Wednesday, July 6, 2011

Where Bat Speed Comes From

The Major League All-Star Game is approaching and that means HOME RUN DERBY! This brings up a topic that I discuss often with players and coaches: Where does bat speed come from?

Many players and coaches spend a multitude of their training time emphasizing forearm, wrist, and hand strength and endurance in the belief that “strong hands = greater bat speed”. However, a 2004 study in the Journal of Strength and Conditioning Research concluded that grip strength and bat velocity are not significantly related. So, where does bat swing velocity come from?

If you subscribe to the kinetic chain model of performance, the movement patterns of the baseball swing and the throw are very similar from the ground to the torso. The basic phases of the swing can be divided into the swing, launch, contact, and finish. The stance is highly individualized and emphasizes comfort and confidence for the hitter. The athlete is relaxed and balanced with a slight flex in his knees and elbow and both eyes on the pitcher. The stride and load take place simultaneously creating rhythm and momentum in order to harness potential energy with the weight back, ready to explode and initiate the swing. The back knee “triggers” the swing and the hand patch is down and directly toward the ball. The hips and torso continue to rotate to the contact point while the hands “stay inside the ball” and continue on the downward approach. The contact point is the strongest position of the swing. The body is balanced with the front side firm and closed while the back knee forms an “L”. The hips and shoulders are level with the chest positioned over the hips. From contact the bat head stays level as the hands drive “through the baseball” to get extension. During the finish, balance is the key.

The development of force and motion illustrated in the baseball swing progresses from the ground to the bat (proximal to distal). Through synergistic force production and interactive moments of the legs and hips and abdominal muscles, energy is stored and the Summation of Speeds creates a transmission of the energy through the core to the upper extremity where it is released through the bat. Placing most of the force development in the central core, allows small changes in rotation around the core to effect large changes in the positioning of the arms and hands. This creates higher angular velocities similar to the cracking of a whip and lets the muscles of the forearms, wrists, and hands be more directed toward precision and control rather than power production.

For those who continue to believe that grip and forearm strength is the key. I agree with you but, not for the same reasons. The baseball season is long. During the season, the typical hitter may take an average of 145 swings per day (early cage work, batting practice, pre-at bat swings, and during their in-game at-bat). The bat may weigh anywhere from 32-34 ounces. Over the course of a season, the hands get fatigued. It is important to maintain strength-endurance of the forearm, wrist, and hand muscles in order to prevent and limit fatigue. Particularly, because as discussed, the last link in the chain is the hands. If the precision and control muscles are not doing their job because their “tired”, then the maximum power and force cannot be transmitted through the bat to the ball.

Unfortunately many of the fallacies in baseball training programs continue to be taught to our younger players. It is important to remember that for the purposes of generating bat swing velocity and power, emphasis should be placed on the lower extremity and core rather than an over abundant amount of wasted time strengthening the forearms and grip.

Suggested Reading:

Hughes SS, Lyons BC, Mayo JL. Effect of grip strength and grip strengthening exercises on instantaneous bat velocity of collegiate baseball players. Journal of Strength and Conditioning Research. 2004; 18(2): 298-301.

Kibler WB, Press J, Sciascia A. The role of core stability in athletic function. Sports Medicine. 2006; 36(3): 189-198.

David Yeager, ATC, CSCS

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