Reducing the upper body effort during FES-assisted arm-supported standing up in paraplegic patients

In this work, the effects of the artificial ankle joint stiffness on the performance of sit-to-stand movement and upper body effort have been assessed during FES-assisted arm-supported standing up in paraplegic patients. An ankle-foot orthosis (AFO) was developed with the plantar-assisting spring. By changing the spring, the rigidity of the AFO could be adjusted. Experimental results on two complete paraplegic subjects indicated that by suitable selection of the stiffness in the plantar flexion direction, the paraplegic patient could stand up comfortably with less upper body effort. The results showed that the peak arm force was reduced from 67.2% to 44.3% of the body weight in subject RR and from 77.7% to 47.9% in subject MS.