His hip is still closed in the rear hip socket. Not open like they believe. Then, from that point forward, both the leg and that belt loop (hip) turn in unison.
REAL separation occurs in the rear hip socket when the socket coils completely and reaches its range of motion limit around the ball of the femur. Hip socket coiling rearward creates a forward turning response from the rear leg. Tug of war. Rearward move versus a forward move.
The REAR LEG becomes the driver as it snaps loose from the resisting hip socket when the tilting action of the hip socket occurs at launch. The absolute, indisputable proof, that they ignore, is the barrel depth
The barrel’s speed, deep behind the hitter, while his hands are still at the shoulder tip or arm pit area, is IMPOSSIBLE to achieve when rotating hips is the driver.
This chart is the result of a hitter with a Rear Leg driver. It gives data that they conclude means the hips were rotating from their hip/shoulder separation definition. Yet, it absolutely was not the case. 
Hitters who do what I teach well, ALWAYS, produce the data they want to see. But their conclusion about what the hitter did to create that data is 100% wrong.
The torsion load around the rear leg creates a far more sudden unload than hip/shoulder separation can achieve. Their golf conclusions about the baseball/softball swing are simply wrong due to the time constraints of the hitter.
Golfers can swing whenever they want. They can achieve their hip/shoulder separation at their pace with no time constraint. Hitters have a need for suddenness. Hip/shoulder separation can’t offer suddenness.
Beyond the need for suddenness, the hitter must have ‘direction ability’. He must be able to swing through an infinite number of points instantly. This requires multiple directions of launch. Hip rotation from hip/shoulder separation has one direction, hard left or hard right....
Which then means, to get barrel to ball, on an infinite number of locations, the hitter must disconnect from that hip rotation and push his barrel with his arms. The greats have learned the ability of the one legged hip socket tilt which releases the leg’s torsion directionally
To not have a sensor on the rear leg, to determine its role, might have been understandable 4 years ago. Now it is malpractice
Soon you will realize the Scientific Method abuse. The technique they now use is Select Your Evidence
Climate. Virus. Hitting. Are there no scientists left?.
