A NASA-engineered piece of equipment is giving some patients their legs, and their lives, back.

Nancy Markey, 74, said she had fallen so many times she was afraid to walk on her own. But then she tried the “Alter G,” which is far from the typical treadmill.

“Oh, it’s wonderful because I know I can’t fall. I’m supported everywhere,” Markey said.

The treadmill is anti-gravity.

“In just three tries, yes, I can tell a difference,” Markey said.

But before Markey used it, astronauts did.

NASA engineers designed the piece of equipment so astronauts could re-introduce themselves to gravity after being in outer space.

“I love it. My knees don’t hurt,” Markey said.

The treadmill uses differential air pressure to help hold the body up, and reduce the impact on the lower body.

“It feels like I’m young, like I could walk when I was young,” Markey said.

Three cameras are placed strategically around the treadmill so therapists can watch the patient’s feet on the screen and make corrections to their walking pattern.

The treadmill costs $47,000.

To find the closest “Alter G” treadmill near you, click here to search for locations.