America's toughest road marathon is an endurance contest, even if you're experiencing the Blue Ridge Marathon course from the seat of a bike.  Just ask Assistant Race Director Molly Bullington.

Bullington has been measuring the course this week, so it can be certified by U.S. Track and Field.

Race organizers have also been figuring out where the mile markers go.

Bullington calibrates the bicycle before and after each ride, and says it gives a more accurate measure than a car, or a GPS device.

"The importance and the reason that we're certifying the course is to guarantee the runners that we have a course that is actually 26.22 miles, which is what it is supposed to be.," Bullington told WDBJ7.

The Foot Levelers Blue Ridge Marathon will take place on Saturday April 26th, starting in downtown Roanoke.