Re: Legs - Linear vs Rotational
>>> When you load, how much percent of your weight should be on your back leg, Ive been told back knee over toe, is this true? <<<
Jack Mankin's reply:
When considering how much weight a batter should have on the back-leg we should also consider the reason why a batter would have more weight on the back side. With linear batting theories, shifting weight from the back-side to the front-side is thought to be a major source of power for the swing. The batter is told that he must first “go back before you go forward.” Or, you must first “load the back-side” before you stride and transfer your weight to the front leg. The linear momentum, or kinetic energy, is believed to be converted into bat speed as the hands reach full extension and slows down. – This theory has been discredited.
Rotational mechanics does not rely on a linear momentum gained from a forward weight shift. It generates its source of power by developing angular momentum around a stationary axis. The axis of rotation (basically the spine) is not vertical for most batters. It is slightly tilted away from the pitcher. As the axis tilts rearward, it places an increasing amount of weight on the back leg as the batter prepares the launch position.
So the rotational batter thinks differently about the stride and preparing his launch position. The linear hitter thinks in in-line terms like, “walk away from your hands.” This is so the hands are propelled (or slingshot) straight back toward the pitcher. To the rotational hitter, the stride is used mainly as a timing step and he prepares his launch position with an “inward turn” of the upper-body and hands. The inward turn is to bring the hands to a position so that when shoulder rotation is initiated, the hands are propelled into a circular path.
At the beginning of the baseball season, a post asked what hitter I thought most represented a good rotational swing. My answer was Barry Bonds. He takes a soft 3 to 5 inch stride, at foot-plant his lead foot and knee points more in the direction of the plate, he rotates around a stationary axis, exhibits an angular hand-path and has great execution of both bottom and top-hand-torque. From the time he takes his stride to contact, there is little to no forward movement of his axis. His head remains almost motionless. That is the mark of a pure rotational swing. A good hitter may take a longer stride and move the axis forward to prepare his launch position – but Barry proves it is not a necessity.
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