That thing with the railroad cars description to 'focus' the power in a figure... that was like someone showing me the WHEEL! That's going to make a difference in my work for sure!
Sorry Jim you made a mistake around 37:40. You in fact do push the same leg forward as the same hand, as you want the power from the hip to be pushed into the punch (if your going for a power punch. This does not count for jabs as your just throwing your shoulders into the punch). As far as punching the ground though, your correct. It makes sense to move your opposite leg out of the way of your fist to make room.
You've never punched someone before, your lead leg and lead hand are only ever both forward when you jab, with any kind of power punch or cross the leg is back from your hand that is punching, you rotate your hips to generate power, with your fist rotating away from the leg on the same side. Watch boxing, mma, or get into a fight and you'll know what I'm talking bout.
Jim's correct. If you're throwing a power punch the opposite leg from the punch is forward - just like throwing a ball. Right-hand punch/left leg forward. JIm's sketch in red is correct.