Stevesmi check out this articles sometime:
Training To Failure: A Look Inside
I have trained to absolute momentary muscular failure in the past using both the 1 set approach and high volume.
Using the 1 set approach I was able to make good progress, BUT my training had to be both very low volume and low frequency because of the demands on my nervous system. This did not produce the size increases I expected which I believe is due to the fact that I was only stimulating any possible increase in size of a given muscle once every 7-9 days.
Training to failure using a high volume routine rapidly lead to nowhere for me. Pretty easy to understand why with high levels of muscle trauma and high recruitment of the PNS and CNS because all the sets to failure. This is how I trained in high school aka using the old Arnold routines. I never benched more than 160lbs for reps nor weighed more than 170lbs because I was grossly overtrained all the time.
It's a proven fact that training to failure is NOT the main determinant of whether you get bigger or stronger. Does it work? Sure. How well it works depends on volume used, frequency of training and a person's own recovery ability/nervous system recovery speed.
I'm a mesomorph with a small mix of both ecto and endo characteristics. I do best on moderate volume/moderate intensity training system Programs like 5x5 or 5-3-1 which work very well for me. I can even tolerate fairly high volume with moderate intensity so long as deloading occurs.
Coming off of a long layoff I typically use a 5x5 program and rapidly rebuild previous strength and size without once ever going to failure. Many might say this is due to muscle memory, but muscle doesn't magically regrow in size and strength just from being around weights. It's clear that muscle memory is playing a role in the rapid increases, but it should also be obvious that I am stimulating strength and growth increases without once going to failure. This should not be possible if training to failure is the main stimulator of muscle growth.
This is actually one of my main issues with the theory of training to failure. If training to failure is the main mechanism for producing gains in strength and size then how come weightlifter's and powerlifter's that rarely purposely train to failure get super strong and huge if they eat alot? Technically this should be impossible based off the theory of high intensity training to failure.
It's kinda sad that the whole use of the word intensity is completely misused by most advocates of training to failure. Intensity as it can be measured has nothing to do with failing to lift a specific weight or a perceived maximum effort threshold. Rather is relates to the percentage of your true 1 rep max effort on a lift. One could be said to be training intensely using 90% of their 1 rep max for singles and doubles and this would be accurate.
I don't have any problem with training to failure in general except for people who believe it is the "only" way or "best" way when in fact these people generally have very limited knowledge on what constitutes effective and productive training.