Hundreds of spandex-clad competitors are slogging uphill in the autumn mud, climbing and carrying bags of sand this weekend near Collingwood, Ont.
The Obstacle Course Racing World Championships at the Blue Mountain Resort is a gruelling test of strength and endurance.
"We have 67 nations here right now. All of the athletes have qualified to be here. These are the best of the best from around the world," spokesperson Margaret Schlachter said.
There are 4,000 competitors at the world championships, a testament to the growing popularity of obstacle course racing.
Video by @cbcnews
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