The use of an inertial dynamometer to explore the design of children's wheelchairs.

In an attempt to provide information for improvements in the design of wheelchairs for children a simulated wheelchair rig has been developed incorporating an original form of dynamometer to examine propulsion factors. 54 children who were experienced users of hand-propelled wheelchairs and 32 able-bodied controls were individually fitted with seats on this test rig and each performed a series of up to fifty subtests. The principal conclusions are that nearly all children who use wheelchairs, even those proficient users with apparently normal arms, are actually weaker than their able-bodied peers; that evidence for changes in wheelchair propulsion design based on the performance of able-bodied subjects or on isometric tests of strength are likely to be misleading; that an improvement of up to 30% in propulsion performance can be obtained by optimal positioning of conventional wheelrims relative to the user; and that this positioning is most crucial for the weaker children, particularly those with cerebral palsy.