Tracking Neural Synergies After Stroke.

Healthy participants: Inclusion Criteria: * Age 18-85 years old * Ambulatory with or without an assistive device * Ability to stand unassisted for at least 15 min * Informed consent provided by participant * English speaking Exclusion Criteria: * Inability to communicate with researchers * Lower extremity joint pain, contractures * Major sensory deficits, or cardiovascular or respiratory symptoms contraindicative of walking * History or evidence of orthopedic, muscular, or physical disability * Taking current medications that may affect balance * History or evidence of vestibular, auditory, or proprioceptive impairment * History or indication of orthostatic hypotension * History of any neurological disease * Open wounds on surfaces in contact with HD-EMG electrodes * Concurrent participation in other lower limb research studies that according to the PI is likely to affect study outcome or confound results * Pregnancy Patients: Inclusion Criteria: * Age 18-85 years old * Unilateral, supratentorial ischemic or hemorrhagic stroke within the past six months * Medical clearance from primary medical team (signed Medical Clearance form) * Unassisted sitting balance at edge of mat or hospital bed ≥ 30 seconds * Baseline Visible muscle contraction in hip flexors, knee extensors, and ankle dorsiflexors ( ≥1 MMT) or manual resistance against one muscle group (\>3 MMT) * Adequate cognitive function as determined by the NIH scale: score ≤1 on question 1b and score =0 on question 1c…