Watch the Laying Down the Backbeat online guitar lesson by Brad Carlton from Guitar Lab: Precision Strumming
The backbeat consists of the second and fourth beats in 4/4 time. In a basic drum groove, the snare drum is struck on the backbeat. As a guitarist, you always want to convey the rhythm just as a drummer would. The palm slap allows you to create a percussive sound which gets the listener on board with the groove.