What's the science behind it? What difference does going to positive failure have over stopping one-two rep short?

I've been going to failure almost all the time when I started lifting. Now I almost always stop ~1 rep short and it seems that I gain more strength and need to rest less.

Can anyone explain the difference or point me to a nice article about this subject?

Thanks.

A little backstory:
I was benching yesterday, and my new gym has one of those shitty benches that only have one place to put the bar on, so you always need a spotter.
I was doing my 3rd (and last) set (8 reps) and asked the trainer to spot for me. Upon doing the 8th rep I realized that I'm 1-1.5 reps before failure and that it's time to put the weight down. I tell him to help me put it back (otherwise it's a huge strain on the shoulders, the way the bench is built) and he tells me that I can do more and should continue.
Eventually I somehow threw the bar back to place myself, and promptly engaged in a failure vs no-failure argument with him.

Happy Reading:

http://forum.avantlabs.com/?act=ST&f=25&t=...re,and,train&s=

i agree, but i also feel that on certain exercises going to failure on a burnout set can be very beneficial. sometimes its those last couple of reps that you really have to work for that gets your type 2b fibers to grow. they are primarily used during a 1 rep max which is in itself is working to failure, because you only have enough for 1 rep. these type 2b fibers are the ones that you want to grow, they have the most force production and volume. when working to failure, you deplete your available acetylcholine, hence cns failure. which you don't want to do every set of every exercise. but in doing so on a burn out set you can get your muscle to recruit those type2b fibers on the last couple of reps before you run out of acetylcholine, mimicking a 1 or 2 rep max. when i am done with my bench and i do a burnout set at 225 by the time i hit rep 19 or 20, i feel like i am going for a 1 rep max. but i haven't lost any strength, and i can still move on to my dumbell inclines without extra recovery time. it works for me, but thats just my opinion. failure on a burnout good, failure on every set bad.

Hey Loki.

What's a burn out set exactly?

A "drop" or "strip"-set.

And once again, I am quite fond of using said type of lift during my routine, however, even after dropping down several levels in terms of poundage, I still do not think you should ever take a drop-set to failure. Same with rest-pause sets too.

I did 1-3 sets / exercise, all sets to failure, always trying to reach the highest pain level, never giving in until I was unable to raise the bar. I could not settle for less no matter what. Hated going to the gym. Then got fed up and stopped training to failure. It was great to complete each workout feeling worked not worn out. Now I enjoy going to the gym 5 times a week, and I have gained!