Abstract
The present study examined the influences of slope gradients and the direction of wheelchair travel on the user’s riding comfort and the helper’s physical strain during wheelchair attendant-controlled locomotion on a longitudinal slope. Fifteen pairs of young helpers and users and 17 pairs of elderly helpers and users participated in this study. The helper-subjects pushed the wheelchair during three operations : going up a slope, going down frontward and down backward at seven different slope gradients ranging from 1/25 to 1/6. During wheelchair locomotion, the speed and variations in wheelchair locomotion were monitored. After locomotion, the helpers and users subjectively evaluated their physical strain and riding comfort, respectively. On both uphill and downhill slopes, one eighth and 1/6 slope gradients were considered unsafe for elderly helpers because the helper’s subjective evaluation of “physical strain” markedly increased, and some elderly helpers could not control the wheelchair properly. In addition, steeper gradients of the slope increased the user’s subjective evaluations of “sense of insecurity” and “scary feeling” and decreased helpers “easiness of technique.” Variations in speed also increased especially when elderly helpers were managing locomotion. On steeper downhill gradients, going down the slope backward showed lower variation of the speed, compared with that going down frontward. These findings suggest that steeper gradients enhance the physical strain on the helper, especially elderly helpers, and promote the user’s riding discomfort, irrespective of whether the direction of movement is up- or downhill. On a downhill slope with a steep gradient, going down backward would be a useful technique to help steady the speed during wheelchair locomotion.
