Operant H-reflex Down-conditioning of Rectus Femoris in Post-stroke Stiff Knee Gait

Inclusion Criteria: * Premorbidly independent * Mild to moderate impairment determined by standard practices per the physical therapist * Ability to stand for 10-minute intervals unassisted * Ability to walk for 10-minutes on a treadmill * Reduced knee flexion during phase and SKG as determined by a clinician * Hemiparesis * Ability to provide informed consent Exclusion Criteria: * History of cerebellar stroke, multiple stroke * History of serious lower limb musculoskeletal injury * Functionally relevant osteoarthritis and weight-bearing restrictions * Have condition related to claustrophobia or other MRI contraindications * Functionally relevant cognitive impairment * Functionally relevant vision impairment * Took antispasmodic medication one day prior to the session * Had Botox injection one week prior to the session * Pregnant women