The Inverted W
The Inverted W, which I originally called
The M, is a
that is used to refer to one of a
family of problematic pitching arm actions that include the...
Recent studies have found that pitchers who make the Inverted W and
who have a
Timing problem as a result, are at a significantly higher
risk of experiencing shoulder and elbow
In the Inverted W the pitcher...
- Lifts their elbows to the point
where they are at, or even above, the level of their shoulders.
- While, and more importantly, their forearms are flat or, worse yet, pointing downwards.
Biomechanically speaking, that means bilateral hyperabduction
and minimal external external, or worse prolonged internal rotation,
of both arms into Foot Plant.
The Inverted W
That can be problematic and
increase the pitcher's risk of elbow and shoulder problems if it
Timing; if their pitching arm isn't up and in the
Ready Position when their front foot plants and their
shoulders start to rotate.
In the pictures above of Anthony Reyes, the primary problem
isn't the height of his elbows. Rather, that primary problem is
that, because his elbows are still high, his forearms are at best
flat, and actually slightly internally rotated, when he's at Foot Plant.
ASMI and the Inverted W
Despite the studies of the Inverted W and Timing that are
starting to come out, I still get considerable pushback on the
idea that the Inverted W is problematic. That is why I was
interested by what an ASMI epidemiologist
recently said about the Inverted W...
The Inverted W is something that we look for during our
biomechanical evaluations here at ASMI. It's essentially a
combination of late external
rotation and high shoulder
abduction at the moment of foot contact during a pitcher's
delivery. Both of these issues have been demonstrated to lead to
problems that can result in injuries requiring surgery. Low
external rotation at foot contact (what we call a "late arm")
results in higher stress on the elbow. The ideal angle of shoulder
abduction is 90°, because the bones and the soft tissues
supporting the joint are able to move the most freely and most
efficiently. When the arm is raised higher, the soft tissues in
the shoulder joint become inpinged, or pinched against the
shoulder socket, and can cause injury. So when you add these two
things together in the Inverted W, a pitcher can really get into
I view the fact that ASMI incorporates the Inverted W into
their evaluative criteria to be a huge advance and validation for
the idea that the Inverted W and the other arm actions are
problematic because they often cause
Timing: The Core Problem
The Inverted W, and many other problematic pitching arm actions, often
leads to a problem called
Flat Arm Syndrome, which is another, easier-to-visualize way of
Timing problem that is the root cause of the injury
problems of a number of pitchers, including...
As I explained in late 2007 in my
of Mark Prior's pitching mechanics, and more recently in my
analysis of Stephen Strasburg's pitching mechanics...
The Inverted W isn't (necessarily)
a problem in and of itself.
Rather, the Inverted W contributes
to injuries in pitchers by creating a
timing problem, and
timing problems are what tend to hurt pitchers' arms.
The Inverted W increases the likelihood that a
pitcher's arm will not be in the proper position when their
front foot plants and their shoulders
start to rotate. That will increase the load on the elbow and the
shoulder, providing a short-term velocity boost but, in the long
run, significantly increasing the risk of injury to the pitching
In the picture above of Anthony Reyes, the primary problem
isn't the height of his elbows. Rather, the problem is that
Anthony Reyes' forearms are pointing downward at the
moment his front foot plants and his shoulders start rotating. That will cause his pitching
arm to externally rotate (flip over backwards) with much more
force than his body can handle.
Justin Verlander and Anthony Reyes c. 2006
If you compare the arm actions of Justin Verlander and Anthony
Reyes, it's obvious why Justin Verlander is still pitching and
Anthony Reyes isn't. As I discuss at length in my piece on
Flat Arm Syndrome, at foot plant Justin Verlander's pitching
arm is UP while Anthony Reyes' pitching arm is at best FLAT.
Anthony Reyes' pitching mechanics
-- his Inverted W and resulting
Timing problem -- are why he only pitched in
the major leagues for a few years before breaking down for good.
a result of the recent discussion about the baseball
pitcher injury epidemic, I have put together a webbook
The Epidemic that gives my view of what is
happening, why, and what coaches, parents, and
physicians can do about it.
The idea that the Inverted W is problematic is controversial,
and I have addressed some of the objections to the theory...
Recently, a number of studies have been completed that are
relevant to the Inverted W in particular and Timing problems in
general. I discuss them on my piece on
The Science Behind The Epidemic.
If you are interested in helping to fund this project, I have
put together a page for