Posted by: ray porco () on Thu Nov 3 17:28:47 2005

Posted by: Jack Mankin (MrBatspeed@aol.com) on Tue Nov 1 15:12:30 2005

Hi Dougdinger

I agree with your opinion. Weight shift, back or forward, is more to maintain balance to the launch position than it is to generate energy for the swing.

Jack Mankin

------------------------------------------------------------------------------------------


More to maintain balance, than generate energy. That is, with all due respect, in my opinion, absolutely wrong.
If you started a swing without a weight shift, could you not maintain your balance? I mean, you would not be moving, what could possibly cause you to loose your balance. Why shift weight then?
And by the way, no-stride hitters do weight shift, right up until heel plant.
And Bagwell’s negative stride, still loads his front leg.

The following is a somewhat condensed reprint of an earlier thread started by me.

Jack, you did not reply.

Would you care to now?






take weight shift out of the equation ray porco Sat Aug 27 17:09:55 2005


here’s the link:

http://www.batspeed.com/messageboard/22834.html



ray porco wrote:

Jack (Board),



OK, instead of DEFINING “weight shift”, why don’t we ask WHAT DOES IT DO?

An elementary experiment can reveal the hidden secret.

To find out what “weight shift” adds to a swing, all one has to do is remove it from the swing and see exactly what is missing.





So if one were to take the “weight shift” out of their swing they should be able to tell what is missing from their swing and therefore what it adds to the swing and therefore why we/everyone “weight shifts”.





If “weight shift” STOPS before body rotation begins, this should be fairly easy for you/anyone to attempt. Assume the position you would be in when rotation starts and simply start your swing (rotate) from that point, with no forward movement of your Center of Gravity. Apply THT or BHT, work your front shoulder all the way back to the catcher while your top hand assumes the “L”,but simply do not allow your Center of Gravity (your belly button is approximate enough) to move forward.

I know what my results are.
In fact I would ask all readers of this post to try this, and disclose their results.

One more thing, I also know (fairly certain) the “why” of my results. It is very evident (at least to me), when you try.


---------------------------------------------------------------------------------------

grc wrote:

ray..."Assume the position you would be in when rotation starts and simply start your swing (rotate) from that point, with no forward movement of your Center of Gravity.".....

as chrley lau said, you have to go back before you can go forward...whether a stride is simply overcoming inertia or whether it is something else in addition to overcomimg inertia, the situation you described is simply starting a swing from a dead stop...so adding the stride/load/go back first, whatever you want to call it, it is needed to overcome inertia...but does that mean it is "weight shift"?...if not, than the question still remains, what is weight shift?....if so (if it IS weight shift), then what IS weight shift over and beyond simply an inertia-busting mechanic?

what i would like to know is how/why some coaches equate x amount of weight shift with y amount of power...

--------------------------------------------------------------------------------------------------------------

ray wrote:


grc,

Excellent reply and it’s very fitting that you should be the first to reply (actually I didn’t think anyone would).
I say “fitting” because you started a thread (one of the best of batspeed) back in 2001 that really has the answer. I certainly won’t take any credit, but I will place it where it is due - Major Dan.

Please read the thread and we will talk (write).

http://www.batspeed.com/messageboard/2679.html

-------------------------------------------------------------------------------------------------



Jim C wrote:

I'm curious about your 'why.'

I can't get as powerful a swing when launching from the experiment position alone. I'd have to surmise that either rotation begins before heel plant or that the weight shift 'rolls-over' into rotation, transitioning through the heel plant in a way that cannot be attained by mere explosive muscular exertion as in the experiment.

"Glide", "swoosh", "swoop", "Gravity is energy" type of descriptors come to mind.

So, what is the evident why?

Thanks.

____________________________________________________________


ray porco wrote:

Jim,


Some definitions:

The centre of mass of a body is the single point about which every particle of its mass is equally distributed. If the body were suspended or supported at this point, it would be perfectly balanced (eg, balance a pen or pencil on your finger). Each body behaves as if its entire mass were acting or being acted upon at its centre of mass. The centre of gravity refers to the centre of mass in one direction only, that defined by the direction of gravity - it is the net location of the centre of mass in the vertical direction. For the human body, of course, the location of the centre of gravity changes with the body configuration or posture. In the anatomical position, the centre of gravity of adult humans has been found to be slightly anterior to the second sacral vertebra (Braune and Fischer 1984) or approximately 55% of a person's height (Hellebrandt et al 1938).]

The line of gravity is the line which passes from the centre of gravity of the mass toward the centre of the earth.

The centre of pressure is the location of the vertical ground reaction vector from a force platform. It is equal and opposite to a weighted average of the location of all downward (action) forces acting on the force plate

http://www.hkin.educ.ubc.ca/biomech/labtour/forcep.htm

http://www.amtiweb.com/bio/force_platform_sys.htm






>>>“So, what is the evident why?”<<<





As Major Dan said, “Simply pushing with the front leg is not as strong as loading the front leg, then pushing the load back.”





We shift weight to LOAD the front leg, but that’s not all.
What we are talking about, (actually not talking about enough) is not JUST a mere SHIFT in WEIGHT, but a CONVEYANCE OF PRESSURE. A TRANSFER of FORCE.
And that conveyance DOES NOT STOP at “heel plant”, rather it stops AT CONTACT.
My proof?
Well force plates can scientifically confirm, but all you really have to look at, is the rear foot off the ground (or barely on the toe) at contact. Where is the “Center of Pressure” at contact?
Quoting Major Dan, “The front leg is not just used to bounce off of, but to catch the body weight and redirect it.”


---------------------------------------------------------------------------------------------------------------------


Hitter wrote:

You DO need to go back to go forward. Unfortunately for Charlie Lau, the swing does not go forward--it rotates. The axis of rotation does not change from the beginning of rotation until the end. That can only tell you one thing. A hitter is no going forward. He is stationary.

--------------------------------------------------------------------------------------------------------

ray wrote:


Hitter,

didn't try the simple experiment did you?

------------------------------------------------------------------------------------------

Hitter wrote:

Believe me or not (I know you probably won't), but I have. It's the same thing. Now, maybe I am not doing something right when I stride that can only be accomplished when striding, but judging by some no-stride Major Leaguers, I doubt that's the case.

--------------------------------------------------------------------------------------------

ray wrote:

Hitter,

This is NOT an issue of stride vs. no-stride. This is weight shift or no.
Weight shift ends with "heel plant".
Rotation starts at “heel plant”. If you think not, then you must argue with Jack who always has contended that rotation does not start until weight shift ceases.
So to try the simple experiment that I suggest, - assume a hitting position that you arrive at when your HEEL is planted, and from that position (without your belly button going no more forward toward the pitcher) try to hit a ball as hard as you could hit a ball if you HAD taken your normal swing with a weight shift.

----------------------------------------------------------------------------------------------------------