back leg leaving ground first

[llll]

could back leg leave ground first because the toss is in front of the body and the front leg is closer to the ball the two legs are almost the same length the back leg would have to be longer to be on the ground since its distance to the ball is longer?

[BrianGordon]

The more likely mechanism along your line of reasoning is that even in generation of forward angular momentum, the back leg has an easier job due to its distance from the center of mass (bigger moment arm => decreased force required) - a valid point - and in fact the back hip both rotates towards contact and raises a bit relative to the front hip.

You would say (I think based on your question) that the back hip raises, causing the back foot to leave the ground early, as the body is leaning forward to reach a forward toss as a matter of geometry - I would say that the raising of the hip is a consequence of rotating the hips by bone on bone force which is not purely horizontal by any means - and the predominant lean at the time is lateral, not forward - and it would seem to me that the purely geometric logic would require the hips to be more perpendicular to the baseline with a pronounced forward lean.

The fact is neither of us knows for sure because measuring the dynamic interactions at the hip joints is not possble (with any accuracy) with 3-D kinematic measurement and even with equipment such as force measuring plates it is spurious at best. My theory is just that, and based on strong indirect evidence and a lot of consideration of all possible permutations.

Your theory is based on critical thinking - which I applaud and which is one of the main reasons I'm doing this series and giving you my data - so you can think it through and come up with your own theories - Brian