Going to failure IS NOT OPTIMAL! Infact it is often counterproductive.
By failure I mean doing descending sets (no break in between)...
most productive way to train is to train for strenth only. And that means stopping short of failure.... Olympic weighjtlifters are extremely strong, and they never go to failure.
Powerlifters the same....
Think about this... If you can bench 135 for 10 times, your chest would be small. But benching 315 for 10 reps, and your chest should be huge...!!!!
Ofcourse before you can bench 315 for 10 times you need to be able to bench it twixe, 3 times, four time, five times and till 10 times...