More than 10,000 people will put their training to the test in Sunday's IMT Des Moines Marathon.
"I've gone up to ten miles already to make sure I can do this," said Cindy Sapp, a runner.
"Regardless of if you do as well as you hoped, when you finish, it's always great,” said Josh Vogler.
This is the most people to ever run the race here in the capitol city.
Many of those runners checked in Saturday and picked up some last minute gear to get through the race.
Big crowds mean a greater need for volunteers and extra law enforcement.
About 2,000 volunteers will make sure the race runs smoothly.
Both uniformed and undercover officers as well as private security guards will monitor the crowds.
The extra security efforts are in response to the Boston Marathon bombings in April.
"We've gone over our policies we have in place, our security policies, what we would do in the event of an emergency situation. We've looked at where we need to fine tune, change, and upgrade," said Chris Burch, executive director of the IMT Des Moines Marathon.