In response to lhowser: Again in high speed video of my DD, Sarah, her hip rotation has actually started prior to the landing foot being firmly planted. As she strides (leaps) out her landing foot is at about a 60 degree angle to the powerline--by the time the foot/heel has planted her foot has counter rotated back to about 45 degrees.
Mark you spend a lot of time looking at elite level hitters, do see some similarities?---I believe I have seen this similar foot rotation(and subsequent hip rotation) prior to heal plant in some big time major league power hitters.
Second point for lhowser---in most elite level pitchers I see the hip rotation initiated prior to the shoulder rotation. This is what is meant by moving up the kinetic chain. This is certainly evident in Ueno and I know it is what my DD does.
Rick
Before you asked the question I was answering it when you spoke of hip rotation prior to foot being planted. I would say in hitting, hip rotation prior to toe touch or, as some say, rotation into foot plant. As to foot rotation, I look at it as a result rather than a cause but it is an indication what the pelvis is doing if the leg is well connected to hip loading and unloading rather than fanning open on it's own.