More and more football teams are having players study a particular self-help book along with their playbooks.

Tennessee coach Butch Jones and Washington coach Chris Petersen each had players read "The Energy Bus: Ten Rules To Fuel Your Life, Work And Team With Positive Energy" during the offseason. They joined a fraternity that also includes Atlanta Falcons coach Mike Smith, Georgia coach Mark Richt and Clemson coach Dabo Swinney among others.

The book's popularity among coaches has surprised its author, Jon Gordon, a former Cornell lacrosse player who says he didn't have sports in mind when he wrote it. Now he's regularly speaking to teams and exchanging text messages with coaches. Gordon says he "never imagined the book would be used by all these teams like it is."