Propelling load of an attendant propelled wheelchair in ascending and descending

Abstract

This study investigated propelling the attendant-propelled wheelchair on a level surface and up slopes, as well as pulling on the wheelchair while descending slopes, with varying resistive loads caused by the slopes and also by changing the weight of the system. The research questions in this study were: 1) How do attendants naturally adapt their walking speed and upper extremity posture when pushing/pulling an attendant-propelled wheelchair? 2) How did this vary with increased resistive loads? 3) What individual differences occurred between participants? When ascending, as the resistive loads increased the wheelchair speeds decreased. The Spearman's rank-order correlation for monotonicity showed was strong, negative correlation between horizontal pushing force and wheelchair speed, which was statistically significant. The maximum mechanical power used by the majority of participants when ascending was approximately 60W at the highest resistive load. The posture learning forward with pushing relatively lower from horizontal direction in ascending, kept joint moments in upper extremity low, up to 60N horizontal force. Over the 60N in horizontal force, the performed pushing force in horizontal direction still kept joint moments low. In descending, the wheelchair speed in most participants did not have clear monotonicity against the increase of the resistive load. Aligned the upper arm and forearm corresponding to the vector of pulling force reduced joint moment in shoulder and elbow. From these findings a model will be established, which can be used in future research to establish how hard different terrains are for wheelchair users and test improvements to the environment as well as the design of the wheelchair.

Keywords

• attendant propelled wheelchair
• ascending
• descending
• propelling force
• wheelchair speed
• mechanical power
• upper extremity
• posture
• joint moment