Effects of the Height of Ball-Backrest on Head and Shoulder Posture and Trunk Muscle Activity in VDT Workers

Yoo, Won Gyu; Yi, Chung Hwi; Cho, Sang Hyun; Jeon, Hye Seon; Cynn, Heon Seock; Choi, Houng Sik

doi:10.2486/indhealth.46.289

Cited by 28 publications

(25 citation statements)

References 44 publications

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“…We also suggest that treatments for poor cervical posture should focus on recovering the normal ROM of neck flexion and extension. The significant correlations between the upper trapezius muscle activity and head-neck angles found in studies represent important evidence of a link between muscle activity and postural control 5,18,26) . We propose that the change in craniocervical angle would be related with shortening of the scalenus muscles in deep muscles, because shortening of scalenus muscles can cause limited range of motion in neck extension.…”

Section: Discussionmentioning

confidence: 88%

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The Relationship between the Active Cervical Range of Motion and Changes in Head and Neck Posture after Continuous VDT Work

Yoo

2009

Ind Health

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This study investigated the relationship between the active cervical range of motion (ROM) and changes in the head and neck posture after continuous visual display terminal (VDT) work. Twenty VDT workers were recruited from laboratories. The active cervical ROM of the participants was measured and videotaped to capture the craniocervical and cervicothoracic angles using a single video camera before and after VDT work. Pearson correlation coefficients were used to quantify the linear relationship between active cervical ROM measurements and the changes in the craniocervical and cervicothoracic angles after continuous VDT work. Active neck extension (r=-0.84, p<0.01) was negatively correlated with the mean craniocervical angle, and active neck flexion (r=-0.82, p<0.01) and left lateral flexion (r=-0.67, p<0.01) were negatively correlated with the mean cervicothoracic angle.

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Section: Discussionmentioning

confidence: 88%

“…The same configuration was maintained for the duration of the 1-h work period. The subjects performed selected VDT work in the Hansoft program of Korea 18) . Each 1-h period of VDT work was divided into three sections separated by 30 s of resting time.…”

Section: Methodsmentioning

confidence: 99%

The Relationship between the Active Cervical Range of Motion and Changes in Head and Neck Posture after Continuous VDT Work

Yoo

2009

Ind Health

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“…Another common potential confounder was that studies (e.g., Bridger, 1988;Cram & Vinitzky, 1995;Hardage et al, 1983;van der Heide et al, 2003;Wu et al, 1998;Yu et al, 1988) did not always state whether seats featured armrests or not. Finally, it appears the effect of a backrest is closely related to its location (Yoo et al, 2008), which may explain some of the variation between studies. Notwithstanding these confounding factors, the results demonstrate moderate evidence that chair backrests reduce paraspinal muscle activation, and limited evidence that chair backrests reduce LBD.…”

Section: Consideration Of Confounding Variablesmentioning

confidence: 99%

Does Using a Chair Backrest or Reducing Seated Hip Flexion Influence Trunk Muscle Activity and Discomfort? A Systematic Review

Curran¹,

O’Sullivan

et al. 2015

Hum Factors

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Objective: This paper systematically reviews the effect of chair backrests and reducing seated hip flexion on low back discomfort (LBD) and trunk muscle activation.Background: Prolonged sitting commonly exacerbates low back pain (LBP). Several modifications to seated posture and chair design have been recommended, including using chairs with backrests and chairs that reduce hip flexion.Method: Electronic databases were searched by two independent assessors. Part 1 of this review includes 26 studies comparing the effect of sitting with at least two different hip angles. In Part 2, seven studies that compared the effect of sitting with and without a backrest were eligible. Study quality was assessed using the PEDro scale.Results: Significant confounding variables and a relatively small number of randomized controlled trials (RCTs) involving people with LBP complicates analysis of the results. There was moderate evidence that chair backrests reduce paraspinal muscle activation, and limited evidence that chair backrests reduce LBD. There was no evidence that chairs involving less hip flexion reduce LBP or LBD, or consistently alter trunk muscle activation. However, participants in several studies subjectively preferred the modified chairs involving less hip flexion. Conclusion:The limited evidence to support the use of chairs involving less seated hip flexion, or the effect of a backrest, is consistent with the limited evidence that other isolated chair design features can reduce LBP.Application: LBP management is likely to require consideration of several factors in addition to sitting position. Larger RCTs involving people with LBP are required.

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“…In the present study, sitting posture alignment was recorded using a digital camera (PL150, Samsung, Seoul, Korea), and the ImageJ image analysis software (US National Institutes of Health, MD, USA) was used to measure the kinematic angle. The digital camera was placed with its lens 1 m from the lateral aspect of the subject's shoulder and with the camera perpendicular to the ground to reduce parallax error . To ensure the consistency of the measurements, one physical therapist (IWP), who has 10 years of experience as a physical therapist, analysed the kinematic data.…”

Section: Measurementsmentioning

confidence: 99%

Effects of sitting posture and bolus volume on activation of swallowing‐related muscles

Moon

Park

et al. 2020

J of Oral Rehabilitation

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Swallowing is a complex physiological movement that involves the oral cavity, pharynx, larynx and oesophagus. 1 The pharyngeal phase is a particularly important clinical factor related to swallowing dysfunctions, such as dysphagia and dysfunctions in elderly individuals. 2 During normal swallowing, precise muscular movements protect the airway from bolus aspiration by moving the hyolaryngeal complex anterior and superior. 3,4 Precise muscular movement is controlled by the supra-hyoid (SH) and infra-hyoid (IH) muscle groups, and these influence the pharyngeal phase. 2,5 Head and neck posture, as well as bolus volume, are important factors affecting the pharyngeal stages of normal swallowing. 6,7 It is well known that head, neck posture and the hyoid bone are closely related to speech, swallowing, breathing, clenching and chewing. 6,8 Previous studies have demonstrated that the hyoid bone position is significantly influenced by an altered head and Abstract Background: The pharyngeal phase is a particularly important clinical factor related to swallowing dysfunctions. Head and neck posture, as well as bolus volume, are important factors affecting the pharyngeal stages of normal swallowing.Objective: The aim of our study was to identify the effects of sitting posture and bolus volume on the activation of swallowing-related muscles. Materials and Methods:Twenty-four subjects participated in the study. The subjects were positioned in three sitting postures-slump sitting (SS), lumbo-pelvic upright sitting (LUS), and thoracic upright sitting (TUS). While sitting in the chair, the subject was instructed to swallow 10 and 20 mL of water. Surface electromyography (EMG) was used to measure the muscle activity of the supra-hyoid (SH) and infra-hyoid (IH) muscles. Also, sitting posture alignment (head, cervical and shoulder angle) was also performed. Data were analysed with a repeated measures analysis of variance (RMANOVA) using a generalised linear model. Results:There was no significant difference in terms of the head angle (P = .395).However, significant differences were found in relation to the cervical angle (P < .001) and shoulder angle (P < .001). The TUS produced the lowest SH EMG activity (P = .001), in comparison to SS and LUS. The bolus volume for 20 mL showed greater SH and IH EMG activity (P < .001) than did the bolus volume for 10 mL. Conclusions:Correcting sitting posture from SS to TUS may better assist swallowingrelated muscles with less effort, irrespective of the bolus volume. K E Y W O R D Sbolus volume, infra-hyoid, sitting posture, supra-hyoid, surface electromyography, swallowing

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Effects of the Height of Ball-Backrest on Head and Shoulder Posture and Trunk Muscle Activity in VDT Workers

Cited by 28 publications

References 44 publications

The Relationship between the Active Cervical Range of Motion and Changes in Head and Neck Posture after Continuous VDT Work

The Relationship between the Active Cervical Range of Motion and Changes in Head and Neck Posture after Continuous VDT Work

Does Using a Chair Backrest or Reducing Seated Hip Flexion Influence Trunk Muscle Activity and Discomfort? A Systematic Review

Effects of sitting posture and bolus volume on activation of swallowing‐related muscles

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