The influence of the distance between the backrest of a chair and the position of the pelvis on the maximum pressure on the ischium and estimated shear force

Kobara, Kazukuni; Eguchi, Atsuko; Watanabe, Susumu; Shinkoda, Koichi

doi:10.1080/17483100802145332

Cited by 14 publications

(11 citation statements)

References 8 publications

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“…CES activity was higher in the N-WC than in the S-WC. Previous studies have reported that neck muscle activity is lower in a neutral posture than in FHP [14,24] and that cervical muscle activity at rest is greater in elderly individuals than in young people [14,18,30]. Elderly individuals tend to have more FHP than younger individuals, and CES activity at rest may also be higher in the elderly.…”

Section: Discussionmentioning

confidence: 94%

The effect of a newly developed wheelchair with thoracic and pelvic support on cervical movement and muscle activity in healthy elderly women

Sawada

Hatta

Kishigami

et al. 2015

European Geriatric Medicine

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Background: As the population ages, the number of elderly individuals using a wheelchair is increasing. A standard wheelchair with a vertical backrest (S-WC) pushes on a kyphotic spine and exacerbates forward head posture. Forward head posture limits cervical movement. We used a new wheelchair (N-WC) that does not exacerbate thoracic kyphosis. The N-WC does not have a flat backrest, but has a support belt for the thorax and pelvis. The purpose of this study was to compare head-neck angle, cervical range of motion, and cervical muscle activity in the N-WC and the S-WC in healthy elderly women. Methods: We measured head-neck alignment, trunk tilt angle, cervical muscle activity, and pressure distribution on the backrest. Data from 17 subjects were analyzed. Results: Head-neck angle was close to neutral in the N-WC. The trunk was tilted further back and the area over which pressure was distributed on the backrest was expanded in the N-WC. Cervical range of motion and cervical muscle activity during neck extension were significantly greater in the N-WC than in the S-WC, but during neck flexion, there was no significant difference between the wheelchairs. Conclusion: In the N-WC, head-neck alignment was close to the neutral posture because the wheelchair support belt accommodated kyphosis and did not push the spine forward, so cervical muscle activity may be reduced when at rest. These results suggest that the N-WC prevented forward head posture and improved cervical movement and muscle activity. (C) 2014 Elsevier Masson SAS and European Union Geriatric Medicine Society. All rights reserved

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Section: Discussionmentioning

confidence: 94%

The effect of a newly developed wheelchair with thoracic and pelvic support on cervical movement and muscle activity in healthy elderly women

Sawada

Hatta

Kishigami

et al. 2015

European Geriatric Medicine

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“…Similar to Kobara et al [20], Van Gefen et al [40, 41] found that posterior pelvic tilt had a minimal effect on ischial pressures when investigating an experimental simulator chair that could independently control the orientation of the trunk, pelvis, and thighs with 18 healthy male subjects. It is possible that the exclusion of trunk movements limited the degree of posterior pelvic tilt, causing the ischial tuberosities to roll within their original area of high pressure and therefore minimally affecting overall pressure measurements.…”

Section: Seat Adjustments To Induce Postural Movementsmentioning

confidence: 58%

“…Conversely, posterior pelvic tilt was found to have no significant effect on maximum pressure for 10 healthy male participants [20] and actually statistically increased the estimated shear force on the seat ( P < 0.01). Shear force is the distortion of a body by two oppositely directed parallel forces; hence, such forces can damage skin and are known to contribute to pressure ulceration [44].…”

Section: Seat Adjustments To Induce Postural Movementsmentioning

confidence: 99%

“…Kobara et al [20] measured pressure distribution while each subject sat in the same chair, at various distances from the backrest and leant back, thus simulating a posterior pelvic tilt. The results showed that the locations of the points of maximum pressure were significantly displaced forward in all positions, upright ( P = 0.005); sitting 5 cms from the backrest ( P = 0.008); sitting 10 cm from the backrest ( P = 0.285).…”

Section: Seat Adjustments To Induce Postural Movementsmentioning

confidence: 99%

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Reviewing the Literature on the Effectiveness of Pressure Relieving Movements

Schofield

Porter-Armstrong

Stinson

2013

Nursing Research and Practice

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Sitting for prolonged periods of time increases seating interface pressures, which is known to increase the risk of developing pressure ulcers. Those at risk of developing pressure ulcers are advised to perform pressure relieving movements such as “pushups” or “forward leans” in order to reduce the duration and magnitude of pressure acting on the vulnerable ischial tuberosity region. The aim of this review was to synthesize and critique the existing literature investigating the effectiveness of pressure relieving movements on seating interface pressures. The twenty-seven articles included in this paper highlight the need for further research investigating the effect of recommended pressure relieving movements on the pressures around the ischial tuberosities. Furthermore, this review found that the majority of individuals at risk of developing pressure ulcers do not adhere with the pressure relieving frequency or magnitude of movements currently recommended, indicating a need for pressure ulcer prevention to be explored further.

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“…These coefficients of friction were calculated based on the maximum static friction force measured using a pull tension gauge and a weight. To reduce the effects of differences in the positions of the lower extremities, the horizontal thigh angle was adjusted by elevating the feet with wooden boards stacked under the experimental chair22 ) , and the foot position was adjusted so that the lower legs were perpendicular to the feet23 ) . Furthermore, to reduce the resistance of the lower extremities, a roller board was placed under the subjects’ feet.…”

Section: Methodsmentioning

confidence: 99%

Effect of Rotational Axis Position of Wheelchair Back Support on Shear Force when Reclining

et al. 2014

Self Cite

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[Purpose] The purpose of this study was to investigate the influence of the rotational axis position of a reclining wheelchair’s back support on fluctuations in the shear force applied to the buttocks while the back support is reclined. [Subjects] The subjects were 12 healthy adult men. [Methods] The shear force applied to the buttocks was measured using a force plate. This study used two different experimental conditions. The rotational axis of the back support was positioned at the joint between the seat and the back support for the rear-axis condition, and was moved 13 cm forward for the front-axis condition. [Results] With the back support fully reclined, the shear forces were 11.2 ± 0.8%BW and 14.1 ± 2.5%BW under the rear-axis and front-axis conditions, respectively. When returned to an upright position, the shear forces were 17.1 ± 3.1%BW and 13.8 ± 1.7%BW under the rear-axis and front-axis conditions, respectively. Significant differences appeared between the two experimental conditions (p < 0.01). [Conclusion] These results suggest that the shear force value could be changed by altering the position of the back support’s rotational axis during reclining.

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The influence of the distance between the backrest of a chair and the position of the pelvis on the maximum pressure on the ischium and estimated shear force

Cited by 14 publications

References 8 publications

The effect of a newly developed wheelchair with thoracic and pelvic support on cervical movement and muscle activity in healthy elderly women

The effect of a newly developed wheelchair with thoracic and pelvic support on cervical movement and muscle activity in healthy elderly women

Reviewing the Literature on the Effectiveness of Pressure Relieving Movements

Effect of Rotational Axis Position of Wheelchair Back Support on Shear Force when Reclining

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