When we walk, our bodies take each step slightly differently. This variability is how the brain explores movements so we can adapt to changing environments (e.g. bump in the sidewalk) or new challenges (e.g. painful motion). Pain from injuries or disease can lower this natural exploration because our brain avoids painful movements, ultimately limiting our ability to adapt. My study aims to understand how pain affects this variability-adaptation process in walking. In these studies, we will use electrical stimulation to create artificial knee pain, since naturally occurring pain fluctuates and is difficult to control. By synchronizing the painful stimulation with walking motions, we can precisely control the timing and severity of pain so we can measure the variability-adaptation process in real-time. First, we will test how knee pain changes movement variability. Then, we will measure how adaptation is affected by lower variability created by the pain. To conduct these projects, we will develop new wearable technology that combines electrical stimulation and motion tracking devices to perform this work in places outside the lab. The results will inform how movement variability can affect rehabilitation of painful conditions.