I'm not really sleep-deprived, but lately I've tried taking coffee before working out. I find that my performance was considerably better than without coffee and that I generally feel good afterwards. I have GERD, however, and I shouldn't really be taking anything with caffeine because it triggers an acid reflux. Are there caffeine-free alternatives to coffee that are safe for those with GERD?
There are pre-workout supplements that are non-stimulant (Magnum's Opus comes to mind).
Most pre-workout formulations rely on trying to stave off CNS fatigue (which is not a thoroughly understood topic). CNS fatigue is prevented (in varying degrees) by:
I'd be a little wary of "I drank a cup of coffee before some workouts, and they didn't go well, so coffee before workouts is bad for me." It's terribly anecdotal you're not controlling for other variables.
But if you don't want caffeine, and you're smart enough to not use amphetamines, then you're left with non-stimulant stuff.
You may want to try something with creatine and beta alanine. Beta alanine tends to give people tingles all over their skin which feels a lot like a stimulant (but isn't, that I'm aware of). And creatine actually does help: arguably the most documented safe performance enhancer out there.