Following injury to the spinal cord, the spinal circuit undergoes a series of adaptations. In parallel with the spinal circuit adaptation, the muscular properties also adapt. In human and animal studies, histochemical and physiological evidences showed that the paralyzed muscle transferred from slow, fatigue-resistant to fast, fatigable after injury.

Reversal of neuromuscular property for persons with SCI needs to be resolved. Studies using high load electrical stimulations showed a reverse change of muscular properties, such as hypertrophy and reversal of fiber type transformations but failed to show a reversal of spinal circuitry function. Previous studies found that fast continuous passive motion (CPM) altered the H reflex excitability in human. Animal studies found that passive cycling and passive stretching delayed atrophy and influenced the transition of type I and IIa MHC. Theses findings lead to a hypothesis that mechanical stimulation might be able to reverse both spinal circuitry and muscular properties after SCI but it has not been confirmed in human study.

The purpose of this project is to investigate the effect of mechanical stimulation by fast CPM on the reversing adaptation of human paralyzed muscle after SCI.

Stage 1 subjects: Spinal cord injury subject

Inclusion Criteria:

• Clinical diagnosis of spinal cord injury < 2 years

Stage 2 subjects: Incomplete spinal cord injury subject

Inclusion Criteria:

• Clinical diagnosis of incomplete spinal cord injury
• ASIA classification:B, C, or D

Stage 3 subjects: Spinal cord injury subjects with high muscle tone

Inclusion Criteria:

• Clinical diagnosis of spinal cord injury.
• ASIA classification: A, B, C, or D