Down Picking and Speed

This is a 4.22 minute video response from David MacKenzie on Dec 3rd, 2008

Question:

"Seppo asked "Hi everybody! I've been trying to play some easy metal song like Walk from Pantera or for whom the bell tolls from Metallica, but I've had some problems with fast downpicking parts. I can't keep up with the speed, just playing the open E string fast is hard for me. I was wondering if I might have something wrong with my technique, 'cos the upper part of my right arm gets painful easily from fast downpicking. Sorry for bad grammar and thanks for helping! :).""