Here are a few observations that may be of help:
- Rotating into foot plant and creating separation.
There is NO rotation to foot plant. What you have is the beginning of the stride where the front knee is closed off but then it opens very gradually and becomes very linear. Velocity is rotation. More specifically velocity is quick rotation. The sequence is keeping the hips closed off by keeping lead leg internally rotated until just before foot plant and then rapidly externally rotating the front leg into foot plant. The goal is to rapidly snapped the hips around while keeping the upper body closed off such that you create a pulling action of the hips across the midsection on the upper torso.
- Lack of effective hip rotation leading to poor or no hips to upper body differential.
Velocity is capturing the rotational momentum of the hips and so doing create additional pulling action by stretching the muscles that connect the hips to the upper torso and then contracting to give an additional boost to rotating the upper torso. This segmentation of hips and then upper torso not only boosts upper torso velocity it also reduces the rotational moment of inertia of the body so that you can create faster rotations.
This is the figure skater effect. A figure skater creates a fast rotational spin by first adding with them arms outstretched i.e. slow-moving large moment of inertia and then pulls the arms in close to the body which reduces the moment of inertia are but for the same momentum creates greater rotational velocity.
In other words by segmenting the rotation hips and upper torso as opposed to rotating hips and upper torso together you minimize how much effort is required to rotate.
- Bleeding momentum forwards by having a soft foot plant.
Once the front foot comes down the lower torso (hips) have to brace up so that the upper body has a firm foundation to work against. Continuing to allow the hips to move forwards bleeds away momentum that can be used by the upper body.
- Throwing around the front hip joint versus throwing over the front hip joint.
The axis of rotation once you going to foot plant is around the foot plant hip joint. What the video shows is more of a “jack knifing” forwards over the front hip joint as opposed to rotating around the front hip joint. Effective utilization of momentum around the front hip joint will cause the body to head towards first-base after release of the baseball.
Again these are a “few” quick observations. I’ll get back to (as time permits) you privately with more discussion.