Posted by: Shawn () on Thu Sep 13 14:27:18 2001

>>> I think some separation and closing are important to permit both
transfer of momentum and rotation around a stationary axis.Turning the
body "in one piece" seems to inevitably give a swaying motion rather
than ground up rotation/momentum transfer.The amount of separation is
probably more dependent on an individuals unique
anatomy/physiology.Theoretically,the more separation you create and
the faster you "unseparate",the more power you can
generate,however,the intricacies of the motor system are much more
complex.
> > >
> > > I would summarize by saying some separation is necessary,but
more is not necessarily better.
> > >
> > > Epstein does believe there is some direct benefit to
increased/max separation and states heuristically that more than 30
degrees "torque angle" means more than 30 homers.Of course,these are
people who are already surviving in the majors,and I doubt he has done
the detailed video analysis you have.He also states that slim build
players separate more than the "thick" ones.
> >
> > Tom - well stated.
> > To all -
> > The key concept here IMO is that 'separation' or 'torque angle' is
a primary component of transfer mechanics. If the hips and shoulders
turn together (unit turn) the shoulders will not turn any faster than
the hips. This would result in a low rate of angular displacement of
the shoulders. The value of separation is using that separation as
part of the kinetic chain to accelerate the shoulders to a greater
rate of angular displacement as the hips decelerate. This is done
through transfer mechanics. Jack, your question is somewhat loaded. If
different amounts of torque angle create the same rate of angular
displacement of the shoulders, then there will be no difference in
batspeed due to the torque angle. However it may take one body type 20
deg more to get a specific rate of angular displacment of the
shoulders than another body type. This could be due to body type,
relative strengths and weaknesses of torso muscles, etc.
> > I think a better question is: Can a hitter increase the rate of
angular displacment of the shoulders by increasing torque angle?
> > I suggest that the answer is probably 'yes' as long as his body
transfer that energy. The answer is 'no' after that point where the
body is unable to transfer any more than it already is.
> > I also suggest that many hitters can improve batspeed in this area
because many do not have enough separation. I don't see to many who
are creating too much/wasted torque angle but it could happen.
> > I also think hitters can improve batspeed by more efficient
transfer mechanics through conditioning and training.
> > I suspect Epstein's 30 degrees is an approximation but if we take
that number as a guideline, then it says that good athletes with
efficient transfer mechanics will have major league homerun power with
30 degrees of separation. You can do it with less (strength vs.
elasticity) and its hard to get more than 40+ degrees (can't track the
ball with your head backwards).
> > Tom, I think your last response explains all this very well. <<<
> >
> > Hi Tom & Major Dan
> >
> > The points made in both of your post are valid and well taken. I
think that either "separation" or "unison" hip to shoulder relation
taken to the extreme is less productive. --- If we mean by "unison"
that the hips and shoulders stay in alignment during rotation, I can
think of no one who would advocate it. For the hips and shoulders to
remain aligned, would mean that the torque supplied by the legs alone
would drive rotation. The powerful muscles the torso would be limited
to just keeping the shoulders in line with the rotating hips.
> >
> > Taking "separation" too far also has limiting consequences.
Allowing the hips to open while keeping the shoulders closed means the
batter is giving up valuable leg torque angle on a low load movement.
Or in other words, the batter gives up valuable leg torque movement on
a freewheeling hip motion. Having the hips open (maximum separation)
while the shoulders remain closed means the legs will figure less in
the equation. They will have expended most of their torque angle and
shoulder rotation will rely mainly on contraction of the torso muscles
alone. --- This may be sufficient for a lower load shoulder rotation
as used in pitching a baseball or swinging a golf club where velocity
is more important than power. But swinging a 35 oz wooden bat requires
more use of both the legs and the torso (in unison- if you will).
> >
> > We would all agree that a 20+ degree separation does occur during
the inward turn to the launch position. But in my opinion, any further
freewheeling of the hips during the stride is not productive. At
initiation, both the legs and torso muscles are contracting in
"unison" to drive rotation. At the start of the swing there will be
another 10+ degrees separation. But that separation is due to
overcoming the added inertia of the upper body and accelerating the
bat-head - not freewheeling. From that point on, the hips and
shoulders rotate simultaneously (in "unison" - may not be the best term).
> >
> > You may wish to bring up the "rubber band effect" or momentum, I
would be happy to discuss them with you.
> >
> > Jack Mankin
> >
>
> "But swinging a 35 oz wooden bat requires more use of both the legs
and the torso (in unison- if you will)"
>
> The word unison is ambiguous here. If you mean the legs and torso
are locked together, we are back where all of us agree hitters
under-perform - unit turn. Jack, you refer to hip turn completely
unattached to transfer mechanics as freewheeling. Good term. A
complete disconnect also doesn't make sense.
> IMO they all work together but in overlapping sequence, not in
unison. In rough terms, the legs/hips turn first creating
separation/torque angle with the shoulders. While the hips are
initially 'freewheeling', the torso is in fact being stretched
(stretch/plyometric response). The torso's contraction response
happens while the hips are still turning - sequentially later but
overlapping.
> In effect, a wave or ripple of energy is moving up the body from the
largest muscles (quads, gluts, etc.) through the torso (transfer
mechanics) to accelerate the shoulders to a higher rate of angular
displacement (shoulder rotation).
> That's the kinetic chain.
> As far as I can tell, none of us think the hips and shoulders should
be in lockstep. None of us think that simply turning the hips open
with no connection to the shoulders through the torso does much good
either. The effective parameters are somewhere in between. AND they
are subtly different for different body types - amt of strength, amt
of elasticity, coordination of movements, length of bones, quickness
of muscular strength (power), etc.
>
> As I reread your post, I think we are in agreement on this issue.
And as always you are right that none of this has any effect unless it
is transferred to increase the rate of angular displacement of the
shoulders and ultimately into batspeed.
>
> Additionally, IMO the deceleration of the hips and shoulders (also
sequential) is part of the chain. They play a part in the later
acceleration of the bat barrel, another area for analysis.
>

Tom,

Here's a clip that I promised many moons ago. One thing, lay off the
reactive torque stuff :).

http://www.angelfire.com/games3/s_bell/seperation.html

Looking at the foot drag in this clip, I would say Griffey is slightly
early (pulling the ball), and he seems to be adjusting the hand launch
(flexing). I can 'follow' what your saying (I doubt anyone else can,
:) ) and depending on the hitter, Hank, Mantle, etc., timing plays a
big role in what you see from swing to swing. Adjustments can create
some dramatic results. Just watch Sheffield, he's all over the place
in the batters box.