Rascal Flatts'  Gary LeVox shapes up with the "Shake Weight!" According to Taste Of Country.

That explains some of the vibrato in his voice. 

Gary LeVox from Rascal Flatts has a personal fitness trainer named Wes, and he has a secret about the country star that he’s sharing. In order to stay in shape on tour, LeVox has the latest infomercial craze, the Shake Weight, on his bus.

And to prove it, in the video he flexes his right bicep. The last shot leaves us with the ‘I Won’t Let Go’ singer’s best body builder pose, complete with appropriate grimace.