Pitching Mechanics Analysis
While many of
Dr. Mike Marshall's ideas have yet to be widely accepted,
one of his ideas that has been taken seriously is the concept of
pronation. Unfortunately, Dr. Marshall is such a miserable
communicator that people have — presumably unwittingly — taken
the concept of pronation in a direction that is causing more
problems than it is fixing. Shelby Miller looks like he may be
one such victim of the misunderstanding, or misapplication, of
the idea of pronation.
In sum, pronation is something that pitchers need to do
through the acceleration
phase of the delivery. However, presumably because of the
limits of Dr. Marshall's communication skills, what I am seeing is
pitchers pronating earlier and earlier, to the point where they
are creating problems in their arm actions.
I first noticed something problematic in Shelby Miller's arm action
when he came up in 2012; his arm looked pretty consistently
I was concerned enough about this that I mentioned Shelby
Miller's timing problem in
my presentation to
the Illinois High School Baseball Coaches Association in
However, while I knew that something was wrong, I
couldn't put my finger on why that was happening; what
the root cause of the problem was.
However, the more I saw of Shelby Miller in 2013, I came to
realize that part of the reason why his arm was late was because
of how he pronated his Pitching Arm Side (PAS) forearm
relatively early on in his arm swing and then held that pronated
position through the start of the acceleration phase.
The movement that I am talking about is very obvious in the
clip above from June 2013. The thing to notice is how, as he
goes through his arm swing, Shelby Miller maintains an
internally rotated and pronated, thumb down position for an
extended period of time and into foot plant.
As a result, during the time when his
PAS forearm should be externally rotating and getting more
vertical as he goes into foot plant, instead his PAS elbow elevates
and his PAS forearm stalls. That makes his arm significantly
late at foot plant and forces him to externally rotate his PAS
upper arm more and faster than is optimal.
In fact, the way that Shelby Miller pronates, and when, is
exactly the opposite of what you want to do. His PAS forearm
should be supinated, and not pronated, during the period of time
when he is at maximum pronation.
A while back I put together a piece on
Pineda in which I labelled showing the ball to center field
as the root cause of his problems. However, it could very well
be that what is going on with Michael Pineda is the same problem
with premature pronation that you see with Shelby Miller. The
showing the ball to center field thing is just a symptom of the
If you compare the arm swings of Nolan Ryan and Shelby
Miller, you will see some significant differences, the most
significant of which is the length of each.
Nolan Ryan vs. Shelby Miller
Nolan Ryan's arm swing is short and direct; his arm goes
quickly and smoothly to the high-cocked position. In contrast,
Shelby Miller's arm swing is long and jerky; Miller breaks his
hands much earlier than Nolan Ryan does, yet he has to rush his
arm up to the high-cocked position due to how he leads with his
Finally, I should note that people like Paul Nyman would have
you believe that Nolan Ryan's arm action is similar to Shelby
Miller's when it is anything but. For going on eight years I
have been telling people that they should ignore people like
Paul Nyman and Tom House when they talk about Nolan Ryan's
pitching mechanics and focus on what Nolan Ryan actually did. I
don't know if people are listening, but one can only hope so.