Stodden DF, Fleisig GS, McLean SP, Lyman SL, Andrews JR. Relationship of pelvis and upper torso kinematics to pitched baseball velocity. Journal of Applied Biomechanics 17(2):164-172, 2001.

Matsuo T, Escamilla RF, Fleisig GS, Barrentine SW, Andrews JF. Comparison of kinematic and temporal parameters between different pitch velocity groups. Journal of Applied Biomechanics 17(1): 1-13, 2001.

Stodden, DF, Fleisig, GS, McLean, SP, Andrews, JR. Relationship of Biomechanical Factors to Basebal Pitching Velocity: Within Pitcher Variation. Journal of Applied Biomechanics 21(1): 44-56, 2005

Methods

In three published studies, Dr. Glenn Fleisig and Dr. James R. Andrews from ASMI worked with other researchers in studying many of the parameters that affect baseball pitch velocity. Two of the studies looked between different pitchers and one study looked at variations within each pitcher. Motions during delivery were analyzed using a high speed (200 frames per second) infrared three-dimensional motion analysis system.

Results

In the study by Matsuo and others, pitchers with higher ball velocity were compared with pitchers with lower ball velocity. Four significant differences were found between these two groups. Compared to the low ball velocity group, the higher ball velocity pitchers demonstrated less lead knee flexion velocity after front foot contact and greater lead knee extension velocity at the time of ball release. Extending the lead knee in this manner may provide stabilization allowing better energy transfer from the trunk to the throwing arm, and could be a critical factor in pitch velocity. Maximum shoulder external rotation and forward trunk tilt at ball release were also greater in the higher velocity group. Greater shoulder external rotation causes a stretch of the internal rotators allowing energy to be stored in these muscles, and creating greater internal rotation during the arm acceleration phase.

Two variations were found in the timing of events. Maximum elbow extension angular velocity and maximum shoulder internal rotation angular velocity occurred earlier in the motion of higher velocity pitchers. The maximum shoulder internal rotation angular velocity also occurred closer to the moment of ball release in the higher velocity pitchers. This optimal timing may aid in generating higher velocity pitches.

Another finding of interest is that early in the pitching motion, the two groups were dissimilar in the timing of their movements, while their later movement timing was much more similar. This implies that early trunk and torso movements are more varied among pitchers than late arm movements.

In the first study by Stodden and others (2001), pelvis and upper torso variables were studied in 19 elite baseball pitchers. The study found that when the arm was completely cocked back (that is, maximum shoulder external rotation, or “MER”), more “open” pelvis and upper torso orientation correlated with increased ball velocity. More open pelvis angle at the time of ball release (REL) also correlated with increased pitch velocity increased. Additionally, pelvis angular velocity from front foot contact to MER, and upper torso angular velocity from MER to REL increased with increased velocity.

The data indicate that a pitcher who is able to position himself properly, and rotate his pelvis and upper torso more quickly is able to generate greater momentum. Theoretically, this increase in momentum leads to greater velocity of the throwing arm and thus greater pitch velocity.

The most recent study by Stodden and others (2005) showed that for a given pitcher, increased elbow flexion torque, shoulder proximal force and elbow proximal force produced greater ball velocity. In addition, the maximum shoulder horizontal adduction occurred later and maximum shoulder internal rotation occurred earlier at greater ball velocities. Higher ball velocity also resulted in decreased shoulder horizontal adduction at foot contact, decreased shoulder abduction during acceleration, and increased trunk tilt forward at ball release.

Conclusion

A pitcher with increased shoulder external rotation, faster pelvis and upper trunk rotation, and greater front knee stabilization and extension will throw with greater ball velocity. Improved timing to maximize arm velocity closer to the time of ball release will also help ball velocity. Increased torque and force produced at both the shoulder and elbow will also lead to greater ball velocity.

Copyright © 2000, American Sports Medicine Institute
December 18, 2007

http://www.asmi.org/asmiweb/research/usedarticles/highlowpitches.htm

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To start the analogy we have a car, a hill and a wall. The car is sitting on top of the hill and the wall is built at the bottom. The wall is high enough to just peak over the hood of the car. There is a passenger in the car not wearing a seat belt. To begin, the car starts down the hill at full throttle. The farther it travels, the more speed it gains. It reaches the end of the hill and slams into the wall at full speed. The wall does not break or move. At this point I would like you to really visualize this event. I am sure you have good enough knowledge about classic physics to know what is going to happen to the passenger. Yes, the passenger is propelled through the windshield and flies through the air and lands about 40 feet in front of the car. So, why did this happen? Yes I could throw a bunch of scientific jargon at you but it shouldn’t be this complicated. The passenger flies out of the vehicle after hitting the wall at full speed because it was the only part of the car that wasn’t secured to it. Energy must go somewhere, so when the wall stopped the car, all the momentum transferred to the passenger because it still had the potential to move.

How does this relate to pitching? Good question! The best way for you to understand this comparison is if I describe the correlation. Let’s start with the car. The frame of the car in the analogy of the car crash is the pitchers core. The hill is of course the pitching mound and the wall is when the pitchers front leg lands and stabilizes in his delivery. Now, the front leg is important in this analogy. It is playing the role of the wall. That is no easy role to fill because the wall, in this case, was able to stop the car dead in its tracks. So as the pitchers core travels down the hill, like the car, gains momentum, then the front leg lands and plays the role of the bionic wall. What happens now? Let’s continue to keep this simple. To understand what happens now we must label the last correlation of the car crash analogy. That being the passenger. What is playing the role of the passenger during the pitching delivery? I will tell you! The ball is the passenger. The ball is along for the ride like the passenger and it also is the only part of the ride that isn’t secured to the vehicle or in this case, the pitcher. So, if the front leg does its job of playing the wall, then the ball will be forced to receive all of the momentum generated; in return reaching its top velocity potential.

You may still be a little confused at this point, so to help you pull it all together I will go into more detail about the wall. Let’s bring back up the event of the car crash again. Let’s say the car speeds down the hill and hits the wall but the wall does not hold. It gives away but manages to slow the car some. What happens now to the passenger? The passenger does not fly through the windshield. This occurs because the wall didn’t completely stop the car. It was allowed to continue moving until all the enegry created from the inertia of the car dissipated. Therefore the pasenger was saved because he wasn’t forced to receive all of the momentum from the car. This will be the same case with the ball, if the wall or leg does not stablize completely. This will mean the pitchers front leg will continue to bend instead of hold and the body will not transfer all of the momentum to the ball. For the pitcher to reach his top velocity potential he must stabilize from the front leg all the way up to the chin. The arm and ball should be the only part of the body moving after the chest has extended as far out as it is capable of going. Watch the video above of Edison Volquez performing this almost perfectly. Also view the pic here of Chien-Ming Wang in complete stablization of his front side.

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