Training system using ground reaction force of the affected leg

Most patients with a paralyzed leg have difficulty in putting the body weight on the heel when they stand up, as well as diminished motor function of the affected part. This paper proposes a new training system for increasing the heel load of the affected leg in several postures. The developed system integrates Ground Reaction Force (GRF) sensors and a graphical monitor with a motion support device. The GRF sensors measure the load of the heel and toe on both legs and the users can recognize their motor information by looking at the monitor. The users can also hold their standing position and half-rising posture by using the motion support device. A basic experiment confirmed that the GRF sensors have measurement accuracy within 5 % error and measures the GRF of the toe and the heel part separately. We carried out a feasibility experiment in two patients to confirm that the users were able to conduct the training by using the system, and the users increased the GRF of the heel part. All the participants recognized their movement of the affected leg by looking at the monitor, and increased the GRF of the heel part when the visual motor information was provided. Moreover, the orthosis decreased the number of times that spasticity occurred and the results suggest that the training is feasible, and the system is effective in helping patients with the affected leg to conduct the training for increasing the GRF of the heel part.