Author: Li, Wai-shan Twinnie
Title: Effects of seat height on propulsion time and pressure distribution during one arm and one leg wheelchair maneuvering among stroke clients
Degree: M.Sc.
Year: 2004
Subject: Hong Kong Polytechnic University -- Dissertations
Cerebrovascular disease -- Patients -- Rehabilitation
Wheelchairs -- Physiological aspects
Department: Jockey Club Rehabilitation Engineering Centre
Pages: 71 leaves : ill. (some col.) ; 30 cm
Language: English
Abstract: A proper choice of wheelchair is important in enhancing the independence of mobility and providing a good sitting support for performing functional tasks. One arm and one leg maneuvering is a common method adopted by the client with stroke. Indeed, the phenomenon of sliding out and undesirable sitting posture are usually observed during and after such maneuvers, which will affect safety and the time required to propel a fixed distance. Although seat height has been suggested to affect leg propulsion performance, the choice of suitable seat height for wheelchair users in leg propulsion is not clear. In this study, the effects of seat height on propulsion time and sitting posture during one arm and one leg wheelchair maneuvering style were investigated. Thirteen subjects with stroke (11 male and 2 female, aged 56.5+-19.7 yrs, average body mass index 22.2+-3.2) were recruited from a local hospital. The subjects were asked to propel a lightweight wheelchair along a 10 m pathway as fast as possible. A modular drop seat was used to configure the different seat heights for evaluation. Propulsion time was measured as the time taken to complete the 10 m propulsion. Change in sitting posture was evaluated by analyzing the dynamic seat interface pressure distributions using a Pressure Mapping System (Tekscan, USA). Repeated measures ANOVA was used to compare the mean value of each parameter at different seat heights. The results showed that there was a significant effect of the seat height on the time required to complete the 10 m course (p=0.007). The seat height set at 95o knee flexion was found to have the minimal average propulsion time with the value of 13.4+-3.4 sec. For the sitting posture, there was a statistically significant difference in the peak pressure difference (P) between the ischial tuberosities (IT) of both sides among 4 different seat heights during the maneuvering task (p=0.029). The minimal average peak pressure difference over both ischial tuberosities (IT) was found at 85o knee flexion with the value of 6.7+- 8.6 kPa (50.7+-64.7 mmHg). This implied that a more even pressure distribution was observed in this condition during this propulsion style. It was also noted that the average peak pressure over the ischial tuberosity (IT) of the unaffected side was higher than the affected side throughout all the conditions. Although, there was no significant difference on the effect of seat heights on the peak pressure (PP) over the ischial tuberosity (IT) of the unaffected side (p=0.145), the peak pressure over IT of the unaffected sides was higher than that of the affected sides at all the seat heights. Significant difference was also found on the effect of seat height on the average peak pressure over the ischial tuberosity (IT) of the affected side (p=0.028). The lowest peak pressure over the IT of the affected side was found at 95o knee flexion with the value of 15+-8.3 kPa (112.3+-62.3 mmHg). In this study, the balance between propulsion time and a mid-line sitting posture have been identified as important consideration in enhancing the mobility level of stroke clients. However, further investigation is required to examine the kinetic and kinematics of the one arm and one leg propulsion style so that repetitive injury can be minimized. Such biomechanical analysis can also provide information to facilitate the wheelchair training in stroke clients so that they can perform propulsion in a more efficient way.
Rights: All rights reserved
Access: restricted access

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