Wednesday, January 5, 2011

Keep Your Eye On The Ball... If You Can

It is impossible for even the best professional baseball hitters to keep their eye on the ball from the time it is released from the pitcher's hand until the point of contact. The best hitters are able to track the ball, that is keep the ball centered on his or her fovea (responsible for visual detail and acuity), up until the last 6 ft of flight [1]. This phenomenon is due to the fact that humans are only capable of tracking objects moving at angular velocities of up to 90 degrees per second [1]. If a baseball is thrown at 100 mph, one would require head and eye movements exceeding 1000 degrees per second as it crosses the plate. Although the ball travels at a constant linear velocity (100 mph) from the pitcher to home plate, the angular velocity with respect to the batter increases drastically. The angular velocity is the rate of change of the angle θ as shown in Figure 1 [1]. To illustrate this point, one finds it easy to track an airplane flying at 5000 ft, but would find it nearly impossible to track if it were flying at 100 ft overhead. Both planes travel at the same linear velocity, but different angular velocities with respect to the observer.


Figure 1. The horizontal angle of the ball defined as θ, is the angle between the line of sight pointing at the ball and the line perpendicular to the batter's body. This angle is about 0 degrees when the pitcher releases the ball, and increases to 90 degrees when the ball crosses the plate.

Remarkably, even though hitters essentially cannot see the ball in its last 6 ft before contact, they are still able to make contact most of the time. A major contributing factor to the likelihood of hitting the ball has to do with how well the hitter can predict where the ball will end up when she wants to hit it. This "prediction" is in direct relation to the 5 questions a hitter must answer. If a softball pitcher were to be pitching from 43 ft, and releases the ball at 65 mph 6 ft in front of the mound, the hitter would only have 31 ft or 0.33 sec to get her bat to the right point of contact. Also, taking into account the time for the hitter to swing, she will start her swing approximately when the ball is 9.25 ft in front of the plate. So, the hitter actually has 27.75 ft or 0.29 sec to decide whether to swing or not. This is not a lot of time to answer 5 questions, therefore it is imperative that a hitter must focus on the pitcher's release point (hip) to give herself the most time to see the ball.

Hitting a baseball is one of the hardest things to do in sport. Not just anyone can pick up a bat and hit live pitching. As hitters, we are trained to swing at strikes and let go balls without thinking. Also, hitters subconsciously create mental pictures in their mind of where the ball will end up, and then gets her bat to that spot to hit it. Hitters create the mental pictures by answering the 5 questions.

This mental picture comes from the experience of hitting soft toss, full pitching and pitching machines. When it comes to the game, most hitters can make contact and be successful by swinging just like they do in practice. However, the best hitters are able to read spin, and therefore adjust their mental picture of where the ball will end up. Those who are unable to recognize spin are more likely to be fooled by pitches that have more movement than what they've seen in practice.

Let's examine what makes different pitchers successful. First, pitchers who throw fast are more likely to strike out hitters than those who throw slow. The simple fact that the ball takes less time to get to the plate, gives the hitter less time to react. And according to golden rule number 2, the faster the ball is traveling the less it drops, which also makes it more difficult to hit. This explains why most fast pitchers are also riseball pitchers, as they use their speed and spin to minimize the time the hitter has to react.

Note: When facing a fast riseball pitcher, hitters must swing higher than they think. That is, swing to a spot where the ball will be, instead of where the ball actually is (NOT EASY!). Hitting a riseball is sometimes a difficult concept to grasp, as the hitter's brain must make an adjustment that goes against the instinctual hand-eye coordination. Going back to spin recognition, the earlier the hitter can recognize the spin, the earlier she can make the adjustment and overcome gravity to get her hands above the ball to make contact. Practice, practice, practice!

On the opposite end of the pitching spectrum, a pitcher who throws a slow change up that drops more than a faster pitch will have hitters swinging over the ball. While change up and dropball pitchers might not strike as many hitters out as fast riseball pitchers, they can be equally as effective. Although hitters are more likely to make contact, they may not be able to get the bat head low enough to hit drop balls for line drives, or wait long enough to hit the change up.

Generally it is harder for hitters to hit higher pitches than lower pitches because a hitter has to hit the ball further out front of her stance. From a low outside pitch to a high inside pitch a player has to hit the ball about 2.5-3 feet closer to the pitcher (more in the front of their stance) which would mean the high inside pitch would appear to be about 8-11 mph faster (reaction time) even if they were the same speed on the radar gun.

References

[1] R.G. Watts and A.T. Bahill. Keep Your Eye on the Ball: The Science and Folklore of Baseball. New York: W.H. Freeman and Company, 1990, pp. 151-175

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