Confusion/heavy bag drill
<u>Jack Mankin's comment:</u>
I have noticed from reading post on other forums that there is some confusion regarding the "heavy bag drill." Many coaches seem to think the batter attempts to develop a more powerful swing by driving through the bag or causing the bag to move or swing. These coaches equate hitting the heavy bag to that of hitting deflated basketballs or similar objects, but nothing could be farther from the truth. The principles to be learned from the heavy bag drills are completely opposite to mechanics developed from swinging at tossed deflated basketballs.
The concepts surrounding the "follow-through" or coast-out phase of the swing have long been misunderstood. Coaches have been taught that to hit the ball hard the batter must continue to drive through the ball well after contact. So it is quite understandable why many coaches would adopt drills that would require the batter to continue "pushing" the bat through the follow-through phase. For example, to propel a deflated basketball forward would require that the basketball remain in contact with the bat for an extended time where the bat could move forward 8 or more inches after the initial contact. Swinging at deflated basketballs would definitely require that the batter continue applying energy to the bat well after contact.
Hitting a baseball is a very different story. The baseball is only in contact with the bat for approximately 1/2000 of a second and the bat moves forward less than 3/4 of an inch. Therefore, any energy applied to the bat after contact has NO effect on the ball's flight and is wasted energy. Good transfer mechanics will deplete all bat speed-generating energy prior to or by contact. This is a major difference between average hitters and great hitters. The mechanics of most average hitters develops bat speed much later in the swing. These hitters continue applying forces to the bat well after passing the optimum contact point. That is why they have little power to the opposite field and many of their better-hit balls are pulled foul.
The purpose of using a heavy bag to absorb the bat's energy at the contact point is to train the batter to expend all bat speed-generating energy (rotational and torque) prior to or by contact. Good transfer mechanics and timing will have the batter depleting his rotational and torque energy as the bat-head reaches maximum velocity. -- Stated another way, all the energy has been sucked out of the system as maximum bat speed is reached.
Therefore, after all of the body's energy has been transferred into bat speed, the body and limb muscles are at rest. The hip and shoulder rotation is complete -- lead-arm pull and back-forearm lowering to horizontal (the "L" position) is complete -- the hand-path has slowed to a stop -- there is NO energy being applied to the bat -- the bat's energy has been expended into the heavy bag -- all motion has ceased -- all muscles are relaxed. Thus, you now have a frozen frame of the batters mechanics at contact.
This is not the case with weaker hitters. Improper initiation of the swing (for example, thrusting the top-hand forward) quickly places the batter behind the power curve and he or she is left trying to develop bat speed after the bat reaches contact. Striking the heavy bag with tense arms that are still driving forward can cause discomfort to the hands and wrist. I would advise taking it easy until the batters' transfer mechanics improve.
I think you can now see that the mechanics developed while swinging at deflated basketballs are quite different than those used in the heavy bag drill. A batters' progress will be slowed when hitting any object that requires the batter to reserve energy for a powerful follow-through. In a good swing, the bat's momentum will pull the body and limbs through the coast-out phase of the swing, not reserved energy.
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