The "Hit" Strum

Here's a demonstration of the "Hit" strum (that's what I call it).  I am holding an Em chord and playing a basic 4/4 strumming pattern.  I am putting a percussive "hit" on beats two and four.  First I play the pattern slowly and then a little faster.  Try cupping your hand so that when you strum your pick and the side of your hand (by your pinky finger) hit the strings at the same time.

If you want to hear this pattern, listen to the begin of "Proud Mary" by Creedence Clearwater Revival (CCR).