The study examined the application of outcome measures to determine changes in function of unilateral transtibial amputees (TTAs) caused by specialized functional prosthetic training (training) and the use of four different prosthetic feet. Two self-report measures i.e. the Prosthetic Evaluation Questionnaire (PEQ-13) and Locomotor Capability Index (LCI-5), and three performance-based measures i.e. the Amputee Mobility Predictor (AMPPRO), Six-minute Walk Test (6MWT), and Step Activity Monitor (SAM) were utilized. Healthy unilateral Transtibial Amputees between the age of 40-65 will participate in the study. Subjects were tested at baseline, after receiving training with their existing prosthesis, and with the study socket and four prosthetic feet i.e. SACH, SAFE, Talux and PROPRIO FOOT over an 8-10 week period. Training was administered between testing sessions.