Posted by: () on Sun Mar 16 17:30:30 2003

A batter with good transfer mechanics will deplete all energy for
> generating bat speed prior to contact. Question: if a batter has
> strong wrists should she delay THT and BHT until the last
> possible moment, which would result in a large amount of
> tension to get the energy depleted. or would it be better to start
> applying the torque at launch, which may result in the energy
> being depleted with less tension at contact. another way to
> phrase the question might be: should torque be initiated or
> timed to culminate at contact with massive tension to
> completion,or a more relaxed slower torque?
> > i think i know the answer but would like to hear some first hand
> experience... thanks very much!!!
> > love this board...Rich
>
> I vote for gradual.
>
> My interpretation of Jack's swing model is that it consists of 3
> arcs.1-hip rotation,2-torso rotation driving handpath,hands fixed
> to torso,3-bathead arc rotating theoretically around point
> between hands.Of course this is a great simplification,but
> seems reasonable.Also.as the bat turn picks up speed(goal is
> max acceleration)the hands role becomes more and more
> reactive to bat motion.
>
> For a quick,short rotational swing,transfer of force and
> momentum through the body appear to require the transfer
> mechanics described by Jack which have the more steady and
> early turning forward of the 3rd arc.
>
> My idiiosyncratic thinking is:The first part of the swing involves
> "cocking" or loading the hips as the stride foot lifts.Then the
> torso loads via what Nyman has described as scapula
> loading(pinch back shoulder blade,back elbow goes up) which
> creates some counter rotation of the torso as the stride foot
> goes out.Then upper/lower body separation is created as the
> hips begin to uncock,usually synchronized with the front thigh
> starting to turn over(external rotation front leg associated with
> opening of hip)and the back elbow beginning to drop as the
> back arm externally rotates.
>
> The hip uncocking/opening also immediately involves the back
> leg internally rotating.The back leg and front arm prefer to work
> synchronously which means that the lead arm internally
> rotates(works up tightening,not loosening connection) as the
> back leg does the same.These coordinated movements are the
> start of the 1st(hip) and 3rd(bat)arcs.These 2 out of phase arcs
> continue loading/separating the body.The hips continue to open
> and the torso/hands continue to "stay back" as the internal
> rotation of the lead arm and the external rotation of the back
> arm("form the box") turn the bat back toward the catcher and
> connect the hands tightly to the torso.This creates a stable/
> efficient configuration to then allow transfer of momentum
> through the body,transforming this energy into quick acceleration
> of the bat arc.
>
> Since before "hip cock" the center of gravity of the body has been
> put in motion and kept in motion,controlled mainly by flexing
> action of the back leg(this also creates a nice shape when its
> time for the back leg to internally rotate to support hip uncocking/
> rotation).As Nyman explains,the hips must be accelerated to
> maximum turning velocity as they hook up and start to turn the
> torso to get the most efficient transfer of momentum.How well
> the hips decelerate is then a measure of how efficient
> momentum transfer was.The front foot resistance to center of
> gravity motion permits the hip turn to accelerate to the
> maximum(if weight has not gotten too far forward) and then
> "launch" the 2nd arc(torso).
>
> This is a different sequence/transfer mechanic from the long
> rotational swing of golf(still ball) for example.In the case of golf,a
> common teaching(and design principle for some testing
> machines) is to keep the wrists cocked as long as possible
> based on the physical principle of the "double
> pendulum".However,in addition to the infinite reaction time of
> golf,the swing is much longer(bigger backswing and contact
> after wrist roll) so you have a different solution to the task.

> THANKS for the well thought out reply... that's what i've been coaching my daughter. Rich