Posted by: Jack Mankin (MrBatspeed@aol.com) on Thu Feb 1 10:17:42 2007

Hi Dave & All

For the past couple weeks, we have been shooting and editing video for our new “Swing Review Analysis” DVD and Motion Analysis Software. Therefore, I must apologize for not responding to many of your posts. We should complete that phase in about a week and I will have more time to devote to the discussion board and your questions.

One of the topics we will address in the dvd is the relationship between “Bat Speed” and “Bat Quickness.” Dave, I agree that the article you posted is interesting but I also find it quite misleading. In exerts of his article I placed below, note that he includes a batter’s “pre-launch” movements of accelerating the bat-head from its ‘cocked toward the pitcher position’ (bat wrap) back to the launch position as part of his swing time.

As an example, Bonds swing, from initiation of shoulder rotation to contact, requires about 4 video frames. Each frame is 1/30th second – or – 4/30th second (from initiation to contact. However, from his “wrapped” position (bat cocked toward the pitcher), Bonds spends 6 to 8 frames accelerating the bat-head back to the launch position before he initiates shoulder rotation. According to the article, that would mean Bonds has a total swing time of nearly .50 second.

By his definition, hitters like Bonds, Williams and Brett may produce great “Bat Speed”, but have less “Bat Quickness” than most Little League hitters.

Jack Mankin

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“However, the concepts of bat velocity and bat quickness must be considered before any discussion of swing mechanics. Recognizing the difference between these two, often misunderstood, concepts is a prerequisite for understanding the mechanics of the baseball swing.

Bat quickness is the time it takes to move the bat head from the launch position to contact with the ball, measured in seconds (Hay, 1993). The relationship between bat velocity and bat quickness is usually inverse in effect (Stellar et al., 1993). That is, players who exhibit high bat velocities tend to have poor bat quickness (high swing times).

The bat quickness of major league hitters has been calculated to be 0.14 to 0.15 of a second in contact hitters, and 0.17 to 0.18 in power hitters, demonstrating the inverse relationship between the two performance variables (Stellar et al., 1993). This relationship has been attributed to changes in decision time (Hay, 1993). Decision time is the amount of time the hitter has to read the pitch and decide if, when, and where to swing the bat. As bat quickness improves, decision time increases, and the chance of making a correct decision increases. Variation in swing mechanics can account for much of the observed relationship between bat velocity and bat quickness.

For example, as bat wrap increases, bat velocity increases, but bat quickness becomes slower. Bat wrap refers to the degree to which the bat points toward the pitcher in the launch position (figure 1). The greater the wrap, the farther the barrel of the bat must travel to get to the contact zone. The greater distance traveled results in higher swing times (slower bat quickness), but the additional time allows the hitter to generate more bat velocity.”
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