Arm angle, continued

Ben Wintringer, pitching the seventh inning for the

Vikings Thursday, shows delivery angle: arm and

hand angle, body tilt sideways and forward.

(Photo by Ed Piper)



Following on my last entry, the pitcher's "arm angle" is broken down into three parts, actually: the angle of the upper arm relative to the body, the forearm relative to the elbow, and how much the pitcher tilts to his left or right, according to Brooks et al in "Evidence from Biomechanics and Pitch Tracking."

The authors of this article discussing the impact of arm angle on pitch movement point out that the pitcher's tilt forward is also important. So, James Whelan's "trunk tilt", how much he tilts left or right and how much he is leaning forward when he releases the ball affects the first three measurements.

A more accurate term for these factors at release is "delivery angle".

What's impressive in Major League statistics is, "Since 2008, every major league park has been home to a set of cameras and associated hardware" that provide data on delivery angle for pitchers. This didn't exist when I was a pre-teen traipsing to Dodger Stadium to watch Sandy Koufax mow down hitters.

A side note is that sabermetrics, which measure WARP (Wins Against Replacement Player) and other relatively new measures beyond the traditional batting average, runs scored, and RBI's, are possible because stringers are now employed to track every pitch of every game in the Major Leagues to provide the data base for these instruments. It's a staggering amount of pitch-tracking, if you've ever tried to keep score in your scorebook of both games of a doubleheader, for instance. Very tiring.

I haven't actually done that. I have scored two games simultaneously, though I missed a lot of info--Padres on one radio station, Dodgers, I think, on another.

The writers of the article in Baseball Prospectus 2015 state that in their "Pitch Info" data, the most important piece is the force exerted on the ball by the spin. Movement is caused by air resistance to the spin.

One thought: What effect do the raised stitches of the ball have? We used to hear controversies over baseballs more tightly stitched in the Dominican Republic or somewhere, and baseballs manufactured in another location.

According to Brooks, "Magnus force" is created by the backspin the pitcher puts on the ball. Magnus force counteracts the effect of gravity. Tell that to Ben Wintringer and the other Viking hurlers. (I'm just having fun with it.)


Copyright 2015 Ed Piper