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Re: Pure Bat Speed vs Pure Power

Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Dec 8 12:03:26 2006

>>> Much has been debated on this site about the importance of great batspeed. And most all would agree that batspeed plays a major part in effective hitting. But the question that is perhaps the most interesting is how does the real tape measure shot result? And what is the most important aspect of the tape measure shot?

After observing some of the best hitters on film, I noticed how big a part the long stride plays a part. Specifically the following hitters used longer strides to facilitate extra power. <<<

Hi Guru

Your post raises a question that has been debated for decades - What forces are at work that induces hip rotation? - On this question, the gurus are divided into 3 main camps.

Camp (1)- As the batter strides, he transferees his weight forward to a firm (posted) front side. As the linear progression of the hips is blocked, its linear momentum is transferred into rotational momentum that causes the back-hip to rotate around the blocked front-hip. -- (Axis of hip rotation is around the front-hip.)

Guru, the theory of your post would fit into this camp. A longer stride generates greater linear momentum that produces a more powerful rotation of the hips.

Camp (2) - The Middle-Out Theory. -- As I understand it, this theory contends that hip rotation is induced solely from the contraction of the muscles in the pelvic region. The legs contribute little or nothing. It is hip rotation that straightens the lead-leg and forces the "L" in the back-leg. -- This would seem to downplay the importance of weight-shift. - (Axis of hip rotation would be around the center of the hips - the base of the spine)

Camp (3) - This theory contends that hip rotation is induced from a combination of muscle contractions in the pelvic region and torque supplied from the legs applying force from opposing directions (back-leg driving forward -- front-leg pushing rearward). This theory also downplays the need for linear weight shift to induce hip rotation. (Axis of rotation -- the base of the spine)

I am in Camp (3). I do not think the blocking of linear momentum is transferred into rotational momentum. Therefore, I do not think the length of a batter's stride or the amount of momentum derived is a major factor in generating hip rotation. - I will explain why below.

The same physics principle that governs the rotation of a bat about a point also governs the rotation of the hips about a point. - For decades, we were told that the batter�s hands should applied force down the length of the bat (knob first). We were told that once the linear progression of the bat was blocked (slowed to a near stop), its linear momentum would be transferred in rotational momentum, which would accelerate the bat-head around to contact ( the "Whip" effect).

As this clip - CHP vs Linear Hand-Path - demonstrates, there is little to no transfer of linear momentum into rotational momentum to accelerate the bat-head as the hand's linear progression is blocked. - The same principle holds true with hip rotation. -- There is little to no transfer of linear momentum into rotational momentum to induce hip rotation as the hip's linear progression is blocked.

Note: At the end of the above clip, I pointed out that Torque applied at the handle was the major factor in generating bat speed with a linear (A to B) hand-path. I will next address this issue in more detail.

Jack Mankin


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