Quantification of therapists' manual assistance on the leg during treadmill gait training with partial body-weight support after spinal cord injury.

We are studying the forces applied by therapists when assisting on the legs of patients with spinal cord injury (SCI) during body-weight supported treadmill training (BWSTT). This paper presents results from three experiments with three patients and six different therapists. We attached a sensorized orthosis to one of the legs of the patients and measured the forces exerted by the therapists when assisting on that leg through the orthosis. We also measured the kinematics of the shank. The hips and opposite leg were assisted by two other therapists as usual. We found a high repeatability across steps for the forces applied by each therapist. Better-skilled therapists elicited significantly better leg extension in stance phase by exerting significantly larger horizontal forces on the knee during stance. Better-skilled therapists also elicited better toe clearance during initial-to-mid swing, with fewer or no episodes of toe dragging. This better toe clearance was not generally correlated with larger therapist push-up forces at the ankle. We did find, however, that better toe clearance in swing was correlated with better extension of the same leg in stance, suggesting that a normative leg extension in stance contributed to better muscle activity of the same leg in swing. These results provide insight into therapist-assisted gait training, which may be useful for optimizing robotic gait-training devices.