Effects of ramp slope, ramp height and users' pushing force on performance, muscular activity and subjective ratings during wheelchair driving on a ramp

We set and examined two hypotheses about effects of ramp slope (1:6, 1:8, 1:10, 1:12, and 1:14) by varying ramp height (0.15 m, 0.30 m, and 0.45 m) and pushing force of wheelchair users (weak, medium, and strong group). Thirty participants were recruited for the experiment, and they have ascended a ramp using a manual wheelchair. Three categories of dependent variables were measured: performance measures (total time and velocity), muscular activity measures (EMG of four upper extremity muscles) and subjective rating measures (physical discomfort and acceptability). Only the strong group used muscles constantly regardless of the ramp slope. Accessibility of the ramp decreased as the slope increased, and accessibility difference between slopes increased as the height increased. Based on the result, we suggest maximum allowable slope by ramp height: 1:8, 1:10 and 1:12 were recommended for the heights of 0.15 m, 0.30 m, and 0.45 m, respectively. This study can provide enhanced understanding concerning effects of ramp slope, ramp height and users' pushing force on accessibility of a ramp. Based on this understanding we suggested ramp slope guidelines by ramp heights. It is possible to design ramp more accessible and safe using this guidelines. •We examined ramp slope effects by ramp height and pushing force of wheelchair users.•We found maximum ramp slope to become steeper as ramp height decreased.•Only strong group used muscle constantly regardless of ramp slope.•We suggest 1:8, 1:10 and 1:12 as maximum slope for 0.15 m, 0.30 m and 0.45 m height.