P.O.F. Training
Bingo Donny.
I like how POF was exploring the topic ages ago. I will say, they did get it a bit backwards, but the intent is well intended.
It's likely best (if one believes in training a muscle in a shortened, then mid, then lengthened position), to start with a movement that trains the muscle in a fully shortened position, then a mid position, then a lengthened position. POF asks to train mid, then lengthened, then shortened, I believe.
If you do as POF instructs, you'll find it's quite hard to put a real good set forward in a contracted position if you've sufficiently challenged yourself with a lengthened position exercise first.
So, here's one way I might structure exercise selection, using the lats as an example:
First exercise: close grip cable rows
Second exercise: close grip lat pulldowns done with arms coming up about 120 degrees of flexion
Third exercise: close grip lat pulldowns done with arms coming up to 180 degrees of flexion
in the above, you go from training the lats in a shortened position, to gradually getting to a more lengthened position. Muscles are generally able to perform better when active tension is high at full moment arms.
But again...I think the effect is rather small.
Know how talked about this years ago, in very well thought out ways? Jordan Peters. Dude had some interesting videos out there.
But yes; the POF style of training definitely had an interesting idea on targeting a muscle with different exercise selection that targeted shortened, mid-, and long-length moment arms. I think there's wisdom to it, for what all that's worth.