TULSA, Oklahoma - Hundreds of cyclists are in town from all over the country for the third annual Cyntergy Hurtland Cyclocross races. 

The races test the athletes' physical abilities by going through different obstacles. 

The races start off on the pavement, but it gets a lot more intense. 

As cyclists move through the course, they reach obstacles that test their limits. 

"It's a little bit crazy," said Tulsa Tough Executive Director Malcolm McCollam. 

"I’m always afraid that I’m gonna fly up in the air cause it's so scary and you're going so fast," said 8-year-old Samuel Briggs. 

Briggs is here with his friend Aiden Wyant.

"It was really hard. And he almost made me crash once. Because he was yelling at me so loud," said Briggs. 

One of the more challenging parts involves cyclists running up stairs on foot, then riding down a hill. 

"It's like a rollercoaster,” said 7-year-old Aiden Wyant. 

Allison Hunt and Ashley Miller are here from Lincoln, Nebraska. 

They travel all over for cyclecross races. 

"Some of them are questionable. This course, though, is absolutely amazing," said Miller. 

It's only the third Cyntergy Hurtland race in Tulsa. 

And Samuel Briggs is already looking forward to next year. 

"You can do whatever you want and go through the dirt and mud and water. So it's pretty fun," he said.