Finishing the San Francisco Marathon was a moment of ecstasy for Claire Conely, followed by months of agony.
"Somewhere in that stretch I hurt my knee, but with the adrenaline I didn't realize what happened. Just felt pain, but didn't want to stop," said Conely.
She might ultimately need surgery, but right now, doctors at St. Francis Medical Center in San Francisco are trying to help Claire strengthen the muscles that naturally support her knee during a run, without exposing her joints to the dangerous pounding.
So instead of hitting the pavement, Claire is hitting her stride on a unique treadmill that allows her to literally defy gravity.
Using an inflatable bladder that surrounds the pelvis, the "Alter-G" gently lifts the runner, controlling how much of her body weight is transferred to her legs. An on-board computer can adjust it from 10 percent of normal, all the way back to 100 percent.
"When I'm running at 80 percent it feels great, but when we increase it to 85 it starts hurting again," said Conely.
"The other thing is, it allows your gait to be more normal," said orthopedic surgeon Dr. Susan Lewis.
Dr. Lewis is leading a clinical trial of the Alter-G at the hospital's sports medicine clinic. She believes it may be particularly effective in rehabilitating patients after joint surgery.
"Even for patients with ACL, we were always taught never let them run for three, four, five months because of the risk of falling," said Dr. Lewis.
The trainer was originally conceived for use by NASA. But earlier this year, the FDA approved it for medical applications.
Although there's no hard data yet on its long term effectiveness, patients like Claire are hoping that as her muscles strengthen, her knee will respond.
"The ultimate goal is to get running again," said Conely.
The trainer is built by a company in Menlo Park with technology developed at NASA to help astronauts returning from long stays in space. It lists for about $55,000.