Athletes are out in force at Horseshoe Valley for the annual Warrior Dash, which this year is supporting SickKids Hospital in Toronto.

The race, billed as the world's longest obstacle race series, sees runners tackle all manner of obstacles (from balancing on wood beams to crawling through tires, running through mud, and dashing through fire) on a three-mile course.

This year, SickKids patient Nicholas Marchand, 14, is competing with his father Dave. Marchand suffered health concerns as a baby, had multiple surgeries, and still visits SickKids regularly.

"It's going to be a lot of work," says his dad, "but I know both of us can do it."

It's held in 50 places around the world. The event in Oro-Medonte is the only one in Canada.