Springfield, MO -

A Drury freshmen just wrapped up a successful year of track and cross country running. It's an amazing journey... Because, she was once told to give up the sport.

Olivia Willoughby told KY3's Paul Adler, "it's pretty much given me... my athletic life back."

Paul says, running pain free is new for Olivia Willoughby.

Olivia remembers, "it was like somebody was stabbing my calves with a knife and twisting it... "

This is how a race used to end for Olivia... (video shows Olivia in pain on the ground).

Olivia says, "as soon as I stopped and crossed the finish line... My legs would just seize up on me... And I wouldn't be able to support my own body weight."

It took a lot of testing and several doctors to find the problem.

Olivia responds,"all I had been told was stop running."

At Mercy Sports Medicine, doctors figured it out-- by asking Olivia to run and they saw her legs lose all color.

Olivia says, "it's called Popliteal Artery Entrapment Syndrome."

Popliteal artery entrapment syndrome (PAES) is a rare cause of exercise-induced leg pain.

Jim Raynor with Mercy Sports Medicine explains, "if this was the artery... (using finger to demonstrate) There were some bands... That surrounded her artery... And then every time she would run... where she would plant her foot and come up... It would restrict and restrict and restrict.."

So, when she ran, the blood flow stopped at her knees... She needed Surgery.

Olivia says, "all I could think was... Yes... This could be my chance to continue doing the sport that I'm so in love with..."

Jim Raynor with Mercy Sports Medicine shows us, "the incision came from here...."

Olivia continues, "across and down.. And opposite on that leg..."

The recovery started--- just 24 hours after that major surgery. She had to learn to walk... well before she could run.

Jim Raynor with Mercy Sports Medicine recalls, "there was a significant amount of conditioning without the pounding... on top of that... To get even more heartrate up.. We would put her on the rowing machine."

And.., she came back in just weeks. She ran at the high school district cross country competition-- made it to sectionals. She missed state. But, she did land a Drury scholarship.

Jim Raynor says, "that is a testament to the group she worked with... But, even more a testament to her as an individual."

Olivia concludes, "it opened up my life to being able to do what I love.."

Her future should remain pain-free.. And by the way, Olivia doesn't limit her athletics to running... She's also on Drury's dive team.