Posted by: tom.guerry (tom.guerry@kp.org) on Sun Jun 26 09:57:00 2005

If people are looking at clips,here is some more stuff to look for.

This stuff is very hard/difficult among other reasons because there is no agreed upon frame of reference from which to make observations. For example,if we say the "axis of rotation is stable" when might it really have to be stable (this does not even address the idead of what stable exactly means).

I would say the axis actually is shifting related to how momentum is generated and transferred and needs to be assessed in this ight.Body parts sequentially separate/twist then untwist then decelerate as the next body part accelerates and so forth. Posture and "balance"/weight shift must be such that momentum is efficiently directed (momentum has direction due to its velocity componant) and transformed into bathead speed (CHP important for ransformation,axis important for transfer).

"Linear" momentum (center of mass of body moves forward andor down),either back to front or up/down/up can be converted to rotational momentum by accentuatng twist/torsion/separation.Bagwell uses more up/down while others might use more back to front/stride.Then all have to block this "shift" with the front foot after the hips have twisted open some so the bloking can accelerate hip opening while the hands/torso "stay back" (linear momnetum stopped to accentuate coil which can then provide more momentum for uncoiling.Dropping/"sitting to hit" can likewise be converted/contribute to twist/coil/separation of the trunk (accentuate "body torque".

Absolute degree of stretch/separation is far less important than 1-the spatial orientation of joints/bones levers or 2-the time/dynamics of the stretch/reversal.(see xfactor
STRETCH with emphasis on "stretch" not xfactor (xfactor is degree of stretch).

Even more complicating is the fact that this momentum creation, transfer, transformation is only as "near instantaneous" as bone and soft tissue (soft tissue including muscle stretch/force production while stretching and contracting with superimposed effect of elastic properties of muscle/ligament/fascial/other non bony tissues) allow which means there is overlapping/simultaneous loading and unloading as coiling and uncoiling are underway simultaneouslly- as body center unloads/hips unock middle out,more stretch is being created at the same time.Thought of another way,this means hips are opening faster than torso to create dynamics such that torso is still loading/stretching AFTER forward handpath/CHP has been initiated.Also more complexly,this is happening in 3D,but with 2D spatial requirements concerning directionality of momentum transfer.

Thought of yet another way,the axis of "rotation" is shifting.So in Mankin terms related to a primary frame of reference concerning how the bat is moved to preferentially accelerate the bathead as efficiently as possible/not waste energy dragging the bat longitudinally, this might mean that "pre-lauch THT" and "THT at initiation" uncok or accelerated the bat mainly by muscle force production with active and reactive forces being involved while at the same time torso stretch/momentum dynamics are being optimized/furthered.

"THT at launch" would be the same as "THT at initiation" or "THT" when the forward handpath begins. This would continue as the bat uncoks and "body torque" increases.Epstein would refer to the same phase of the swing as "drop and tilt".

At this point.the already opening hips are turned open at max velocity to increase twist/coil/separation.There does have to be a "stable axis of rotation" which at this point is somewhat centered so there is no "hip slide"/sway present that would prevent optimal
body coil/twist.

In general,at this point,the center of gravity is still moving forward and the upper body/"head" needs to be behind or even with the belybutton.While the hips are turning around a stable/centered axis during "THT at initiation" or "drop and tilt" with no
significant "hip slide",at the same time the shoulders head continue forward as the shoulders/scaps are tilting.This combination of lead shoulder elevation and upper body "forward weight shift" finishes the stretching of the torso/creates "xfactor stretch" and prepares for sending momentum UP.Bat is still uncoking,not accelerated by momentum transformation yet. The timing is such that maximum stretch is about when the center of mass of the bat leaves the arc of the handpath which will initaite unloading/launch of the bathead as "body toque" reverses primarily via tissue elastic properties.

This point in the swing is more at or before the traditional "lag" position. At which point the forward progress of the body's center of mass has stopped and after which it will go UP slightly- the sit to hit has ended and you will then get out of chair from here to contact as Bagwell's belt going up shows. Bagwell does NOT show much upper body going forward to accentuate the effect of shoulder "tilt"/lead shoulder elevation,but many others do-see Sosa for example.

The axis for bathead launch from lag to contact is more toward the front hip as it is shifting from the more central/spinal axis of hip turn to a more forward axis after the hips have decelerated and center of gravity is being forced up. By the time of contact there has been even more shift of axis toward lead shoulder,perhaps moreso with handpath hook.

A quick wethervaning note-the cue is a mix of spatial change (lead elbow located/working up or down in slot) and feel. When the lead elbow lifts for a "higher" connected position to "get on top" for the high location,the subsequent "feel" is that the swing is relatively level/down as compared to the elbow being low in the "slot" (lead elbow NOT back elbow "slot") for the low location where you swing much more UP.

Cues are of course always a double edged sword.They can always cause massive confusion,but they occasionally add value by permitting communication and by confirming the importance/presence of "universals" where the same swing "requirement" has been described by various teachers/terms that emphasize different underlying aspects of the "universal reqirement".

For example,THT at launch is the same swing phase as "drop and tilt" which is the same as "pulling knob of bat with hands not shoulders" (Lau).Important elements of truth concerning the same universal swing phase is present in each of these descriptions.