You know, the more I think about it, the less clear all of this becomes. I did some research on the RE method, and found a lot good information. I found it interesting that Westside sometimes uses timed sets of 1-5 minutes for recovery and/or hypertrophy. But I also found that this is not the only way.
Training to failure with moderate to high reps makes sense, because failure is the result of a large portion of intermediate fibers fatigued, plus all of the fast twitch fibers. And something like a drop set, or rest pause can be used to make sure you hit a lot of the largest fibers.
But CW’s methods make much sense also. If you train with heavier weights, and the intent of maximal acceleration, you recruit the largest fibers in the beginning. After a few sets, these fibers are no longer able to keep the speed or reps up, and the intermediate fibers have to take over. A few more sets like this, and the intermediate fibers will get fatigued.
Both methods will potentially stimulate and fatigue a large portion of the biggest muscle fibers. The first method will likely be better for endurance, due to the exposure of lactic acid, and glycogen depletion, while the second method might be better for strength, since the large fibers are exposed to heavier weights.
The point is, both methods can and will work. The key is to progress. Whether or not your actually hitting “true failure” doesn’t matter, as long as the stimulus is greater each workout.
There is one other thing I got out of looking into fatigue more. As a general rule, if your not fatiguing or very highly activating a MU then your not going to progress or stimulate hypertrophy. Whether fatigue is monitored by rep speed, or how close you are to concentric failure does not matter. If your training with higher reps then you can probably get away with stopping 1-2 reps short of failure, and occasionally use failure, rest pause, or drop sets to reach a new pr. If your trainig CW’s way, you NEED to take each set till the speed noticably decreases, and then likely decrease the weight and do one or more sets with higher reps to near failure.
This was a good discussion though, and it shows that whether you train with 3 reps per set, or 20 reps per set, you can stimulate hypertrophy if you pay attention to certain details.