“his most recent coach really preached back leg - very firm, push into the ground, minimal bend of his knee of the foot, stride as long and far as possible and push with 100% effort every time.”
Unfortunately, most coaches do not understand how it works Kinesiologically for Human forwards movement.
Think of it as how do we walk, trot or run. This motion known as gate is contracted from the glove side leg up into and across the pelvis creating rotation, this is where you should concentrate your effort maximally. Then watch the Velo rise.
There are 3 Kinetic chains involved in the pitching or throwing motion;
The first kinetic chain “Dropping in” or lengthening is used to set the muscles to length.
The second Kinetic chain “Drive” or shortening can not start until the Humerus is fully or close to fully outwardly rotated and should be timed with glove side foot plant stability.
The third Kinetic chain “recovery” or eccentric contractions (contraction while lengthening)
“ive been reading about Trevor Bauer - drift, drop, rotate and block. what he says makes a lot of sense. also read that driving / pushing off the rubber to almost creating a jump diminishes the power of the backleg”
There is no forwards power from the ball side leg when using the traditional approach, it us used to lengthen you, then you come to a complete stop until the Humerus is transitioned then ready to throw! It should be performed nominally and under smooth control.
“what are peoples opinion on how a pitcher maximizes power from the backleg?”
No amount of maximal effort is transferred into the second kinetic chain if the ball is not making forwards math.
“any ideas on how best to coach this?”
As long as this understanding continues coaches will try to add effort into this chain and will fail in getting it done because this is not how it works.
“I also saw on baseball rebellion, they were suggested to “hook” the rubber to actually create a forward tilt to presumably help with the drift”
Forwards tilt during the lengthening chain only serves to unbalance you by putting your center of mass to far ahead to take full advantage of the next kinetic chain, shortening.
The best way to take advantage of gate is to turn you ball side foot towards home plate 30 degrees, stay tall, stride shorter and rotate fast off the glove side leg by pulling back against it by continuing to stay tall.
Any question just ask?