Some great hitters seem to often use their hips in a manner that causes their back foot to move "forward and behind" thru contact. I see the rear toes moving under the rear heel as the foot moves "forward and behind". Many youth hitters seem to have the opposite movement where the rear heel moves over the toes. It seems to me that the "toes under" "forward and behind" encourages hip drive and a quicker inside bat path but I would be interested in your thoughts about what it means and how to coach it...if at all.
Hope these links work.
https://1drv.ms/i/s!AtBvUEZaQJY1gjsE3uVgNyvYV0Qi Chamberlin
https://1drv.ms/i/s!AtBvUEZaQJY1gkeDMnDxzJsgGwmQ Yee
https://1drv.ms/i/s!AtBvUEZaQJY1gjg0dipsKZhNb3Xs Altuve
https://1drv.ms/i/s!AtBvUEZaQJY1gjmBDbGNoMWpIuBe Cabrera
https://1drv.ms/i/s!AtBvUEZaQJY1gnHg6OoRCDuEt6ml Clemente
Hope these links work.
https://1drv.ms/i/s!AtBvUEZaQJY1gjsE3uVgNyvYV0Qi Chamberlin
https://1drv.ms/i/s!AtBvUEZaQJY1gkeDMnDxzJsgGwmQ Yee
https://1drv.ms/i/s!AtBvUEZaQJY1gjg0dipsKZhNb3Xs Altuve
https://1drv.ms/i/s!AtBvUEZaQJY1gjmBDbGNoMWpIuBe Cabrera
https://1drv.ms/i/s!AtBvUEZaQJY1gnHg6OoRCDuEt6ml Clemente