A physical therapist is treating a patient with T10 AIS C SCI on a body weight-supported treadmill. The patient shows significant lower-extremity clonus during stepping at 0.5 mph. Based on locomotor training evidence, which modification would MOST likely reduce the clonus?

A physical therapist is treating a patient with T10 AIS C SCI on a body weight-supported treadmill. The patient shows significant lower-extremity clonus during stepping at 0.5 mph. Based on locomotor training evidence, which modification would MOST likely reduce the clonus?

• A. Decrease the treadmill speed to 0.2 mph
• B. Increase the amount of body weight support to 80%
• C. Have the patient hold onto the parallel bars for stabilization
• D. Increase the treadmill speed toward a more normal walking pace

Answer: (D)

Locomotor training works by engaging the brain–spinal circuits that control stepping and by promoting rhythmic, coordinated muscle activation. Clonus is a hyperactive stretch reflex that tends to be more pronounced when stepping is very slow and the nervous system isn’t being driven to produce normal, alternating flexion and extension patterns. Pushing the treadmill toward a more normal walking speed increases the neuromuscular demand in a purposeful, repetitive way, which helps recruit the locomotor networks more effectively and enhances reciprocal inhibition between opposing muscles. This faster, task-specific practice tends to desensitize the stretch reflexes and reduce clonus during stepping. Lowering speed further keeps the system in a slower, less dynamic pattern, which can sustain exaggerated reflex activity. Increasing body weight support too much reduces loading and proprioceptive input necessary for training, and holding onto bars limits active trunk and leg control, diminishing the neuromodulatory effects of the therapy. So, moving toward a more normal walking speed aligns with the evidence that higher, functional speeds during training promote better motor control and reduce clonus.

Locomotor training works by engaging the brain–spinal circuits that control stepping and by promoting rhythmic, coordinated muscle activation. Clonus is a hyperactive stretch reflex that tends to be more pronounced when stepping is very slow and the nervous system isn’t being driven to produce normal, alternating flexion and extension patterns. Pushing the treadmill toward a more normal walking speed increases the neuromuscular demand in a purposeful, repetitive way, which helps recruit the locomotor networks more effectively and enhances reciprocal inhibition between opposing muscles. This faster, task-specific practice tends to desensitize the stretch reflexes and reduce clonus during stepping.

Lowering speed further keeps the system in a slower, less dynamic pattern, which can sustain exaggerated reflex activity. Increasing body weight support too much reduces loading and proprioceptive input necessary for training, and holding onto bars limits active trunk and leg control, diminishing the neuromodulatory effects of the therapy. So, moving toward a more normal walking speed aligns with the evidence that higher, functional speeds during training promote better motor control and reduce clonus.