Posted by: JJA () on Mon Nov 1 06:55:42 2004

>>>> I hope this has made some sense, Regards, Rich<<<<
>
> Rich,
>
> Good post.
>
> Particularly:
>
> >>>the uncocking of the bottom hand wrist is like casting with a fishing pole. when you're getting ready to cast and the pole is over your shoulder your wrist is cocked. when you whip the pole forward you uncock your wrist as the pole travels over and forward.<<<
>
> and
>
> >>>The top hand is being rotated back by the forearm muscles rotating the hand.(into the palm up position) this is the opposite force on the bat from the uncocking of the bottom wrist.<<<
>
> and
>
>
> >>>i can lower my back elbow and not apply THT.<<<
>
> and
>
> >>>...i'll coin the phrase WHT(wrist hand torque...<<<
>
>
> Arguement against has it that the wrists/hands cocking/uncocking are a by-product.
> That the wrist muscles (and forearm muscles) cannot contribute a whole helluva lot.
>
> BUT THEY DO.
>
> I’ve tried to go down this path before, here at batspeed [“discussion board down again” wiped it out] and at hitting-mechanics.org, but no takers. It is extremely involved, and quite frankly I don’t have the inclination to try again. But for those eggheads that do, - go to “Google” and type in ‘interaction torques’.
>
>
> ray porco
>
>
>
>
>
Ray,

I actually did go out and purchase the golf paper you recommended some time ago: "Examining the delayed release in the golf swing using computer simulation" by Springings, and Mackenzie, Sports Engineering (2002) 5, 23-32.

According to this paper, page 27, the maximum muscular torque generated by the torso was 112 Newton-meters, for the shoulder joint 87 Nm, and the wrist joint peak torque was 22 Nm, which the authors state compares well with direct measurements on low handicap golfers. Thus, the torques generated by the wrist are rather small compared to the large muscles of the body, which I hope isn't a surprise to anyone.

Of course this is the golf swing, but the baseball swing seemingly can't be appreciably far from this model. Furthermore, as you know, this article does quantify that late wrist release can increase clubhead speed (albeit less than 5%). In particular, it is advocating exactly the opposite of what is shown by Jack in his video: keeping the wrists angle at a 90 degree angle (or even more, as Tom Guerry likes to note) as late as possible, not "casting the fishing pole" at swing initiation as given in the video.

Your excellent reference has cemented, for me, what I had concluded by other reasoning. That wrist torque (i.e., top hand torque and bottom hand torque) is only a small component of the swing and that Dr. Adair's explanation of the whip like action in his book is the correct way of looking at the swing process. Indeed, the last line of your paper reads "In the simulated golf swing, the main source of power delivered to the golfclub originated at the wrist joint as a result of the whip-like kinematics produced by the torso and arms."

Thanks again for the great reference. I don't advocate most people buy it at $30, but for me it was a great reference.

-JJA