It would be prudent to assume, if doing each body part twice/week, doing one time rest pause training -and the second time higher weights with 5-6 reps in 2 sets, could yield more gains, having both, the resistance -and strength component.
Do you agree?
HIT4ME
I don't disagree. I think the process is pretty straight forward and maybe I oversimplify, but I never claimed to be smart or clever. The process is:
1. Stimulate - a sufficient stress needs to be experienced to stimulate an adaptation.
2. Recover - give your body time to do its work and nutrients to replace burned energy and repair damage.
3. Grow - this is similar to #2 but not the same and won't happen until AFTER you repair damage and recover fully.
Meltzer believed, and I agree, that most people don't stick to this process and start training again while they are still in the recovery phase. This means they have not yet repaired all damage, which means they have not grown yet because they haven't gotten to that step yet even.
So, in Mentzers approach, you should be growing (getting stronger) with every workout. If you are not - something is wrong in one of those three steps. So if you are SURE you have trained the muscle with sufficient stress (exposure to failure was his hypothesis) then if you aren't stronger the next workout, then you need more time between workouts because you didn't allow for adaptation. And the more volume you do in a workout, the bigger your energy expenditure, the more you have to replace before you are fully recovered. In other words, volume increases stimulus but digs a hole that has to be refilled before you can overcompensate.
So, back to your question - I think mixing styles has a place. But I've always questioned the logic of training in a fashion that doesn't actually provide a stimulus because it still spends energy even if it doesn't cause growth. Lots of people will disagree and say active recovery is more effective than sitting around, but I am not sure.
If you have a heavy workout and can truly overcompensate before a second workout in the same week - then doing a second workout with higher volume and lower weights may be effective, but then you are also training for two different outcomes and it may be better to just double down on one outcome?
I will say that training to failure at or above 80% 1RM seems to really destroy your CNS which I think is a bigger factor in recovery than just muscle recovery. Training, as you suggest, with 70% to or beyond failure will be easier on the CNS and speed recovery from a systemic perspective, and based on studies we have seen, I would think the adaptations would be the same as going to failure with a slightly heavier weight. Actually, another argument may be that using a lighter weight allows you to get even more INTO failure than a heavier weight.
For instance, if you can do 4 reps of something with 80 pounds ...on the 5th rep, you may be able to push 78 pounds, but I will fail because I have 80 on the bar. If I did 70, after 4 reps I could still do 78 pounds and only have 70 on the bar, so I get more reps l. But at rep 6, maybe 8 have 74 pounds of force available, rep 6 I only have 70, a and rep 7 I fall to 65 and fail. Not sure if what I am saying is making sense, but in the first example I failed with a 2 pound deficit, and in the second it was a 5 pound deficit.
Anyway, I believe in mixing things up and doing both methods...but I also believe in keeping things simple and constantly improving.