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Wolffsohn JS, Lingham G, Downie LE, Huntjens B, Inomata T, Jivraj S, Kobia-Acquah E, Muntz A, Mohamed-Noriega K, Plainis S, Read M, Sayegh RR, Singh S, Utheim TP, Craig JP. TFOS Lifestyle: Impact of the digital environment on the ocular surface. Ocul Surf 2023; 28:213-252. [PMID: 37062428 DOI: 10.1016/j.jtos.2023.04.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as "the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing". Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not 'diagnostic' of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).
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Affiliation(s)
- James S Wolffsohn
- College of Health & Life Sciences, School of Optometry, Aston University, Birmingham, UK; Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.
| | - Gareth Lingham
- Centre for Eye Research Ireland, Technological University Dublin, Dublin, Ireland
| | - Laura E Downie
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Byki Huntjens
- Division of Optometry and Visual Sciences, City, University of London, EC1V 0HB, UK
| | - Takenori Inomata
- Department of Ophthalmology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Saleel Jivraj
- College of Health & Life Sciences, School of Optometry, Aston University, Birmingham, UK
| | | | - Alex Muntz
- Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Karim Mohamed-Noriega
- Department of Ophthalmology, University Hospital and Faculty of Medicine, Autonomous University of Nuevo León (UANL). Monterrey, 64460, Mexico
| | - Sotiris Plainis
- College of Health & Life Sciences, School of Optometry, Aston University, Birmingham, UK; Laboratory of Optics and Vision, School of Medicine, University of Crete, Greece
| | - Michael Read
- Division of Pharmacy and Optometry, The University of Manchester, Manchester, UK
| | - Rony R Sayegh
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Sumeer Singh
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Tor P Utheim
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway
| | - Jennifer P Craig
- College of Health & Life Sciences, School of Optometry, Aston University, Birmingham, UK; Department of Ophthalmology, New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
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Jain R, Rana KB, Meena ML. An integrated multi-criteria decision-making approach for identifying the risk level of musculoskeletal disorders among handheld device users. Soft comput 2023; 27:3283-3293. [PMID: 33551675 PMCID: PMC7856850 DOI: 10.1007/s00500-021-05592-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In work-from-home (WFH) situation due to coronavirus (COVID-19) pandemic, the handheld device (HHD) users work in awkward postures for longer hours because of unavailability of ergonomically designed workstations. This problem results in different type of musculoskeletal disorders (MSDs) among the HHD users. An integrated multi-criteria decision-making approach was offered for identifying the risk level of MSDs among HHD users. A case example implemented the proposed approach in which, firstly, the best-worst method (BWM) technique was used to prioritize and determine the relative importance (weightage) of the risk factors. The weightages of the risk factors further used to rank the seven alternatives (HHD users) using Vlse Kriterijumska Optimizacija Kompromisno Resenje (VIKOR) technique. The outcomes of the BWM investigation showed that the three most significant risk factors responsible for MSDs are duration of working, poor working posture and un-ergonomic design. The outcome of the VIKOR technique exhibited that computer professionals were at the highest risk among all users. The risk factor priority must be used for designing a working strategy for the WFH situation which will help to mitigate the risks of MSDs.
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Affiliation(s)
- Rahul Jain
- Department of Mechanical Engineering, University Teaching Department, Rajasthan Technical University Kota, Rawatbhata Road, Akelgarh, Kota, Rajasthan 324010 India
| | - Kunj Bihari Rana
- Department of Mechanical Engineering, University Teaching Department, Rajasthan Technical University Kota, Rawatbhata Road, Akelgarh, Kota, Rajasthan 324010 India
| | - Makkhan Lal Meena
- Department of Mechanical Engineering, Malaviya National Institute of Technology, JLN Marg, Malaviya Nagar, Jaipur, Rajasthan 302017 India
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Argus M, Pääsuke M. Musculoskeletal disorders and functional characteristics of the neck and shoulder: Comparison between office workers using a laptop or desktop computer. Work 2023; 75:1289-1299. [PMID: 36683484 DOI: 10.3233/wor-220080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Using a laptop for work is gaining rapid popularity, but there is little evidence of how it influences musculoskeletal disorders (MSDs) and functional characteristics of the neck and shoulder area. OBJECTIVE This study aimed to compare the prevalence of upper body MSDs and functional characteristics of the neck between office workers using a laptop or desktop computer. METHODS A total of 110 office workers with a mean age of 41±10 years participated. 45 office workers (73% female) used a laptop and 65 office workers (86% female) used desktop computers. The prevalence of MSDs was recorded using the Nordic Musculoskeletal Questionnaire. Active range of motion (AROM), maximal voluntary isometric contraction (MVC) force, joint position error (JPE), and pain-pressure threshold (PPT) of the neck and shoulder area were measured. RESULTS Laptop users experienced significantly more MSDs in the right shoulder area on the day of participation (p < 0.001, OR = 4.47), during the previous 7 days (p < 0.01, OR = 3.74), and at 6 months (p < 0.01, OR = 3.57). Laptop users also experienced significantly more MSDs in the left shoulder during the previous 7 days (p < 0.05, OR = 2.44). There were no statistically significant differences in any of the functional characteristics of the neck and shoulder area between the groups. CONCLUSION Using the laptop computer for office work may pose a higher risk of developing MSDs in the right shoulder area, but might not have long-term effects on the functional characteristics of the neck and shoulder area.
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Affiliation(s)
- Martin Argus
- Institute of Sport Sciences and Physiotherapy, University of Tartu, Tartu, Estonia
| | - Mati Pääsuke
- Institute of Sport Sciences and Physiotherapy, University of Tartu, Tartu, Estonia
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Rafiee M, Mokhtarinia HR, Parsons D, Hosseinpouri M, Gabel CP. Laptop use and muscle activity in adult females: Ground sitting has lower muscular demand than using a chair. Work 2023; 76:1113-1123. [PMID: 37212082 DOI: 10.3233/wor-220473] [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] [Indexed: 05/23/2023] Open
Abstract
BACKGROUND With progressing technology in the portable computing field, laptops are now integral for work, home and social settings. Different working postures adopted by laptop users impose different loads on the relevant muscles, which can be associated with musculoskeletal discomfort in the various body regions. Some Arabic and Asian cultures adopted postures are not well investigated, particularly for the 20-30 years age-group. OBJECTIVE This study compared muscle activity in the cervical spine, arm, and wrist among different laptop workstation setups. METHODS In this cross-sectional study, 23 healthy female university students (age = 24.2±2.28 years, range 20-26 years) performed a standardized 10 minute typing task in four different laptop workstation setups: DESK, SOFA, GROUND sitting with back support, and laptop table (LAP-Tab). Differences between electromyography (EMG) muscle activity recorded in the trapezius (TR), cervical extensors (CE), deltoid (DEL), and wrist extensors (WE) were determined using one-way repeated ANOVA measures with a post-hoc Bonferroni test. RESULTS Significantly higher muscle activity was observed respectively in the workstations of DESK > LAP-Tab > SOFA > GROUND. Significant differences were found between WE muscle activity and the three other muscle groups (p < 0.001). There was a significant interaction between workstations and muscle activity (F(9,264) = 3.81, p < 0.001, = 0.11), where the WE and DEL muscles showed respectively higher and lower muscle activity in all setups. CONCLUSION Muscles showed variable activity in different workstations such that the GROUND workstation provided the minimum load, while the DESK workstation showed the maximum load on the measured muscle groups. These findings require further investigation in different cultural and gender specific groups.
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Affiliation(s)
- Mahsa Rafiee
- Department of Ergonomics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hamid Reza Mokhtarinia
- Department of Ergonomics, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Dave Parsons
- Curtin School of Allied Health, Curtin University, Perth, WA, Australia
| | - Mahdi Hosseinpouri
- Center of Planning, Budgeting and Performance Evaluation, Department of Environment, Tarbiat Modares University, Tehran, Iran
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Molaeifar S, Yazdani F, Yoosefinejad AK, Karimi MT. Correlation between craniovertebral angle in the sagittal plane and angles and indices measured in the frontal plane at the moment of inducing forward head posture. Work 2021; 68:1221-1227. [PMID: 33867381 DOI: 10.3233/wor-213451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Forward head posture (FHP) is the most common malposition in the head and neck area. With the growing use of digital devices, the prevalence of FHP may be expected to increase dramatically. Thus far, FHP has been evaluated only in the sagittal plane. OBJECTIVE The objective of this study was to measure angles and indices from anatomical landmarks in the frontal plane and determine the possible correlations between these variables and craniovertebral angle (CVA) as an index of FHP in the sagittal plane. METHODS Fifty eight healthy individuals (29 men, 29 women) between 18 and 40 years old participated in this cross-sectional study. Participants were evaluated with an 8-camera motion analysis system. After markers were placed on predetermined landmarks, the participants were asked to maintain their head and neck in the neutral position for 5 seconds. Then participants induced FHP by flexing and lowering their head. The correlation between CVA and a set of angles and indices was calculated at the moment of FHP induction. RESULTS A moderate correlation was observed between 3-D CVA and the angle formed between the sternum and both tragi for the whole sample and separately in both sexes. A moderate negative correlation was observed between 3-D CVA and height, weight, and BMI in women. A moderate negative correlation was observed between 3-D CVA and height, weight, BMI, and hours on digital devices in men. CONCLUSIONS Changes in CVA in the sagittal plane can be predicted from changes in the angle formed between the midpoint of the sternum and the left and right tragi in the frontal plane.
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Affiliation(s)
- Samira Molaeifar
- Physical Therapy Department, School of Rehabilitation, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Farzaneh Yazdani
- Physical Therapy Department, School of Rehabilitation, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amin Kordi Yoosefinejad
- Physical Therapy Department, School of Rehabilitation, Shiraz University of Medical Sciences, Shiraz, Iran.,Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Taghi Karimi
- Rehabilitation Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Orthotics and Prosthesis Department, School of Rehabilitation, Shiraz University of Medical Sciences, Shiraz, Iran
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Mingels S, Dankaerts W, van Etten L, Bruckers L, Granitzer M. Lower spinal postural variability during laptop-work in subjects with cervicogenic headache compared to healthy controls. Sci Rep 2021; 11:5159. [PMID: 33664350 PMCID: PMC7933416 DOI: 10.1038/s41598-021-84457-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/15/2021] [Indexed: 11/12/2022] Open
Abstract
Spinal postural variability (SPV) is a prerequisite to prevent musculoskeletal complaints during functional tasks. Our objective was to evaluate SPV in cervicogenic headache (CeH) since CeH is characterized by such complaints. A non-randomized repeated-measure design was applied to compare SPV between 18 participants with reporting CeH aged 29–51 years, and 18 matched controls aged 26–52 years during a 30-min-laptop-task. Habitual spinal postures (degrees) of the cervical, thoracic and lumbar spine were analysed using 3D-Vicon motion analysis. SPV, to express variation in mean habitual spinal posture, was deducted from the postural analysis. Mean SPV of each spinal segment was lower in the CeH-group compared to the control-group. Within the CeH-group, SPV of all except one spinal segment (lower-lumbar) was higher compared to the group’s mean SPV. Within the control-group, SPV was more comparable to the group’s mean SPV. SPV differed between groups. Averaging data resulted in decreased SPV in the CeH-group compared to the control-group during the laptop-task. However, the higher within-group-SPV in the CeH-group compared to the group’s mean SPV accentuated more postural heterogeneity. It should be further determined if addressing individual SPV is a relevant intervention.
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Affiliation(s)
- Sarah Mingels
- REVAL Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Rehabilitation Sciences, Hasselt University, 3500, Hasselt, Belgium. .,Musculoskeletal Research Unit, Department of Rehabilitation Sciences, Faculty of Kinesiology and Rehabilitation Sciences, Leuven University, 3000, Leuven, Belgium.
| | - Wim Dankaerts
- Musculoskeletal Research Unit, Department of Rehabilitation Sciences, Faculty of Kinesiology and Rehabilitation Sciences, Leuven University, 3000, Leuven, Belgium
| | - Ludo van Etten
- Department of Biometrics, Zuyd Hogeschool, 6419, Heerlen, The Netherlands
| | - Liesbeth Bruckers
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, 3500, Hasselt, Belgium
| | - Marita Granitzer
- REVAL Rehabilitation Research Centre, Biomedical Research Institute, Faculty of Rehabilitation Sciences, Hasselt University, 3500, Hasselt, Belgium
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Effects of Prolonged Sitting with Slumped Posture on Trunk Muscular Fatigue in Adolescents with and without Chronic Lower Back Pain. ACTA ACUST UNITED AC 2020; 57:medicina57010003. [PMID: 33374520 PMCID: PMC7822118 DOI: 10.3390/medicina57010003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 11/16/2022]
Abstract
Background and Objectives: This study investigated the effects of prolonged sitting on trunk muscular fatigue and discomfort in participants with and without chronic lower back pain (LBP). Material and Methods: This study included 15 patients with LBP and 15 healthy controls. All participants were instructed to sit on a height-adjustable chair with their knee and hip joints bent at 90° for 30 min, in slumped sitting postures. Surface electromyography was used to assess the median frequency of the internal obliques (IO)/transversus abdominis (TrA) and multifidus (MF) muscles. Perceived discomfort was measured using a Borg category ratio-scale. Median frequency of the trunk muscles and perceived discomfort after 30 min of sitting were compared with baseline. Result: There were no significant differences within the group and between both groups in the median frequency of bilateral IO and MF muscles. The LBP group showed significantly greater perceived discomfort after prolonged sitting, as compared to the control group. Conclusions: Prolonged sitting with slumped posture could increase the risk of experiencing lower back discomfort.
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Eldar R, Fisher-Gewirtzman D. E-worker postural comfort in the third-workplace: An ergonomic design assessment. Work 2020; 66:519-538. [PMID: 32623415 DOI: 10.3233/wor-203195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Biomechanical simulation is an important tool in human-centred design, allowing for the assessment of comfort interactions between user, product and space, to optimize design features from an ergonomics perspective. OBJECTIVE The aim of this study was to develop a biomechanical model for the evaluation of postural comfort levels. METHODS The study used the scenario-based method to focus on the electronic-worker (e-worker) sedentary tablet tasks at public workplace (third-workplace) configurations. An empirical method determined work-related musculoskeletal disorders (WMSDs) risk levels. The experimental method was based on a motion-capture marker-based laboratory protocol and biomechanical model. Body postures were analysed to determine the WMSDs risk to the joints, and were compared to subjective questionnaires. RESULTS Posture was affected by the tablet target location and workplace setting. The findings confirmed our hypothesis, that neutral-position cost functions govern human motion. Almost half of the time, the e-workers' joints tended to remain in the neutral position range; of the three third-workplaces, high-risk variability was less significant between the 'restaurant' and 'lounge' settings, compared to the 'anywhere' configuration. CONCLUSIONS This evaluation model can contribute to optimizing comfort level in design for third-workplace settings and other sedentary work activities; it can be used to develop guidelines for minimizing work-related strain and health hazards.
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Affiliation(s)
- Ranit Eldar
- Faculty of Architecture and Town Planning, Technion - Israel Institute of Technology, Technion City, Haifa, Israel
| | - Dafna Fisher-Gewirtzman
- Faculty of Architecture and Town Planning, Technion - Israel Institute of Technology, Technion City, Haifa, Israel
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Intolo P, Shalokhon B, Wongwech G, Wisiasut P, Nanthavanij S, Baxter DG. Analysis of neck and shoulder postures, and muscle activities relative to perceived pain during laptop computer use at a low-height table, sofa and bed. Work 2019; 63:361-367. [DOI: 10.3233/wor-192942] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Pattariya Intolo
- Faculty of Physical Therapy, Srinakharinwirot University, Nakhon Nayok, Thailand
| | - Bunnawat Shalokhon
- Faculty of Physical Therapy, Srinakharinwirot University, Nakhon Nayok, Thailand
| | - Geerapong Wongwech
- Faculty of Physical Therapy, Srinakharinwirot University, Nakhon Nayok, Thailand
| | - Pushaya Wisiasut
- Faculty of Physical Therapy, Srinakharinwirot University, Nakhon Nayok, Thailand
| | - Suebsak Nanthavanij
- Sirindhorn International Institute of Technology, Thammasat University, Bangkok, Thailand
| | - David G. Baxter
- Faculty of Health Sciences, University of Otago, Dunedin, New Zealand
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Jin S, Kim M, Park J, Jang M, Chang K, Kim D. A comparison of biomechanical workload between smartphone and smartwatch while sitting and standing. APPLIED ERGONOMICS 2019; 76:105-112. [PMID: 30642514 DOI: 10.1016/j.apergo.2018.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 11/26/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
Increasing concerns about musculoskeletal disorders in the upper back arising from excessive daily use of the smartwatch have been widely validated by the rising prevalence of discomfort. This study explored the smartwatch as a potential ergonomic intervention over the smartphone. Fourteen healthy participants completed five tasks (application setting, calling, message typing, message checking and vocal message entry) with smartphone and smartwatch in both sitting and standing postures. The neck-shoulder kinematics and muscle activation levels were monitored to assess the effects of the tasks, devices, and postures. The results indicated greater head flexion, head rotation and shoulder abduction and greater muscle activities for smartwatch use compared to smartphone use, but the performance measure (i.e., elapsed time) was superior for smartwatch use in all tasks except message typing. Collectively, only short and simple tasks such as message checking and application setting should be conducted with the smartwatch.
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Affiliation(s)
- Sangeun Jin
- The Human and Safety Engineering Laboratory, Department of Industrial Engineering, Pusan National University, Busan, 46241, Republic of Korea.
| | - Minsung Kim
- The Human and Safety Engineering Laboratory, Department of Industrial Engineering, Pusan National University, Busan, 46241, Republic of Korea.
| | - Jihyeon Park
- The Human and Safety Engineering Laboratory, Department of Industrial Engineering, Pusan National University, Busan, 46241, Republic of Korea.
| | - Minsung Jang
- The Human and Safety Engineering Laboratory, Department of Industrial Engineering, Pusan National University, Busan, 46241, Republic of Korea.
| | - Kyuseok Chang
- The Human and Safety Engineering Laboratory, Department of Industrial Engineering, Pusan National University, Busan, 46241, Republic of Korea.
| | - Daemin Kim
- The Human and Safety Engineering Laboratory, Department of Industrial Engineering, Pusan National University, Busan, 46241, Republic of Korea.
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Jia B, Nussbaum MA. Influences of continuous sitting and psychosocial stress on low back kinematics, kinetics, discomfort, and localized muscle fatigue during unsupported sitting activities. ERGONOMICS 2018; 61:1671-1684. [PMID: 29985116 DOI: 10.1080/00140139.2018.1497815] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 06/26/2018] [Accepted: 07/03/2018] [Indexed: 05/23/2023]
Abstract
Continuous seated postures may increase the risk of adverse health outcomes such as low-back pain, and this risk may be influenced by several modifying factors. In the present study, we aimed to quantify the effects of continuous sitting and psychosocial stress under an unsupported sitting condition. Fourteen participants completed continuous, 40 min. periods of computer-based tasks, involving both low and higher levels of psychosocial stress, while using a laptop computer without a desk. Continuous sitting significantly increased perceived discomfort (particularly in the upper and lower back), trunk flexion and metrics of localized muscle fatigue. A higher level of psychosocial stress increased estimated lumbosacral compression forces (by ∼12%). Only weak correlations were found between subjective and objective measures, while various fatigue metrics showed a good level of correspondence with each other. These results could support the future evaluation or design of diverse seated work configurations. Practitioner Summary: Continuous, 40 min. periods of unsupported sitting had broad impacts on subjective and objective outcomes, including discomfort, postures, spine loads and localized muscle fatigue, while psychosocial stress only had a substantial influence on lumbosacral compression. These results extend our understanding of sitting behaviors and provide information for designing future sitting environments.
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Affiliation(s)
- Bochen Jia
- a Department of Industrial and Manufacturing Systems Engineering , University of Michigan-Dearborn , Dearborn , MI , USA
| | - Maury A Nussbaum
- b Department of Industrial and Systems Engineering , Virginia Tech , Blacksburg , VA , USA
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Jafarvand M, Varmazyar S, Hematgar MA, Rezapour M. Evaluation the fitness of anthropometric dimensions of students the best-selling laptop desks. THE JOURNAL OF QAZVIN UNIVERSITY OF MEDICAL SCIENCES 2018. [DOI: 10.29252/qums.22.3.68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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13
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Roh J, Hyeong J, Kim S. Influence of folding mechanism of bicycles on their usability. APPLIED ERGONOMICS 2018; 69:58-65. [PMID: 29477331 DOI: 10.1016/j.apergo.2018.01.003] [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: 01/26/2017] [Revised: 01/05/2018] [Accepted: 01/05/2018] [Indexed: 06/08/2023]
Abstract
In this study, foldable bicycles were evaluated in terms of their usability. Four types of folding mechanisms were identified depending on the number of pivots and the pivot axis direction: single lateral pivot (SLP), single vertical pivot, dual lateral pivot, and combined vertical-lateral pivot. Next, four bicycles-one each of these four types-were selected as test specimens. Ten subjects performed folding and unfolding tasks on each of these bicycles, and three-dimensional body motions and ground reaction forces were measured. The maximum trunk flexion angles and maximum increments in the ground reaction force were used as governing parameters for evaluating the comfort level for each bicycle type. The SLP type provided the lowest upper body flexion and ground reaction force and was hence judged to be the most comfortable folding system. Hence, a promising type of easily foldable bicycle was proposed, thereby encouraging its incorporation into public transit systems.
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Affiliation(s)
- Jongryun Roh
- Human and Culture Convergence Technology Group, Korea Institute of Industrial Technology, 143 Hanggaulro, Ansan 15588, Republic of Korea
| | - Joonho Hyeong
- Human and Culture Convergence Technology Group, Korea Institute of Industrial Technology, 143 Hanggaulro, Ansan 15588, Republic of Korea
| | - Sayup Kim
- Human and Culture Convergence Technology Group, Korea Institute of Industrial Technology, 143 Hanggaulro, Ansan 15588, Republic of Korea.
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14
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Jafarvand M, Marandi N, Varmazyar S, Mohammadi E. Investigation of student's satisfaction from the laptop desks using satisfaction questionnaire. THE JOURNAL OF QAZVIN UNIVERSITY OF MEDICAL SCIENCES 2018. [DOI: 10.29252/qums.22.1.60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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15
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Farias Zuniga AM, Côté JN. Effects of Dual Monitor Computer Work Versus Laptop Work on Cervical Muscular and Proprioceptive Characteristics of Males and Females. HUMAN FACTORS 2017; 59:546-563. [PMID: 28060526 DOI: 10.1177/0018720816684690] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
OBJECTIVE The effects of performing a 90-minute computer task with a laptop versus a dual monitor desktop workstation were investigated in healthy young male and female adults. BACKGROUND Work-related musculoskeletal disorders are common among computer (especially female) users. Laptops have surpassed desktop computer sales, and working with multiple monitors has also become popular. However, few studies have provided objective evidence on how they affect the musculoskeletal system in both genders. METHODS Twenty-seven healthy participants (mean age = 24.6 years; 13 males) completed a 90-minute computer task while using a laptop or dual monitor (DualMon) desktop. Electromyography (EMG) from eight upper body muscles and visual strain were measured throughout the task. Neck proprioception was tested before and after the computer task using a head-repositioning test. EMG amplitude (root mean square [RMS]), variability (coefficients of variation [CV]), and normalized mutual information (NMI) were computed. RESULTS Visual strain ( p < .01) and right upper trapezius RMS ( p = .03) increased significantly over time regardless of workstation. Right cervical erector spinae RMS and cervical NMI were smaller, while degrees of overshoot (mean = 4.15°) and end position error (mean = 1.26°) were larger in DualMon regardless of time. Effects on muscle activity were more pronounced in males, whereas effects on proprioception were more pronounced in females. CONCLUSION Results suggest that compared to laptop, DualMon work is effective in reducing cervical muscle activity, dissociating cervical connectivity, and maintaining more typical neck repositioning patterns, suggesting some health-protective effects. APPLICATION This evidence could be considered when deciding on computer workstation designs.
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Affiliation(s)
| | - Julie N Côté
- McGill University, Montreal, and Jewish Rehabilitation Hospital, Laval, Canada
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Taib MFM, Bahn S, Yun MH. The effect of psychosocial stress on muscle activity during computer work: Comparative study between desktop computer and mobile computing products. Work 2017; 54:543-55. [PMID: 27372893 DOI: 10.3233/wor-162334] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The popularity of mobile computing products is well known. Thus, it is crucial to evaluate their contribution to musculoskeletal disorders during computer usage under both comfortable and stressful environments. OBJECTIVE This study explores the effect of different computer products' usages with different tasks used to induce psychosocial stress on muscle activity. METHODS Fourteen male subjects performed computer tasks: sixteen combinations of four different computer products with four different tasks used to induce stress. Electromyography for four muscles on the forearm, shoulder and neck regions and task performances were recorded. RESULTS The increment of trapezius muscle activity was dependent on the task used to induce the stress where a higher level of stress made a greater increment. However, this relationship was not found in the other three muscles. Besides that, compared to desktop and laptop use, the lowest activity for all muscles was obtained during the use of a tablet or smart phone. The best net performance was obtained in a comfortable environment. However, during stressful conditions, the best performance can be obtained using the device that a user is most comfortable with or has the most experience with. CONCLUSIONS Different computer products and different levels of stress play a big role in muscle activity during computer work. Both of these factors must be taken into account in order to reduce the occurrence of musculoskeletal disorders or problems.
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Affiliation(s)
- Mohd Firdaus Mohd Taib
- Department of Industrial Engineering, Seoul National University, Seoul, South Korea.,Department of Material, Manufacturing and Industrial Engineering, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia
| | - Sangwoo Bahn
- Department of Industrial and Management Engineering, Myongji University, Yongin, South Korea
| | - Myung Hwan Yun
- Department of Industrial Engineering, Seoul National University, Seoul, South Korea
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Chang J, Jung K, Lee W, You H. Development of a usability evaluation method using natural product-use motion. APPLIED ERGONOMICS 2017; 60:171-182. [PMID: 28166876 DOI: 10.1016/j.apergo.2016.11.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 10/05/2016] [Accepted: 11/27/2016] [Indexed: 06/06/2023]
Abstract
The present study developed and tested a new usability evaluation method which considers natural product-use motions. The proposed method measures both natural product-use motions (NMs) and actual product-use motions (AMs) for a product using an optical motion capture system and examines the usability of the product based on motion similarity (MS; %) between NMs and AMs. The proposed method was applied to a usability test of four vacuum cleaners (A, B, C, and D) with 15 participants and their MSs were compared with EMG measurements and subjective discomfort ratings. Cleaners A (44.6%) and C (44.2%) showed higher MSs than cleaners B (42.9%) and D (41.7%); the MSs mostly corresponded to the EMG measurements, which could indicate that AMs deviated from NMs may increase muscular efforts. However, the MSs were slightly different from the corresponding discomfort ratings. The proposed method demonstrated its usefulness in usability testing, but further research is needed with various products to generalize its effectiveness.
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Affiliation(s)
- Joonho Chang
- Department of Industrial and Manufacturing Engineering, Pennsylvania State University, University Park, PA 16802, USA
| | - Kihyo Jung
- School of Industrial Engineering, University of Ulsan, Ulsan, 44610, Republic of Korea
| | - Wonsup Lee
- Faculty of Industrial Design Engineering, Delft University of Technology, 2628 CE, Delft, The Netherlands
| | - Heecheon You
- Department of Industrial and Management Engineering, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
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18
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Bubric K, Hedge A. Differential patterns of laptop use and associated musculoskeletal discomfort in male and female college students. Work 2016; 55:663-671. [DOI: 10.3233/wor-162419] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Lin MIB, Hong RH, Chang JH, Ke XM. Usage Position and Virtual Keyboard Design Affect Upper-Body Kinematics, Discomfort, and Usability during Prolonged Tablet Typing. PLoS One 2015; 10:e0143585. [PMID: 26629989 PMCID: PMC4667996 DOI: 10.1371/journal.pone.0143585] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/07/2015] [Indexed: 11/18/2022] Open
Abstract
Purpose The increase in tablet usage allows people to perform computer work in non-traditional office environments. The aim of this study was to assess the effects of changes in tablet keyboard design on postures of the upper extremities and neck, discomfort, and usability under different usage positions during prolonged touch-typing. Methods Eighteen healthy participants familiar with touch-screen devices were randomized into three usage positions (desk, lap, and bed) and completed six, 60-minute typing sessions using three virtual keyboard designs (standard, wide, split). Electrogoniometers continuously measured the postures of the wrists, elbow, and neck. Body discomfort and system usability were evaluated by questionnaires before and immediately after each typing session. Results Separate linear mixed effects models on various postural measures and subjective ratings are conducted with usage position as the between-subject factors, keyboard design and typing duration as the with-in subject factors were conducted. Using the tablet in bed led to more extended wrists but a more natural elbow flexion than the desk position. The angled split virtual keyboard significantly reduced the extent of wrist ulnar deviation than the keyboard with either standard or wide design. However, little difference was observed across the usage position and keyboard design. When the postural data were compared between the middle and end of typing sessions, the wrists, elbow, and neck all exhibited a substantially increased range of joint movements (13% to 38%). The discomfort rating also increased significantly over time in every upper body region investigated. Additionally, the split keyboard design received a higher usability rating in the bed position, whereas participants had more satisfactory experience while using the wide keyboard in the traditional desk setting. Conclusions Prolonged use of tablets in non-traditional office environments may result in awkward postures in the upper body that may expose users to greater risks of developing musculoskeletal symptoms. Adequate virtual keyboard designs show the potential to alleviate some postural effects and improve the user experience without changing the tablet form factors.
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Affiliation(s)
- Ming-I Brandon Lin
- Department of Industrial and Information Management, National Cheng-Kung University, Tainan, Taiwan
| | - Ruei-Hong Hong
- Department of Industrial and Information Management, National Cheng-Kung University, Tainan, Taiwan
| | - Jer-Hao Chang
- Department of Occupational Therapy, National Cheng-Kung University, Tainan, Taiwan
| | - Xin-Min Ke
- Department of Industrial and Information Management, National Cheng-Kung University, Tainan, Taiwan
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20
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21
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Kietrys DM, Gerg MJ, Dropkin J, Gold JE. Mobile input device type, texting style and screen size influence upper extremity and trapezius muscle activity, and cervical posture while texting. APPLIED ERGONOMICS 2015; 50:98-104. [PMID: 25959323 DOI: 10.1016/j.apergo.2015.03.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 02/26/2015] [Accepted: 03/02/2015] [Indexed: 06/04/2023]
Abstract
This study aimed to determine the effects of input device type, texting style, and screen size on upper extremity and trapezius muscle activity and cervical posture during a short texting task in college students. Users of a physical keypad produced greater thumb, finger flexor, and wrist extensor muscle activity than when texting with a touch screen device of similar dimensions. Texting on either device produced greater wrist extensor muscle activity when texting with 1 hand/thumb compared with both hands/thumbs. As touch screen size increased, more participants held the device on their lap, and chose to use both thumbs less. There was also a trend for greater finger flexor, wrist extensor, and trapezius muscle activity as touch screen size increased, and for greater cervical flexion, although mean differences for cervical flexion were small. Future research can help inform whether the ergonomic stressors observed during texting are associated with musculoskeletal disorder risk.
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Affiliation(s)
- David M Kietrys
- School of Health Related Professions, Rutgers, The State University of New Jersey, 40 E. Laurel Road, Stratford, NJ, USA.
| | - Michael J Gerg
- Occupational Therapy Assistant Program, Harcum College, 750 Montgomery Ave., Bryn Mawr, PA, USA; Department of Rehabilitation Sciences, Temple University, 3307 N. Broad St., Philadelphia, PA 19140, USA.
| | - Jonathan Dropkin
- Department of Occupational Medicine, Epidemiology, and Prevention, Hofstra North Shore-LIJ School of Medicine, 175 Community Drive, Great Neck, NY 11021, USA.
| | - Judith E Gold
- Centre for Musculoskeletal Research, University of Gävle, 801 76 Gävle, Sweden; Department of Public Health, Temple University, 3307 N. Broad St., Philadelphia, PA 19140, USA(1).
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22
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Werth A, Babski-Reeves K. Effects of portable computing devices on posture, muscle activation levels and efficiency. APPLIED ERGONOMICS 2014; 45:1603-1609. [PMID: 24934983 DOI: 10.1016/j.apergo.2014.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 05/14/2014] [Accepted: 05/25/2014] [Indexed: 06/03/2023]
Abstract
Very little research exists on ergonomic exposures when using portable computing devices. This study quantified muscle activity (forearm and neck), posture (wrist, forearm and neck), and performance (gross typing speed and error rates) differences across three portable computing devices (laptop, netbook, and slate computer) and two work settings (desk and computer) during data entry tasks. Twelve participants completed test sessions on a single computer using a test-rest-test protocol (30min of work at one work setting, 15min of rest, 30min of work at the other work setting). The slate computer resulted in significantly more non-neutral wrist, elbow and neck postures, particularly when working on the sofa. Performance on the slate computer was four times less than that of the other computers, though lower muscle activity levels were also found. Potential or injury or illness may be elevated when working on smaller, portable computers in non-traditional work settings.
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Affiliation(s)
- Abigail Werth
- Department of Industrial and Systems Engineering, Mississippi State University, PO Box 9542, Mississippi State, MS 39762 USA.
| | - Kari Babski-Reeves
- Department of Industrial and Systems Engineering, Mississippi State University, PO Box 9542, Mississippi State, MS 39762 USA
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23
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Abstract
Repetitive or prolonged head flexion posture while using a smartphone is known as one of risk factors for pain symptoms in the neck. To quantitatively assess the amount and range of head flexion of smartphone users, head forward flexion angle was measured from 18 participants when they were conducing three common smartphone tasks (text messaging, web browsing, video watching) while sitting and standing in a laboratory setting. It was found that participants maintained head flexion of 33-45° (50th percentile angle) from vertical when using the smartphone. The head flexion angle was significantly larger (p < 0.05) for text messaging than for the other tasks, and significantly larger while sitting than while standing. Study results suggest that text messaging, which is one of the most frequently used app categories of smartphone, could be a main contributing factor to the occurrence of neck pain of heavy smartphone users. Practitioner Summary: In this laboratory study, the severity of head flexion of smartphone users was quantitatively evaluated when conducting text messaging, web browsing and video watching while sitting and standing. Study results indicate that text messaging while sitting caused the largest head flexion than that of other task conditions.
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Affiliation(s)
- Sojeong Lee
- a Department of Human and Systems Engineering , Ulsan National Institute of Science and Technology , Ulsan , Korea
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24
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Nanthavanij S, Udomratana C, Hansawad S, Thepkanjana J, Tantasuwan W. Worksheets for computing recommended notebook computer and workstation adjustments. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2013; 19:259-74. [PMID: 23759196 DOI: 10.1080/10803548.2013.11076984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This paper discusses the design and development of worksheets for helping notebook computer (NBC) users to compute NBC and workstation adjustments so as to assume an appropriate seated posture. The worksheets (one for male users, the other for female ones) require the following information: body height, NBC screen size, work surface height, and seat height. The worksheets contain tables for estimating recommended NBC base angle, NBC screen angle, body-NBC distance, work surface height, and seat height. Additionally, they include flow charts to help NBC users to determine necessary adjustment accessories and their settings.
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Affiliation(s)
- Suebsak Nanthavanij
- Sirindhorn International Institute of Technology, Thammasat University, Pathumthani, Thailand.
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25
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Werth AJ, Babski-Reeves K. Assessing Posture While Typing on Portable Computing Devices in Traditional Work Environments and at Home. ACTA ACUST UNITED AC 2012. [DOI: 10.1177/1071181312561223] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mobile computers are becoming increasingly popular for many user populations, since they allow owners to perform computing activities in a number of settings (e.g., home, office). However, little research exists that quantifies ergonomic exposures associated with using mobile computing devices, particularly in non-traditional environments or for newer, compact mobile computers (e.g., slate computers). Therefore, the objective of this study was to quantify posture differences between mobile computing devices when performing data entry tasks at a traditional workstation and on a sofa. Wrist and neck flexion/extension (FE) and wrist radial/ulnar deviation (RU) were measured using electrogoniometers. When working at the non-traditional work station (i.e., sofa), postures were found to be degraded particularly when typing on the slate computer. These findings indicate that the potential or injury or illness may be elevated when working on smaller computers in non-traditional work settings.
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26
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Van Eerd D, Hogg-Johnson S, Cole DC, Wells R, Mazumder A. Comparison of occupational exposure methods relevant to musculoskeletal disorders: Worker–workstation interaction in an office environment. J Electromyogr Kinesiol 2012; 22:176-85. [DOI: 10.1016/j.jelekin.2011.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 12/01/2011] [Accepted: 12/02/2011] [Indexed: 10/14/2022] Open
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27
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Asundi K, Odell D, Luce A, Dennerlein JT. Changes in posture through the use of simple inclines with notebook computers placed on a standard desk. APPLIED ERGONOMICS 2012; 43:400-407. [PMID: 21774912 DOI: 10.1016/j.apergo.2011.06.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 05/03/2011] [Accepted: 06/11/2011] [Indexed: 05/31/2023]
Abstract
This study evaluated the use of simple inclines as a portable peripheral for improving head and neck postures during notebook computer use on tables in portable environments such as hotel rooms, cafés, and airport lounges. A 3D motion analysis system measured head, neck and right upper extremity postures of 15 participants as they completed a 10 min computer task in six different configurations, all on a fixed height desk: no-incline, 12° incline, 25° incline, no-incline with external mouse, 25° incline with an external mouse, and a commercially available riser with external mouse and keyboard. After completion of the task, subjects rated the configuration for comfort and ease of use and indicated perceived discomfort in several body segments. Compared to the no-incline configuration, use of the 12° incline reduced forward head tilt and neck flexion while increasing wrist extension. The 25° incline further reduced head tilt and neck flexion while further increasing wrist extension. The 25° incline received the lowest comfort and ease of use ratings and the highest perceived discomfort score. For portable, temporary computing environments where internal input devices are used, users may find improved head and neck postures with acceptable wrist extension postures with the utilization of a 12° incline.
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Affiliation(s)
- Krishna Asundi
- Department of Environmental Health, Harvard School of Public Health, Boston, USA
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28
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Gold JE, Driban JB, Yingling VR, Komaroff E. Characterization of posture and comfort in laptop users in non-desk settings. APPLIED ERGONOMICS 2012; 43:392-399. [PMID: 21726854 DOI: 10.1016/j.apergo.2011.06.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 05/03/2011] [Accepted: 06/11/2011] [Indexed: 05/31/2023]
Abstract
Laptop computers may be used in a variety of postures not coupled to the office workstation. Using passive motion analysis, this study examined mean joint angles during a short typing/editing task in college students (n=20), in up to seven positions. Comfort was assessed after task execution through a body map. For three required postures, joint angles in a prone posture were different than those while seated at a couch with feet either on floor or on ottoman. Specifically, the prone posture was characterized by comparatively non-neutral shoulders, elbows and wrists, and pronounced neck extension. Significantly greater intensity and more regions of discomfort were marked for the prone posture than for the seated postures. It is recommended that the prone posture only be assumed briefly during laptop use. Exposure to laptops outside of the office setting should be assessed in future epidemiologic studies of musculoskeletal complaints and computer use.
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Affiliation(s)
- J E Gold
- Department of Public Health, Temple University, 1301 Cecil B. Moore Avenue 004-09, Philadelphia, PA 19122, USA.
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29
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Yoo WG. Comparison of Sitting with and without A Backrest during Computer Work. J Phys Ther Sci 2012. [DOI: 10.1589/jpts.24.409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Won-gyu Yoo
- Department of Physical Therapy, College of Biomedical Science and Engineering, Inje University
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30
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Abstract
This research study analysed the interaction between people's postures and activities while in semi-public/leisure situations and during transportation (journey by train). In addition, the use of small electronic devices received particular emphasis. Video recordings in German trains and photographs in Dutch semi-public spaces were analysed using a variation of Branton and Grayson's (An evaluation of train seats by observation of sitting behaviour. Ergonomics, 10 (1), (1967), 35-51) postural targeting forms and photos. The analysis suggests a significant relationship between most activities and the position of the head, trunk and arms during transportation situations. The relationship during public situations is less straightforward. Watching, talking/discussing and reading were the most observed activities for the transportation and leisure situations combined. Surprisingly, differences in head, trunk, arm and leg postures were not significant when using small electronic devices. Important issues not considered in this study include the duration of the activities, the gender and age of observed subjects and the influence of the time of day. These are interesting issues to consider and include for future research. STATEMENT OF RELEVANCE: This study shows what activities people choose to carry out and their related postures when not forced to a specific task (e.g. driving). The results of this study can be used for designing comfortable seating in the transportation industry (car passenger, train, bus and aircraft seats) and semi-public/leisure spaces.
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Affiliation(s)
- Irene Kamp
- BMW AG Forschungs- und Innovationszentrum, München, Germany.
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31
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Bronner S, Agraharasamakulam S, Ojofeitimi S. Reliability and validity of electrogoniometry measurement of lower extremity movement. J Med Eng Technol 2010; 34:232-42. [DOI: 10.3109/03091900903580512] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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32
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Asundi K, Odell D, Luce A, Dennerlein JT. Notebook computer use on a desk, lap and lap support: effects on posture, performance and comfort. ERGONOMICS 2010; 53:74-82. [PMID: 20069483 DOI: 10.1080/00140130903389043] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study quantified postures of users working on a notebook computer situated in their lap and tested the effect of using a device designed to increase the height of the notebook when placed on the lap. A motion analysis system measured head, neck and upper extremity postures of 15 adults as they worked on a notebook computer placed on a desk (DESK), the lap (LAP) and a commercially available lapdesk (LAPDESK). Compared with the DESK, the LAP increased downwards head tilt 6 degrees and wrist extension 8 degrees . Shoulder flexion and ulnar deviation decreased 13 degrees and 9 degrees , respectively. Compared with the LAP, the LAPDESK decreased downwards head tilt 4 degrees , neck flexion 2 degrees , and wrist extension 9 degrees. Users reported less discomfort and difficulty in the DESK configuration. Use of the lapdesk improved postures compared with the lap; however, all configurations resulted in high values of wrist extension, wrist deviation and downwards head tilt. STATEMENT OF RELEVANCE: This study quantifies postures of users working with a notebook computer in typical portable configurations. A better understanding of the postures assumed during notebook computer use can improve usage guidelines to reduce the risk of musculoskeletal injuries.
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Affiliation(s)
- Krishna Asundi
- Department of Environmental Health, Harvard School of Public Health, Boston, USA
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33
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Samani A, Holtermann A, Søgaard K, Madeleine P. Active pauses induce more variable electromyographic pattern of the trapezius muscle activity during computer work. J Electromyogr Kinesiol 2009; 19:e430-7. [PMID: 19135388 DOI: 10.1016/j.jelekin.2008.11.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 11/25/2008] [Accepted: 11/25/2008] [Indexed: 11/28/2022] Open
Affiliation(s)
- Afshin Samani
- Laboratory for Ergonomics and Work-related Disorders, Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7 D-3, 9220 Aalborg East, Denmark
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34
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Straker L, Pollock C, Burgess-Limerick R, Skoss R, Coleman J. The impact of computer display height and desk design on muscle activity during information technology work by young adults. J Electromyogr Kinesiol 2008; 18:606-17. [PMID: 17329126 DOI: 10.1016/j.jelekin.2006.09.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 09/09/2006] [Accepted: 09/11/2006] [Indexed: 11/20/2022] Open
Abstract
Computer display height and desk design are believed to be important workstation features and are included in international standards and guidelines. However, the evidence base for these guidelines is lacking a comparison of neck/shoulder muscle activity during computer and paper tasks and whether forearm support can be provided by desk design. This study measured the spinal and upper limb muscle activity in 36 young adults whilst they worked in different computer display, book and desk conditions. Display height affected spinal muscle activity with paper tasks resulting in greater mean spinal and upper limb muscle activity. A curved desk resulted in increased proximal muscle activity. There was no substantial interaction between display and desk.
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Affiliation(s)
- L Straker
- School of Physiotherapy, Curtin University of Technology, Perth 6845, Australia.
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35
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Yoo WG, Yi CH, Cho SH, Jeon HS, Cynn HS, Choi HS. Effects of the height of ball-backrest on head and shoulder posture and trunk muscle activity in VDT workers. INDUSTRIAL HEALTH 2008; 46:289-297. [PMID: 18544890 DOI: 10.2486/indhealth.46.289] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This study was designed to elucidate the effects of a ball-backrest at different heights on the head and shoulder posture and neck and trunk muscles of visual display terminal (VDT) workers who adopted a forward head posture when working at a VDT. Twenty-three VDT workers with forward head posture performed the keyboard typing work at a VDT without and with a ball-backrest at the L3, T10, and T4 levels. Surface electromyograms were recorded from the neck, shoulder, and trunk muscles, and the forward head angle and forward shoulder angle were analyzed using a 3-D motion analysis system. The significance of differences for the ball-backrest at different heights was tested by repeated one-way ANOVA, with the significance cutoff set at p=0.05. The mean forward head angle and forward shoulder angle decreased in the order of no backrest, T10-level ball-backrest, T4-level ball-backrest. Compared with not using a backrest, the activity of midcervical muscles was significantly lower and that of the lower trapezius was significantly higher when using a T4-level ball-backrest, and the activity of the internal oblique abdominal muscle was significantly higher when using a T10-level ball-backrest. We suggested that using T4 and T10-level ball-backrests would produce similar effects to active exercise, such as ball exercise for trunk stabilization, and that a ball-backrest would prevent kinematics changes. Therefore, the height of the backrest must be determined on the basis of the characteristics of work-related musculoskeletal disorders when applying a ball-backrest to VDT workers with such disorders.
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Affiliation(s)
- Won-gyu Yoo
- Department of Physical Therapy, College of Biomedical Science and Engineering, Inje University, 607 Obangdong, Gimhae, Gyeongsangnam-do, 621-749 Republic of Korea
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36
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Straker L, Burgess-Limerick R, Pollock C, Murray K, Netto K, Coleman J, Skoss R. The impact of computer display height and desk design on 3D posture during information technology work by young adults. J Electromyogr Kinesiol 2008; 18:336-49. [PMID: 17188894 DOI: 10.1016/j.jelekin.2006.10.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 09/09/2006] [Accepted: 10/18/2006] [Indexed: 11/24/2022] Open
Abstract
Computer display height and desk design to allow forearm support are two critical design features of workstations for information technology tasks. However there is currently no 3D description of head and neck posture with different computer display heights and no direct comparison to paper based information technology tasks. There is also inconsistent evidence on the effect of forearm support on posture and no evidence on whether these features interact. This study compared the 3D head, neck and upper limb postures of 18 male and 18 female young adults whilst working with different display and desk design conditions. There was no substantial interaction between display height and desk design. Lower display heights increased head and neck flexion with more spinal asymmetry when working with paper. The curved desk, designed to provide forearm support, increased scapula elevation/protraction and shoulder flexion/abduction.
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Affiliation(s)
- L Straker
- School of Physiotherapy, Curtin University of Technology, Perth 6845, Australia.
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