With support from the National Science Foundation’s Human-Centered Computing Program (HCC), Stanford University mechanical engineer Mark Cutkosky and his team are using volunteer test subjects to find out if the way walk is wearing out their knees. One of the major problems at the root of knee pain is uneven wear and tear on the knee cartilage, which leads to arthritis. Cutkosky’s research, known as Movement Retraining, focuses on alleviating pain by analyzing and possibly changing a person's stride. The goal is to slow the rate at which arthritis progresses and thereby delay or even eliminate the need for surgery. Part of the National Science Foundation Series “Science Nation.”