Academic journal article
By Lund, Robin J.; Heefner, Dan
JOPERD--The Journal of Physical Education, Recreation & Dance , Vol. 76, No. 3
Former baseball star Jim Lefebvre (1983) claimed that hitting a baseball may be the most talked about but least understood skill in all of sports. Historically, hitting instruction has been based on intuitive thinking by "hitting gurus," rather than on scientific fact, which has contributed to this lack of understanding (DeRenne, Stellar, & Blitzbau, 1993). Compared to other sports, baseball has lagged in regard to the application of science to the development of the swing and training methodology.
Although athletes and coaches have many hitting drills to choose from, few of these drills are grounded in science. A thorough understanding of the mechanics of the baseball swing is critical to formulating a sound training methodology. Therefore, the purpose of this article is to use previous studies to describe proper swing mechanics and to provide a few examples of drills that could be used to train these mechanics. 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.
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Bat Velocity and Bat Quickness
Bat velocity is the speed at which the bat head is traveling at the moment of contact (Stellar, House, DeRenne, & Blitzblau, 1993). Bat velocity is important for several reasons. According to the equation, force equals mass times acceleration, the greater the velocity of the bat at contact, the greater the force that can be imparted to the ball and the farther the ball will travel once it is hit (Hamilton & Luttgens, 2002). In addition, if energy equals one-half mass times velocity squared, a bat swung with more velocity will result in greater energy imparted to the ball. In short, the higher the velocity of the bat at contact, the higher the velocity of the batted ball (Adair, 1990). This is true both for wooden bats and aluminum bats (Crisco, Greenwald, Blume, & Penna, 2002).
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. Varying the extension of the lead elbow has a similar effect. In other words, as extension increases, so does the length of this segment as a lever. The end result is a wider radius from launch to contact and a subsequent increase in angular velocity and swing time (Bunn, 1965).
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It is important to realize that high bat velocity does not necessarily mean a more productive hitter. …