Re: Always tense?
I know exactly what you are talkin about. I've found that you need to be aware of "mental overtraining" as much as the physical one we talk about often. You know how when you start a new routine like the ones you mentioned, you are motivated, you want to find your limits, you want to push as hard as you can. I think that like typical overtraining, you build mental fatigue from constantly having to pour 110% into each set.
What has worked well for me when I hit that mental wall is switching to a non-failure type program for a few weeks. I know most low-volume, failure-oriented programs have a week long (or longer) deloading phase, but sometimes its not enough. I think teaching your body again to embrace your training without it having to go to failure for a few weeks will help. Once you are done, you can go back anbd attack your original program reinvigorated, physically and mentally.