Posted by: tom.guerry (tom.guerry@kp.org) on Sat May 15 08:27:35 2004

>>> I have been reviewing many clips of hitters such as Sosa, Jones and the likes and
have been noticing that most are getting their back heel pointing to the sky prior to
contact with the baseball. Most of these players are actually dragging their foot, like a
pitcher would coming off the mound, prior to contact. In the clip I have of Chipper Jones
he is actually off the ground with his back foot prior to contact. I do not notice any
mention of this in any of your information and I would like an analysis of this in your own
words. I have my own theories on this which may or may not be correct (theories are not
usually 100% correct, as they would then be called FACTS).
>
> My theories revolve around the ability to generate more seperation between the hips
and shoulder rotation (xfactor) due to no internal rotation of the back foot and subsequent
upward placement of the back heel. Increased ability of the hitter to keep their hands back
during the initiation of weight transfer to the front foot prior to the application of THT.
>
> For me to explain my theories in deteail without a video or personally showing them is
very wordy and difficult and will require a couple of days to find the time to capture them
in writing. If you need them prior to responding please email me personally. <<<
>
> Hi Dave
>
> Let us first address your theory. You stated, “more seperation between the hips and
shoulder rotation (xfactor) due to no internal rotation of the back foot and subsequent
upward placement of the back heel. Increased ability of the hitter to keep their hands back
during the initiation of weight transfer to the front foot prior to the application of THT.” –
Dave, that is an excellent observation. Keeping the hips and shoulders in-line restricts the
upper-body movements necessary for THT. Opening the hips 20 to 30 degrees allows
much freer movements of the arms and shoulders especially while the back-elbow in
lowering.
>
> I am not sure of the definition of “xfactor.” I do not agree that a batter should try and
attain "maximum separation” before initiating shoulder rotation. Below are couple of post
from the archives on this topic. Your input would be appreciated.
>
> Great post Dave.
>
> Jack Mankin
> ##
>
> It is quite obvious to anyone who has studied the baseball/softball swing that the hips
are ahead of the shoulders or hands at the start of the swing. The hips start to lead the
shoulders well before the swing is initiated. In the Frame-by-Frame section of the site
(Swing Mechanics) I wrote, “The batter has rotated (inward turn) his lead shoulders away
from the pitcher.” So the hips already lead the shoulders by 20 to 30 degrees as the batter
prepares his launch position (look at Frame #B).
>
> Frame #D shows that some (not all) batters develop even more separation during their
stride. I stated, “The lead knee has started rotating around toward the pitcher;” (not all -
after Barry Bonds' stride his lead knee still points more toward the plate than the pitcher).
This means the hips now lead the shoulders by approximately 30 degrees. All of this
occurred before the swing was fully initiated. From viewing the “Frame-by-Frame” section,
everyone should see and understand that the hips lead the shoulders at the “start” of the
swing. ---But we must also remember that at the “finish” of the swing, the shoulders will
have rotated past (and now lead) the hips. And after full initiation, the hips and shoulders
do rotate at the same time. When studying the swing in frame-by-frame motion, you can
really see this happening.
>
> I used the term “unison” to denote mechanics that during initiation have all the muscles
in the legs and torso are contracting in unison to drive shoulder rotation. This is to
distinguish it from “sequential” mechanics where the batter first contracts the leg muscles
to rotate the hip (while holding the shoulders back) and then later fire the torso muscles.
>
> Note: There is a 3-stage type of mechanics being taught where the batter is taught to
(1) stride, (2) use the leg muscles to fully rotate the hips while keeping the shoulders
closed (3) fire the arm and torso muscles to bring the hands and rotate the shoulders. ---
I refer to the hips rotating while keeping the shoulders closed (no load rotation) as
“freewheeling.” For there to be a “kinetic chain” (or rubber-band effect), continuously
energy must be supplied from the ground upward to rotate the shoulders. This means, all
muscles in the legs and torso must be contracting in “unison,” not “sequentially.”
>
> Although all the muscles are contracting in unison at initiation, the hips will still rotate a
few more degrees ahead of the shoulders due to the increased load of accelerating the
upper-body mass and overcoming the inertia offered by the bat to acceleration – not from
sequential timing.
>
> ##
> You stated, “This is what Mike Epstein called "tilting to avoid the tilt." In other words,
you must tilt if you are going to get on the plane of the low pitch.” - A number of good
hitters, including Hank Aaron, swung around a more upright axis. On a few of Aaron’s
home runs, his axis actually leaned forward on some low pitches and he did not swing
down at the ball. Therefore, even though I teach hitters to have their axis leaning 10 to 15
degrees away from the pitcher, I cannot call it a “must” or absolute.
>
> BHL, as I tried to explain to you before, you are equating body tilt at contact to having
more weight on the back-foot at contact. This is just not the case. Many hitters, especially
those with longer strides, have a tilted axis but will have little to no weight on the back-
foot at contact. In fact, some will have the back-toe off the ground or sliding forward. I
seriously doubt that those hitters feel a lot of weight on the “back of the rear thigh.”
>
> I also feel little weight on the back of my rear thigh at contact when I use the extension
of the lead-leg to assist in body rotation. Even though my axis is tilted, my front leg
seems to be supporting most of my weight through contact. --- As far as controlling
lunging, I have found that stressing to the batter to have their lead-shoulder pulling back
toward the catcher at contact is more effective (and produces a better swing) than having
them drop the back-shoulder.
>
> Jack Mankin
>

a couple of theoretical/hypothetical comments.

1- degree of separation is not nearly as important as the dynamics of coiling/
uncoiling.Uncoiling or reversal or unloading or shortening is when momentum transfer
happens.Nyman desribes this as eccentric to concentric muscle action (muscles applying
force while lengthening,then shortening).this key last quick
bit of stretch and shortening is called xfactor stretch in golf by zig's
company,skilltechnologies:

http://www.skilltechnologies.com/XFactorStretch.htm

2- while looking at video to identify universals is an important method,it can also be
important to look at some of the extremes/exaggerations to illustrate actions that may be
present to some degree in all good swings.In the case of "internal rotation of the back
leg",an important action repeatedly seen in some hitters is the reactive EXTERNAL rotation
of the back leg/slipping back of back foot when the hips begin to twist open during the
end of the forward stride.staying internally rotated could possibly be thought of as
resulting in reactive external rotation.See youthbaseball clips of back foot of Lugo or
Glauss,for example.Good coil/uncoil also requires good coordination/synchronization
between upper and lower body.As the hips open and the torso stays back (rotating/
twisting/coiling separating/creating xfactor) going into toe touch,the lead leg and back
arm externally rotate together to open the front foot some and drop the back elbow
toward the slot.This is when the back foot can be seen to reactively turn backwards.

Later at heel drop,blocking of forward/downward weight shift can then transform "linear"
momentum into rotational momentum since the body is already twisted open and the
front foot has created a base for leverage.This ends the "translational" portion of the
swing.This boosts the angular opening velocity of the hips to maximum and creates
xfactor stretch in preparation for optimium uncoiling/unloading which happens(maximum
separation) after the torso has turned forward some,analagous to maximum separation/
end of xfactor stretch during the downswing( hands back down to about 11 oclock for full
driver) in golf.

More separation may be better,to a point,as long as the dynamics of xfactor stretch/
reversal are not degraded.

3- back foot video landmarks-In general,the motions of the back foot are an interesting
video landmark(seen well in some) to use as a sign of good momentum transfer/
sequencing.after the reactive external rotation,the heel then turns over as the foot goes up
on the toe (hips continue twisting open),then the back toe drags reactively when the
uncoiling/unloading from the middle up is happening (bat should be in lag position at this
point).Center of mass of bat should be ready to extend past/out of arc of handpath to
capture momentum at this point.THT/uncocking of the bat prior to this makes this more
effective (in double pendulum terms,hinge/wrist angle between bottom hand and bat stays
about 90 degrees due to application of torque resisting narrowing of hinge angle).See
carini reference from prior discussions on double pendulum.

Finally,the back foot will turn back reactively when the lead arm disconnects/bat
decelerates at/after/near contact.