930 2361Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Catarina Nordander
- grid.4514.40000 0001 0930 2361Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Yiyi Xu
- grid.8761.80000 0000 9919 9582Occupational and Environmental Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Christina Isaxon
- grid.4514.40000 0001 0930 2361Ergonomics and Aerosol Technology, Lund University, Lund, Sweden
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Forsman M, Fan X, Rhen IM, Lind CM. Mind the gap - development of conversion models between accelerometer- and IMU-based measurements of arm and trunk postures and movements in warehouse work. APPLIED ERGONOMICS 2022; 105:103841. [PMID: 35917697 DOI: 10.1016/j.apergo.2022.103841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 06/09/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Sensor type (accelerometers only versus inertial measurement units, IMUs) and angular velocity computational method (inclination versus generalized velocity) have been shown to affect the measurements of arm and trunk movements. This study developed models for conversions between accelerometer and IMU measurements of arm and trunk inclination and between accelerometer and IMU measurements of inclination and generalized (arm) velocities. Full-workday recordings from accelerometers and IMUs of arm and trunk postures and movements from 38 warehouse workers were used to develop 4 angular (posture) and 24 angular velocity (movement) conversion models for the distributions of the data. A power function with one coefficient and one exponent was used, and it correlated well (r2 > 0.999) in all cases to the average curves comparing one measurement with another. These conversion models facilitate the comparison and merging of measurements of arm and trunk movements collected using the two sensor types and the two computational methods.
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Affiliation(s)
- Mikael Forsman
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-141 57, Huddinge, Sweden; IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65, Stockholm, Sweden
| | - Xuelong Fan
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden.
| | - Ida-Märta Rhen
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65, Stockholm, Sweden; Department of Industrial and Materials Science, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Carl Mikael Lind
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden
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Lamontagne R, Delisle A, Major ME. Prevention of musculoskeletal disorders among animal research technicians: Understanding difficulties and their determinants through a work activity analysis. APPLIED ERGONOMICS 2022; 103:103792. [PMID: 35609346 DOI: 10.1016/j.apergo.2022.103792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
This study aimed at understanding animal research technicians (ART) work activity to identify difficulties encountered by workers and their determinants which may increase musculoskeletal disorders (MSD) risks. The methods for the work activity analysis combined interviews, observations, events and operations chronicles as well as inclinometry. From the work activity analysis of the three main tasks (changing mouse cages, preparation of water bottles and unloading dirty material), difficulties such as awkward postures, heavy load handling, repetitiveness, high workload, supplementary tasks, interruptions and difficult social interactions emerged. The work activity analysis further allowed the identification of determinants of these difficulties. Some are related to the physical, organizational or social work environment, and others to the interdependence between these determinants. Such an improved understanding of ART work activity will lead to solutions best suited for MSDs prevention in this understudied setting.
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Affiliation(s)
- R Lamontagne
- Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec, Canada.
| | - A Delisle
- Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - M E Major
- Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche interdisciplinaire sur le bien-être, la santé et l'environnement (CINBIOSE), Université du Québec à Montréal, Canada
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6
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Greene RL, Lu ML, Barim MS, Wang X, Hayden M, Hu YH, Radwin RG. Estimating Trunk Angle Kinematics During Lifting Using a Computationally Efficient Computer Vision Method. HUMAN FACTORS 2022; 64:482-498. [PMID: 32972247 PMCID: PMC10009882 DOI: 10.1177/0018720820958840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
OBJECTIVE A computer vision method was developed for estimating the trunk flexion angle, angular speed, and angular acceleration by extracting simple features from the moving image during lifting. BACKGROUND Trunk kinematics is an important risk factor for lower back pain, but is often difficult to measure by practitioners for lifting risk assessments. METHODS Mannequins representing a wide range of hand locations for different lifting postures were systematically generated using the University of Michigan 3DSSPP software. A bounding box was drawn tightly around each mannequin and regression models estimated trunk angles. The estimates were validated against human posture data for 216 lifts collected using a laboratory-grade motion capture system and synchronized video recordings. Trunk kinematics, based on bounding box dimensions drawn around the subjects in the video recordings of the lifts, were modeled for consecutive video frames. RESULTS The mean absolute difference between predicted and motion capture measured trunk angles was 14.7°, and there was a significant linear relationship between predicted and measured trunk angles (R2 = .80, p < .001). The training error for the kinematics model was 2.3°. CONCLUSION Using simple computer vision-extracted features, the bounding box method indirectly estimated trunk angle and associated kinematics, albeit with limited precision. APPLICATION This computer vision method may be implemented on handheld devices such as smartphones to facilitate automatic lifting risk assessments in the workplace.
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Affiliation(s)
| | - Ming-Lun Lu
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | | | - Xuan Wang
- University of Wisconsin-Madison, Madison, WI, USA
| | - Marie Hayden
- National Institute for Occupational Safety and Health, Cincinnati, OH, USA
| | - Yu Hen Hu
- University of Wisconsin-Madison, Madison, WI, USA
| | - Robert G. Radwin
- University of Wisconsin-Madison, Madison, WI, USA
- Address correspondence to Robert G. Radwin, PhD, Department of Industrial and Systems Engineering, 1550 Engineering Drive, Madison, WI 53706,
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Haraldsson P, Areskoug-Josefsson K, Rolander B, Strengbom E, Jonker D. Comparing the Structured Multidisciplinary work Evaluation Tool (SMET) questionnaire with technical measurements of physical workload in certified nursing assistants in a medical ward setting. APPLIED ERGONOMICS 2021; 96:103493. [PMID: 34116412 DOI: 10.1016/j.apergo.2021.103493] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 04/29/2021] [Accepted: 06/02/2021] [Indexed: 06/12/2023]
Abstract
The Certified Nursing Assistant (CNA) is an important part of the workforce in hospitals and nursing homes, whose work includes heavy and repetitive work tasks including patient manual handling. The Structured Multidisciplinary work Evaluation Tool (SMET) questionnaire is an Occupational Health Service method for evaluation of the work environment. The aim of this study is to compare the SMET questionnaire with technical measurements of physical workload in CNAs in a medical ward setting. 16 CNA's participated voluntarily to 8 h of measurements during one workday. Physical workload was measured with surface electromyography and inclinometers, and the work environment was evaluated with the SMET questionnaire during the same working day. Spearman's rho was used in the statistical correlation analysis between measurements. This study shows strong, statistically significant correlations between the items in the SMET questionnaire and measured physical workload, n CNAs.
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Affiliation(s)
- P Haraldsson
- Occupational Safety and Health Care, Region Jönköping County, Jönköping, Sweden; School of Health and Welfare, Jönköping Academy for Improvement of Health and Welfare, Jönköping University, Jönköping, Sweden.
| | - K Areskoug-Josefsson
- School of Health and Welfare, Jönköping Academy for Improvement of Health and Welfare, Jönköping University, Jönköping, Sweden; Faculty of Health Studies, VID Specialized University, Sandnes, Norway; Department of Behavioural Science, Oslo Metropolitan University, Oslo, Norway
| | - B Rolander
- Futurum - Academy for Healthcare, Region Jönköping County, Jönköping, Sweden; School of Health and Welfare, Department of Behavioural Science and Social Work, Jönköping University, Jönköping, Sweden
| | - E Strengbom
- Occupational Safety and Health Care, Region Jönköping County, Jönköping, Sweden
| | - D Jonker
- Occupational Safety and Health Care, Region Jönköping County, Jönköping, Sweden; School of Health and Welfare, Jönköping Academy for Improvement of Health and Welfare, Jönköping University, Jönköping, Sweden
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8
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Lee R, James C, Edwards S, Skinner G, Young JL, Snodgrass SJ. Evidence for the Effectiveness of Feedback from Wearable Inertial Sensors during Work-Related Activities: A Scoping Review. SENSORS (BASEL, SWITZERLAND) 2021; 21:6377. [PMID: 34640695 PMCID: PMC8512480 DOI: 10.3390/s21196377] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/16/2021] [Accepted: 09/18/2021] [Indexed: 01/03/2023]
Abstract
Background: Wearable inertial sensor technology (WIST) systems provide feedback, aiming to modify aberrant postures and movements. The literature on the effects of feedback from WIST during work or work-related activities has not been previously summarised. This review examines the effectiveness of feedback on upper body kinematics during work or work-related activities, along with the wearability and a quantification of the kinematics of the related device. Methods: The Cinahl, Cochrane, Embase, Medline, Scopus, Sportdiscus and Google Scholar databases were searched, including reports from January 2005 to July 2021. The included studies were summarised descriptively and the evidence was assessed. Results: Fourteen included studies demonstrated a 'limited' level of evidence supporting posture and/or movement behaviour improvements using WIST feedback, with no improvements in pain. One study assessed wearability and another two investigated comfort. Studies used tri-axial accelerometers or IMU integration (n = 5 studies). Visual and/or vibrotactile feedback was mostly used. Most studies had a risk of bias, lacked detail for methodological reproducibility and displayed inconsistent reporting of sensor technology, with validation provided only in one study. Thus, we have proposed a minimum 'Technology and Design Checklist' for reporting. Conclusions: Our findings suggest that WIST may improve posture, though not pain; however, the quality of the studies limits the strength of this conclusion. Wearability evaluations are needed for the translation of WIST outcomes. Minimum reporting standards for WIST should be followed to ensure methodological reproducibility.
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Affiliation(s)
- Roger Lee
- School of Health Sciences, The University of Newcastle, Newcastle 2308, Australia; (C.J.); (S.J.S.)
- Centre for Brain and Mental Health Research, The University of Newcastle, Newcastle 2308, Australia
| | - Carole James
- School of Health Sciences, The University of Newcastle, Newcastle 2308, Australia; (C.J.); (S.J.S.)
- Centre for Resources Health and Safety, The University of Newcastle, Newcastle 2308, Australia
| | - Suzi Edwards
- School of Health Sciences, The University of Sydney, Sydney 2006, Australia;
| | - Geoff Skinner
- School of Information and Physical Sciences, The University of Newcastle, Newcastle 2308, Australia;
| | - Jodi L. Young
- Department of Physical Therapy, Bellin College, Green Bay, WI 54311, USA;
| | - Suzanne J. Snodgrass
- School of Health Sciences, The University of Newcastle, Newcastle 2308, Australia; (C.J.); (S.J.S.)
- Centre for Brain and Mental Health Research, The University of Newcastle, Newcastle 2308, Australia
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Fan X, Lind CM, Rhen IM, Forsman M. Effects of Sensor Types and Angular Velocity Computational Methods in Field Measurements of Occupational Upper Arm and Trunk Postures and Movements. SENSORS 2021; 21:s21165527. [PMID: 34450967 PMCID: PMC8401405 DOI: 10.3390/s21165527] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/05/2021] [Accepted: 08/12/2021] [Indexed: 12/15/2022]
Abstract
Accelerometer-based inclinometers have dominated kinematic measurements in previous field studies, while the use of inertial measurement units that additionally include gyroscopes is rapidly increasing. Recent laboratory studies suggest that these two sensor types and the two commonly used angular velocity computational methods may produce substantially different results. The aim of this study was, therefore, to evaluate the effects of sensor types and angular velocity computational methods on the measures of work postures and movements in a real occupational setting. Half-workday recordings of arm and trunk postures, and movements from 38 warehouse workers were compared using two sensor types: accelerometers versus accelerometers with gyroscopes-and using two angular velocity computational methods, i.e., inclination velocity versus generalized velocity. The results showed an overall small difference (<2° and value independent) for posture percentiles between the two sensor types, but substantial differences in movement percentiles both between the sensor types and between the angular computational methods. For example, the group mean of the 50th percentiles were for accelerometers: 71°/s (generalized velocity) and 33°/s (inclination velocity)-and for accelerometers with gyroscopes: 31°/s (generalized velocity) and 16°/s (inclination velocity). The significant effects of sensor types and angular computational methods on angular velocity measures in field work are important in inter-study comparisons and in comparisons to recommended threshold limit values.
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Affiliation(s)
- Xuelong Fan
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden; (X.F.); (I.-M.R.); (M.F.)
| | - Carl Mikael Lind
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden; (X.F.); (I.-M.R.); (M.F.)
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, SE-141 57 Huddinge, Sweden
- Correspondence:
| | - Ida-Märta Rhen
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden; (X.F.); (I.-M.R.); (M.F.)
- Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65 Stockholm, Sweden
- Department of Industrial and Materials Science, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Mikael Forsman
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden; (X.F.); (I.-M.R.); (M.F.)
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, SE-141 57 Huddinge, Sweden
- Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65 Stockholm, Sweden
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Rhén IM, Forsman M. Inter- and intra-rater reliability of the OCRA checklist method in video-recorded manual work tasks. APPLIED ERGONOMICS 2020; 84:103025. [PMID: 31987511 DOI: 10.1016/j.apergo.2019.103025] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/30/2019] [Accepted: 12/01/2019] [Indexed: 05/27/2023]
Abstract
Observation-based risk assessments are often used for evaluation of biomechanical workload and the condition of the workplace ergonomics. However, the inter- and intra-rater reliability of the methods used for the assessments are insufficiently studied. The OCRA checklist method, included as a reference method in the ISO and CEN standards regarding upper limb repetitive risk assessment, was in this study investigated regarding its reliability. Eleven ergonomists were educated within the method. Each ergonomist risk-assessed ten video-recorded manual work tasks, on two occasions. The average inter-rater agreement of the five overall risk levels was 39% and the linearly weighted kappa was 0.43, the intra-rater dittos were 45% and 0.52. Both indicating a moderate reliability, but lower than what could be expected. The levels might be sufficient for coarse surveys. However, for risk assessments before and after an intervention, complementing technical methods should be considered.
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Affiliation(s)
- Ida-Märta Rhén
- Department of Industrial and Materials Science, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden; IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65, Stockholm, Sweden.
| | - Mikael Forsman
- IMM Institute of Environmental Medicine, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Centre for Occupational and Environmental Medicine, Stockholm County Council, SE-113 65, Stockholm, Sweden; School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-141 57, Huddinge, Sweden
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Barramuño M, Valdés-Badilla P, Guevara E. Variations in glenohumeral movement control when implementing an auditory feedback system: A pilot study. REVISTA DE LA FACULTAD DE MEDICINA 2019. [DOI: 10.15446/revfacmed.v67n4.69456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Introduction: Human motor control requires a learning process and it can be trained by means of various sensory feedback sources.Objective: To determine variations in glenohumeral movement control by learning in young adults exposed to an auditory feedback system while they perform object translation tasks classified by difficulty level.Materials and methods: The study involved 45 volunteers of both sexes (22 women), aged between 18 and 32 years. Glenohumeral movement control was measured by means of the root mean square (RMS) of the accelerometry signal, while task execution speed (TES) was measured using an accelerometer during the execution of the task according to its difficulty (easy, moderate and hard) in four stages of randomized intervention (control, pre-exposure, exposure-with auditory feedback, and post-exposure).Results: Statistically significant differences (p<0.001) were found between the pre-exposure and exposure stages and between pre-exposure and post-exposure stages. A significant increase (p <0.001) in TES was identified between the pre-exposure and exposure stages for tasks classified as easy and hard, respectively.Conclusion: The use of an auditory feedback system in young adults without pathologies enhanced learning and glenohumeral movement control without reducing TES. This effect was maintained after the feedback, so the use of this type of feedback system in healthy individuals could result in a useful strategy for the training of motor control of the shoulder.
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Palm P, Gupta N, Forsman M, Skotte J, Nordquist T, Holtermann A. Exposure to Upper Arm Elevation During Work Compared to Leisure Among 12 Different Occupations Measured with Triaxial Accelerometers. Ann Work Expo Health 2019; 62:689-698. [PMID: 29945157 PMCID: PMC6037214 DOI: 10.1093/annweh/wxy037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 06/21/2018] [Indexed: 01/15/2023] Open
Abstract
Regarding prevention of neck and shoulder pain (NSP), unsupported arm elevation is one factor that should be taken into account when performing work risk assessment. Triaxial accelerometers can be used to measure arm elevation over several days but it is not possible to differentiate between supported and unsupported arm elevation from accelerometers only. Supported arm elevation is more likely to exist during sitting than standing. The aim of the study was to evaluate the use of whole workday measurements of arm elevation with accelerometers to assess potentially harmful work exposure of arm elevation, by comparing arm elevation at work with arm elevation during leisure, in a population with diverse work tasks, and to assess how the exposure parameters were modified when upper arm elevation during sitting time was excluded. The participants, 197 workers belonging to 12 occupational groups with diverse work tasks, wore triaxial accelerometers on the dominant arm, hip, and back for 1–4 days to measure arm elevation and periods of sitting. None of the groups were found to have higher exposure to arm elevation during work compared to leisure. Even though some occupations where known to have work tasks that forced them to work with elevated arms to a large extent. A high proportion of arm elevation derived from sitting time, especially so during leisure. When arm elevation during sitting time was excluded from the analysis, arm elevation was significantly higher at work than during leisure among construction workers, garbage collectors, manufacturing workers, and domestic cleaners. Together this illustrates that it is not suitable to use whole workday measurments of arm elevation with accelerometer as a sole information source when assessing the risk for NSP due to arm elevation. Information on body posture can provide relevant contextual information in exposure assessments when it is known that the potential harmful exposure is performed in standing or walking.
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Affiliation(s)
- Peter Palm
- Department of Medical Sciences Occupational and Environmental Medicine, Dag Hammarsjköldsväg, Uppsala, Sweden.,Occupational and Environmental Medicine, Akademiska sjukhuset, Dag Hammarsjköldsväg, Uppsala, Sweden
| | - Nidhi Gupta
- National Research Centre for the Working Environmnent, Lersø Parkallé, Copenhagen Ø, Denmark
| | - Mikael Forsman
- IMM Institute of Environmnental Medicine, Nobels väg, Stockholm, Sweden.,Centre for Occupational and Environmental Medicine, Solnavägen, Stockholm, Sweden
| | - Jørgen Skotte
- National Research Centre for the Working Environmnent, Lersø Parkallé, Copenhagen Ø, Denmark
| | - Tobias Nordquist
- Department of Medical Sciences Occupational and Environmental Medicine, Dag Hammarsjköldsväg, Uppsala, Sweden
| | - Andreas Holtermann
- National Research Centre for the Working Environmnent, Lersø Parkallé, Copenhagen Ø, Denmark.,Department of Sports Science and Clinical Biomechanics, University of Odense, Campusvej, Odense, Denmark
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13
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Oliv S, Gustafsson E, Baloch AN, Hagberg M, Sandén H. The Quick Exposure Check (QEC) - Inter-rater reliability in total score and individual items. APPLIED ERGONOMICS 2019; 76:32-37. [PMID: 30642522 DOI: 10.1016/j.apergo.2018.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 11/16/2018] [Accepted: 11/20/2018] [Indexed: 06/09/2023]
Abstract
The development of musculoskeletal disorders has been linked to various risk factors in the work environment including lifting heavy loads, machine and materials handling, work postures, repetitive work, work with handheld vibrating tools, and work stress. The Quick Exposure Check (QEC) was designed to assess exposure to work-related musculoskeletal risk factors affecting the back, shoulder/arm, wrist/hand, and neck. We investigated the inter-rater reliability of the summary scores and individual items of the QEC by comparing two simultaneous assessments of 51 work tasks, performed by 14 different workers. The work tasks were mainly "light" to "moderately heavy". For total scores, the level of disagreement for shoulder/arm had a Relative Position of 0.13 (95% CI: 0.02; 0.23) and no statistically significant random disagreement. Percentage agreement was 63-100% for individual items and 71-88% for total score. Weighted Kappa of agreement for the individual items rated by the assessors were -0.94-0.77; highest for back motion, and lowest for wrist/hand position. The Swedish translation of the Quick Exposure Check has moderate to very good inter-rater reliability with fair to slight levels of systematic disagreement. There was no statistically significant random disagreement.
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Affiliation(s)
- Stefan Oliv
- Department of Occupational and Environmental Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Ewa Gustafsson
- Department of Occupational and Environmental Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Adnan Noor Baloch
- Department of Occupational and Environmental Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Mats Hagberg
- Department of Occupational and Environmental Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Helena Sandén
- Department of Occupational and Environmental Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
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14
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Vega-Barbas M, Diaz-Olivares JA, Lu K, Forsman M, Seoane F, Abtahi F. P-Ergonomics Platform: Toward Precise, Pervasive, and Personalized Ergonomics using Wearable Sensors and Edge Computing. SENSORS 2019; 19:s19051225. [PMID: 30862019 PMCID: PMC6427483 DOI: 10.3390/s19051225] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/01/2019] [Accepted: 03/06/2019] [Indexed: 12/03/2022]
Abstract
Preventive healthcare has attracted much attention recently. Improving people’s lifestyles and promoting a healthy diet and wellbeing are important, but the importance of work-related diseases should not be undermined. Musculoskeletal disorders (MSDs) are among the most common work-related health problems. Ergonomists already assess MSD risk factors and suggest changes in workplaces. However, existing methods are mainly based on visual observations, which have a relatively low reliability and cover only part of the workday. These suggestions concern the overall workplace and the organization of work, but rarely includes individuals’ work techniques. In this work, we propose a precise and pervasive ergonomic platform for continuous risk assessment. The system collects data from wearable sensors, which are synchronized and processed by a mobile computing layer, from which exposure statistics and risk assessments may be drawn, and finally, are stored at the server layer for further analyses at both individual and group levels. The platform also enables continuous feedback to the worker to support behavioral changes. The deployed cloud platform in Amazon Web Services instances showed sufficient system flexibility to affordably fulfill requirements of small to medium enterprises, while it is expandable for larger corporations. The system usability scale of 76.6 indicates an acceptable grade of usability.
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Affiliation(s)
- Mario Vega-Barbas
- Institute of Environmental Medicine, Karolinska Institutet, Solnavägen 1, 17177 Solna, Sweden.
| | - Jose A Diaz-Olivares
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, 14157 Huddinge, Sweden.
| | - Ke Lu
- Institute of Environmental Medicine, Karolinska Institutet, Solnavägen 1, 17177 Solna, Sweden.
| | - Mikael Forsman
- Institute of Environmental Medicine, Karolinska Institutet, Solnavägen 1, 17177 Solna, Sweden.
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, 14157 Huddinge, Sweden.
| | - Fernando Seoane
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Hälsovägen 7, 14157 Huddinge, Sweden.
- Swedish School of Textiles, University of Borås, Allégatan 1, 50190 Borås, Sweden.
- Departm and t of Biomedical Engineering, Karolinska University Hospital, 1, 17176 Solna, Sweden.
| | - Farhad Abtahi
- Institute of Environmental Medicine, Karolinska Institutet, Solnavägen 1, 17177 Solna, Sweden.
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, 14157 Huddinge, Sweden.
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15
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Dahlqvist C, Nordander C, Forsman M, Enquist H. Self-recordings of upper arm elevation during cleaning - comparison between analyses using a simplified reference posture and a standard reference posture. BMC Musculoskelet Disord 2018; 19:402. [PMID: 30442141 PMCID: PMC6238373 DOI: 10.1186/s12891-018-2328-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 10/29/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND To reduce ergonomic risk factors in terms of awkward and constrained postures and high velocities, it is important to perform adequate risk assessments. Technical methods provide objective measures of physical workload. These methods have so far mainly been used by researchers. However, if written instructions how to apply the sensors and how to adopt the reference posture are provided, together with triaxial accelerometers, it may be possible for employees to record their own physical workload. The exposure in terms of e.g. upper arm elevations could then easily be assessed for all workers in a workplace. The main aims of this study were: 1) to compare analyses for self-recording of upper arm elevation during work using a simplified reference posture versus using a standard reference posture, and 2) to compare the two reference postures. METHODS Twenty-eight cleaners attached an accelerometer to their dominant upper arm and adopted a simplified reference according to a written instruction. They were thereafter instructed by a researcher to adopt a standard reference. Upper arm elevations were recorded for 2 or 3 days. Each recording was analysed twice; relative to the simplified reference posture and relative to the standard reference posture. The group means of the differences in recorded upper arm elevations between simplified and standard reference analyses were assessed using Wilcoxon signed ranks test. Furthermore, we calculated the group mean of the differences between the simplified reference posture and the standard reference posture. RESULTS For arm elevation during work (50th percentile), the group mean of the differences between the two analyses was 0.2° (range -7 - 10°). The group mean of the differences between the two references was 9° (range 1 - 21°). The subjects were able to follow the instructions in the protocol and performed self-recording of upper arm elevation and velocity. CONCLUSIONS The small difference between the two analyses indicates that recordings performed by employees themselves are comparable, on a group level, with those performed by researchers. Self-recordings in combination with action levels would provide employers with a method for risk assessment as a solid basis for prevention of work-related musculoskeletal disorders.
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Affiliation(s)
- Camilla Dahlqvist
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE-221 85 Lund, Sweden
| | - Catarina Nordander
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE-221 85 Lund, Sweden
| | - Mikael Forsman
- Division of Ergonomics, KTH Royal Institute of Technology, SE-141 57 Huddinge, Sweden
| | - Henrik Enquist
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, SE-221 85 Lund, Sweden
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16
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Waleh Åström A, Heiden M, Mathiassen SE, Strömberg A. Uncertainty in monetary cost estimates for assessing working postures using inclinometry, observation or self-report. APPLIED ERGONOMICS 2018; 71:73-77. [PMID: 29764616 DOI: 10.1016/j.apergo.2018.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/15/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVE To assess uncertainty in cost estimates for collecting posture data by inclinometry, observations and self-report. METHOD In a study addressing physical workloads at a paper mill, costs were calculated for measuring postures of twenty-eight workers during three shifts. Uncertainty in costs was assessed for all three methods as the range between an assumed best case (lowest cost) and worst case (highest cost) using scenario analysis. RESULTS The cost for observation was larger, but also more uncertain (€16506 and €89552 in the best and worst case, respectively) than that of inclinometry (€7613 - €45896). Self-report costs were both lower and less uncertain (€3743 - €23368). CONCLUSIONS The extent of uncertainty in cost estimates implies that observation could be less expensive than inclinometry, e.g., in a scenario where experienced observers could use existing software, while inclinometers would have to be purchased. We propose adding uncertainty assessments to cost estimates when selecting a method for measuring working postures, and offer guidance in how to proceed in a specific setting.
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Affiliation(s)
- Amanda Waleh Åström
- Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies, University of Gävle, SE-801 76, Gävle, Sweden.
| | - Marina Heiden
- Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies, University of Gävle, SE-801 76, Gävle, Sweden.
| | - Svend Erik Mathiassen
- Centre for Musculoskeletal Research, Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies, University of Gävle, SE-801 76, Gävle, Sweden.
| | - Annika Strömberg
- Faculty of Health and Occupational Studies, University of Gävle, SE-801 76, Gävle, Sweden.
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17
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Gupta A, Wilkerson GB, Sharda R, Colston MA. Who is More Injury‐Prone? Prediction and Assessment of Injury Risk. DECISION SCIENCES 2018. [DOI: 10.1111/deci.12333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ashish Gupta
- Department of Systems & TechnologyHarbert College of Business, Auburn University 405 West Magnolia Ave. Auburn Al 36849
| | - Gary B. Wilkerson
- Graduate Athletic Training Program University of Tennessee at Chattanooga 615 McCallie Avenue – Department 6606 Chattanooga TN 37403
| | - Ramesh Sharda
- Watson Graduate SchoolSpears School of Business, Oklahoma State University Stillwater OK 74074
| | - Marisa A. Colston
- Health and Human PerformanceUniversity of Tennessee Chattanooga Metro Building – Dept 6606, 615 McCallie Avenue Chattanooga TN 37403
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18
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Dahlqvist C, Nordander C, Granqvist L, Forsman M, Hansson GÅ. Comparing two methods to record maximal voluntary contractions and different electrode positions in recordings of forearm extensor muscle activity: Refining risk assessments for work-related wrist disorders. Work 2018; 59:231-242. [PMID: 29355119 PMCID: PMC5870034 DOI: 10.3233/wor-172668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND: Wrist disorders are common in force demanding industrial repetitive work. Visual assessment of force demands have a low reliability, instead surface electromyography (EMG) may be used as part of a risk assessment for work-related wrist disorders. For normalization of EMG recordings, a power grip (hand grip) is often used as maximal voluntary contraction (MVC) of the forearm extensor muscles. However, the test-retest reproducibility is poor and EMG amplitudes exceeding 100% have occasionally been recorded during work. An alternative MVC is resisted wrist extension, which may be more reliable. OBJECTIVE: To compare hand grip and resisted wrist extension MVCs, in terms of amplitude and reproducibility, and to examine the effect of electrode positioning. METHODS: Twelve subjects participated. EMG from right forearm extensors, from four electrode pairs, was recorded during MVCs, on three separate occasions. RESULTS: The group mean EMG amplitudes for resisted wrist extension were 1.2–1.7 times greater than those for hand grip. Resisted wrist extension showed better reproducibility than hand grip. CONCLUSIONS: The results indicate that the use of resisted wrist extension is a more accurate measurement of maximal effort of wrist extensor contractions than using hand grip and should increase the precision in EMG recordings from forearm extensor muscles, which in turn will increase the quality of risk assessments that are based on these.
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Affiliation(s)
- Camilla Dahlqvist
- Department of Laboratory Medicine Occupational and Environmental Medicine, Lund University, Skane Medical Services, Lund, Sweden
| | - Catarina Nordander
- Department of Laboratory Medicine Occupational and Environmental Medicine, Lund University, Skane Medical Services, Lund, Sweden
| | - Lothy Granqvist
- Department of Laboratory Medicine Occupational and Environmental Medicine, Lund University, Skane Medical Services, Lund, Sweden
| | - Mikael Forsman
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Gert-Åke Hansson
- Department of Laboratory Medicine Occupational and Environmental Medicine, Lund University, Skane Medical Services, Lund, Sweden
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Lee W, Seto E, Lin KY, Migliaccio GC. An evaluation of wearable sensors and their placements for analyzing construction worker's trunk posture in laboratory conditions. APPLIED ERGONOMICS 2017; 65:424-436. [PMID: 28420483 DOI: 10.1016/j.apergo.2017.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 06/07/2023]
Abstract
This study investigates the effect of sensor placement on the analysis of trunk posture for construction activities using two off-the-shelf systems. Experiments were performed using a single-parameter monitoring wearable sensor (SPMWS), the ActiGraph GT9X Link, which was worn at six locations on the body, and a multi-parameter monitoring wearable sensor (MPMWS), the Zephyr BioHarness™3, which was worn at two body positions. One healthy male was recruited and conducted 10 experiment sessions to repeat measurements of trunk posture within our study. Measurements of upper-body thoracic bending posture during the lifting and lowering of raised deck materials in a laboratory setting were compared against video-captured observations of posture. The measurements from the two sensors were found to be in agreement during slow-motion symmetric bending activities with a target bending of ≤45°. However, for asymmetric bending tasks, when the SPMWS was placed on the chest, its readings were substantially different from those of the MPMWS worn on the chest or under the armpit.
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Affiliation(s)
- Wonil Lee
- Department of Construction Management, College of Built Environments, University of Washington, Seattle, WA 98195, USA; Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA 98195, USA.
| | - Edmund Seto
- Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington, Seattle, WA 98195, USA
| | - Ken-Yu Lin
- Department of Construction Management, College of Built Environments, University of Washington, Seattle, WA 98195, USA
| | - Giovanni C Migliaccio
- Department of Construction Management, College of Built Environments, University of Washington, Seattle, WA 98195, USA
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Greene RL, Azari DP, Hu YH, Radwin RG. Visualizing stressful aspects of repetitive motion tasks and opportunities for ergonomic improvements using computer vision. APPLIED ERGONOMICS 2017; 65:461-472. [PMID: 28284701 DOI: 10.1016/j.apergo.2017.02.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 06/06/2023]
Abstract
Patterns of physical stress exposure are often difficult to measure, and the metrics of variation and techniques for identifying them is underdeveloped in the practice of occupational ergonomics. Computer vision has previously been used for evaluating repetitive motion tasks for hand activity level (HAL) utilizing conventional 2D videos. The approach was made practical by relaxing the need for high precision, and by adopting a semi-automatic approach for measuring spatiotemporal characteristics of the repetitive task. In this paper, a new method for visualizing task factors, using this computer vision approach, is demonstrated. After videos are made, the analyst selects a region of interest on the hand to track and the hand location and its associated kinematics are measured for every frame. The visualization method spatially deconstructs and displays the frequency, speed and duty cycle components of tasks that are part of the threshold limit value for hand activity for the purpose of identifying patterns of exposure associated with the specific job factors, as well as for suggesting task improvements. The localized variables are plotted as a heat map superimposed over the video, and displayed in the context of the task being performed. Based on the intensity of the specific variables used to calculate HAL, we can determine which task factors most contribute to HAL, and readily identify those work elements in the task that contribute more to increased risk for an injury. Work simulations and actual industrial examples are described. This method should help practitioners more readily measure and interpret temporal exposure patterns and identify potential task improvements.
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Affiliation(s)
| | | | - Yu Hen Hu
- University of Wisconsin-Madison, United States
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21
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Yang L, Grooten WJA, Forsman M. An iPhone application for upper arm posture and movement measurements. APPLIED ERGONOMICS 2017; 65:492-500. [PMID: 28274467 DOI: 10.1016/j.apergo.2017.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/28/2016] [Accepted: 02/16/2017] [Indexed: 05/27/2023]
Abstract
There is a need for objective methods for upper arm elevation measurements for accurate and convenient risk assessments. The aims of this study were (i) to compare a newly developed iOS application (iOS) for measuring upper arm elevation and angular velocity with a reference optical tracking system (OTS), and (ii) to compare the accuracy of the iOS incorporating a gyroscope and an accelerometer with using only an accelerometer, which is standard for inclinometry. The iOS-OTS limits of agreement for static postures (9 subjects) were -4.6° and 4.8°. All root mean square differences in arm swings and two simulated work tasks were <6.0°, and all mean correlation coefficients were >0.98. The mean absolute iOS-OTS difference of median angular velocity was <13.1°/s, which was significantly lower than only using an accelerometer (<43.5°/s). The accuracy of this iOS application compares well to that of today's research methods and it can be useful for practical upper arm measurements.
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Affiliation(s)
- Liyun Yang
- Unit of Ergonomics, School of Technology and Health, KTH Royal Institute of Technology, Stockholm, Sweden.
| | - Wilhelmus J A Grooten
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Forsman
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Eliasson K, Palm P, Nyman T, Forsman M. Inter- and intra- observer reliability of risk assessment of repetitive work without an explicit method. APPLIED ERGONOMICS 2017; 62:1-8. [PMID: 28411720 DOI: 10.1016/j.apergo.2017.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 01/30/2017] [Accepted: 02/02/2017] [Indexed: 06/07/2023]
Abstract
A common way to conduct practical risk assessments is to observe a job and report the observed long term risks for musculoskeletal disorders. The aim of this study was to evaluate the inter- and intra-observer reliability of ergonomists' risk assessments without the support of an explicit risk assessment method. Twenty-one experienced ergonomists assessed the risk level (low, moderate, high risk) of eight upper body regions, as well as the global risk of 10 video recorded work tasks. Intra-observer reliability was assessed by having nine of the ergonomists repeat the procedure at least three weeks after the first assessment. The ergonomists made their risk assessment based on his/her experience and knowledge. The statistical parameters of reliability included agreement in %, kappa, linearly weighted kappa, intraclass correlation and Kendall's coefficient of concordance. The average inter-observer agreement of the global risk was 53% and the corresponding weighted kappa (Kw) was 0.32, indicating fair reliability. The intra-observer agreement was 61% and 0.41 (Kw). This study indicates that risk assessments of the upper body, without the use of an explicit observational method, have non-acceptable reliability. It is therefore recommended to use systematic risk assessment methods to a higher degree.
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Affiliation(s)
- Kristina Eliasson
- School of Technology and Health, KTH Royal Institute of Technology, Huddinge, Sweden.
| | - Peter Palm
- Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University and Uppsala University Hospital, Sweden
| | - Teresia Nyman
- School of Technology and Health, KTH Royal Institute of Technology, Huddinge, Sweden; Department of Medical Sciences, Occupational and Environmental Medicine, Uppsala University and Uppsala University Hospital, Sweden
| | - Mikael Forsman
- IMM Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Centre for Occupational and Environmental Medicine, Stockholm County Council, Sweden
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