JOLIET, IL - SEPTEMBER 17: Kevin Harvick, driver of the #4 Jimmy John's Chevrolet, gives his son Keelan "knuckles" prior to practice for the NASCAR Sprint Cup Series Teenage Mutant Ninja Turtles 400 at Chicagoland Speedway on September 17, 2016 in Joliet, Illinois. (Photo by Sean Gardner/Getty Images)