After losing both of her legs in the Boston Marathon bombings, Celeste Corcoran is showing what it means to be Boston Strong.

On Tuesday, the Lowell, Mass., woman ran, swam and even rock-climbed for the very first time since the attack with new prosthetic legs. Corcoran spent several days at the Prosthetic and Orthotic Association in Orlando, Fla., where she was fitted for prosthetic sockets and running blades, and within two days she was running on her own, according to WCVB.

“I was never a runner. I hated running,” Corcoran told the Boston ABC affiliate. “I feel myself getting stronger and stronger and more and more steady.

“The first time I did it myself, I kept saying to myself, ‘I can’t believe I just did that. I can’t believe I just did that. I just did that myself.'”

Corcoran credited her family, including her daughter, Sydney, who was also hurt in the attack, for helping her make the amazing strides.

“You can dig down deep and find that strength,” Corcoran said. “I just want to have the best life I can possibly have.”

Check out Corcoran’s incredible story in the video below.