Posted by: Jack Mankin (MrBatspeed@aol.com) on Sat Jan 6 15:10:44 2007

Hi All

Jimmy gave us his analysis of the Sosa clip (http://www.youthbaseballcoaching.com/mpg/sosa_sammy2.mpeg ) from his linear perspective (extension of the back-arm accelerates the bat-head). Now, I will present my analysis of the clip from a rotational transfer perspective.

Using Jimmy's statement, “Through the point of contact the bottom hand is more a fulcrum for the top hand to apply leverage to the bat. If the front shoulder was intentionaly pulled back towards the catcher to increase bottom hand torque, the top hand would lose force and drive on the bat. In the Sosa (middle-in) clip, if you click back and forth between the frames of contact and just before contact, you will see that the most action is comming from his top hand and the barrel.”

Let us do as Jimmy asked and advance the frames forward to the frame just before contact (knob of the bat can be seen just above the catcher's mitt). Note the position of the back-elbow at Sosa’s side. Now advance to the next frame (bat at, or just before contact). Note that the elbow did not extend. It is still in the “L” position at his side as the bat arrives at contact.

Does the elbow remaining back in the “L” position mean the top-hand is not applying a forward force to the handle? No, it is exerting a powerful forward force. However, it is being driven forward from shoulder rotation rather than the extension of the arm. This is a far more powerful force because it is being driven from the large muscles of the legs and torso rather than the smaller muscles of the arm. – Ask yourself, had you rather be hit with a boxer’s “hook” (arm remaining in the “L” position), or, from his “jab”(arm extending)?

Now, advance forward to the next frame (ball leaving the bat). – The ball is only in contact with the bat for 1/2000 second. During that time, the bat only moves forward about 5/8 to 3/4 inch. Once the ball exits the bat, any further force applied to the bat has no impact on the ball’s flight. – Note that the extension of Sosa’s arm occurred after the ball was on its way.

Now, let's take a look at the lead-shoulder rotation Jimmy discounts. -- Return to the frame just before the knob arrives at the catcher’s mitt (2 frames from contact). Note the rearward rotation of the lead-shoulder in the next 2 frames. Note that this rearward rotation of the lead-shoulder exerts a strong pull (through the bottom-hand) on the knob end of the bat.

We now have back-shoulder rotation driving the top-hand forward as the rearward rotation of the lead-shoulder pulls the knob rearward. This is how maximum torque (forces exerted from opposing directions) is applied. – In order to generate maximum bat speed, a batter’s mechanics must make maximum use of the body’s larger muscle groups of the legs and torso.

Jack Mankin