Effect of the use of electric assistance on the propulsion of the manual wheelchair Smartdrive on the biomechanical parameters of the propulsion in ecological situation

Objective Several studies have quantified the benefit of using Pushrim-Activated Power-Assisted Wheelchairs (PAPAW) to facilitate the daily travel of manual wheelchairs users (MW). Recently, new technological solutions have been proposed. They do not aim to replace the rear wheels MW, but to add a fifth motorized wheel. SmartDrive system is assisted propulsion is activated when the user performs a first push. This study aims to evaluate the effect of using the SmartDrive on the biomechanical parameters of MW propulsion cycle while traveling on asphalt road. Material/Patients and methods Twenty-two spinal cord injury were recruited and all subjects used their personal MW added the Smartdrive system. The push rim kinetic, during the propulsion, data were collected by an instrumented wheel was used to collect kinetic data. All subjects underwent two 6-minute outdoor displacement sessions (goings and comings, 150 m mixed smooth asphalt, consisting of a flat and 3% slope): with and without SmartDrive. The analyzed variables were: distance and speed over the total duration of the test. Concerning the kinetic parameters, the following parameters were quantified over the first 150 meters: power, number of cycle, total force, and tangential force. Results The main results show significant changes for all the parameters analyzed. Using the SmartDrive increases the distance traveled during the 6-minute test. Indeed with SmartDrive the subjects travel 538 ± 104 m and without SD 470 ± 124 m. In addition, there is a decrease in the biomechanical parameters during the displacement of the MW with SmartDrive: Tangential force, total force, as well as the external mechanical power. Discussion/Conclusion This work aims to evaluate the usefulness of PAPAW in a situation similar to an urban displacement. Our results suggest that the autonomy movement is increased with SmardDrive system since the subjects performed a greater distance in the same time while reducing the effort.