Fig. 1

Study design flowchart. Following a telephone screening, participants undergo the consenting process and in-person screening to confirm their eligibility. Enrolled participants undergo a baseline assessment and have their physical activity monitored for one week before beginning locomotor training. Participants are stratified based on their baseline overground preferred walking speed and use of assistive devices and then randomly assigned to either the experimental or control group. Both groups undergo high intensity treadmill-based locomotor training for a total of 20 sessions. The experimental group completes locomotor training within the movement amplification environment created by the Agility Trainer. Mid-training (after training session ten), post-training (after training session 20) and follow-up (three months after training session 20) assessments are performed by a licensed physical therapist blinded to group allocation. Physical activity monitoring is performed for one week immediately after the 20th training session and 3-months following the 20th training session