#1
I picked up a guitar 13 years ago and learned and got real good, then for the better of seven years, I didn't play because I fell on hard times, No money, ect. After getting back into the swing of things 2 years ago, mostly everything came back to me except stamina in my strumming arm/wrist, When I was 13 it came naturally, Now it's not. Any advice on building up stamina in the right hand/wrist/arm. Surprisingly I can't find much on the subject if anything. I've heard some ideas but I haven't found over the past 2 years that they've been all that effective. Any ideas?
#2
Start with the easy stuff always.... go for the down, down, up, up, down and go really slow and once you have the jist of it then go a little faster, if you muck up go back to the previous speed get back on track and then go a bit faster again. ect.

try practicing just this for half an hour I promise you improvment.