Ok, we can all agree that there are many ways to achieve muscle growth and that the most important factor is progression right?
To truly determine which method is BEST one would have to do a comparative study under controlled conditions which is not feasible (and there seems to be "studies" supporting numerous claims).
So let's go back to basics.
We lift, we signal the muscles to rebuild, we eat and rest and we grow.
I think the magic question is this:
[b]At what point do we stop stimulating growth and start cutting into recouperation?[\b]
Consider the following scenarios (for the time being, assume you are resting enough days to recouperate b4 repeating)
(1) One all out set to failure.
(2) Multiple sets with at least the last one to failure.
(3) Multiple sets but all stopped b4 failure.
(4) Drop (descending) sets to failure (ie. failure, immediately drop weight and repeat, etc.)
If we can analyse each of the above with respect to two criteria:
(a) adequate stimulation
(b) minimal damage to recovery time (and minimum chance of overtraining)
then we might get somewhere.
Ok, maybe this is just intellectual masturbation but it's a topic that I think about a lot so I'll give it a shot:
(1) One all out set to failure
(a) disadv : requires extreme mental toughness to really maximize stimulation
(b) adv : little chance of cutting into failure (ie. overtraining)
(2) Multiple sets with at least the last one to failure
(a) adv : easier and maybe more effective than (1) to achieve maximum stimulation
(b) very marginal increase in chance of overtraining, not necessarily the most effective use of time if taken to extreme (ie. too many sets)
(3) Multiple sets but none to failure
(a) disadv : risk of stopping short of maximum stimulation unless you truly know what 1 rep short of failure is
(b) adv : may allow for faster recovery and decrease chance of overtraining
(4) Drop sets
(a/b) this is where it gets interesting. when you are lifting lower weights following failure on heavier ones, are you stimulating more growth or cutting into recovery???