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Pitching Mechanics Analysis
Stephen Strasburg

If you are interested in my latest opinion of what's going on with Stephen Strasburg and why, I recently together a new overview and summary of my views of...

To read what I said about Stephen Strasburg prior to 2016, see below.

Inverted W or Timing?

As I have been saying since at least late 2007, while the Inverted W is likely related to Stephen Strasburg's injury problems, the Inverted W did not cause his injury problems.

At least, not directly.

Instead, the root cause of Stephen Strasburg's injuries is a problem with his Timing. That Timing problem is overloading his arm. It was originally caused by an Inverted W but has since morphed into more of a Horizontal W.

That lingering Timing problem is what got, and is still getting, Stephen Strasburg's elbow and will eventually getting his shoulder.

Flat Arm Syndrome

In the past, I have referred to the root cause of Stephen Strasburg's elbow issues as a Timing problem.

Stephen Strasburg

Stephen Strasburg

However, I have recently started using a more descriptive term...

In the clip below, see how Stephen Strasburg's elbow starts to move to the left while his pitching arm is flat?

Stephen Strasburg

Stephen Strasburg's Flat Arm Syndrome

That's bad.

It's also increasingly common.

2010.8.31 Stephen Strasburg Podcast

My August 2010 Stephen Strasburg Pitching Mechanics and Inverted W Podcast was conducted with a D.C. radio station after his season ended due to Tommy John Surgery. It's a good overview of my views on Stephen Strasburg's pitching mechanics, his long-term fate, the Inverted W, and the ultimate root cause of Stephen Strasburg's problems.

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.

Out of this interview came a study of the Inverted W.

2011.3.15 Comments on Verducci

Tom Verducci just put together a piece that is clearly based on my analysis of the pitching mechanics of Stephen Strasburg and Stephen Strasburg's problem with the Inverted W. However, either Verducci, or the person who quoted my information to him pretty much word for word, never talked to me about it.

As a result, he didn't get it quite right.

While I discuss this topic at greater length in my new piece on injuries to pitchers, let me quickly go through Tom Verducci's piece and point out what he got right and what he got wrong.

Because his front foot lands too soon, Stephen Strasburg’s shoulder and elbow must bear a dangerous amount of force.

This is a perfect example of what happens when you borrow someone else's work without really understanding what you are borrowing.

The problem isn’t that Stephen Strasburg's front foot is early; that his front foot lands too soon. There’s nothing you can do about that because the front foot has to get down at some point. Rather, the problem is that Stephen Strasburg’s arm is late; his arm isn't in the correct position at the moment when his front foot heel plants and his shoulders start rotating.

As the picture below shows, at the moment Stephen Strasburg's front foot lands, and his shoulders start rotating, his Pitching Arm Side (PAS) forearm, instead of being vertical and at 90 degrees of external rotation, is pretty much horizontal and at 0 degrees of external rotation.

Stephen Strasburg

Stephen Strasburg

This is caused by the Inverted W in his arm action; it forces his arm to take a longer path to the high-cocked position and creates what is commonly known as a problem with rushing. As a result, his PAS upper arm will externally rotate especially hard and much, increasing the load on both his elbow and his shoulder.

But above all others one link of the chain is most important: the "late cocking phase," or the phase during which the shoulder reaches its maximum external rotation with the baseball raised in the "loaded" position (typically, above the shoulder) and ready to come forward.

The line above is very confusing, and reflects a problem with the conventional model of the baseball pitching cycle. The delineation between the early cocking and the late cocking phases of the throw are very ambiguously defined. It's one reason why I have come up with a simplified and revised baseball pitching cycle.

In addition, it's not correct that the shoulder is at maximum external rotation when the baseball is in the "loaded" or high-cock position. Instead, maximum external rotation occurs after the Pitching Arm Side forearm is vertical and the shoulders start to rotate.

Deja Verducci

Here's where things get REALLY interesting in Tom Verducci's piece about Stephen Strasburg.

Here is the key to managing the torque levels in the late cocking phase: timing. The ball should be loaded in the late cocking phase precisely when the pitcher’s stride foot lands on the ground.

Verducci goes on to say...

The problem is the timing associated with that move, not the move itself.

This is correct, but I feel like I've heard it before, perhaps when I said something remarkably similar about Mark Prior's pitching mechanics in late 2007...

This position isn't damaging in and of itself. However, by coming to this position, Mark Prior is ensuring that his pitching arm will not be in the proper position at the moment his shoulders start to turn.
   As with pitchers with other timing problems like rushing, because his pitching arm is so late, he will dramatically increase the stress on both his elbow and shoulder.

This can be verified using The Wayback Machine.

I say the same thing elsewhere on my web site...

(T)he Inverted W is not (that) bad in and of itself. The Inverted W doesn't directly lead to injuries. Instead, the problem with the Inverted W is that it can create a Timing problem...


The problem with the Inverted W is that it can (and I mean can and not always does) create a timing problem (aka rushing) and cause the arm to be late.

If you doubt what I said when, here's The Wayback Machine's capture of this page from August 2008.

Tom Verducci then goes on to say...

Without the energy from the rest of the body, the shoulder and elbow must bear higher levels of torque in what in even optimum circumstances is a maneuver that taxes the physical limits of what an arm can bear.

“Without” should really be “Because of.”

The timing problem that can be created by the use of the Inverted W increases the energy, and thus the force, on the elbow and the shoulder, which can overload them.

I spoke with a key decision maker for one club last week who, speaking on the condition of anonymity, said his club will not consider any pitcher — by draft, trade or free agency — who does not have the baseball in the loaded position at the time of foot strike.

I wouldn’t be surprised if this is the Mets. I have talked to people with them since 2007 and they have bought into my ideas.

However, once Strasburg takes the ball out of the glove, down and away from his body, his right elbow, not his right hand, literally takes the leading role. Like re-writing a script, the roles in the kinetic chain are switched. Now it is the elbow that raises higher than the shoulder and the hand.

This is correct.

There is one moment in this sequence when both of Strasburg’s elbows are higher than his shoulders, as if he were locked in medieval village stocks. Many people have frozen that moment of his delivery and assigned it as the point of risk. That’s not entirely true.

The problem is the timing associated with that move, not the move itself.

OK, so Tom Verducci's clearly been reading my stuff. I say the same exact thing in my piece on the Inverted W...

(T)he Inverted W is not (that) bad in and of itself. The Inverted W doesn't directly lead to injuries. Instead, the problem with the Inverted W is that it can create a timing problem

There's also this line from my own web site where I say...

The problem with the Inverted W is that it can (and I mean can and not always does) create a timing problem (aka rushing) and cause the arm to be late.

I wish that Tom Verducci, or whoever he's talking to who is referencing my work, would just give me a call so that I can make sure that he gets this right. As it is, he's just confusing people and making this look muddier and more confused than it actually is.

When Strasburg gets his elbows above his shoulders and the baseball is below or about even with his right shoulder, his stride foot is hitting the ground. The ball should be in the loaded position at that point, but because Strasburg uses the funky “high elbow” raise, he still has to rotate his arm above his shoulder to get it there. The energy from landing on his stride foot has passed too early to the shoulder and elbow — before the joints are ready to use it.

Again, while this is mostly correct, the last line isn’t quite right. It’s not that this is an efficiency problem. Rather, because of the timing problem that is created by the Inverted W, his arm and shoulder aren’t in a good position to handle the forces that are generated by the rest of his body. As a result, instead of externally rotating smoothly, his PAS arm gets externally rotated especially much and hard (as happens to the last person in the chain in a game of crack the whip).

I asked Riggleman and Rizzo if they considered Strasburg’s mechanics put him at risk of injury and whether they intend to alter his mechanics when he returns to the mound. Neither one expressed much concern.

Strasburg’s shoulder is the next thing that is going to fail.

While this time off from throwing will probably buy him a few years, he is going to encounter major shoulder problems is he doesn't correct the problem with his arm action and his timing.

Rizzo did not draw a connection between Strasburg’s mechanics and his injury. He called the tearing of the ulnar collateral ligament “a freak accident.”

If I was a Nats fan, I would be nervous because Rizzo doesn't seem to understand how pitchers get injured.

2010.08.27 2:30PM Update

I posted the previous piece while waiting on the results of Stephen Strasburg's MRI. Well, the results of the MRI just came back and it looks like Strasburg is going to need Tommy John surgery.

I'm not at all surprised.

In terms of his having elbow problems rather than shoulder problems, the fact is that it's hard to predict which will fail first because there are lots of variables involved. However, in many cases the elbow will fail before the shoulder does (especially if the pitcher relies heavily on his slider). For example, fellow Inverted W pitcher Anthony Reyes went down with elbow problems before his shoulder problems were able to take their toll.

Going forward, the way this typically works for Inverted W guys -- at least for those who don't change their mechanics -- is that they come back from the surgery and look great for a while. Then their mechanics again take their toll, but on the shoulder this time (think B.J Ryan who is technically an Inverted L guy). Given Strasburg's velocity, I'm thinking that, if nothing changes in his mechanics and he remains a starter, then the Nats will get one or two years of value out of him before his shoulder blows up.

For Strasburg to have any chance of pitching more than 5 years he's got to change his arm action and get rid of the Inverted W. He also needs to ditch the slider because that is an absolute killer of the elbows. Changing his arm action may knock 5 or so MPH off of his velocity, but that's what it's going to take to reduce the load on his arm.

2010.8.27 10:00AM Update

In my prior comments about Stephen Strasburg, I say his arm action is borderline, but the long-term implications for the health of his arm depend on whether he has a timing problem or not.

As I also say below, the pictures below are very suggestive of a timing problem.

Notice how he is pulling back with his Glove Side elbow well before his Pitching Arm Side upper arm has reached 90 degrees of external rotation (PAS forearm vertical).

Stephen Strasburg

Stephen Strasburg

Stephen Strasburg

Stephen Strasburg

Stephen Strasburg

Stephen Strasburg

I've been going over some of the video of Stephen Strasburg that's been hitting the web over the past few weeks -- much of which incorrectly extols Strasburg's pitching mechanics and compares him to greats like Greg Maddux, Randy Johnson, and Roger Clemens -- and it's clear that Stephen Strasburg does in fact have a significant timing problem, the same timing problem that he has had for years.

Video Clip of Stephen Strasburg

Stephen Strasburg

As was evident in the video above, which is from 2007 or 2008 and which I reference in detail further down on the page, Stephen Strasburg's shoulders start rotating well before his PAS upper arm has reached 90 degrees of external rotation. In fact, while his arm action isn't exactly the same -- but it is pretty close -- Stephen Strasburg's timing problem is pretty much identical to Mark Prior's.

None of this bodes well for Stephen Strasburg's long-term health.

He is a plus plus velocity guy with a significant timing problem who is pitching longer into the season than he ever has. If the Nats are smart, they will shut him down. However, I don't know what the results of the second MRI are going to say, but it might be too late to salvage his 2011 season if not his career.

2010.6.10 Update

The bottom line on Stephen Strasburg is that I don't think he'll be another Mark Prior. While I'm working to get some video to confirm this -- because still photos can only tell you so much -- Stephen Strasburg's mechanics and timing don't seem to be as bad as those of Mark Prior.

However, Strasburg also isn't completely clean.

I see things that concern me in his arm action and timing and the pitcher they again bring to mind is John Smoltz, another pitcher who had a borderline Inverted W and some arm problems as a result. I could very easily see Stephen Strasburg having a comparable career; years of total dominance accompanied by lost years due to shoulder and elbow problems.


I have spent the past week collecting as many recent pictures of Stephen Strasburg as I can, and here are some of the better and more telling ones.

Stephen Strasburg

Stephen Strasburg

Lots of people will say that the picture above shows Stephen Strasburg's clear Inverted W. I wouldn't say that is anything other than a borderline Inverted W. Because he is leaning forward toward third base, his elbows look higher than they actually are.

Stephen Strasburg

Stephen Strasburg

The picture above makes me nervous for three reasons. First, I see a suggestion of a timing problem. It looks like Stephen Strasburg may pull back with his glove elbow a bit early, which can create a timing problem and which is the likely cause of Mark Mulder and Jeff Francis' shoulder problems. Second, Stephen Strasburg's elbows are well behind his shoulders. Third, his elbows are quite high relative his shoulders.

Greg Maddux

Greg Maddux

Nolan Ryan

Nolan Ryan

If you look at how greats like Greg Maddux and Nolan Ryan Scapular Load, their elbows never get that high (because the higher the elbows get, the greater the strain on the shoulder).

Stephen Strasburg

Stephen Strasburg

Stephen Strasburg

Stephen Strasburg

The two pictures above show a similar pattern from slightly different angles. Notice how Stephen Strasburg is pulling back with his Glove Side (GS) elbow while his Pitching Arm Side (PAS) forearm is still only horizontal.

Stephen Strasburg

Stephen Strasburg

The photo above is from a slightly later moment in time. Notice how Stephen Strasburg has continued to pull back with his glove side elbow and how his PAS forearm is still not yet vertical. I'd need video to confirm this, but this is often characteristic of a timing problem.

Stephen Strasburg

Stephen Strasburg

Similarly, the photo above gives some suggestion of a timing problem and a resulting increased load on the front of the PAS shoulder. Look at how much Stephen Strasburg's scaps are pinched together. At a minimum, you don't see this degree a scap pinching in Nolan Ryan.


The video clip below, which I obtained from Driveline Mechanics, is of the pitching mechanics of Stephen Strasburg. The problem is that Stephen Strasburg's pitching mechanics appear to have been influenced by, and are remarkably similar to, those of Mark Prior. The thing to pay attention to in this clip is the borderline Inverted W that is clearly visible in Frame 23 and Frame 24.

Video Clip of Stephen Strasburg

Stephen Strasburg

Stephen Strasburg's Inverted W

Stephen Strasburg's Inverted W

While the Inverted W isn't automatically bad, in Stephen Strasburg's case it does appear to create a significant timing problem.

Notice that in Frame 26, when Stephen Strasburg's Glove Side (GS) foot plants and his shoulders start to rotate, his Pitching Arm Side (PAS) forearm is just above the horizontal rather than being vertical (or nearly so) as I prefer. In Frame 27, when Stephen Strasburg's shoulder's have clearly rotate a significant amount, his PAS is still not yet vertical.

All of this causes Stephen Strasburg's PAS upper arm to externally rotate especially hard and much (see Frame 29) which significantly increases the load on the elbow and the shoulder. What's more it looks like this external rotation, as with Mark Prior, occurs with his PAS upper arm elevated in a position of hyperabduction.

If you combine this with Stephen Strasburg's plus to plus plus velocity and the fact that he seems to be a fastball/slider guy, rather than a fastball/change-up guy, you've got someone who is putting tremendous, and likely excessive, stress on his elbow and his shoulder.

The Bottom Line

The bottom line on Stephen Strasburg is that, while he may be a consensus number one like David Price, mechanically speaking Stephen Strasburg is no David Price.

Like Mark Prior, Stephen Strasburg has some Inverted W in his arm action and a timing problem as a result (aka habitual rushing). This will significantly increase the load on his elbow and his shoulder and make him a very high risk draft choice. I could even see him pulling a Cole St. Clair and blowing up mid-season.

However, because his mechanics in some of the frames I have seen aren't quite as bad as Mark Prior's, and at times he sometimes makes the Horizontal W rather than the Inverted W...

Stephen Strasburg

Stephen Strasburg

...there is a chance that Stephen Strasburg could have a career more like a John Smoltz. In that case, he would be effective for periods of time but would also struggle with elbow and shoulder problems.

It's a bit hard to say for sure, since Stephen Strasburg seems to show significant variability in his arm action from year to year.

What I Said, When

If you have any questions or doubts about what I said about Stephen Strasburg and when, you can verify my claims using the Wayback Machine.


[1] I just put together a new piece that discusses my views on the overlap between pitching mechanics, injuries, the Verducci Effect, and Pitcher Abuse Points.

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