The aim of this study was to characterize muscle property in patients with spinal cord injury (SCI). Ten SCI patients and ten age-matched normal subjects (Normal) participated to obtain ultrasound images of the calf muscles during slow passive ankle dorsiflexion (5deg/sec). Changes of the muscle fiber length (MFL), pennation angle (PA), displacement of deep aponeurosis (dAp), muscle thickness (MT), and displacement of muscle tendon junction (dMTJ) were quantified. Ankle angle and passive ankle torque were simultaneously recorded. The results showed that static PA and MT in SCI significantly decreased as compared to those in Normal. During passive ankle motion, MFL, PA and dAp showed different changes in response to ankle angle between SCI and Normal. These results suggest that substantial alteration of the muscle mechanical property would happen following spinal cord injury.
