Actually just FYI, it sucks working out when you're high (at least for me). You always feel like you are about to reach your fail point. Your desire to give up and go relax is greater than when you're sober.
I always work out before I get stoned. The high feels that much better afterward on your sore muscles too.
or right in middle when you hate that you still only half way done and your feeling bit of soreness. Could help to get you to the end. Your right on the before hand thing tho.