| Summary: | 碩士 === 國立成功大學 === 醫學工程研究所 === 87 === Till now, we don’t have sufficient information about the number of wheelchair users in Taiwan. It is believed that the wheelchair plays a key role for the disabled daily mobility. Hand/wrist problems, shoulder pain and other upper extremity injuries are well-known health problems among these manual wheelchair propulsion activities. Literatures demonstrate that the high incidence of upper extremity musculoskeletal problems may be due to overuse or incorrect use of manual wheelchair. To reduce even prevent the injuries, it is necessary to understand the wheelchair propulsion activity. In this study, we analyze three-dimensional kinematics and kinetics to facilitate the understanding of how net joint resultant loads may predispose wheelchair users to musculoskeletal problems at the shoulder, elbow, and wrist. Especially, the effect of hand-rim diameter was investigated from biomechanical point of view. The data collected were expressed in terms of a wheelchair propulsion strength rating (WPSR). The WPSR is being defined as the ratio between an intersegmental joint moment generated during propulsion and that generated during an isometric maximum strength test.
Twelve normal subjects (age 23.51.88 yrs, weight 66.38.09 kg) without any history of upper extremity injury participated in this study. A six-camera Expert Vision™ motion analysis system was used to collect the three-dimensional trajectories data of the markers placed on the right upper limb. A standard type manual wheelchair with an instrumented wheel consists of a six-component load cell was used to collect the forces and moments applied on the hand-rim by users. The joint isolated maximum isometric voluntary moments of upper extremity were collected by the Kin-Com dynamometer. To evaluate the effect of hand-rim diameter, each subject performed at least three tests for three different diameter of hand-rims. Their diameters are 32, 43, 54 cm, respectively. To compare the performance parameters in propelling the three different hand-rim sizes, a one-factor analysis of variance was used.
The results of this study indicated that the hand-rim diameter affected the performance in wheelchair propulsion including kinematic and kinetic parameters. The movement patterns of wheelchair propulsion were similar in three conditions. The motion pattern of individual subjects was highly consistent, similar, and repeatable during wheelchair propulsion. The subjects perform greater range of motion during pushing larger hand-rim. The large diameter hand-rim was more advantageous in mechanical efficiency in consideration of propulsive force and fraction effective force. It required, however, greater joint moments, joint power and joint WPSR of upper extremity.
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