Stroke Training to Advance Balance During Locomotor Experiences (STABLE) Trial

The goal of this clinical trial is to learn if a treadmill gait training performed with a new robotic device will improve walking balance and everyday participation in walking activities for adults who have had a stroke. The main questions it aims to answer are: 1. Does treadmill gait training performed with a new robotic device that challenges their walking balance improve a person's balance and steadiness while walking? 2. Does treadmill gait training performed with a new robotic device help people with stroke walk better and take more steps in their daily lives? We will compare the new robotic training (which uses a cable device to gently pull the participant side-to-side to challenge their balance) to standard high-intensity treadmill training (where no extra pulling forces are applied) to see if combination of high intensity treadmill training in a balance challenging environment works better for stroke recovery specifically for walking balance. Participants will: * Complete 20 sessions of high-intensity walking training on a treadmill * Undergo special walking and balance tests at the Human Agility laboratory 4 different times: before the training, halfway through the training (after 10 sessions), at the end of the training (after 20 sessions), and 3 months after training is completed. * Have their daily walking activity (steps per day) tracked to measure improvements at home and in the community.

Inclusion Criteria: 1. 18 to 80 years of age; 2. diagnosis of hemiparetic stroke; 3. more than 6 months post-stroke; 4. ability to ambulate over ground for 10 meters with no physical assistance, use of unilateral assistive devices, such as a single cane, and use of braces that do not cross the knee joint, such as an ankle-foot orthosis, are permitted; 5. passive range of motion of the legs within functional limits and not restricting the ability to engage in locomotor training and 6. medically stable with medical clearance from physician to participate. Exclusion Criteria: 1. cognitive impairment (score ≤22/30 on the Montreal Cognitive Assessment scale); 2. aphasia (score ≥71/100 on the Mississippi Aphasia Screening Test); 3. excessive spasticity in lower limbs (score \>3 on the Modified Ashworth Scale); 4. unable to tolerate 10-min. of standing; 5. enrollment in concurrent physical therapy; 6. use of orthotics crossing the knee joint; 7. known pregnancy; and 8. severe cardiovascular, musculoskeletal or other neurological conditions affecting gait and balance.