Posted by: tom.guerry (tom.guerry@kp.org) on Wed Aug 22 09:11:02 2007

shawn -

Take a look at the old Nyman models:

http://www.setpro.com/stuff/rotational_simulation4.wmv

http://www.setpro.com/stuff/rotational_simulation5.wmv

http://www.setpro.com/stuff/rotational_simulation6.wmv


These simulations are basically a simple double pendulum with a couple of key modifications:

1 - the first pendulum is much more massive than the second.

the first pendulum (torso/flywheel) is analagous to the torso and connected lead arm and forearm. "connection" is assured by locking the front strut to the front of the flywheel mass ("front shoulder") and not letting the strut/"lead arm" (strut from front of torso/flywheel to handle of bat simulates lead arm/forearm/bottom hand gripping handle) lengthen as the swing proceeds. In other words, this is how a CHP is assured from launch/"initiation" (flywheel starts turning) to contact (max bat tip velocity).

2- the second pendulum is the less massive "bat"

3- the hinge between the two pendulums simulates the wrists

4-+++KEY POINT++++ the bat is also connected to a strut to the back of the torso/flywheel simulating the back arm connection from the back shoulder to the grip of the top hand on the bat handle.


When the simulation is run, the more force applied in a compatible direction by torque applied through the top hand, the more the swing "quickens", in other words, the sooner the bat accelerates or the "earlier" the batspeed.

This can only be demonstrated "reactively" in this model in 2D beginning with turning of the torso flywheel due to the limitations of the simulation, HOWEVER, the conclusion is that a torquing force DOES exist AND has a huge imact on trajectory where the larger the force (measured by increasing the mass of the back arm strut) the quicker the swing (this also fits with Jack's understanding that the longer the swing radius/higher the load, the more you need THT to prevent drag).


Nyman then showed aditional simulations where (due to either his lack of understanding OR his lack of appropriate motivation) he applied the top hand torquing force with the wrong direction timing and showed that the swing degraded.

This is simply a sign that misdirected top hand force is ruinous, which we already know as Jack has pointed out. It is what is traditionally known as the "top hand dominance flaw". As Jack points out of course, the force is generated early by the arms and forearms and shoulders and transmitted through the hands, not generated by the hands.

The simulation results are NOT "proof" that active/conscious application of THT can not exist as Nyman incorrectly concludes. Quite the opposite. They SUPPORT as much as possible Jack's "transfer mechanics" description.

This simulation shows that the torquing force is important even in the most simplified situation when 2 hands grip the bat just measuring in 2D only with pure turning of torso.

"REAL" mlb swings happen in 3D AND the development of body coil to drive these "transfer mechanics" (what gets transferred to the bat to drive it to contact) consists not just of torso "turn", but of torso resisting turn so that the torso stays back/motionless as the hips start open, then the torso tilts more than turns to create a cusp to permit hands to control timing and direction of swing by directing torso tilt, and only then to shoulders more purely "TURN" as hips DEcelerate.

This provides a LARGE 3D window for the swing trajectory to be controlled with THT/handle torque prior to the launch of the bathead out of the arc of the handpath. This "bathead launch" (approaching the traditional "lag" position)is analagous to the "pure torso turn" where the Nyman sims start.

This is way after the hands start torquig the handle and well after shoulder turn (often way more tilt than turn) "initiates".

Nyman set out to disprove JAck's transfer mechanics model and ended up objectively/unwittingly supporting just what Jack has described.

When you look at good power mlb swings, it is OBVIOUS (once the typical holes in human perception due to expectations is somewhat mitigated) that the bat starts turning before the shoulders move.

How can the shoulders be doing this ?