@conner74 Sure, I couldn't agree with you more! Of course that's gonna be stimulating growth too, especially if your asshole is falling out! :'D
But some thoughts that come to my mind are: is it the most efficient way for muscle growth?
you see there are some powerlifters, or olympic weightlifters that don't have much mass but still move considerable weights. It's because in very low rep-ranges it is very dependant on your Central Nervous Systems abilities to recruit muscles...
I mean if you do 1-3 reps, how high is the tension on the main muscle or to which extent is it more your whole body that just struggles? imagine a 1RM attempt...
Is it intense in the way, that you nearly feel your muscle tearing and you contract so hard against the resistance or is it hard in the way that coordinatively you fail?
Also, how long are those 3 reps that you describe, if they are forced negatives? that might mean quite some time under huge tension, which actually might make it even more stimulative compared to some higher-rep set but with bouncing or momentum...
You see it's not black and white, and no one has a definitive answer. If someone says they know the absolute truth they are always wrong.
And yet there are some general things that simply work. You want to have tension on your muscle and bring it to or close to it's limit. it's propably intelligent to do some amount of reps and a few sets for efficiancy, to target a muscle, to be able to focus, whatever... how much will be highly individual...
All training systems that do these basic things work. That might be super high reps and to absolute failure, that might be low reps with high intensity. high-volume, low-volume, whatever... you'll see that each time those approaches just prioritize one variable over the other..