McFadden was born with spina bifida (a hole in her spine) and is paralyzed from the waist down. She grew up in a Russian orphanage with next to nothing — not even a wheelchair — and learned to walk on her hands. As you might imagine, that led to some serious upper-body strength. She was adopted by American Deborah McFadden in 1994, introduced to various sports, and eventually came to love wheelchair racing. She made her Paralympic debut in 2004 in Athens at age 15 — and brought home her first two medals.McFadden’s strength, training, and experience helped her go from those first silver and bronze medals to a gold in London in 2012. But there's another tool that's key to her success: her racing wheelchair. “A racing chair, like a pair of running shoes, has to fit perfectly,” McFadden explains. “It’s not like a bike; it’s very different. There are no gears. Our arms are our own gears. However fast you want to go is how fast you’ll go. They’re lightweight, aerodynamic, and very stiff.”Whether racing on the road, like in the Boston Marathon, or on the track doing the 400m, it’s important that the chair McFadden uses can pick up a lot of speed quickly — and then maintain that speed, even over various road conditions. It’s different from an everyday wheelchair, which is more compact. In a racing chair, McFadden needs to be in an aerodynamic, tucked position, kneeling. The chair has two wheels in back, and one in front.