....a hitter who turns the barrel from behind the corner....who launches and spends....COMPLETELY....REARWARD....NOT get proper extension.

The IMMEDIATE launch....the SUDDEN launch....of the high level swing....REARWARD....creates such force that extension is automatic.

If you're not getting extension....you are not launching ALL IN EARLY ENOUGH.

If someone had to teach you to 'get extension'....you've been taught wrong.

Keep in mind....the AMOUNT of extension....MUST BE....a factor of pitch location and timing.