Biomechanical comparison of a rigid and dynamic seating system for children with special needs

In wheelchair users who experience strong extensor spasms, high muscular forces exerted during the episode may lead to high contact forces between the child and the wheelchair. The forces may be physically powerful enough to cause pain and injury to the child, and can damage or break components of the wheelchair. Dynamic seating systems have been used in an attempt to reduce these contact forces. Such systems permit forward and backward movements as the occupant extends and retracts their body, consequently they are assumed to be beneficial to patients with strong extensor spasms. Questions about the magnitude and direction of the loads which these children can exert through a seating system have been raised. Additionally, the effectiveness of using dynamic components and the advantages of prolonged use remain unclear. The aim of this study was to quantify and compare the imparted forces on equivalent rigid and dynamic seating systems throughout activities of daily living. To achieve this, a mobile strain gauged seating system was developed which allowed the strain generated in the back and footrest components to be measured. At a certain instant of exerted force, the strain data was converted into force and moments acting on the backrest and footrests in three dimensions, assuming static equilibrium. The position of the resultant force on the backrest, termed the centre of pressure (COP), was also calculated. This project shows that the development of a fully mobile data acquisition system is achievable and practical. Results obtained from twelve children during their community based activity of daily living showed no significant differences in the mean and peak interface forces on the backrest between the rigid and dynamic systems. However, when using the dynamic backrest system, a significant decrease in force and bending moments were observed on the right footrest, the dominant side of most participants. Conversely, for the left footrest only the average bending moment about the transverse axis through the ankle showed a statistically significant decrease, with no significant difference demonstrated between the other variables for the two backrest systems. This work included a long-term case study using the dynamic backrest seating system. The data did not elicit any observable differences of changing in movement, probably due to the relative inactivity of the recruited volunteer. Further work and recruitment should focus on users who exhibit strong extensor spasms, as this work suggest that these are the population who may benefit the most from dynamic seating.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2014

Author dc:creator

• Samaneein, Katika

DOI

10.48730/vbad-1049

Identifier

T13626

OAI identifier oai:identifier

oai:strathclyde:0r967372b