easier to see what you can feel
The IR/IR/IR demonstrated in that video and in bb/fp swings (like below right) is completely void of rear hip flexion - which is one of the main ingredients you see all of the best use.sadlowski with some held ER, not as much as snead.
https://www.youtube.com/watch?v=euVph0P9Cq0
The IR only is good for the high level swing to enable spatially early bat speed,equivalent to halfway down into the downswing in golf, therefore not a stall problem as encountered for IR only in golf.