Variable-ratio pushrim-activated power-assist wheelchair eases wheeling over a variety of terrains for elders

Abstract

Levy CE, Chow JW, Tillman MD, Hanson C, Donohue T, Mann WC. Variable-ratio pushrim-activated power-assist wheelchair eases wheeling over a variety of terrains for elders. Arch Phys Med Rehabil 2004;85:104-12. Objectives To test (1) whether a prototype variable-ratio pushrim-activated power-assist wheelchair would decrease effort and perceived exertion associated with wheeling and (2) whether the prototype would be acceptable to elders. Design Repeated-measures design. Setting Biomechanics laboratory. Participants Eleven elderly wheelers (mean age ± standard deviation, 70.7±7.8y). Interventions Wheelers propelled their own wheelchairs and the prototype on a level surface, a carpet, and an incline. Main outcome measures Surface electromyographic activity from upper limb and torso, heart rate, number of pushes, category-ratio scale of perceived exertion, and Consumer Assessment of Power Assist Wheelchairs. Results Compared with subjects’ own manual wheelchairs, the prototype was associated with lower heart rate elevation ( P<.0125), lower perceived exertion ( P<.0125), and reduced electromyographic activity in 5 of 8 muscles. Of the 11 participants, 10 found the prototype to be “very easy” or “easy” to push on level and inclined surfaces; 9 gave that assessment on carpeted and inclined surfaces. Seven would “definitely” or “probably” trade their manual chairs for the power-assist chair if given the opportunity. Nine thought they would venture to new and different places in a power-assist wheelchair. Time and number of pushes to complete tasks did not differ significantly between chairs. Conclusions The prototype reduced the effort associated with wheeling and was an acceptable alternative to manual wheelchairs. Further testing outside the laboratory is warranted.