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Cappetti N, Manso ED. Study of the relationships between articular moments, comfort and human posture on a chair. Work 2020; 68:S59-S68. [PMID: 33337408 DOI: 10.3233/wor-208006] [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 One of the aspects that influences the sitting comfort is the distribution of the pressure applied to the skin by the seat surface. In the scientific literature, many studies show experimental activities in order to evaluate the influence of pressure distribution at the seat-human interface on the comfort evaluation. The main limitation in seat design is based on the difficulties to predict the contact pressures distribution without prototypes because of the complex interaction among body muscles, wearing, human's anthropometric characteristics, shape and materials of the seat. Moreover, the same human can assume different postures on the same seat, and different people, seated on the same chair, can assume different postures even if they have the same anthropometric percentile. OBJECTIVE The aim of this study is to propose a mathematical model evaluating interaction loads between human segments and seat segments. METHOD In this model, a human body represented by 8 segments is placed on a 6 segments seat with posture dependent on seat segments and on position of the coccyx on seat and feet on floor. Human segments can be configured in length and weight and friction between body and seat is considered. A model validation study based on an experimental comparison with contact pressures is also presented. RESULTS The experiment showed that there is a remarkable recursion of some stress values of the articular joints of the pelvis, hip and knee. By imposing these values in the calculation model, it is possible to determine, for each chair configuration, which postures will be assumed by a person, and to make a preliminary assessment of the level of comfort possible.
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Affiliation(s)
- Nicola Cappetti
- Department of Industrial Engineering, University of Salerno -Fisciano, Italy
| | - Emmanuel Di Manso
- Department of Industrial Engineering, University of Salerno -Fisciano, Italy
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Smulders M, Naddeo A, Cappetti N, van Grondelle ED, Schultheis U, Vink P. Neck posture and muscle activity in a reclined business class aircraft seat watching IFE with and without head support. APPLIED ERGONOMICS 2019; 79:25-37. [PMID: 31109459 DOI: 10.1016/j.apergo.2018.12.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 07/10/2018] [Accepted: 12/17/2018] [Indexed: 05/23/2023]
Abstract
The purpose of this study is to research if a headrest benefits the comfort of the passenger and lowers muscle activity in the neck when sitting in a reclined (slouched) posture while watching in flight entertainment (IFE) in an aircraft business class seat. No significant differences in muscle activity in the musculus sternocleidomastoid and musculus trapezius pars descendant were found between the conditions with headrest and without headrest. A significant difference in expected comfort rating was found. Subjects indicated they expect to experience more comfort with a headrest when watching IFE for a duration of two movies during a long-haul flight. This study also found a significant difference in posture. In the condition without headrest the head was more upright compared to the condition with headrest. The lack of significant difference in muscle activity and the significant difference in posture may indicate that humans tend to look for a head position that is neutral, in the sense of minimal muscle effort. This study shows that the use of a headrest may benefit the comfort experience of the passenger during flight. However, further research is necessary on the design of the headrest and the long-term effects of head support on comfort, discomfort, muscle activity and fatigue for watching IFE in a slouched posture.
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Affiliation(s)
- M Smulders
- Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands; Human Factors and Ergonomics, Zodiac Seats U.S. LLC, 2000, Weber Drive, Gainesville, TX 76240, USA.
| | - A Naddeo
- Department of Industrial Engineering, University of Salerno, Via Ponte Don Melillo, 1, 84084, Fisciano, Salerno, Italy
| | - N Cappetti
- Department of Industrial Engineering, University of Salerno, Via Ponte Don Melillo, 1, 84084, Fisciano, Salerno, Italy
| | - E D van Grondelle
- Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands
| | - U Schultheis
- Human Factors and Ergonomics, Zodiac Seats U.S. LLC, 2000, Weber Drive, Gainesville, TX 76240, USA
| | - P Vink
- Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands
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Architecture and Design of a Wearable Robotic System for Body Posture Monitoring, Correction, and Rehabilitation Assist. Int J Soc Robot 2019. [DOI: 10.1007/s12369-019-00512-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Chiang HYA, Liu CH. Exploration of the associations of touch-screen tablet computer usage and musculoskeletal discomfort. Work 2017; 53:917-25. [PMID: 26967038 DOI: 10.3233/wor-162274] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Tablet users may be at high risk of developing physical discomfort because of their usage behaviors and tablet design. OBJECTIVE Investigate the usage of tablets, variations in head and neck posture associated with different tablet tilt angles, and the association of tablet use with users' musculoskeletal discomfort. METHODS A survey of users' subjective perceptions conducted by questionnaire and measurements of users' postures by a 3D Motion analysis system was used to explore the effects of tablet use. RESULTS The questionnaire results indicated that over half of the participants reported physical discomfort after using tablets, with the most prevalent discomfort in the neck and shoulders, and more intensity of discomfort for the back although only few participants experienced it. Chi-squared tests indicated that significantly more participants who tended to use tablet computers to play games reported having musculoskeletal discomfort after using a tablet. In addition, preferences for tablet tilt angles varied across tasks (reading and game playing). The results from the 3D motion analysis revealed that head and neck flexion angles were significantly reduced when the tablets were positioned at relatively steep tilt angles. Neck flexion angle was significantly higher in game playing. CONCLUSIONS These data add information regarding to the usage of tablet and its associations with physical discomfort (significantly more participants who tended to use tablet computers to play games reported having musculoskeletal discomfort after using a tablet). Steep tilt angles (such as 60°) may cause tablet users to decrease their head and neck flexion angles, which could lead to a more neutral, effortless, and ergonomically correct posture. Maintaining proper neck posture during active activities such as game playing is recommended to avoid neck discomfort.
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Gaffney BM, Maluf KS, Davidson BS. Evaluation of Novel EMG Biofeedback for Postural Correction During Computer Use. Appl Psychophysiol Biofeedback 2015; 41:181-9. [DOI: 10.1007/s10484-015-9328-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kamp I, Van Veen S, Vink P. Comfortable mobile offices: A literature review of the ergonomic aspects of mobile device use in transportation settings. Work 2015; 52:279-87. [DOI: 10.3233/wor-152165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- I. Kamp
- University of Technology Delft, Delft, The Netherlands
| | - S.A.T. Van Veen
- University of Technology Delft, Delft, The Netherlands
- BMW AG Forschungs-und Innovationszentrum, Munich, Germany
| | - P. Vink
- University of Technology Delft, Delft, The Netherlands
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Guan X, Fan G, Wu X, Zeng Y, Su H, Gu G, Zhou Q, Gu X, Zhang H, He S. Photographic measurement of head and cervical posture when viewing mobile phone: a pilot study. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2015. [PMID: 26206292 DOI: 10.1007/s00586-015-4143-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE With the dramatic growth of mobile phone usage, concerns have been raised with regard to the adverse health effects of mobile phone on spinal posture. The aim of this study was to determine the head and cervical postures by photogrammetry when viewing the mobile phone screen, compared with those in neutral standing posture. METHODS A total of 186 subjects (81 females and 105 males) aged from 17 to 31 years old participated in this study. Subjects were instructed to stand neutrally and using mobile phone as in daily life. Using a photographic method, the sagittal head and cervical postures were assessed by head tilt angle, neck tilt angle, forward head shift and gaze angle. RESULTS The photographic method showed a high intra-rater and inter-rater reliability in measuring the sagittal posture of cervical spine and gaze angle (ICCs ranged from 0.80 to 0.99). When looking at mobile phone, the head tilt angle significantly increased (from 74.55° to 95.22°, p = 0.000) and the neck angle decreased (from 54.68° to 38.77°, p = 0.000). The forward head posture was also confirmed by the significantly increased head shift (from 10.90 to 13.85 cm, p = 0.000). The posture assumed in mobile phone use was significantly correlated with neutral posture (p < 0.05). Males displayed a more forward head posture than females (p < 0.05). The head tilt angle was positively correlated with the gaze angle (r = 0.616, p = 0.000), while the neck tilt angle was negatively correlated with the gaze angle (r = -0.628, p = 0.000). CONCLUSIONS Photogrammetry is a reliable, quantitative method to evaluate the head and cervical posture during mobile phone use. Compared to neutral standing, subjects display a more forward head posture when viewing the mobile phone screen, which is correlated with neutral posture, gaze angle and gender. Future studies will be needed to investigate a dose-response relationship between mobile phone use and assumed posture.
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Affiliation(s)
- Xiaofei Guan
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Guoxin Fan
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Xinbo Wu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Ying Zeng
- Tongji University School of Medicine, 200092, Shanghai, People's Republic of China
| | - Hang Su
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Guangfei Gu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Qi Zhou
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Xin Gu
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Hailong Zhang
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China
| | - Shisheng He
- Department of Orthopedics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072, Shanghai, People's Republic of China.
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Weidling P, Jaschinski W. The vertical monitor position for presbyopic computer users with progressive lenses: how to reach clear vision and comfortable head posture. ERGONOMICS 2015; 58:1813-29. [PMID: 26010363 DOI: 10.1080/00140139.2015.1035764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
UNLABELLED When presbyopic employees are wearing general-purpose progressive lenses, they have clear vision only with a lower gaze inclination to the computer monitor, given the head assumes a comfortable inclination. Therefore, in the present intervention field study the monitor position was lowered, also with the aim to reduce musculoskeletal symptoms. A comparison group comprised users of lenses that do not restrict the field of clear vision. The lower monitor positions led the participants to lower their head inclination, which was linearly associated with a significant reduction in musculoskeletal symptoms. However, for progressive lenses a lower head inclination means a lower zone of clear vision, so that clear vision of the complete monitor was not achieved, rather the monitor should have been placed even lower. The procedures of this study may be useful for optimising the individual monitor position depending on the comfortable head and gaze inclination and the vertical zone of clear vision of progressive lenses. PRACTITIONER SUMMARY For users of general-purpose progressive lenses, it is suggested that low monitor positions allow for clear vision at the monitor and for a physiologically favourable head inclination. Employees may improve their workplace using a flyer providing ergonomic-optometric information.
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Affiliation(s)
- Patrick Weidling
- a Leibniz Research Centre for Working Environment and Human Factors , Ardeystraße 67, D-44139 Dortmund , Germany
| | - Wolfgang Jaschinski
- a Leibniz Research Centre for Working Environment and Human Factors , Ardeystraße 67, D-44139 Dortmund , Germany
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Gadotti IC, Magee DJ. Validity of surface measurements to assess craniocervical posture in the sagittal plane: a critical review. PHYSICAL THERAPY REVIEWS 2013. [DOI: 10.1179/174328808x309250] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Fortin C, Feldman DE, Cheriet F, Gravel D, Gauthier F, Labelle H. Reliability of a quantitative clinical posture assessment tool among persons with idiopathic scoliosis. Physiotherapy 2011; 98:64-75. [PMID: 22265387 DOI: 10.1016/j.physio.2010.12.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 12/28/2010] [Indexed: 12/17/2022]
Abstract
OBJECTIVE To determine overall, test-retest and inter-rater reliability of posture indices among persons with idiopathic scoliosis. DESIGN A reliability study using two raters and two test sessions. SETTING Tertiary care paediatric centre. PARTICIPANTS Seventy participants aged between 10 and 20 years with different types of idiopathic scoliosis (Cobb angle 15 to 60°) were recruited from the scoliosis clinic. MAIN OUTCOME MEASURES Based on the XY co-ordinates of natural reference points (e.g., eyes) as well as markers placed on several anatomical landmarks, 32 angular and linear posture indices taken from digital photographs in the standing position were calculated from a specially developed software program. Generalisability theory served to estimate the reliability and standard error of measurement (SEM) for the overall, test-retest and inter-rater designs. Bland and Altman's method was also used to document agreement between sessions and raters. RESULTS In the random design, dependability coefficients demonstrated a moderate level of reliability for six posture indices (ϕ=0.51 to 0.72) and a good level of reliability for 26 posture indices out of 32 (ϕ≥0.79). Error attributable to marker placement was negligible for most indices. Limits of agreement and SEM values were larger for shoulder protraction, trunk list, Q angle, cervical lordosis and scoliosis angles. The most reproducible indices were waist angles and knee valgus and varus. CONCLUSIONS Posture can be assessed in a global fashion from photographs in persons with idiopathic scoliosis. Despite the good reliability of marker placement, other studies are needed to minimise measurement errors in order to provide a suitable tool for monitoring change in posture over time.
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Affiliation(s)
- Carole Fortin
- Centre de Recherche, Centre Hospitalier Universitaire Sainte-Justine, 3175, Côte-Sainte-Catherine, Montréal, Quebec, Canada.
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Breen PP, Nisar A, Olaighin G. Evaluation of a single accelerometer based biofeedback system for real-time correction of neck posture in computer users. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:7269-7272. [PMID: 19965101 DOI: 10.1109/iembs.2009.5334726] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The worldwide adoption of computers is closely linked to increased prevalence in neck and shoulder pain. Many ergonomic interventions are available; however, the lifetime prevalence of neck pain is still estimated as high as 80%. This paper introduces a biofeedback system using a novel single accelerometer placement. This system allows the user to react and correct for movement into a position of bad posture. The addition of visual information provides artificial proprioceptive information on the cranial-vertebral angle. Six subjects were tested for 5 hours with and without biofeedback. All subjects had a significant decrease in the percentage of time spent in bad posture when using biofeedback.
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Affiliation(s)
- Paul P Breen
- The National Centre for Biomedical Engineering Science and Electrical & Electronic Engineering, National University of Ireland Galway, University Road, Galway, Ireland.
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Straker L, Burgess-Limerick R, Pollock C, Coleman J, Skoss R, Maslen B. Children's posture and muscle activity at different computer display heights and during paper information technology use. HUMAN FACTORS 2008; 50:49-61. [PMID: 18354971 DOI: 10.1518/001872008x250575] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVE The 3-D posture and muscle activity in the neck and upper limb were assessed in children using high-, mid-, and book-level displays, which correspond to working conditions frequently observed when children interact with computers or books and paper. BACKGROUND The 3-D posture and muscle activity of children reading and inputting data with computers and paper had not been previously assessed. METHODS Twenty-four children aged 10 to 12 years and of normal height performed an interactive task involving reading from a book and writing on paper or reading from a computer display and inputting data using a mouse and keyboard. RESULTS Head and neck flexion increased as the visual target was lowered. The high display resulted in mainly upper cervical relative extension, and the book display resulted in both upper and lower cervical flexion. The book condition resulted in greater cervical erector spinae and upper trapezius activity than did the mid and high conditions. CONCLUSION The data suggest that a mid-level display may be more appropriate for children than a high display (e.g., when the display is placed on top of the central processing unit). The mid display also results in a more upright and symmetrical posture and lower mean muscle activity than does working with books and paper flat on the desk. APPLICATION This study provides short-term laboratory study evidence for the formulation of guidelines for workstation design and adjustment for children. Use of computers by children is increasing, yet ergonomic guidelines lag behind those for adults.
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Affiliation(s)
- Leon Straker
- School of Physiotherapy, Curtin University of Technology, GPO Box U 1987, Perth, WA, 6845, Australia.
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Briggs A, Straker L, Greig A. Upper quadrant postural changes of school children in response to interaction with different information technologies. ERGONOMICS 2004; 47:790-819. [PMID: 15204289 DOI: 10.1080/00140130410001663569] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The objective of this study was to quantitatively analyse the sitting posture of school children interacting with both old (book) and new (laptop and desktop computers) information technologies to test the hypothesis that posture is effected by the type of information technology (IT) used. A mixed model design was used to test the effect of IT type (within subjects) and age and gender (between subjects). The sitting posture of 32 children aged 4-17 years was measured whilst they read from a book, laptop, and desktop computer at a standard school chair and desk. Video images were captured and then digitized to calculate mean angles for head tilt, neck flexion, trunk flexion, and gaze angle. Posture was found to be influenced by IT type (p < 0.001), age (p < 0.001) and gender (p = 0.024) and significantly correlated to the stature of the participants. Measurement of resting posture and the maximal range of motion of the upper and lower cervical spines in the sagittal plane was also undertaken. The biophysical impact and the suitability of the three different information technologies are discussed.
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Affiliation(s)
- Andrew Briggs
- School of Physiotherapy, Curtin University of Technology, Perth, Western Australia
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