# Arm length and pitch speed in softball

The big event of the softball season, the Women's College World Series, begins Thursday. One aspect I find interesting is that many of the dominant pitchers are very tall. Many of you are probably familiar with the underhand delivery of fastpitch softball, which implicates angular motion. The question is, does longer arm length lead to faster pitches (all else equal)? As I non-physicist, I have explored various sports-related writings and consulted with physicists to address this topic. What I've come up with, for now, is displayed on my college softball blog:

http://collegesoftball.blogspot.com/2006/05/one-thing-that-cannot-have-escaped.html

Any comments, corrections, clarifications, etc., are welcome. Just add them below. Thanks!

## Answers and Replies

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Danger
Gold Member
That's mighty interesting. For the same angular speed, the longer arm would indeed have a higher circular speed. Intuitively, though, and from having some experience in the matter, it seems that a shorter arm can accelerate faster. A very large factor is also how much of a 'whiplash' effect the pitcher uses.

rcgldr
Homework Helper
Not only longer arms, but longer legs, which allows a pitcher to step more forwards when pitching. While flipping channels, I just happened to catch the pitcher for Texas, and she apparently has the highest average number of strikeouts per 7 innings. She was tall and moderately thin. I'm not sure if she throws the fastest, or just has more variety of pitches and good placement. The windup is a bit over 360 degrees, and the leg motion and body twist seem to add to the delivered velocity.

Danger
Gold Member
I'm not too sure how others do it. What worked best for me was to step forward and across with my left foot, timed so that it planted exactly when my hand was passing my hip. At that point, my lower body would be facing about 80 degrees to the right of the target, with my upper body still facing toward it. I would then violently stop my upper arm as it was vertical, and use my bicep to further accelerate my forearm to about a 45 degree downward angle, at which point I would release the ball.
It seems pretty weird in print, but it was effective.