In the beginning...

The purpose of this blog is to start a conversation about softball pitching. I want to start from the beginning of the research, lay out what it has to say and then discuss the possible implications for the sport. I will leave the reference for anyone who wants to read the articles for themselves.

Barrentine, S.W., Fleisig, G.S., Whiteside, J.A., Escamilla, R.F., and Andrews, J.R. (1998). Biomechanics of Windmill Softball Pitching with Implications about injury mechanisms at the shoulder and elbow. Journal of Orthopaedic & Sports Physical Therapy, 28 (6), pp. 405-414.

The basis of this study was to determine what forces, movements, etc. are implicated with injuries of softball pitchers. Based upon Loosli, et al.’s (1992) research on the prevalence and relevance of certain injuries, particularly in the shoulder. According to previous research, both then and more recently, the shoulder is still the area with the highest incidence of injury for softball pitchers (Hill, Humphries, Weidner & Newton, 2004; Loosli, et al., 1992).

The study used 8 upper level college pitchers with an average height of 1.73m and 65 kg. They were asked to get warmed up and then throw 10 pitches as hard as they could. They measured for average velocity at 55.8 mph. They found that the average pelvis rotation was 430˚/s, while the upper trunk rotated at 650˚/s. Internal shoulder rotation velocity was at 4650˚/s, which was the movement most related to ball velocity. They also found that the body’s linear velocity was 3.2 m/s and that the body, in particular the arm, had proximal to distal acceleration.

As it was one of the earliest studies on the biomechanics of the pitch, the researchers covered quite a bit of the spectrum of how the body works. The study maps the forces and torques on the arm during the pitch. The study illustrates the proximal to distal acceleration, which essentially means that the shoulder rotates, then decelerates, then the elbow accelerates and then decelerates giving way to the hand, then fingers, etc. It also means that the arm has to have a slight bend to it around the circle. In fact, an argument can be made for more flexion at the elbow to give the arm more whip.

The study also reconfirms a finding from Werner’s (1987) master’s thesis that the internal shoulder rotation is most related to the speed of the pitch. Intriguingly, this is a major movement of the overhand throw as well. Moreover, it gives credit to the fact that the follow through of the pitch should NOT be to touch the shoulder, or for that matter to flex the shoulder and bicep on the way to the sky. If, at release, the shoulder and bicep flex, internal shoulder rotation stops. For a myriad of reasons this is not only less effective, but possibly injurious. Where have you seen this movement? Look no further than Ernie Parker videos or even the old Monica Abbott commercial for the power band. Not Monica, notice that her follow through was long and whippy, while the demonstrator was flexing shoulder and bicep.

With heavy internal shoulder rotation leading to more speed, this also means that externally rotating the arm prior to release. In baseball, they call the external rotation just prior to release “arm cocking” and those who do it best have good “arm action”. Finding ways to increase external rotation prior to release may be the key to opening the door for greater velocities and less effort due to a greater stretch reflex.

Finally, this is the only study to date to study the linear velocity of the body. It seems relatively elementary that the speed of the body would be related to pitch speeds, but there was no attempt to correlate the two. Future research may do well to measure body velocity vs. speed, and furthermore, how the best pitchers create more linear velocity. This is where we are at with softball. It will be up to us to start to answer these questions objectively.