Janet Corral, 53, stands on the mobility platform at UCHealth Physical Therapy and Rehabilitation Clinic – Stapleton. She unweights herself with her hands on the stainless-steel rails running the length of the apparatus. Her black New Balances rise and fall as she slowly and gingerly walks in place. Guy Lev, the physical therapist who leads the rehab clinic, observes and corrects. He’s focusing on her posture, and so is a visitor who, like Lev, has a doctorate in physical therapy. Ruud Leijendekkers, in from Radboud University Medical Center in the Netherlands, has long experience in helping leg amputees walk again – as does Lev. Corral, though, is no ordinary above-the-knee amputee.