Increasing exercise intensity during outside walking training with a wearable robot

For many neuromuscular conditions including spinal cord injury, physical exercise training is a recommended part of treatment. High intensity exercise has been found to more effectively promote ambulatory function than moderate intensity exercise. To reach optimal intensity levels, fully ambulatory individuals can adjust their walking speed. In contrast, individuals with neuromuscular deficits may not be able to walk, or only at slow speeds that elicit an insufficient cardiovascular response. In our case study with one spinal cord injured patient, we investigated if assistance from a wearable robot, the Myosuit, can increase exercise intensity towards more effective training. During outside uphill-walking trials, assistance from the Myosuit allowed the patient to increase his walking speed by 30 % to 0.48 m/s and increased energy expenditure by 17 % compared to not wearing the suit. An analysis of gait kinematics suggests that the Myosuit facilitated faster walking by replacing missing hip extensor function and promoting a more upright posture. The metabolic equivalents (METS) during walking with the Myosuit of 7.15 indicate a consistently high exercise intensity. In contrast, one of two unassisted trials only reached a moderate intensity (METS <; 6). The concurrent increase in speed and energy expenditure when wearing the Myosuit corresponds to a 9 % increase in the efficiency of walking. Our findings show that the Myosuit can increase the efficiency of walking for a user with incomplete spinal cord injury and suggest that the Myosuit can act as a tool to increase the efficacy of movement training.