Objective. To investigate wrist kinematic characterization at various wheelchair seat positions.
Design. A comparative study using a repetitive measures design.
Background. People who use wheelchairs often sit on pressure-relief cushions, increasing the
seat height. Wrist kinematic properties during manual propulsion could be altered.
Wrist kinematics from a clinical perspective has not been previously investigated.
This study characterizes wrist kinematic performance of subjects during manual wheelchair
propulsion at various seat positions.
Methods. Subjects for this investigation were 11 people with disabilities who use wheelchairs.
Combinations of horizontal positions of the rear wheel and vertical seat height were
evaluated. Consecutive EMG, wrist joint angle, and trigger signals were collected.
Results. Altered seat height resulted in significant changes to temporal phases and wrist
kinematic parameters; however, altered horizontal seat position did not cause significant
variations. For all seat positions investigated, wrist extensor and flexor EMG signals
maintained a similar level of contraction.
Conclusion. During wheelchair propulsion, seat height was found to be a critical factor affecting
the temporal parameters of movement and wrist kinematic properties of the subjects.
Wrist joint angles and wrist flexion–extension range of motion all varied according
to seat height. Observations and statistical analysis of the results provided useful
information; however, an ideal seat position was not indicated.Relevance
Study results have enhanced our understanding of wheelchair design, and should aid
in development of future designs. In addition, the results may provide a strategy
for dealing with the onset of arm/wrist pain and the prevention of carpal tunnel syndrome
and other soft tissue injuries in people who use wheelchairs.