Contrary to what my detractors say, my work draws upon the science that is being done to understand why injuries in pitchers are increasing.

Science is too often being ignored.

I discuss these studies and others at length in The Science Behind The Epidemic, but let me give you an overview of the relevant studies and how they impact my work, here.

An Overview of the Science Behind the Epidemic

My efforts to understand why pitchers were getting hurt first led me to study the work of Dr. Mike Marshall. However, when I compared what he was saying, and what scientific studies were saying, I found a number of problems.

Problems that led me to move on from the work of Dr. Mike Marshall and to dive into the science.


The first paper I dove into was Effect of Pitch Type, Pitch Count, and Pitching Mechanics on Risk of Elbow and Shoulder Pain in Youth Baseball Pitchers by Stephen Lyman PhD, Glenn S. Fleisig PhD, James R. Andrews MD, and E. David Osinski MA that was published in The American Journal of Sports Medicine, Vol. 30, No. 4 (2002).

I read this paper first because I had first read it when I was talking to Dr. Marshall and because it contained a paragraph that I found to be both telling and terrifying.

(T)wo mechanical flaws, backward lean in the balance position and early hand separation, correlated with a decreased risk of elbow pain.Two other flaws, a long arm swing and arm ahead of the body at the time of ball release, correlated with a decreased risk of shoulder pain.

Those two sentences contain a single, massive logical problem.

Here it is again, with emphasis added.

(T)wo mechanical flaws, backward lean in the balance position and early hand separation, correlated with a decreased risk of elbow pain.Two other flaws, a long arm swing and arm ahead of the body at the time of ball release, correlated with a decreased risk of shoulder pain.

What's the problem?

If something REDUCES the risk of elbow and shoulder pain, then how is it a FLAW?

Isn't that backwards?

And don't tell me it's a flaw just because you or your biomechanical model says it's a flaw.

I'm not buying it.

I didn't, and still don't, know how a collection of highly-educated people -- PhD's, MD's, and MA's -- could think, much less say, something like that, but it alerted me to the likelihood that people were thinking badly about the question of pitching injuries. I didn't know what the issue was, but I had a sense that it was because people were focusing on velocity above all else.

That meant what, when reading papers, I had to be prepared to disregard the authors' conclusions and read the papers backwards; I had to keep in mind the possibility that what they said was good was actually bad, and vice versa.


My sense that I had to be prepared to read studies backwards -- to draw conclusions the opposite of the authors -- was validated by one of the next papers I read, The Effect of Pitching Biomechanics on the Upper Extremity in Youth and Adolescent Baseball Pitchers by J. T. Davis MD, Orr Limpisvasti MD, Derrick Fluhme MD, Karen J. Mohr PT, Lewis A. Yocum MD, Neal S. ElAttrache MD, and Frank W. Jobe MD that was published in The American Journal of Sports Medicine, Vol. 37, No. 8 (2009).

Click on the Image to View a Larger Version

What alerted me to the presence of a possible problem was the diagrams in the piece, many of which advocated movement patterns that were increasingly being taught and at least correlated with pitching injuries. That then led me to this line.

We believe that the hand-on-top position initiates early shoulder abduction while delaying humeral external rotation because when the forearm is pronated, the humerus remains internally rotated. This causes the shoulder to abduct while delaying humeral external rotation (Figure 2A).

I had caught up to the present by 2009, and was -- and still am -- watching and reading the journals them monthly, so I knew enough to be suspicious about this statement for two reasons.

First, I had noticed the Dr. Mike Marshall's advocacy of the concept of Pronation -- which is often taught using the cue Point the Ball at Second Base -- had taken on a life of its own and had morphed into a flaw that I called Premature Pronation at the time and now refer to as the Timmy John Twist.

Second, it was obvious that every pitcher who made the Inverted W didn't have problems - Tom Glavine made the Inverted W and was both dominant and durable -- so, while positions were (and remain) relevant, I had shifted my focus from positions to Timing. And, when I talk about Timing, I am talking about External and Internal Rotation.

...when the forearm is pronated, the humerus remains internally rotated. This causes the shoulder to abduct while delaying humeral external rotation.

By advocating Pronation for the purpose of delaying External Rotation, the authors are talking about creating a Timing problem, and I had come to find that Timing problems were correlated with injury problems in pitchers.

Yes, that is a little complicated because you have to read the study backwards -- what they say is desirable is actually problematic -- but I had Internal Rotation and External Rotation in mind when I came across the next relevant piece of work a couple of years later.


In 2011, Dr. Cynthia LaBella presented a study to the AAOS that very directly relates to the topics I discuss, and in particular the core problem with the Inverted W, Inverted L, and Inverted V. I know, because she asked me if she could use some of my clips to illustrate her presentation.

The most relevant portion of this study is the following...

Paired t-tests compared the pain group to the no-pain group for the following three variables that had the greatest difference in mean scores between groups:
  • Internal shoulder rotation at initiation of external shoulder rotation in stride.
  • Shoulder elevation at initiation of elbow extension in stride.
  • Average shoulder elevation from start of pitching cycle to time of maximum shoulder elevation.
...The pain group had greater internal shoulder rotation at the initiation of external rotation in the stride.

Jeff Passan knows about this study but has completely disregarded it.

I know he knows about it because I told him about it multiple times, but I have never heard him discuss it. However, I find it both relevant and interesting because of Dr. LaBella's focus on and findings with respect to Internal and External Rotation.

Davis (2009) advocates pronation-creating or reinforcing movements because they inhibit external rotation. I don't know why, but I assume it's because they also increase velocity. Or maybe it's just what everybody teaches. However, regardless of why Davis (2009) advocates those movements, LaBella (2011) calls into question whether that it good advice, at least if you also care about pain in youth baseball pitchers.

LaBella (2011) is also why I keep talking about the Inverted W and the other inverted arm actions. They, by definition, create more Internal Rotation than is typical and natural and delay the onset of External Rotation. LaBella (2011) indicates that any cue or arm action that prolongs internal rotation may increase the likelihood that pitchers will experience pain.


In 2010 Dr. Weimi Douoguih, Medical Director for MedStar Sports Medicine and, at the time, Medical Director for the Washington Nationals, heard me say the following during an interview about the Inverted W on a D.C. radio station.

What the not so durable guys do is they take their elbows back but they also take them up. Now, that's actually painful to do, but it's not that bad in and of itself. The problem is that when you take the elbows back and up, you CAN end up with a Timing problem.

Curious about what I was saying and seeing, Dr. Douoguih then put together a "Is this guy crazy or could he be on to something" study to test both of the claims I made...

  1. The Inverted W isn't (that) bad in and of itself. It can cause problems but doesn't always do so.
  2. The real problem with the Inverted W is the Timing problem it can create. Again, CAN not always DOES.

Dr. Douoguih's summarized his findings in a 2012 poster and a 2015 paper...

I discuss the results of the study at length in my review of the Douoguih study of the Inverted W and Timing.

The gist of Dr. Douoguih's findings was that...

  1. He couldn't say anything definitive about the Inverted W because of a methodological limitation of the study. In sum, he studied a much more rare problem, not the more common form of the Inverted W.
  2. He could say that the studied showed that Timing problems were related to injury problems in pitchers.