This Small Business Innovation Research (SBIR) Phase I project seeks to demonstrate the technical and commercial viability of wireless instrumentation and smartphone technology used for feedback to amputees about their real-time performance for ubiquitous rehabilitation in situ. The goal is to improve the mobility and quality of life of persons with ambulatory disabilities (5.2% of U.S. adults ages 18-64). This research will provide a new paradigm for rehabilitation that occurs throughout the patient's daily life with reduced reliance on a therapist. The intellectual merit of the proposed research lies in the opportunity to profoundly transform the field of rehabilitation and to advance healthcare by enabling a fundamental shift toward low cost, ubiquitous rehabilitation that can be used away from the clinic. The technology seeks to provide feedback anytime and anywhere to enhance the proprioception - the sense of where limbs are in space- that has been impaired by disability. Active cueing (in contrast to current reactive cueing methods) will provide a more proprioceptive feedback that will better enable persons with amputations due to systemic complications (e.g. diabetes) to respond and make changes in their gait. <br/><br/>The broader impact/commercial potential of this project includes the focus on mobility limitations in persons with lower-limb amputations, which affect twice as many minorities as Caucasians. The commercial potential is vast: with diabetes as the major contributor to amputations, the number of amputees is forecast to triple to 3.6 million by 2050. In addition, the knowledge gained can be expanded to impact individuals with a wide variety of mobility limitations, e.g. stroke, Parkinson's disease, multiple sclerosis, cerebral palsy, etc. The orthopedic market- 773,000 total hip/knee replacements performed annually in U.S.- is also commercially relevant, as patients must effect an asymmetric gait following fracture repair or joint replacement to reduce weight-bearing on the healing limb. Another significant group are athletes seeking to improve performance or recover from injury through precision gait analysis and real-time feedback. In this Phase I proposal, this research will quantify the effect of this research by enabling persons with amputations due to diabetes to use individualized proprioceptive feedback and to participate in the design of the personalized feedback methods. This work will enable a wealth of information collected away from the clinic, including a way to investigate how and whether patients follow treatment protocols.