高低节段脊髓损伤截瘫患者轮椅推进的生物力学特征

o determine the effects of injury level on shoulder joint weight bearing during wheelchair pro-pulsion biomechanical characteristics so as to provide theoretical basis for explaining the biomechanicalmechanism behind chronic shoulder pain in individuals with spinal cord injury. Sixteen subjects with paraplegia ( high level group with eight subjects and low level group with eight subjects) and eight able-bodiedadults were recnuited to simulate wheelchair propulsion activities. The pushrim forces , joint kinematics andsurface EMG data were collected synchronously during the test for biomechanical analysis of the main fac-tors inducing the chronic shoulder pain. The results showed that the push phase was about the first 60% ofthe complete cycle.There was no significant difference in upper limb kinematics between the groups.'Thepushrim forces showed significantly lower peak values in high level paraplegia group than in low level par-aplegia group ( P <0.05) , while the average surface electromyography ( sEMG) amplitudes of all fourmuscles were found significantly the highest in high level paraplegia group (P<0.05).The results alsoshowed that there was no difference in propulsion habits between individuals with high or low injury levelparaplegia.The pushrim forces in high level paraplegia group was only about 70% of that in low level par-aplegia group , while the muscle activation in high level paraplegia group was 1.4-1.7 times that in lowlevel paraplegia group , suggesting that the efficiency of muscle work in high level group was lower than thatin low level group. 'The prevalence of shoulder pain was higher in individuals with high level paraplegiathan that in individuals with low level paraplegia. Since the pushrim forces was lower in high level group,the muscle fatigue may be the main factor leading to chronic shoulder pain and causing the difference inthe incidence.