Sometimes Marissa Siebka can't help but feel the bitterness well up in her gut.

And feel her heart wrench.

Sometimes Siebka, a Slippery Rock High graduate who had a standout collegiate basketball career in front of her before a series of knee injuries torpedoed it, finds it difficult to be in a gym because of the bombarding thoughts of what could have been.

“I get annoyed, honestly,” Siebka said.

It's understandable.

Siebka was a terror on the basketball court as a scorer, rebounder and defensive whirlwind for the Rockets — and then the first of her knee injuries struck nine games into her junior season in 2014-15 season.

Still, Siebka had a scholarship to Gannon University in the bag and was looking for big things there after she came back from the ACL tear with a big senior campaign for Slippery Rock.

Then the knee injuries piled up at Gannon.

- Dec. 30, 2016 — another torn ACL in left knee.

- Dec. 27, 2017 — torn meniscus in left knee.

- Dec. 17, 2018 — torn ACL in right knee.

In all, Siebka has had four knee surgeries — three on her left and one on her right.

As many surgeries as she made starts for the Gannon women's basketball team.

“I get bitter to a point because I wanted to be able to show certain people up here what I was capable of doing,” Siebka said.

That never happened. Her last game was on that fateful Dec. 30, 2016 against Indiana (Pa.) University.

She ended her career with 57 points, 36 rebounds and 14 steals in 11 games.

Just 11 games.

“Everyone just saw me as the girl who kept getting hurt,” Siebka said.

Siebka, though, finds that bothers her less and less these days.

That's because Siebka channeled her energy into other pursuits.

December had not been kind to Siebka in the past.

It was this year.

- Dec. 8, 2019 — Siebka graduated a semester early with a dual degree in early childhood education and special education.

As her Instagram post perfectly summed up: 3½ years, 3 knee surgeries, 2 degrees. All for 1 passion.

Teaching.

“Off she went to change the world.”

Adversity is a like a grindstone. Whether it grinds you down or polishes you up depends on what you're made of.

Siebka refused to let it grind her down.

“People who truly know me know how hard I worked,” Siebka said. “I had three different doctors clear me to play with a torn ACL (in her final year), but it just didn't work out. I wish I could have played, but my knees hurt. When I'm standing all day in a classroom, my knees hurt. When I'm sitting on the floor, my knees hurt. I'm only 21.

“I don't regret anything I did.”

The experience has helped Siebka relate to her students, some of whom are grappling with their own adversity.

She empathizes. She feels their frustration and pain.

It's going to make her a better teacher.

It's already made her a better person. A stronger person.

It's polished her.

Mike Kilroy is a staff writer for the Butler Eagle.