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Nail-Ulloa I, Zabala M, Sesek R, Chen H, Schall MC, Gallagher S. Estimating Compressive and Shear Forces at L5-S1: Exploring the Effects of Load Weight, Asymmetry, and Height Using Optical and Inertial Motion Capture Systems. SENSORS (BASEL, SWITZERLAND) 2024; 24:1941. [PMID: 38544203 PMCID: PMC10976016 DOI: 10.3390/s24061941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/08/2024] [Accepted: 03/15/2024] [Indexed: 04/01/2024]
Abstract
This study assesses the agreement of compressive and shear force estimates at the L5-S1 joint using inertial motion capture (IMC) within a musculoskeletal simulation model during manual lifting tasks, compared against a top-down optical motion capture (OMC)-based model. Thirty-six participants completed lifting and lowering tasks while wearing a modified Plug-in Gait marker set for the OMC and a full-body IMC set-up consisting of 17 sensors. The study focused on tasks with variable load weights, lifting heights, and trunk rotation angles. It was found that the IMC system consistently underestimated the compressive forces by an average of 34% (975.16 N) and the shear forces by 30% (291.77 N) compared with the OMC system. A critical observation was the discrepancy in joint angle measurements, particularly in trunk flexion, where the IMC-based model underestimated the angles by 10.92-11.19 degrees on average, with the extremes reaching up to 28 degrees. This underestimation was more pronounced in tasks involving greater flexion, notably impacting the force estimates. Additionally, this study highlights significant differences in the distance from the spine to the box during these tasks. On average, the IMC system showed an 8 cm shorter distance on the X axis and a 12-13 cm shorter distance on the Z axis during lifting and lowering, respectively, indicating a consistent underestimation of the segment length compared with the OMC system. These discrepancies in the joint angles and distances suggest potential limitations of the IMC system's sensor placement and model scaling. The load weight emerged as the most significant factor affecting force estimates, particularly at lower lifting heights, which involved more pronounced flexion movements. This study concludes that while the IMC system offers utility in ergonomic assessments, sensor placement and anthropometric modeling accuracy enhancements are imperative for more reliable force and kinematic estimations in occupational settings.
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Affiliation(s)
- Iván Nail-Ulloa
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL 36849, USA; (I.N.-U.); (R.S.); (S.G.)
- Institute of Industry and Management, Universidad Austral de Chile, Puerto Montt 5480000, Chile
| | - Michael Zabala
- Department of Mechanical Engineering, Auburn University, Auburn, AL 36849, USA;
| | - Richard Sesek
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL 36849, USA; (I.N.-U.); (R.S.); (S.G.)
| | - Howard Chen
- Department of Industrial and Systems Engineering and Engineering Management, The University of Alabama at Huntsville, Huntsville, AL 35899, USA
| | - Mark C. Schall
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL 36849, USA; (I.N.-U.); (R.S.); (S.G.)
| | - Sean Gallagher
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL 36849, USA; (I.N.-U.); (R.S.); (S.G.)
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Zadeh SM, MacDermid J, Johnson J, Birmingham TB, Shafiee E. Applications of wearable sensors in upper extremity MSK conditions: a scoping review. J Neuroeng Rehabil 2023; 20:158. [PMID: 37980497 PMCID: PMC10656914 DOI: 10.1186/s12984-023-01274-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 10/30/2023] [Indexed: 11/20/2023] Open
Abstract
PURPOSE This scoping review uniquely aims to map the current state of the literature on the applications of wearable sensors in people with or at risk of developing upper extremity musculoskeletal (UE-MSK) conditions, considering that MSK conditions or disorders have the highest rate of prevalence among other types of conditions or disorders that contribute to the need for rehabilitation services. MATERIALS AND METHODS The preferred reporting items for systematic reviews and meta-analysis (PRISMA) extension for scoping reviews guideline was followed in this scoping review. Two independent authors conducted a systematic search of four databases, including PubMed, Embase, Scopus, and IEEEXplore. We included studies that have applied wearable sensors on people with or at risk of developing UE-MSK condition published after 2010. We extracted study designs, aims, number of participants, sensor placement locations, sensor types, and number, and outcome(s) of interest from the included studies. The overall findings of our scoping review are presented in tables and diagrams to map an overview of the existing applications. RESULTS The final review encompassed 80 studies categorized into clinical population (31 studies), workers' population (31 studies), and general wearable design/performance studies (18 studies). Most were observational, with 2 RCTs in workers' studies. Clinical studies focused on UE-MSK conditions like rotator cuff tear and arthritis. Workers' studies involved industrial workers, surgeons, farmers, and at-risk healthy individuals. Wearable sensors were utilized for objective motion assessment, home-based rehabilitation monitoring, daily activity recording, physical risk characterization, and ergonomic assessments. IMU sensors were prevalent in designs (84%), with a minority including sEMG sensors (16%). Assessment applications dominated (80%), while treatment-focused studies constituted 20%. Home-based applicability was noted in 21% of the studies. CONCLUSION Wearable sensor technologies have been increasingly applied to the health care field. These applications include clinical assessments, home-based treatments of MSK disorders, and monitoring of workers' population in non-standardized areas such as work environments. Assessment-focused studies predominate over treatment studies. Additionally, wearable sensor designs predominantly use IMU sensors, with a subset of studies incorporating sEMG and other sensor types in wearable platforms to capture muscle activity and inertial data for the assessment or rehabilitation of MSK conditions.
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Affiliation(s)
- Sohrob Milani Zadeh
- Biomedical Engineering, Physical Therapy, Western University, London, ON, Canada.
| | - Joy MacDermid
- Physical Therapy and Surgery, Western University, London, ON, Canada
- Clinical Research Lab, Hand and Upper Limb Center, St. Joseph's Health Center, London, ON, Canada
- Rehabilitation Science McMaster University, Hamilton, ON, Canada
| | - James Johnson
- Roth-McFarlane Hand and Upper Limb Centre, St. Joseph's Health Care, London, ON, Canada
| | - Trevor B Birmingham
- Biomedical Engineering, Physical Therapy, Western University, London, ON, Canada
| | - Erfan Shafiee
- School of Rehabilitation Therapy, Queen's University, Kingston, ON, Canada
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Chen H, Schall MC, Martin SM, Fethke NB. Drift-Free Joint Angle Calculation Using Inertial Measurement Units without Magnetometers: An Exploration of Sensor Fusion Methods for the Elbow and Wrist. SENSORS (BASEL, SWITZERLAND) 2023; 23:7053. [PMID: 37631592 PMCID: PMC10458653 DOI: 10.3390/s23167053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/05/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023]
Abstract
Joint angles of the lower extremities have been calculated using gyroscope and accelerometer measurements from inertial measurement units (IMUs) without sensor drift by leveraging kinematic constraints. However, it is unknown whether these methods are generalizable to the upper extremity due to differences in motion dynamics. Furthermore, the extent that post-processed sensor fusion algorithms can improve measurement accuracy relative to more commonly used Kalman filter-based methods remains unknown. This study calculated the elbow and wrist joint angles of 13 participants performing a simple ≥30 min material transfer task at three rates (slow, medium, fast) using IMUs and kinematic constraints. The best-performing sensor fusion algorithm produced total root mean square errors (i.e., encompassing all three motion planes) of 6.6°, 3.6°, and 2.0° for the slow, medium, and fast transfer rates for the elbow and 2.2°, 1.7°, and 1.5° for the wrist, respectively.
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Affiliation(s)
- Howard Chen
- Industrial & Systems Engineering and Engineering Management Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA
| | - Mark C. Schall
- Department of Industrial & Systems Engineering, Auburn University, Auburn, AL 36849, USA;
| | - Scott M. Martin
- Department of Mechanical Engineering, Auburn University, Auburn, AL 36849, USA;
| | - Nathan B. Fethke
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA 52242, USA;
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Chen H, Schall MC, Fethke NB. Gyroscope vector magnitude: A proposed method for measuring angular velocities. APPLIED ERGONOMICS 2023; 109:103981. [PMID: 36739779 DOI: 10.1016/j.apergo.2023.103981] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/07/2022] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
High movement velocities are among the primary risk factors for work-related musculoskeletal disorders (MSDs). Ergonomists have commonly used two methods to calculate angular movement velocities of the upper arms using inertial measurement units (accelerometers and gyroscopes). Generalized velocity is the speed of movement traveled on the unit sphere per unit time. Inclination velocity is the derivative of the postural inclination angle relative to gravity with respect to time. Neither method captures the full extent of upper arm angular velocity. We propose a new method, the gyroscope vector magnitude (GVM), and demonstrate how GVM captures angular velocities around all motion axes and more accurately represents the true angular velocities of the upper arm. We use optical motion capture data to demonstrate that the previous methods for calculating angular velocities capture 89% and 77% relative to our proposed method.
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Affiliation(s)
- Howard Chen
- Industrial & Systems Engineering and Engineering Management Department, The University of Alabama in Huntsville, Huntsville, AL, USA; Department of Mechanical Engineering, Auburn University, Auburn, AL, USA.
| | - Mark C Schall
- Department of Industrial & Systems Engineering, Auburn University, Auburn, AL, USA
| | - Nathan B Fethke
- Department of Occupational & Environmental Health, The University of Iowa, Iowa City, IA, USA
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Lind CM, Abtahi F, Forsman M. Wearable Motion Capture Devices for the Prevention of Work-Related Musculoskeletal Disorders in Ergonomics-An Overview of Current Applications, Challenges, and Future Opportunities. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23094259. [PMID: 37177463 PMCID: PMC10181376 DOI: 10.3390/s23094259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/14/2023] [Accepted: 04/22/2023] [Indexed: 05/15/2023]
Abstract
Work-related musculoskeletal disorders (WMSDs) are a major contributor to disability worldwide and substantial societal costs. The use of wearable motion capture instruments has a role in preventing WMSDs by contributing to improvements in exposure and risk assessment and potentially improved effectiveness in work technique training. Given the versatile potential for wearables, this article aims to provide an overview of their application related to the prevention of WMSDs of the trunk and upper limbs and discusses challenges for the technology to support prevention measures and future opportunities, including future research needs. The relevant literature was identified from a screening of recent systematic literature reviews and overviews, and more recent studies were identified by a literature search using the Web of Science platform. Wearable technology enables continuous measurements of multiple body segments of superior accuracy and precision compared to observational tools. The technology also enables real-time visualization of exposures, automatic analyses, and real-time feedback to the user. While miniaturization and improved usability and wearability can expand the use also to more occupational settings and increase use among occupational safety and health practitioners, several fundamental challenges remain to be resolved. The future opportunities of increased usage of wearable motion capture devices for the prevention of work-related musculoskeletal disorders may require more international collaborations for creating common standards for measurements, analyses, and exposure metrics, which can be related to epidemiologically based risk categories for work-related musculoskeletal disorders.
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Affiliation(s)
- Carl Mikael Lind
- IMM Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Farhad Abtahi
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 141 57 Huddinge, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 171 77 Stockholm, Sweden
- Department of Clinical Physiology, Karolinska University Hospital, 141 86 Huddinge, Sweden
| | - Mikael Forsman
- IMM Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 141 57 Huddinge, Sweden
- Centre for Occupational and Environmental Medicine, Stockholm County Council, 113 65 Stockholm, Sweden
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Lind CM, De Clercq B, Forsman M, Grootaers A, Verbrugghe M, Van Dyck L, Yang L. Effectiveness and usability of real-time vibrotactile feedback training to reduce postural exposure in real manual sorting work. ERGONOMICS 2023; 66:198-216. [PMID: 35466852 DOI: 10.1080/00140139.2022.2069869] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Vibrotactile feedback training may be used as a complementary strategy to reduce time in demanding postures in manual handling. This study evaluated the short- and medium-term effects of concurrent posture-correction vibrotactile feedback training on trunk inclination exposure in real manual sorting work. Fifteen warehouse workers completed the training and the follow-up sessions. Trunk inclination angles were recorded using the ambulatory Smart Workwear System. Questionnaires were used for assessing system usability, perceived physical exertion, and work ability. The results showed reduced time in trunk inclination >30°, >45°, and >60°, and reductions in the 90th, 95th, and 99th percentile trunk inclination angles, when receiving feedback and immediately after feedback withdrawal. No significant reduction was retained after one and three weeks. The wearer's comfort was scored high, and the feedback did not increase the perceived cognitive demands. No significant effects attributed to changed trunk inclination exposure were observed for perceived physical exertion or work ability. The training program has the potential of contributing to reduced trunk inclination exposure in the short term. Future studies are needed to evaluate if improvements in the feedback training can transfer the short-term results to retained median- and long-term effects.Practitioner summary: A two-day training program with concurrent posture-correction vibrotactile feedback can contribute to reduced exposure of trunk inclination in real manual sorting work in the short term. More research is needed on how to design the feedback training programs in order to be effective in the long term.
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Affiliation(s)
- Carl Mikael Lind
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | | | - Mikael Forsman
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Huddinge, Sweden
- Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden
| | | | | | | | - Liyun Yang
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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A Narrative Review on Wearable Inertial Sensors for Human Motion Tracking in Industrial Scenarios. ROBOTICS 2022. [DOI: 10.3390/robotics11060138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Industry 4.0 has promoted the concept of automation, supporting workers with robots while maintaining their central role in the factory. To guarantee the safety of operators and improve the effectiveness of the human-robot interaction, it is important to detect the movements of the workers. Wearable inertial sensors represent a suitable technology to pursue this goal because of their portability, low cost, and minimal invasiveness. The aim of this narrative review was to analyze the state-of-the-art literature exploiting inertial sensors to track the human motion in different industrial scenarios. The Scopus database was queried, and 54 articles were selected. Some important aspects were identified: (i) number of publications per year; (ii) aim of the studies; (iii) body district involved in the motion tracking; (iv) number of adopted inertial sensors; (v) presence/absence of a technology combined to the inertial sensors; (vi) a real-time analysis; (vii) the inclusion/exclusion of the magnetometer in the sensor fusion process. Moreover, an analysis and a discussion of these aspects was also developed.
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Fan X, Forsman M, Yang L, Lind CM, Kjellman M. Surgeons' physical workload in open surgery versus robot-assisted surgery and nonsurgical tasks. Surg Endosc 2022; 36:8178-8194. [PMID: 35589973 PMCID: PMC9613719 DOI: 10.1007/s00464-022-09256-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 04/08/2022] [Indexed: 01/06/2023]
Abstract
BACKGROUND Musculoskeletal disorders (MSDs) are common among surgeons, and its prevalence varies among surgical modalities. There are conflicting results concerning the correlation between adverse work exposures and MSD prevalence in different surgical modalities. The progress of rationalization in health care may lead to job intensification for surgeons, but the literature is scarce regarding to what extent such intensification influences the physical workload in surgery. The objectives of this study were to quantify the physical workload in open surgery and compare it to that in (1) nonsurgical tasks and (2) two surgeon roles in robot-assisted surgery (RAS). METHODS The physical workload of 22 surgeons (12 performing open surgery and 10 RAS) was measured during surgical workdays, which includes trapezius muscle activity from electromyography, and posture and movement of the head, upper arms and trunk from inertial measurement units. The physical workload of surgeons in open surgery was compared to that in nonsurgical tasks, and to the chief and assistant surgeons in RAS, and to the corresponding proposed action levels. Mixed-effects models were used to analyze the differences. RESULTS Open surgery constituted more than half of a surgical workday. It was associated with more awkward postures of the head and trunk than nonsurgical tasks. It was also associated with higher trapezius muscle activity levels, less muscle rest time and a higher proportion of sustained low muscle activity than nonsurgical tasks and the two roles in RAS. The head inclination and trapezius activity in open surgery exceeded the proposed action levels. CONCLUSIONS The physical workload of surgeons in open surgery, which exceeded the proposed action levels, was higher than that in RAS and that in nonsurgical tasks. Demands of increased operation time may result in higher physical workload for open surgeons, which poses an increased risk of MSDs. Risk-reducing measures are, therefore, needed.
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Affiliation(s)
- Xuelong Fan
- IMM Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Mikael Forsman
- IMM Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Hälsovägen 11C, 14157 Huddinge, Sweden
- Centre for Occupational and Environmental Medicine, Stockholm County Council, 113 65 Stockholm, Sweden
| | - Liyun Yang
- IMM Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Carl M. Lind
- IMM Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Magnus Kjellman
- Department of Molecular Medicine and Surgery, Department of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, 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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Schall MC, Chen H, Cavuoto L. Wearable inertial sensors for objective kinematic assessments: A brief overview. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2022; 19:501-508. [PMID: 35853137 DOI: 10.1080/15459624.2022.2100407] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
- Mark C Schall
- Department of Industrial and Systems Engineering, Auburn University, Auburn, Alabama
| | - Howard Chen
- Department of Mechanical Engineering, Auburn University, Auburn, Alabama
| | - Lora Cavuoto
- Department of Industrial and Systems Engineering, University at Buffalo, Buffalo, New York
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11
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Zhang X, Schall MC, Chen H, Gallagher S, Davis GA, Sesek R. Manufacturing worker perceptions of using wearable inertial sensors for multiple work shifts. APPLIED ERGONOMICS 2022; 98:103579. [PMID: 34507084 DOI: 10.1016/j.apergo.2021.103579] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Wearable inertial sensors may be used to objectively quantify exposure to some physical risk factors associated with musculoskeletal disorders. However, concerns regarding their potential negative effects on user safety and satisfaction remain. This study characterized the self-reported daily discomfort, distraction, and burden associated with wearing inertial sensors on the upper arms, trunk, and dominant wrist of 31 manufacturing workers collected over 15 full work shifts. Results indicated that the workers considered the devices as generally comfortable to wear, not distracting, and not burdensome to use. Exposure to non-neutral postures (discomfort, right arm, beta = 0.02; trunk, beta = -0.01), non-cyclic tasks (distraction, beta = -0.26), and higher body mass indices (discomfort, beta = 0.05; distraction, beta = 0.02) contributed to statistically significant (p < 0.05), albeit practically small increases in undesirable ratings. For instance, for each additional percentage of time working with the right arm elevated ≥60°, self-reported discomfort ratings increased 0.02 cm on a standard 10 cm visual analog scale. Female workers reported less discomfort and distraction while wearing the sensors at work than males (discomfort, beta = -0.93; distraction, beta = -0.3). In general, the low ratings of discomfort, distraction, and burden associated with wearing the devices during work suggests that inertial sensors may be suitable for extended use among manufacturing workers.
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Affiliation(s)
- Xuanxuan Zhang
- Department of Applied Science and Technology, College of Engineering and Computer Sciences, Marshall University, Huntington, WV, USA; Department of Industrial and Systems Engineering, Samuel Ginn College of Engineering, Auburn University, Auburn, AL, USA.
| | - Mark C Schall
- Department of Industrial and Systems Engineering, Samuel Ginn College of Engineering, Auburn University, Auburn, AL, USA.
| | - Howard Chen
- Department of Mechanical Engineering, Samuel Ginn College of Engineering, Auburn University, Auburn, AL, USA.
| | - Sean Gallagher
- Department of Industrial and Systems Engineering, Samuel Ginn College of Engineering, Auburn University, Auburn, AL, USA.
| | - Gerard A Davis
- Department of Industrial and Systems Engineering, Samuel Ginn College of Engineering, Auburn University, Auburn, AL, USA.
| | - Richard Sesek
- Department of Industrial and Systems Engineering, Samuel Ginn College of Engineering, Auburn University, Auburn, AL, USA.
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12
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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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