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Kazemi Z, Arjmand N, Mazloumi A, Karimi Z, Keihani A, Ghasemi MS. Effect of muscular fatigue on the cumulative lumbar damage during repetitive lifting task: a comparative study of damage calculation methods. ERGONOMICS 2024; 67:566-581. [PMID: 37418312 DOI: 10.1080/00140139.2023.2234678] [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: 04/14/2023] [Accepted: 07/02/2023] [Indexed: 07/09/2023]
Abstract
Several methods have been put forward to quantify cumulative loads; however, limited evidence exists as to the subsequent damages and the role of muscular fatigue. The present study assessed whether muscular fatigue could affect cumulative damage imposed on the L5-S1 joint. Trunk muscle electromyographic (EMG) activities and kinematics/kinetics of 18 healthy male individuals were evaluated during a simulated repetitive lifting task. A traditional EMG-assisted model of the lumbar spine was modified to account for the effect of erector spinae fatigue. L5-S1 compressive loads for each lifting cycle were estimated based on varying (i.e. actual), fatigue-modified, and constant Gain factors. The corresponding damages were integrated to calculate the cumulative damage. Moreover, the damage calculated for one lifting cycle was multiplied by the lifting frequency, as the traditional approach. Compressive loads and the damages obtained through the fatigue-modified model were predicted in close agreement with the actual values. Similarly, the difference between actual damages and those driven by the traditional approach was not statistically significant (p = 0.219). However, damages based on a constant Gain factor were significantly greater than those based on the actual (p = 0.012), fatigue-modified (p = 0.017), and traditional (p = 0.007) approaches.Practitioner summary: In this study, we managed to include the effect of muscular fatigue on cumulative lumbar damage calculations. Including the effect of muscular fatigue leads to an accurate estimation of cumulative damages while eliminating computational complexity. However, using the traditional approach also appears to provide acceptable estimates for ergonomic assessments.
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Affiliation(s)
- Zeinab Kazemi
- Department of Industrial Engineering, Clemson University, Clemson, SC, USA
| | - Navid Arjmand
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Adel Mazloumi
- Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Sports Medicine Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Zanyar Karimi
- Department of Ergonomics, School of Public Health, Urmia University of Medical Sciences, Tehran, Iran
| | - Ahmadreza Keihani
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Ghaneh-Ezabadi S, Abdoli-Eramaki M, Arjmand N, Abouhossein A, Zakerian SA. The Validity and Inter-Rater Reliability of a Video-Based Posture-Matching Tool to Estimate Cumulative Loads on the Lower Back. J Biomed Phys Eng 2022; 12:417-430. [PMID: 36059286 PMCID: PMC9395627 DOI: 10.31661/jbpe.v0i0.2203-1474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Low back pain (LBP) is known as one of the most common work-related musculoskeletal disorders. Spinal cumulative loads (CLs) during manual material handling (MMH) tasks are the main risk factors for LBP. However, there is no valid and reliable quantitative lifting analysis tool available for quantifying CLs among Iranian workers performing MMH tasks. OBJECTIVE This study aimed to investigate the validity and inter-rater reliability of a posture-matching load assessment tool (PLAT) for estimating the L5-S1 static cumulative compression (CC) and shear (CS) loads based on predictive regression equations. MATERIAL AND METHODS This experimental study was conducted among six participants performing four lifting tasks, each comprised of five trials during which their posture was recorded via a motion capture (Vicon) and simultaneously a three-camera system located at three different angles (0°, 45°, and 90°) to the sagittal plane. RESULTS There were no significant differences between the two CLs estimated by PLAT from the three-camera system and the gold-standard Vicon. In addition, ten raters estimated CLs of the tasks using PLAT in three sessions. The calculated intra-class correlation coefficients for the estimated CLs within each task revealed excellent inter-rater reliability (> 0.75), except for CS in the first and third tasks, which were good (0.6 to 0.75). CONCLUSION The proposed posture-matching approach provides a valid and reliable ergonomic assessment tool suitable for assessing spinal CLs during various lifting activities.
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Affiliation(s)
- Saeed Ghaneh-Ezabadi
- PhD Candidate, Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Abdoli-Eramaki
- PhD, Professor, School of Occupational and Public Health, Ryerson University, Toronto, Canada
| | - Navid Arjmand
- PhD, Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Alireza Abouhossein
- PhD, Department of Ergonomics, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- PhD, Workplace Health Promotion Research Center (WHPRC), School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Abolfazl Zakerian
- PhD, Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Johnen L, Mertens A, Nitsch V, Brandl C. Why cumulative loading calculated using non-weighted integration may not be suitable for assessing physical stress of the lower back: an empirical investigation of strain during lifting and lowering tasks. ERGONOMICS 2022; 65:134-146. [PMID: 34427545 DOI: 10.1080/00140139.2021.1962547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
When work-related physical stress is assessed using non-weighted integration, it is assumed that different loading conditions have a sufficiently comparable effect on the human body as long as the area under the loading curve is the same. Growing evidence cast doubt on whether this simple calculation can adequately estimate physical work-related strain. This study investigates in vivo, focussing on the lower back, whether the non-weighted method adequately reflects work-related physical strain of the lower back. Strain data resulting from lifting/lowering tasks performed in a laboratory study with an identical area under the loading curve but different load intensities were compared. Results showed that the non-weighted method does not sufficiently reflect the resulting muscular, cardiovascular and perceived strain but underestimates the influence of higher load intensity even in the range of medium physical exposure. Further research is needed regarding the determination of weighting factors and limit values. Practitioner Summary Given the dynamic nature of most physical work activities, the assessment of time-varying loading of the lower back is of particular interest in practice. Results show that the widely used non-weighted calculation method does not accurately reflect the resulting physical strain but underestimates the influence of higher load intensity.Abbreviations: MSD: musculoskeletal disorders; WMSD: work-related musculoskeletal disorders; KIM-LHC: Key Indicator Method Lifting, Holding, Carrying; RES: right erector spinae longissimus; LES: left erector spinae longissimus; HR: heart rate; RPE: rating of perceived exertion; EMG: surface electromyography; ECG: electrocardiography; SENIAM: Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles; MVC: maximum voluntary contraction; ANOVA: analysis of variance; Std. error: standard error HIGHLIGHTSResults of this empirical investigation suggest that the widely used non-weighted calculation method is not fully suitable for calculating cumulative loading of the lower back.Even in the range of medium physical exposure the non-weighted calculation method does not accurately reflect the resulting strain on the human body but tends to underestimate the influence of higher load intensity due to higher external weight.Despite the same cumulative loading value obtained when using the non-weighted method, the resulting physical strain values are generally about 20-25% higher.The results may be used to further develop ergonomic assessment methods in order to avoid a misclassification of loading conditions and to prevent the risk of overexertion.
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Affiliation(s)
- Laura Johnen
- Chair and Institute of Industrial Engineering and Ergonomics, RWTH Aachen University, Aachen, Germany
| | - Alexander Mertens
- Chair and Institute of Industrial Engineering and Ergonomics, RWTH Aachen University, Aachen, Germany
| | - Verena Nitsch
- Chair and Institute of Industrial Engineering and Ergonomics, RWTH Aachen University, Aachen, Germany
| | - Christopher Brandl
- Chair and Institute of Industrial Engineering and Ergonomics, RWTH Aachen University, Aachen, Germany
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Cardoso M, McKinnon C, Viggiani D, Johnson MJ, Callaghan JP, Albert WJ. Biomechanical investigation of prolonged driving in an ergonomically designed truck seat prototype. ERGONOMICS 2018; 61:367-380. [PMID: 28697645 DOI: 10.1080/00140139.2017.1355070] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/07/2017] [Indexed: 06/07/2023]
Abstract
A postural evaluation during a prolonged driving task was conducted to determine the ergonomic validity of a new freely adjustable truck seat prototype. Twenty participants were recruited to perform two 2-h simulated driving sessions. Postures were assessed using motion capture, accelerometers and pressure pads. Subjective discomfort was also monitored in 15-min increments using ratings of perceived discomfort (RPD) and the Automotive Seating Discomfort Questionnaire. Participants had a more neutral spine posture during the first hour of the drive and reported lower RPDs while sitting in the prototype. Pairing the gluteal backrest panel with the adjustable seat pan helped reduce the average sitting pressure. The industry-standard truck seat may lead to the development of poor whole body posture, and the proposed ergonomic redesign of a new truck seat helped improve sitting posture and reduce perceived discomfort. Practitioner Summary: A new freely adjustable truck seat prototype was compared to an Industry standard seat to assess hypothesised improvements to sitting posture and discomfort for long haul driving. It was found that the adjustable panels in the prototype helped promote spine posture, reduce sitting pressure and improved discomfort ratings.
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Affiliation(s)
- Michelle Cardoso
- a Faculty of Kinesiology , University of New Brunswick , Fredericton , Canada
| | - Colin McKinnon
- b Faculty of Applied Health Sciences, Department of Kinesiology , University of Waterloo , Waterloo , Canada
| | - Dan Viggiani
- b Faculty of Applied Health Sciences, Department of Kinesiology , University of Waterloo , Waterloo , Canada
| | - Michel J Johnson
- c École de kinésiologie et de loisir, Université de Moncton , Moncton , Canada
| | - Jack P Callaghan
- b Faculty of Applied Health Sciences, Department of Kinesiology , University of Waterloo , Waterloo , Canada
| | - Wayne J Albert
- a Faculty of Kinesiology , University of New Brunswick , Fredericton , Canada
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Gyemi DL, van Wyk PM, Statham M, Casey J, Andrews DM. 3D peak and cumulative low back and shoulder loads and postures during greenhouse pepper harvesting using a video-based approach. Work 2017; 55:817-829. [PMID: 28059807 DOI: 10.3233/wor-162442] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In agricultural field work many tasks have been cited as high priority risk factors for the development of work-related musculoskeletal disorders (WRMDs). Although video-based biomechanical approaches have been effective in documenting the physical demands and risks associated with various occupational and non-occupational tasks, to date, this method has yet to be used to document jobs such as crop harvesting in a greenhouse environment. OBJECTIVE To document and assess the postural characteristics and 3D peak and cumulative low back and shoulder loads associated with greenhouse pepper harvesting using a video-based posture sampling approach. METHODS Nine male (28.2 (4.1) years) pepper harvesters from a greenhouse in Southwestern Ontario, Canada were videotaped during a normal shift. 3DMatch was used to document working trunk and shoulder postures, from which 3D peak and cumulative forces and moments were quantified. RESULTS On average, workers spent the majority of their time in neutral trunk postures (lateral bend: 99.1%; axial twist: 59.9%; flexion: 89.8%). Consistent results were found for the left and right shoulder, with the arms held in a neutral flexion posture 50% of the time or more. Four participants experienced peak L4/L5 compression forces (between 4116.3 N and 5937.0 N) which exceeded the NIOSH Action Limit (3400 N) during the cart pushing/pulling task, but remained below the threshold during picking. Mean cumulative L4/L5 extension and shoulder flexion moments ranged in magnitude from 18.5 Nm to 28.2 Nm, and between 19.4 Nm and 23.2 Nm, respectively, across all tasks. CONCLUSIONS The postural characteristics and biomechanical loads associated with greenhouse pepper harvesting were quantified with a video-based biomechanical approach. Further investigations of the physical risk factors for low back and shoulder musculoskeletal disorders is warranted in pepper harvesting, given the postures and loads documented in this study.
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Affiliation(s)
- Danielle L Gyemi
- Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Paula M van Wyk
- Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Melissa Statham
- Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Jeff Casey
- Occupational Health Clinics for Ontario Workers, Windsor, ON, Canada
| | - David M Andrews
- Department of Kinesiology, University of Windsor, Windsor, ON, Canada
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Coenen P, Kingma I, Boot CRL, Bongers PM, van Dieën JH. Inter-rater reliability of a video-analysis method measuring low-back load in a field situation. APPLIED ERGONOMICS 2013; 44:828-834. [PMID: 23465944 DOI: 10.1016/j.apergo.2013.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 06/01/2023]
Abstract
Valid and reliable low-back load assessment tools that can be used in field situations are needed for epidemiologic studies and for ergonomic practice. The aim of this study was to assess the inter-rater reliability of a low-back load video-analysis method in a field setting. Five raters analyzed 50 work site manual material handling tasks of 14 workers. Peak and mean moments at the level of L5S1, and segment angles were obtained using the video-analysis method. Intra-class correlation coefficients (ICCs) and median standard deviations across raters were calculated. ICCs revealed excellent inter-rater reliability (>0.9) for peak and mean moments, ICCs of segment angles were variable. Median standard deviations showed relatively small inter-rater variance for moments (standard deviation <10 Nm) and segment angle variation ranging from 0° to 20°. The proposed video-analysis method, provides a reliable tool for obtaining low-back loads from occupational field tasks.
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Affiliation(s)
- Pieter Coenen
- MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands.
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Mota YL, Mochizuki L, Carvalho GDA. Influência da resolução e da distância da câmera nas medidas feitas pelo software de avaliação postural (sapo). REV BRAS MED ESPORTE 2011. [DOI: 10.1590/s1517-86922011000500008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
O erro na medida de um sistema de avaliação da postura está relacionado com a digitalização, a resolução da câmera, a distância da câmera em relação ao voluntário estudado, entre outros. Estes erros somam-se no procedimento metodológico e muitos deles não são possíveis evitar, porém devem ser conhecidos e quantificados. OBJETIVO: Quantificar o erro na medida realizada pelo SAPO (Software para avaliação postural) em diferentes situações experimentais. MÉTODOS: Foram realizadas 16 fotos de um manequim de 1,40m articulado nos planos anterior, posterior, lateral direita e lateral esquerda com câmeras de 3,2 e 12,0 megapixels, posicionadas a 3,0m e a 5,0m de distância do manequim. Para a quantificação do erro, foram calculadas as diferenças das medidas obtidas por meio do SAPO com as medidas feitas diretamente no manequim. Apenas um avaliador realizou o registro das imagens, porém a digitalização no software dos pontos demarcados no manequim foi realizada por três digitalizadores, sendo dois inexperientes e um experiente. RESULTADOS: Os valores médios das medidas horizontais, verticais, angulares e de distância são próximos de zero, embora algumas variáveis angulares apresentem valores maiores, como nas medidas de ângulo Q direito e esquerdo. A câmera com resolução de 3,2 megapixels posicionada a 3m apresentou o menor erro. CONCLUSÃO: O SAPO é um método acurado para uso clínico; são necessários estudos para verificar a influência do plano de posicionamento do voluntário em relação à câmera, o efeito do reposicionamento e da palpação nas medidas oferecidas pelo software.
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Waters TR, Lu ML, Werren D, Piacitelli L. Human posture simulation to assess cumulative spinal load due to manual lifting. Part I: methods. THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2011. [DOI: 10.1080/14639221003639921] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Xiong S, Goonetilleke RS, Witana CP, Lee Au EY. Modelling foot height and foot shape-related dimensions. ERGONOMICS 2008; 51:1272-1289. [PMID: 18608473 DOI: 10.1080/00140130801996147] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study. Their foot lengths, foot widths, ball girths and foot heights were measured and then evaluated using mathematical models. The results showed that there were no significant allometry (p > 0.05) effects of foot length on ball girth and foot width. Foot height showed no direct relationship with foot length. However, a normalisation with respect to foot length and foot height resulted in a significant relationship for both males and females with R(2) greater than 0.97. Due to the lack of a direct relationship between foot height and foot length, the current practice of grading shoes with a constant increase in height or proportionate scaling in response to foot length is less than ideal. The results when validated with other populations can be a significant way forward in the design of footwear that has an improved fit in the height dimension.
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Affiliation(s)
- Shuping Xiong
- Human Performance Laboratory, Department of Industrial Engineering and Logistics Management, Hong Kong University of Science and Technology, Kowloon, Hong Kong
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Cann AP, Connolly M, Ruuska R, MacNeil M, Birmingham TB, Vandervoort AA, Callaghan JP. Inter-rater reliability of output measures for a posture matching assessment approach: a pilot study with food service workers. ERGONOMICS 2008; 51:556-572. [PMID: 18357541 DOI: 10.1080/00140130701711455] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Despite the ongoing health problem of repetitive strain injuries, there are few tools currently available for ergonomic applications evaluating cumulative loading that have well-documented evidence of reliability and validity. The purpose of this study was to determine the inter-rater reliability of a posture matching based analysis tool (3DMatch, University of Waterloo) for predicting cumulative and peak spinal loads. A total of 30 food service workers were each videotaped for a 1-h period while performing typical work activities and a single work task was randomly selected from each for analysis by two raters. Inter-rater reliability was determined using intraclass correlation coefficients (ICC) model 2,1 and standard errors of measurement for cumulative and peak spinal and shoulder loading variables across all subjects. Overall, 85.5% of variables had moderate to excellent inter-rater reliability, with ICCs ranging from 0.30-0.99 for all cumulative and peak loading variables. 3DMatch was found to be a reliable ergonomic tool when more than one rater is involved.
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Affiliation(s)
- A P Cann
- Doctoral Program in Rehabilitation Sciences, Faculty of Health Sciences, University of Western London, Ontario, Canada
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Sutherland CA, Albert WJ, Wrigley AT, Callaghan JP. A validation of a posture matching approach for the determination of 3D cumulative back loads. APPLIED ERGONOMICS 2008; 39:199-208. [PMID: 17586458 DOI: 10.1016/j.apergo.2007.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Accepted: 05/01/2007] [Indexed: 05/15/2023]
Abstract
The purpose of this project was to investigate the amount of error in calculating cumulative lumbar spine kinetics using a posture matching approach (3DMatch) compared to a 3D coordinate electromagnetic tracking approach (FASTRAK). Six subjects were required to perform five repeats each of two symmetrical and two asymmetrical lifts while being simultaneously recorded from 4 camera views at viewing angles of 0 degrees , 45 degrees , 60 degrees and 90 degrees to the sagittal plane while wearing eight FASTRAK sensors to define an 8 segment rigid link model (RLM) of the head, arms, and trunk. Four hundred and eighty lifts (6 subjects x20 lifts x4 camera views) were analyzed using the 3DMatch posture-matching program to calculate the following cumulative loads at the L4/L5 joint: compression, anterior shear, posterior shear, reaction shear and extension moment. The errors in cumulative load calculation were determined as the difference between the values calculated for the same lifts using a 3D RLM that used electromagnetic motion tracking sensors (FASTRAK) positioned at the segment center of masses as model inputs. No significant difference (p<0.05) in the relative error for any of the cumulative loading variables between the four camera views and the 3D RLM approach was found. Furthermore the relative errors for cumulative compression, joint anterior shear, reaction anterior shear and extension moment were all below 12%. These results suggest that posture matching by trained users can provide reasonable 3D data to calculate cumulative low back loads with a biomechanical model.
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Affiliation(s)
- Chad A Sutherland
- Department of Kinesiology, Faculty of Human Kinetics, University of Windsor, 401 Sunset Ave, Windsor, Ontario, Canada N9B 3P4
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Sutherland CA, Albert WJ, Wrigley AT, Callaghan JP. The effect of camera viewing angle on posture assessment repeatability and cumulative spinal loading. ERGONOMICS 2007; 50:877-89. [PMID: 17457747 DOI: 10.1080/00140130701237675] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Video-based task analysis in the workplace is often limited by equipment location and production line arrangement, therefore making it difficult to capture the motion in a single plane. The purpose of this study was to investigate the effects of camera placement on an observer's ability to accurately assess working postures in three dimensions and the resultant influence on the reliability and repeatability of calculated cumulative loading variables. Four video cameras were placed at viewing angles of 0 degrees, 45 degrees, 60 degrees and 90 degrees to the frontal plane, enabling the simultaneous collection of views of four lifting tasks (two symmetric and two asymmetric). A total of 11 participants were trained in the use of the 3DMatch 3-D posture matching software package (developed at the University of Waterloo) and were required to analyse 16 lifting trials. Four of the participants were randomly selected to return within 72 h and repeat the analysis protocol to test intra-observer repeatability. Posture matching agreement between camera views was higher when the body segments had a minimal range of motion during the task. There was no significant participant main effect; however, there was a significant (p < 0.05) task main effect. Intraclass correlation coefficients (ICC) were calculated to assess the between day reliability. Compression, reaction anterior shear and extension moment were all found to have excellent reliability (ICC > 0.75). Joint anterior shear and joint posterior shear both provided fair to good reliability (0.4 > ICC < 0.75). Overall, the impact of the camera viewing angle on an observer's ability to match working postural exposure was found to be small.
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Affiliation(s)
- C A Sutherland
- University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick E3B 5A3, Canada
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Dunk NM, Lalonde J, Callaghan JP. Implications for the use of postural analysis as a clinical diagnostic tool: reliability of quantifying upright standing spinal postures from photographic images. J Manipulative Physiol Ther 2006; 28:386-92. [PMID: 16096037 DOI: 10.1016/j.jmpt.2005.06.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 03/15/2005] [Indexed: 12/16/2022]
Abstract
OBJECTIVES A repeated measures design was used to test the reliability of standing spine postures within subjects using a biologically relevant measure determined by digitization of images and to compare the results to a previously tested vertical reference method. METHODS Twenty subjects attended 3 sessions consisting of 5 trials each. Photographs of the sagittal and posterior views of normal upright standing were taken. Landmarks were digitized and cervical, thoracic, and lumbar spinal angles were calculated using the algebraic dot product. Intraclass correlation coefficients were used to evaluate intrasubject reliability across sessions. RESULTS According to the intraclass correlation coefficients, posture had good to excellent reliability in the sagittal view and provided a more stable measure of spinal angles than the posterior view. Mean repositioning errors were less than 6 degrees and 2 degrees in the sagittal and posterior views, respectively. CONCLUSIONS Although the repeatability of posture was improved in the sagittal view, when a biological measure was used instead of an external vertical reference to calculate spinal angles, individual subject posture was still variable. This brings into question the effectiveness and validity of using surface skin markers to track postural changes due to clinical interventions. If the postural analysis approach is to be used to detect changes due to clinical treatment, such changes must be larger than the baseline repositioning errors seen in healthy subjects.
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Affiliation(s)
- Nadine M Dunk
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Waters T, Yeung S, Genaidy A, Callaghan J, Barriera-Viruet H, Deddens J. Cumulative spinal loading exposure methods for manual material handling tasks. Part 1: is cumulative spinal loading associated with lower back disorders? THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2006. [DOI: 10.1080/14639220500111392] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Waters T, Yeung S, Genaidy A, Callaghan J, Barriera-Viruet H, Abdallah S, Kumar S. Cumulative spinal loading exposure methods for manual material handling tasks. Part 2: methodological issues and applicability for use in epidemiological studies. THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2006. [DOI: 10.1080/14639220500111459] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Callaghan JP, Dunk N. The Reliability of Quantifying Upright Standing Postures as a Baseline Diagnostic Clinical Tool. J Manipulative Physiol Ther 2004. [DOI: 10.1016/j.jmpt.2004.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dunk NM, Chung YY, Compton DS, Callaghan JP. The reliability of quantifying upright standing postures as a baseline diagnostic clinical tool. J Manipulative Physiol Ther 2004; 27:91-6. [PMID: 14970809 DOI: 10.1016/j.jmpt.2003.12.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To assess the reliability of posture across and within subjects, specifically the repeatability of spinal angles determined by digitization of images in the anterior, posterior, and sagittal views. DESIGN A repeated measure design was used in which subjects were required to attend 3 sessions, each consisting of 3 trials. Photographs of the anterior, posterior, and lateral views of normal, relaxed upright standing were taken during each trial. Landmarks were digitized and cervical, thoracic, and lumbar angles were calculated with respect to a vertical reference line. SUBJECTS Fourteen healthy and active subjects (7 male subjects and 7 female subjects) were recruited from a university student population. All had been free of low back pain during the previous 6 months. RESULTS When comparing mean angles, no significant differences were detected for any angle in any view. However, large variability within subjects was observed, likely leading to the lack of significance found with respect to the main factors in the analysis of variance (ANOVA). Large coefficients of variance (CVs) reflect the substantial intrasubject variability, as well as poor to moderate agreement indicated by intraclass correlation coefficients (ICCs). There were no apparent trends indicating that gender affected repeatability of posture. CONCLUSIONS The poor repeatability of postures documented using the studied method brings into question the validity of this postural analysis approach for either diagnostic use or tracking changes in response to treatment. Users of such postural analysis tools should interpret postural deviations from a vertical reference with caution, as there are many inherent factors that can contribute to the variability of these measured postures.
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Affiliation(s)
- Nadine M Dunk
- Faculty of Applied Health Sciences, Department of Kinesiology, University of Waterloo, Ontario, Canada
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