Posted by: Jim (jwelborn@lexcominc.net) on Sun Nov 6 08:18:16 2005

> >>> I find it impossible to quantify positive hip movement in clip mac03 (http://www.youthbaseballcoaching.com/mpg/mac03.mpeg). This clip is a back view shot at an angle that makes positive hip movement relative to head movement difficult to judge. The clip only shows a portion of the swing excluding any negative movement. When I measure positive hip movement (hip slide), I begin measurement at the limit of all negative hip movement and end it at a point where all positive linear movement has been replaced by rotation. In this clip, the camera also appears to be either panning or zooming out throughout the swing. This further makes it impossible to measure linear hip movement.
>
> I would direct your attention to the other McGuire clip, mac01.mpeg. This front quarter view also is extremely short in duration, showing only a portion of the swing. However, in this swing there IS greater forward linear hip movement than there is head movement. This definitely gives the rotation axis its backward lean.
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> I wish I could load this clip into my Rightview Pro Capture Viewer and physically measure the head and hip movement as I have done with 25 pro baseball and 6 Olympic softball players . Unfortunately, not enough of the swing is shown to make this possible. Of the 31 clips I have analyzed, every one showed more hip than head movement.
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> I do not agree with your statement that “once the axis is set, the hips move forward at about the same rate as the head.” Once the axis is set, rotation has begun and there is no longer any forward movement. My point is that the action of moving the hips forward further than the head allows the axis to become properly set. Any batter who begins with a balanced stance must make this move to get the axis into the correct alignment.
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> I would also add that when coaching our young players who have problems with establishing a correct axis of rotation, we emphasize creating this type of movement prior to and leading into rotation. It DOES help improve their power.
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> Jim <<<
>
> Hi Jim
>
> There is probably not as great a difference between our positions on this topic as you might think. In my opining reply to you, I agreed that in order to set an axis angle, the hips must be ahead of the head when rotation is initiated. Where we may differ is with your contention that, “during the positive move prior to rotation, hips ALWAYS move forward farther than the head.”
>
> There are batters whose mechanics do have the hips moving farther than the head during the stride. However, that is no absolute rule. I have also studied many clips where the axis angle is set prior to a positive move forward and during the stride the head and hips move forward about the same distance (Example - http://www.youthbaseballcoaching.com/mpg/bagwell1.mpegI ). I think it largely depends on the lower-body mechanics the batter uses to initiate rotation.
>
> I am just guessing at this point, but from this discussion and an earlier statement you made, it appears you may believe in a 3 or 4 stage type of swing. You stated; “First, it seems to me that to initiate the swing and accelerate the bat with maximum force, the muscles of the body must be given the opportunity to sequentially fire. All of the muscles cannot instantly fire at the time and yield a powerful, controllable swing.”
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> I have studied other programs that teach a sequentially approach. Basically they teach, (1) stride to a fairly firm front leg, (2) open the hips while keeping the shoulder closed, (3) rotate the shoulders and swing. This obviously does segment the firing of the muscles that rotate the hips from the firing of the muscles used to rotate the shoulders.
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> Jim, I do not believe in nor teach the sequentially approach to hitting. Once the “hips” issue is concluded, we can discuss it if you wish.
>
> Jack Mankin



Jack,

I did not mean to imply that rotation is a series of disjointed steps. I am talking about the body’s process of initiating movement beginning from the stance.

I have seen some coaches actually teach placing the batter in a rigid looking stance with their “weight back” resembling what the body should look like at the beginning of rotation, and then having them suddenly rotate to swing. I know this is not your approach.

The body cannot efficiently accelerate its parts in this manner. Acceleration must build. It takes time and coordination for muscle groups to accomplish this. It doesn’t take much time (fractions of a second), but it certainly can’t occur instantly. This process gets well under way during the time it takes to go from stance to heel plant or the beginning of actual rotation. The visual image this process produces can be described as fluid motion.

After heel plant we are past “hip slide”, but acceleration continues to build as rotation takes over. Angular momentum amplifies kinetic energy the muscles have produced. The energy is transmitted through the upper body, arms, hands, and bat to the ball.

I think of batting as an overall two step process. The first step is a linear phase (being discussed here) and the second step is the rotation phase.

Getting back to the “hip slide’ discussion, in an earlier post I presented the following:

“I am curious about a possible energy source that I have never seen in any swing discussions. That is gravity. I have noticed that during rotation at contact and slightly beyond, batters with great swings appear to be very light on their feet. The rear heel is up dragging the toe. The front foot torques around seemingly on the heel (perhaps the true bottom end of the axis of rotation???). The batter’s weight for a brief instant appears to not be bearing totally on the ground. Have the dynamic forces of rotation captured some of the potential energy of gravity, converted it to kinetic energy, and transmitted it to the bat? Could this be an explanation of how the batter sent the ball over the fence with what is described as a seemingly effortless swing?”

I believe when we see “hip slide” or “positive linear hip movement” or whatever you want to call it, we may actually be seeing the body in the process of converting some of the force of gravity to kinetic energy. If this is the case, it may explain the need for a tilted axis of rotation. Or maybe it’s more accurate to say that the tilted axis is the result. That is, “the correct swing causes a tilted axis” rather than “the tilted axis causes a correct swing”.

Gravity pulls objects toward the center of the earth. The human body constantly resists this downward force with its own upward force. If this potential energy is momentarily converted to kinetic energy, movement has to occur in some direction. To me it is logical that what we see during the “hip slide” could be the process of the body attempting to direct some of this energy into the swing.

The primary source of energy, of course, comes from the body’s muscles. But if my ideas are correct, gravity could be providing a source of extra energy. It could certainly be a good explanation of why sometimes a batter swings as hard as he can, makes good contact and creates an average hit, while other times an easy swing sends a line drive over the scoreboard.

Do you (or anyone) have thoughts on this?

Jim