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Re: Big Mac's Front Knee

Posted by: Jack Mankin (MrBatspeed@aol.com) on Mon May 8 01:35:27 2000

>>> The front knee seemed to bent on that swing, and a tape my mother made of the home run McGwire hit--which I saw personally at Shea--showed McGwire making contact with a firm, but bent front leg rotating in a circular pattern (my mother taped it while I was away).
> Any thoughts on this Jack? Now that I have given example how a person can hit the ball a long way with a firm, bent, rotating front leg at impact, are you still going to argue that the front leg must be locked at contact? <<<


Good observation and Question --- I do not think of the front leg as being "locked" at contact. I think it would be more accurate to think of the leg as being fully rotated and extended. A fully extended lead leg indicates a full rotation of the hips and shoulders were required for the swing. This is usually true for pitches from the-middle-in where a tight hand-path is needed to get the meat of the bat on the ball and much of the bat speed is generated from bottom hand torque. To apply maximum bottom hand torque, the lead shoulder needs to be pulling back toward the catcher at contact. This requires the full rotation and extension of the front leg. In this case the hips rotate about 90 degrees and the shoulders about 120 degrees.

On outside pitches the hands must take a wider path to get the meat of the bat on the ball. This means the lead shoulder can not rotate as far. On pitches on the outside part of the plate, the shoulders rotate about 70 or 90 degrees and the hips around 60 degrees or so. Therefore, full extension of the lead leg would not be required to rotate the hips to that point.

BHL, in the instructional video (now in final editing), I discuss the very point you raised. How a hitter with less shoulder rotation (thus a bent front leg) can hit 500 ft shots. Less shoulder rotation means less bottom hand torque is available to generate bat speed. Great hitters like Big Mac don't just naturally possess bat speed -- they generate it. It comes from the transfer of their body's rotational energy (via an angular hand-path) and torque. But it appears that on outside pitches they had to be applying less torque. Things just don't seem to be adding up correctly.

It puzzled me for quite some time, why some hitters could go out and kill outside pitches while others with equally good rotation couldn't. Really good hitters like Ron Gant and Matt Williams for example, could rip the cover off inside pitches. But as their hands went out wider for outside pitches they got behind the power curve and not being able to apply bottom hand torque they wound up just waving at the ball. --- What was it about the mechanics of Big Mac or Juan Gonzales that allowed them to generate enough bat speed to hit outside pitches 500 ft? They had to be applying torque somehow - I just didn't know what that "somehow" was.

The answer came while watching a video of George Brett's swing. George had hit a low outside pitch that cleared the 425 ft mark before the center fielder could move. That ball was smoking. When he sets up his swing, he wrapped the bat to a point where the barrel is pointing at the shortstop. I wondered, how could he wrap the bat that much and still get around and pull an outside fastball. --- Then came one of the luckiest days of my life - They showed that swing in slow motion from behind the batter.

It showed George pulling his top hand back toward the catcher before he started his rotation. I wondered - what is he doing? So I picked up a bat and got into that position. Then it dawned on me, this is a great position to apply torque. By keeping the bottom hand at the armpit as a pivot point and pulling back with the top hand, the batter can generate a lot of bat speed even before he fully initiated the swing. This allows the batter to stay with the power curve and apply torque as the hands take a wider path. ---- So, on outside pitches, the great hitters apply more "top hand torque" early in the swing and on inside pitches they keep it tighter and apply "bottom hand torque" as they approach contact.

Jack Mankin


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