Análise eletromiográfica da fase inicial da autopropulsão de cadeira de rodas manual

Abstract

Propelling wheelchair (CR) is related to high incidences of pain and injury in wheelchair users (WCU). Although this locomotion way be known as low efficient locomotion mode, it represents fundamental importance for these people performance in daily living activities, occupational, leisure and in their social participation. Over the studies course on propulsion in recent decades, it has recently been noted, particularly, that the initial stage of wheelchair propulsion which retires the user-wheelchair system from resting, putting it into motion, presents greater mechanical stresses. It considering this situation is executed several times during the typical wheelchair usage, it makes this relevant study object. As until current moment, there are few studies about initial stage of wheelchair propulsion and, from the neuroactivation point of view, this movement was not approached, this study aims to describe the gesture of initial stage of manual wheelchair propulsion from WCU, across electromyography, presenting the muscular activation levels achieved and the recruited behavior profile during the propulsion gesture execution. For this problem, eight muscle groups involved in this gesture were evaluated from eleven WCU. Electromyographic signals were collected from these eight muscle groups, simultaneously, during ten propulsions execution, starting from resting, of each WCU participant of the research. Regarding the muscular activation levels, an alternative normalization method was introduced. This method consists in performing the maximum isometric contraction test on the wheelchair itself. The results were showed in boxplot in order to demonstrate the activation peak as well as the remaining activation levels distribution. As the new method proposed showed limitations, a better results interpretation was not possible on calculated intensities. Regarding the muscular activation profile during the propulsion execution, the results were exposed in graphs normalized by the dynamic peak as well as in relation to a single propulsion cycle, evidencing the activated behavior at each cycle moment. According to the results based on second methodology, among the eight muscle groups examined, the ones which presented the highest activation peaks values were: the anterior deltoid (80.27%), the pectoralis major (79.27%), the wrist flexors (78, 93%) and the wrist extensors (80.65%). The findings agree with previous studies by other authors that the main effector muscle groups in CR propulsion are anterior deltoid (DA) and pectoralis major (PM).