Biomechanical and electromyographic assessment of spastic hypertonus in motor complete traumatic spinal cord-injured individuals

Study design: Between-groups design with repeated measures. Objective: To quantify spastic hypertonia in spinal cord-injured (SCI) individuals. Setting: Rehabilitative Center, Italy. Subjects: 29 individuals with a motor complete SCI (American Spinal Injury Association impairment scale grade A or B) and 22 controls. Methods: According to the modified Ashworth scale (MAS), patients were subgrouped as SCI-1 (MAS=1, 1+) and SCI-2 (MAS=2, 3). Passive flexo-extensions of the knee were applied using an isokinetic device (LIDO Active) at 30°, 60°, 90° and 120° s −1 . We measured the peak torque, mean torque (MT) and work. Simultaneous electromyography (EMG) was recorded from leg muscles. Results: At the speed of 120° s −1 all SCI-2 patients presented EMG reflex activities in the hamstring muscle. All biomechanical parameter values increased significantly according to speed, but analysis of variance revealed a significant interaction between the angular velocity and group (F(d.f. 6, 138)=8.89, P