This is a very early essay in which I discuss a concept that I have since come to call the Tommy John Twist.

Pronate Early
But Not Too Early

4.27.2007

In Saving The Pitcher, Will Carroll talks about how pitchers must pronate (twisting the wrist as when turning a doorknob counter-clockwise) upon releasing the ball. Based on his conversations with pitching gurus like Tom House and Dr. Mike Marshall, Will has come to believe that pronation is the key to protecting the elbow. Carroll uses Tom House's student Mark Prior as an example of a pitcher who does an excellent job of pronating upon releasing the ball.

The Problem

I initially took this advice as gospel, but two things happened that led me to question some of what Mr. Carroll had said.

First, Mark Prior experienced a series of arm problems. Sure, some of them were flukes (like getting hit on the elbow by a batted ball). However, some of his elbow injuries weren't. I suspect that were due to Mark Prior's pitching motion and mechanics.

The second thing that led me to question what Mr. Carroll had said in his book was when I started putting together a number of analyses of the motions of professional pitchers.

I saw much more pronation than I expected to see.

Nearly everybody — including both injury-plagued and injury-free pitchers — seemed to be doing it.

The Resolution

This threw me at first, but I believe that I have since figured out what's going on. Based on my understanding of the physiology of pitching, it is my opinion that merely pronating upon releasing the ball is not enough to reduce the risk of injury. Instead, I believe that you must pronate earlier in the motion, just after the shoulders have begun to turn and the arm has just begun to accelerate, for it to have the desired effect of protecting the elbow.

Late Pronation vs. Premature Pronation

The problem is that if you pronate the forearm through the Release Point (which I call Late Pronation), it will impart some spin on the ball, which is good (a screwball is a pitch that is thrown with a very large amount of pronation). However, pronating late will not enable the Pronator Teres muscle to bear some of the load that is normally born by the UCL, which is bad. As a result, Late Pronators like Mark Prior are vulnerable to tearing their UCL and/or irritating the parts of the bone to which the UCL attaches.

The only way to enable the Pronator Teres to take some of the load off of the UCL, and to protect the UCL, is to — as Dr. Mike Marshall recommends — pronate during the Acceleration phase (which I call Early Pronation). By doing this, Early Pronators like Chad Bradford reduce the likelihood that they will experience serious elbow problems.

Premature Pronation

One very common piece of advice to pitchers (and really to all throwers) is that they should show the ball to Center Field as they pass through what is variously referred to as the High Cocked, High Guard, or the Power Position. The problem with doing this is that it forces you to pronate your forearm too early. This then forces you to supinate your forearm, at exactly the wrong moment, in order to get your palm around to facing the target. This then focuses the load on the UCL and may irritate it and/or the bones to which it attaches.

The Limits of Pronation

As I discuss in my essay The Limits Of Pronating, for a number of physiological reasons pronating is of only limited value in pitchers that are younger than 16 or 17.

Questions and Answers

Q: Sorry to bother you, but I have a burning question I always wanted to know. Now, if I'm teaching players to pronate early and while releasing how can I effectively incorporate magnus force on the ball? According to the studies I've looked at, backspin on the baseball makes it travel further and with more velocity. How can I create backspin with the pronation of the forearm? Or is backspin not safe on the elbow?

A: Good question. The answer is that they are not mutually exclusive.

You want to pronate before (and through the moment that) you release the ball but still release a 4-seam fastball or 2-seam fastball with pure backspin (which lets you take advantage of the magnus force).

Unlike the case of a screwball, where the spin does come from the pronation, in the case of a fastball the spin and the pronation are pretty much two different things. In order to protect the elbow, you pronate as you accelerate the arm and extend the elbow. However, at the release point, the rate at which you are pronating should be slowing down (since you are pronating early), which allows you to release the ball with pure backspin (by letting it roll off of your index and middle fingers).

The case of a curveball is similar but slightly different. As before, you pronate through the acceleration and the extension of the elbow in order to protect the elbow but in this case you release the ball with topspin (which means you have to cant the wrist differently and snap your fingers).

There's nothing inherently bad for the elbow in terms of putting backspin on the ball (and it's very good aerodynamically). There's also nothing inherently wrong in terms of putting topspin or sidespin on the ball.

What matters is how you do it.

If you generate that back, top, or sidespin while (or by) pronating the wrist, then that's good. If you generate that back, top, or sidespin while (or by) supinating the wrist, then that's bad.

Part of what might confusing about is the words we use. The best way to say it is that (in the case of all pitches but the screwball) you generate backspin "while" pronating rather than saying that you generate backspin "by" pronating. While in the case of a curveball or slider it's possible to generate spin by supinating the wrist, that is a bad thing to do (because it strains the UCL and causes the bones of the elbow to smash together). In the case of a curveball or slider, you want to generate that spin while pronating the wrist.

Q: Are you saying that you advocate supination? I thought you have said elsewhere that supination is bad.

A: Yes, I do advocate supination, but it must be done at the correct moment.
     By definition, if you are to be able to powerfully and significantly pronate through the acceleration phase, then your forearm must be supinated going into the acceleration phase. If your forearm is neutral going into the acceleration phase, then you won't be able to pronate as hard or as much.
     Supinating before the acceleration phase isn't problematic because the forces on the elbow and shoulder are relatively low (since the shoulders haven yet started turning).

Q: I know you talk about early pronation, but I was wondering if you could be more specific? How do you do it? Could a cue for early pronation be keeping the ball on the chest side, either pointing at the 1st or 3rd baseman, depending on what arm they throw with? Or does it matter as long as when the pitching arm gets to driveline height that the ball is pointing at the 3rd/1st baseman?

A: The proper cue depends on where you are in the motion.

Assuming we are talking about a RHP, at what some people call the "high-cocked", "high guard", or "power" position the proper cue would be to either show the ball to 3B (good), to show the ball to Home Plate (better), or to show the ball to 1B (best but really hard to do). At a minimum you don't want to show the ball to CF/2B.

As soon as the shoulders start to turn and the pitching arm side forearm starts to bounce back, a cue that might work is to show the ball to the sky (palm up).

The logic is that to get from showing the ball to Home Plate at the high cocked position to showing the ball to the sky as the shoulders start to turn and the forearm starts to fly out you would have to pronate the forearm.

Q: I am an Athletic Training student in college, and came upon your "essays".  I am reading the sections where you write about early vs. late pronation.  I myself played baseball with one Adam Ottavino, who you have used as an example in this.  I tried to replicate this "early" pronation you discussed, but am having a hard time replicating it.  I feel that you may be mistaking pronation with supination.  If I (a left handed thrower) keep my elbow and wrist the same from the time the ball leaves my gloves, the ball will face somewhere between 2b and 1b.  If I supinate (the act of opening up the palm so it faces the sky when in anatomical position), the ball will now face home plate like you state it should.  If you pronate in this motion, the ball will end up facing centerfield, as you (and your pitching "guru") state. Could you please explain this to me?

A: For a pitcher to be able to powerfully pronate their forearm as their elbow extends and through the release point, their forearm must first be supinated. It could also be in a neutral position, but then you wouldn't be able to pronate as much as you would if your forearm was supinated at this moment.

Just to be clear, I am not advocating supination through or after the release point. That is bad because it focuses the load on the UCL. What I am advocating is pronation through the release point. However, this requires that the forearm be supinated as the acceleration phase begins.