Affiliations: [a] Department of Physical Medicine and Rehabilitation, NeuRRo Lab, Michigan Medicine, Ann Arbor, MI, USA
| [b] Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
Correspondence:
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Corresponding author: Chandramouli Krishnan, Director, Department of Physical Medicine and Rehabilitation, Neuromuscular and Rehabilitation Robotics Laboratory (NeuRRo Lab), University of Michigan, 325 E Eisenhower Parkway (Suite 3013), Ann Arbor, MI - 48108, USA. Tel.: +1 319 321 0117; Fax: +1 734 615 1770; E-mail: mouli@umich.edu.
Abstract: Background:Robotic-resisted treadmill walking is a form of task-specific training that has been used to improve gait function in individuals with neurological injury, such as stroke, spinal cord injury, or cerebral palsy. Traditionally, these devices use active elements (e.g., motors or actuators) to provide resistance during walking, making them bulky, expensive, and less suitable for overground or in-home rehabilitation. We recently developed a low-cost, wearable robotic brace that generates resistive torques across the knee joint using a simple magnetic brake. However, the possible effects of training with this device on gait function in a clinical population are currently unknown. Objective:The purpose of this study was to test the acute effects of resisted walking with this device on kinematics, muscle activation patterns, and gait velocity in chronic stroke survivors. Methods:Six stroke survivors wore the resistive brace and walked on a treadmill for 20 minutes (4×5 minutes) at their self-selected walking speed while simultaneously performing a foot trajectory-tracking task to minimize stiff-knee gait. Electromyography, sagittal plane gait kinematics, and overground gait velocity were collected to evaluate the acute effects of the device on gait function. Results:Robotic-resisted treadmill training resulted in a significant increase in quadriceps and hamstring EMG activity during walking. Significant aftereffects (i.e., improved joint excursions) were also observed on the hip and knee kinematics, which persisted for several steps after training. More importantly, training resulted in significant improvements in overground gait velocity. These results were consistent in all the subjects tested. Conclusion:This study provides preliminary evidence indicating that robotic-resisted treadmill walking using our knee brace can result in meaningful biomechanical aftereffects that translate to overground walking.
