“Why is it the Inverted W? Isn’t it just an M?”

This is an age-old question that gets asked pretty much every time I see it on a blog or messageboard that’s unfamiliar with the history of the term – “Inverted W.” So let’s get this out of the way – yes, an Inverted W is simply an M. Obviously. But this terminology didn’t come about because someone forgot the fact that M was a letter – the focus is too much on the “W” and not the “Inverted” portion of this term. Like phonetics, the emphasis is on Inverted and not on W when it comes to this term.

Paul Nyman coined this term when he did much of the first amateur video analysis of pitchers available – on a VCR, no less! He counted frames using his VCR and did stop motion work with crude technology long before the proliferation of the Internet. Paul determined that most of the pitchers in MLB could be broken up into three groups:

  • Pitchers who had a mostly long (and straight) arm swing back leading into shoulder horizontal abduction. He called this group slingers.
  • Pitchers who started with their elbow more bent than the slingers, leading to a more horizontally loaded position with the letter W laying on its side.
  • Pitchers who started with their arm hanging down in an inverted position. He said this group displayed an inverted W.

He wasn’t out to name the group the “M group” but was rather specifying the fact that the pitcher’s arm began in an inverted position and formed the “W” above the level of his shoulders rather than behind his back like most others did.

John Smoltz - Inverted W

John Smoltz - Inverted W

You can find all of this information (and more) on the recently opened SETPRO forums. Paul wrote many posts about arm action, and the classifications of the arm actions can be found in Arm Action Chapter 1.

Paul initially believed pitchers with the Inverted W (and to a lesser extent, the Horizontal W) could throw harder than pitchers with the slinging / “going to high cock” motion.  However, after some time, he decided that it was mostly a wash but that “slingers” were more likely to turn into Steve Avery where they’d suddenly lose their ability to throw hard due to immature throwing patterns by getting the arm into the high cock / loaded position too early, leading to “pushing” the ball to the target.

Steve Avery - Slinger

We can debate and discuss whether or not Paul’s findings and/or teachings through SETPRO led to destroyed arms (I used to think that his teachings were harmful; today I believe that pitching mechanics aren’t that simple to understand) but the reality is that there’s really not enough research to even come to a reasonable conclusion. There are research studies showing that a more extended elbow at foot contact leads to lower humeral torques, but mechanical tweaks like this can cause kinks in the sequencing of body parts in an efficient kinetic chain.

I hope this clears up some confusion over what the Inverted W is. Remember, the emphasis is on the inverted positioning of the arm and not the letter made by the elbows, which is why it’s not simply called the “M.”