"Gotta run for the ones who can't:" Thousands of runners push their limits at 2015 Spartan Race

MILWAUKEE (WITI) -- It's the ultimate test of strength, endurance and willpower. Thousands of runners laced up their shoes at Miller Park on Saturday to take their body to the limits at this year's Spartan Race.

Professional runners and beginners took on the grueling 3 mile Spartan course with 20 obstacles. If you can't complete an obstacle, there's a penalty -- you have to do 30 burpees before you can advance.

Men and women of all ages and athletic abilities make their way around Miller Park, the home of the Milwaukee Brewers.

"That was one of the really big draws for us. Something unique, you know, you're not outside on a course, you're inside. It kind of feels like a gladiator feel so it was great," said Brendan Ryan, lives in Chicago.

Spartans are a group of people who go beyond their comfort zones and challenge themselves both mentally and physically to achieve greatness.

Both Earl and Nicholas were wounded in combat by a road side bomb. Saturday, Nicholas will crawl the course without his wheelchair.

"I don't like to give myself a lot of excuses. I like to try and challenge myself as much as possible, so this by far is going to be the most challenging, I think physical anyway since being injured," said Nicholas Koulshar, veteran.

And Earl will carry a cinder block, a symbol of all the weight veterans carry when they return home.

"You know she's nice and heavy just like that mental weight may be," said Earl Granville, veteran.

They spent two years recovering at Walter Reed, and today they run to help veterans stay 'Oscar Mike' or on the move.

"Gotta run for the ones who can't," said Granville.

It's an inspiration to us all.

To learn more about the Oscar Mike Company and foundation, CLICK HERE.