In virtually every other aspect of sports training training to muscle failure is usually avoided. But for the bodybuilder it is often the quoted Goldem Mantra. IMO it was promotedly heavily back in the 1950's days of Joe Weider who wanted champion bodybuilders, and could then sell his training methods to the public. However....back in those days steroids were legal... so ripping up muscles to failure wasn't half as daunting because they had all the juice they could handle for bad-ass results. So going to failure became ingrained in the psyche of the weightlifting public. After all....who wouldn't want to look like the guys in the magazines? Many of the so-called "natural" lifters, it turns out, were in fact getting juiced behind closed doors. The Great Arnold for one......so shred those muscles and "better living through chemistry"...... I think this is where it gets complicated on a forum where there are many types of practioners responding to posts . New lifters sometimes start off on a strict bodybuilding routine where "failure training" (e.g HIT) is part and parcel of the routine, no matter the frequency of the required failure (momentary or other-wise). Then they see posts where someone is doing a completely different program with different protocols and different goals, but is getting results. Or.....they are infatuated with the novelty of a new exercise they've seen a guy do...they incorporate it into their routine and go to failure, even though it does not call for failure on that particular regimen. And that's when the fun starts. Guys trying to approach other regimens looking at them through the eyes of a failure-indoctrinated bodybuilder. And not knowing whether to to go to failure or not. Muscular failure bodybuilder-style is all about hypertrophy,bigger muscles and nothing else...as Joe Weider would have been glad to tell you. Now some authors and trainers have tried to get around the failure issue by calling it "momentary failure"....as if this was "Failure Light". Failure is failure...end of story. When you "rip" a muscle to failure, you are destroying tissue.....so of course there is the necessary repair time. "Recovery" as it were. The domain of bodybuilding is where this effect is most cherished. There are dozens and dozens of other sports where the issue of ripping a muscle to shreds doesn't even come up in the conversation. Because in these, it is never sought. They are not looking for hypertrophy. So if you are a new bodybuilder and you are looking for bigger muscles, so be it.......you'll more than likely be going to failure on more than one occasion. But don't try to carry this type of regimen (program-hopping,novelty exercising and the like...)into areas where it is not required and could actually be highly detrimental to your results.