Posted by: tom.guerry (tom.guerry@kp.org) on Sun Sep 18 10:44:36 2005

> Post 1:
> My question is at what point during shoulder rotation do you feel the arms should swing
away from the body, where should the hands be relative to the chest (ie perpindicular to
sternum, back shoulder, etc).
>
> Post 2:
> .....when do you feel, in an ideal situation (because in trying to reenforce mechanics mith my son I try to work under ideal onditions) as in hitting off a tee, should the arms begin to move away from the body, and where should the hands be relative to the chest at contact? Also, when should the bat head begin its upward approach (assuming that if the plane of the swing is circular and the bat head must swing down, parallel to, and then up relative to the ground), relative to contact.


phil-

Thanks for sticking with it and repeating and restating your questions.

ray- thanks for the detailed reply.

Here are some of my general theoretical/analytical thoughts for consideration.

I believe Jack is describing a high batspeed rotational/connected swing that is optimized for quickness. For this reason he "ideally" likes the top hand to stay near the back shoulder and for the back arm not to lose flex in the elbow prematurely during loading.

It is hard to discuss details like phil mentions without some agreement on a basic swing model. When does loading vs unloading start,for example. What is a swing plane/how is it important.

Now to tackle the actual restatement of post 1 and 2 questions:

"during shoulder rotation" would mean after shoulders start turning forward,which I believe jack calls "initiation" until contact. Also according to jack,ideally shoulders continue to turn until contact,not stopping prematurely.

One complexity here is that the body is continuing to coil/twist/load even after the shoulder turn has started as the load and unload motions of the body overlap. Just at/after "initiation", the hips and shoulders turn on a different plane at this point and the hips turn more quickly. This means that during this time which includes,I believe, what jack calls "tht at launch", the arms must be doing something to finish loading properly (including accelerating the bathead as final quick coil of the body s "stored") and prepare for unloading (release of stored momentum is triggered by bathead firing out of radius of handpath, after initiation- this would argue that semantically speaking at a detailed level "launch" could be defined as occurring AFTER "initiation"). As far as "swing away from the body", it may be more important/easier to esimate (as phil says "where the hands will be") when the hands get away from the body or perhaps more "accurately"/importantly when/if the handpath extends or distance/radius from bathead/sweetspot/center of mass (all slightly different) to center of rotation starts to lengthen (it should not before contact)..

Jack's theory would appear to me to predict that a certain swing radius must be set before any unloading starts to fire the bathead and that this radius should not lengthen before contact.

Whatever arm action there is must then establish and continue this type of connection from launch to contact to enable the "rotational component" of a good swing.


Before and after this according to jack's theory,the arm action must transmit and create forces that also torque the bat via push pull action of the hands.Prior to launch this must optimize coil/load of the body. After launch arm action must allow good transfer mechanics to transfer momentum to the bat and preferentially transform the momentum into turning/angular acceleration of the bat,not dragging the bat longitudinally.

So,of your choices,I would recommend more focus on "where the hands should be" as opposed to arm location.Still both can be analytically informative.

"Ideal..as in hitting off a tee"- I would say hitting off a tee has little to do with a real swing and most tee work as it is traditionally described will be a waste of time. Jack's use of a
heavy bag is far more useful in demonstrating/learning,whether or not it is combined with tee use or batspeed measurement (I look forward to new info frm Jack about the steering wheel knob type training device).

Next comes the swing plane which is a complex but crucial topic necessary to relate how ideally the bat moves in space to how the body needs to move to swing the bat quickly in the desired adjustable plane with quick acceleration maxing out at contact (contact likely to be soilid due to also maximizing spatial contact zone as a secondary requirement to minimizing timing error) with a "bat angle" that results in a fair ball.

Body coil,swing plane and the relation of body action to shaping the swing plane are much better understood in golf due to the nature of the task (infinite reaction time and premium in trajectory and exactly where ball ends up) and the big money in the sport.

The hitting swing plane will be a somewhat elongated oval due to the fact that the hand path IS still arcing as the bat swings out,but the circular plane description is fairly close to the quick swing which results from the mechanics that jack describes where the shoulders turn the handpath (given good arm action providing adequate loading and good transfer mechaniques enabling well blended torque and rotational swing components) since the shoulders pretty much stop at contact/max speed in this type of short quick swing.

Given this the position of the bathead question phil asks can be addressed somewhat. The arm question probably requires further breaking things down into back arm which is more likely to extend in some "ideal" cases (long swing radius as for middle out) and lead arm which must retain connection and a handpath arc that does not let the radius of rotation of the bathead lengthen.

With regard to the lead arm and swing radius,then this brings us to the KEY question of when/how the swing radius is set.

This in turn depends on some agreement that there is a universal sequence of swing, and on what the sequence is/how it can be described.

Then you could state the requirements of arm action as necessary to permit good enough loading to then adequately power the right swing radius that is set for unloading and maintained without extension until contact without deceleration.

From reading a lot of hitting and golf sources, I would say one universal hitting phase sequence that can work to support adequate analysis is:

1-inward turn

2-hip cok

3-handcok (primarily finishing bat cok with back scap pinch)

4-wind rubber band-"pre-launch tht" is associated with this-as unload motion starts middle out,overlapping with ongoing load motion which is working its way further out via torque

5-drop and tilt- associated with "THT at launch"/sit to hit,where last bit of quick coil stretch is produced before load program is finished with good storage of energy ready to release in next phase with firing of the bathead-last adjustments must be set by the end
of this phase-swing radius,swing plane amd swing is no longer under much conscious control (actually,I think checking swing can still supervene at/after this point in some hitters).

6-swing/get out of chair/maintain box/hook handpath if necessary/do not let handpath extend/"bht"/pull with bottom hand/lead shoulder 105,etc,etc

With some sort of agreement,then on a lot of context/modelling,then your question could be answerred,or at least discussed in a meaningful way.