Project Summary Walking enables independence and exploration in daily life. For people with cerebral palsy (CP), a brain injury near the time of birth alters their ability to move and participate in daily activities. Treatments seek to improve walking function, but the processes by which people with CP adapt and learn new movement patterns are poorly understood. Our prior research demonstrated that patient-specific measures of motor control (i.e., how an individual recruits and coordinates their muscles) are important indicators of walking function and treatment outcomes. Children with more impaired motor control compared to nondisabled peers have worse function and worse outcomes after treatments like orthopedic surgery or selective dorsal rhizotomy. The premise of our proposed research is that patient-specific measures of adaptation are equally important to understand and inform care, but we lack methods to quantify adaptation or effectively induce motor learning. Whether adaptation is altered in CP and whether targeted training can amplify adaptation to improve walking function remains unknown. Multimodal feedback training is a promising approach to support adaptation and motor learning, but few studies have evaluated adaptation with real-time feedback training during walking or its impacts on walking function. The proposed research seeks to fill these gaps by completing the systematic experimental analyses necessary to quantify walking adaption rates (Aim-1) and determine whether repeated exposure to multimodal feedback training can alter adaptation rates (Aim-2) to induce motor learning and improve walking function (Aim-3). Specifically, we examine adaptation rates in response to multimodal feedback training that targets plantarflexor function, a key muscle group for walking that is nearly universally impaired in CP. We provide multimodal feedback using (1) sensorimotor feedback from adaptive ankle resistance delivered via a light-weight, wearable robot and (2) audiovisual feedback of plantar flexor activity from EMG recordings. By evaluating responses of children with CP to this feedback training – both individually and combined – this research will establish the scientific basis to quantify and understand adaptation and motor learning in CP.