Posted by: greg m (gmartin@vci.net) on Wed Sep 27 10:45:31 2006

Dear Mr. Mankin,
I recently watched a softball video by the legendary player/bat manufacturer Ray Demarini. While entertaining and motivating, I didn't feel the video was very strong on the technical aspects of the swing. However, one interesting subject area that Ray talked about was the speed of the bat after contact was made. He stated that the more powerful hitters maintained their batspeed after impact better than lesser hitters. He used a demonstration with two batspeed monitors to show how much the bat slows after impact, and how a more powerful hitter (Larry Carter, brother of big-leaguer Joe Carter) maintained his pre-impact batspeed better than did Ray.
This got me thinking about an addtional role of top-hand torque in producing a more powerful swing. Now I realize that the idea of "driving thru the ball" is a fallacy, since the bat-ball collision occurs way to quickly for "driving thru" to have an effect. Therefore, in one sense the idea that maintaining the pre-contact batspeed after impact is somewhat flawed at the outset. But imagine a bat suspended from a string and perfectly balanced (i.e. NOT held by a player). Now go on to imagine that we could arrange an apparatus that can accelerate this suspended, balanced bat to approximately 80 miles an hour. If we place a ball on a tee and strike it with this suspended, moving, non-held bat its easy to see that the ball would travel a fair distance, even though the bat would be slowed down after impact. (In this thought experiment, it doesn't matter if the direction of movement of the bat is circular or straight, the speed of the bat at the moment of impact is what's important.)
If, however, we could arrange for our imaginary bat to be moving in such a plane as to come into contact with a MOVING (i.e. pitched) ball, then its easy to imagine that the ball would not travel nearly as far, and that the bat would recoil by an amount proportional to the speed of the ball. In fact, I'm sure the physicists among us could calculate the speed that the ball would have to be traveling to exactly counterbalance the force generated by the moving bat so that the ball would fall straight down (i.e. the force of the moving ball would be exactly the same as the force of the moving bat, and since they are in opposite directions the forces would cancel out.)
Now what in the world does a silly thought experiment like I just described above have to do with THT? Maybe nothing, but a bat that is swung by a person transmits the force generated by the swing better than a bat suspended and balanced by a string. This is intuitive, and its because the hands absorb the recoil of the bat-ball collision. (If we just throw a ball at a suspended, balanced bat it would simply spin like a top. If we attach the handle of the bat to a fixed object and then throw a ball at it, the ball would bounce back.) A moving object has more momentum (and "force") than a stationary one, and an object moving at a faster speed has more momentum/force than one moving at a lesser speed.
If a person swings with "stationary" wrists (i.e. without actively swinging with top-hand torque), they will less effectively transmit the force of their swing than will someone using THT. Therefore, I think that in addition to helping to generate maximum pre-contact batspeed, THT also helps to more effectively transmit the speed generated by the swing to the ball. I think this line of reasoning would apply even in the case where two swings have exactly the same speed at the moment of impact, but one swing-speed is obtained using THT and the other swing-speed is obtained without THT. In other words, its not necessarily just the amount of batspeed that's important, but HOW that batspeed is generated and applied. I realize I've made a somewhat convoluted post, but I'd be interested to hear your thoughts on the matter.

Greg