Rotational Hitting | Analysis of Back Arm Mechanics
This article discusses the back arm mechanics used in rotational hitting. Video analysis of rotational hitters shows the back-arm remains back at the batter's side in an "L" position during rotation rather than being extended at contact. Rotational mechanics relies on body rotation rather than back arm extension to drive the top-hand to contact.
Therefore, in order to develop a high quality rotational swing, the batter should practice keeping the back-elbow back at his side and allow the rotation of his body to drive the forearm and hand forward. Allowing body rotation to power the arm means the energy is coming from the large muscle groups of the legs, hips and torso. Using the larger muscles to drive the back-arm is much more powerful than using the muscles of the arm to extend the hand.
With that in mind, consider the sport of boxing. Would you rather be hit by an opponent's jab (extension of his arm) or his hook (arm remains in the "L" shape and power by shoulder rotation)? Now let's see how this appears in the baseball swing with this clip the back-arm of 4 good hitters.
In our Swing Analysis Instructional Video, we point out another important reason for keeping the back-arm in an "L" position to contact. The "L" position of the back-arm and the lead-shoulder pulling back at contact are the key components in generating the "hook" in the hand-path. The "hook" indicates the arc radius of the hand-path is rapidly shrinking which maximizes the transfer of the body's rotational energy to the bat, and greatly increases the bat's rate of angular displacement. The "hook" also indicates maximum bottom-hand-torque is being applied to the bat. In other words, great bat speed is being developed when these two positions (the "L" position and lead-shoulder pull) occur.
Average hitters apply a good deal of torque to the bat by driving the top-hand past the bottom-hand. But, the farther the back-arm extends to produce the torque, the more sweeping the hand-path becomes, and therefore producing less hook effect. The better hitters apply torque by using lead-shoulder rotation to pull the bottom-hand around the top-hand (back-arm in "L" position). This pulling back action also generates the hook effect.
Therefore, the average hitter may apply as much torque to the bat as a better hitter, but his sweeping (or straighter) hand-path does not transfer as much of the body's rotational energy. To become a great hitter requires both torque and the transfer of rotational energy.