In 2009, I published a win-curve that predicted Texas Rangers attendance for a given win level. The Rangers won 87 games, and my win-curve predicted 27,958 attendees per game for that win level. Actual attendance was only 27,641. The difference was 317, only a 1.15% difference.
Yeah, I'm late to the party on this one, but I wanted to share some of what has been written in the blogosphere about Stephen Strasburg's elbow injury.
To start this post off, here are two quotes from my March 2009 analysis of his mechanics after watching him pitch against TCU:
His flexed elbow moves well behind his back and reaches shoulder height before the ball. From there, he must forcefully externally rotate his arm to get the ball to driveline height. This causes late forearm turnover and increases the valgus torque that occurs during reverse forearm bounce. This is a risk factor for his ulnar collateral ligament.
Strasburg has some of the common flaws of traditional pitching mechanics and carries with him the associated risks. These risks will almost certainly not affect his draft status because it could be 10 years before anything goes wrong.
The second paragraph is included to give context for my analysis.
Around the same time as my analysis, Kyle Boddy (then writing for Driveline Mechanics - the now-defunct SBN blog) compared Strasburg's mechanics to those of Pedro Martinez and Mark Prior. The three pitchers demonstrated striking mechanical similarities.
Notably, Pedro Martinez pitched relatively injury free for most of his career until his age 34 season, the one exception being rather severe shoulder inflammation in 2001.
Mark Prior, of course, was not as lucky. After initially injuring his shoulder in a baserunning collision, Prior suffered from a string of elbow and shoulder injuries. Some people blame the collision for his problems, and while it seems like a possibilty, it is impossible to know for sure.
After Strasburg's injury, Kyle wrote two articles concerning Strasburg and elbow injuries in general.
His first article (Elbow Injuries and What Causes Them (Stephen Strasburg Bonus Content!)) is a lengthy discussion of how horizontal shoulder abduction -- referred to as "scap loading" or "scapular loading" by some -- leads to increased horizontal adduction velocities that increase valgus stress in the elbow. He notes that while this clearly can't be labeled as the sole contributor to Strasburg's injury, it certainly played a role.
Kyle's second article (Strasburg, The Inverted W, and Pitching Mechanics) attacks some misconceptions and naysaying about the reputation of the inverted W position. In his discussion, he brings it back to Mark Prior by comparing Prior's peak horizontal shoulder abduction position to Strasburg's peak horizontal shoulder abduction position.
Finally, Eric Cressey offered his thoughts -- The Skinny on Stephen Strasburg’s Injury. Much of the article explains how important the health of the anterior forearm musculature (flexor-pronator mass) is in helping take valgus stress in the UCL. He briefly tackles overall tissue quality and links back to the great series he wrote on elbow pain.
Cressey puts some of the blame on the inverted W, but he is quick to mention that mechanical quirks like that aren't always a sign of impending injury.
A lot of people subscribe to the idea that a pitcher "only has so many bullets" in his arm. Cressey quotes J.P. Ricciardi and seems to agree with him. The idea is hard to argue with, since "so many bullets" could be 1,000 or 1,000,000 or even 1,000,000,000.
As a stand-alone theory, it leaves a lot to be desired, and leads to a series of questions:
How many bullets do I have?
What's the best way to conserve my bullets?
Can I get more bullets? If so, how?
With a boiled-down, unexplained idea like this, people are likely to misapply it by any number of means. That could include keeping strict pitch counts to protect the arm but still pitching year-round without rest. Alternatively, some people may wind up thinking that there's nothing they can do to extend the life of their arms and then neglect appropriate strength and conditioning.
Cressey, however, applies idea very well in a brief discussion of how to save those bullets. If you haven't read his thoughts, you should.
I have some of my own thoughts to share about Strasburg, but it may take me some time to pull them all together. Stay tuned.
If you've ever spent any time around a pitching coach, you've probably heard the phrase "good extension" or "great extension." This is a reference to how a pitcher uses his arm. Unfortunately, there are a lot of people -- pitching coaches included -- who simply do not know good or great extension when they see it because they don't really know what it means.
The other day I saw a very good pitching coach complement his pitcher's extension on a particular pitch. The player kind of mimed extension by reaching toward home plate. The pitching coach stopped him and asked, "What does 'extension' mean?"
I'm sure that some of you are confused. You probably think of extension the same way this pitcher did -- drive off the rubber, extend toward the target. Unfortunately, that's not the type of extension that should be extolled.
In any athletic action, several extensions take place in several different places throughout the body. In the act of pitching, the term "extension" should refer to the position of the arm when the baseball leaves the pitcher's hand.
In pitching, "extension" is a generalized term that refers to elbow extension, but good extension isn't just about releasing the baseball with an extended elbow. Finding good extension is about releasing the baseball in a mechanically efficient position.
The most efficient release will occur when the hand reaches its maximum velocity in the direction of home plate.
The physics of rotational acceleration tells us that this happens when the forearm (the acting lever for the hand and ball) is perpendicular to the target because at this point, the hand is moving directly toward the target. 100% of the hand's -- and therefore the ball's -- velocity is directed toward home plate.
When this physics concept is applied to elbow extension in the throwing motion, "good extension" is seen in a full extension release point that is perpendicular to home plate rather than one that is reaching forward toward the plate.
Because the hand is connected to the elbow, the faster the elbow moves, the faster the hand will move. The elbow is connected to the shoulder, so the faster the shoulder moves, the faster the elbow will move.
Put together, these ideas build a concept of the release point in which the pitching shoulder, elbow, hand, and the baseball itself are moving straight toward home plate with near-peak velocity. The problem with that concept is that the human body is not made up of perfect levers like the ones that introductory physics classes love to pretend exist.
The result is that good extension can take many forms -- varying widely from pitcher to pitcher -- but true extension looks the same from pitcher to pitcher no matter how different their deliveries are. In most pitchers, good extension will occur slightly in front of perpendicular.
Now that you have an idea what good extension looks like, how important is it? That's a question that's not easy to answer.
As with most pitching concepts, there are always exceptions to "rules" like this. UCLA's Trevor Bauer is very good at what he does, has been clocked in the mid- to upper-90s, and is a great example of someone who does not have "complete" extension.
Inefficient extension -- such as short-arming the ball (a lack of extension) or "reaching through the target" (the wrong kind of extension) -- will likely result in lower velocities, but that doesn't mean that someone can't throw hard without efficient extension. On the other hand, overly aggressive extension can lead to cartilage irritation, joint swelling, and even olecranon fractures (Jay Powell, Joel Zumaya).
Proper understanding of concepts like this are essential for coaches that work with youth pitchers. Once improper techniques are assimilated, especially in kids with less natural athleticism, they can be extremely difficult to overcome.
Eric Cressey, of Cressey Performance, published a series of posts on his personal blog over the past two weeks that takes a fairly comprehensive look at the elbow. His series progresses through anatomy, pathology, and injury before discussing how to go about protecting pitchers.
The first three parts are factual in nature, heavy on scientific facts but without beating you over the head with mumbo-jumbo.
Part 4 of Cressey's series builds on the information from the first three. He uses a 4-category approach to make general suggestions for keeping a pitcher healthy. The last three categories are spot-on, but I have a few issues with his ideas about injurious pitching mechanics.
To kick it off, Cressey shows a photo of a 5' 7" pitcher and a 6' 7" pitcher standing side-by-side and says, "Anyone who thinks these two are going to throw a baseball with velocity and safety via the same mechanics is out of his mind."
This is a very interesting statement to me, since Cressey seems to be suggesting that "safe" mechanics for a tall pitcher are different from "safe" mechanics for a short pitcher. I may be out of my mind, but that's just plain wrong.
Now, in real life, dealing with two different pitchers, yes, safe mechanics for one pitcher aren't necessarily safe for another pitcher, but height has as much to do with it as a pitcher's choice in footwear. The basics of functional anatomy do not vary with a person's height.
Things that will cause variations in "safe" mechanics are long-term training and congenital joint laxity. Long-term training is a very general term that I am using here to refer to how the body has adapted over time to throwing a baseball. This encompasses principles involving conformational changes in the skeleton (i.e. humeral retroversion), increased bone density, changes in muscle contractile force, and changes in tensile strength of ligaments. Congenital joint laxity can be thought of as natural flexibility, and it varies from person to person.
Cressey might as well have included a photo of any two pitchers standing side-by-side.
Kinetically speaking, shorter people have shorter levers, so an equal amount of force applied at a given joint results in less torque for a shorter person than for a taller person. This, however, is unavoidable.
The safest mechanics for an individual will be the same no matter how tall or short that person is. There is no height at which certain mechanics become safe and others become unsafe.
Cressey then discusses two biomechanical studies that correlate horizontal shoulder adduction and external rotation, respectively, to elbow valgus stress. Neither study supports his proposition, but the points are well taken, if somewhat incomplete.
My chief complaint about studies like these is that they focus mainly on peak torque values instead of the loading rates of those torques (i.e. How much time did the joint tissues have to adapt to the stress?). This is a topic for another day, though.
He follows this up with a discussion about balancing health-risk with performance as it pertains to deception and pitch movement. This is an excellent point, but it's one that I think far too many young pitchers fail to understand. This is also a topic for another day.
Cressey has two more posts in this series, and if you aren't already a reader of his, I highly suggest you become one. Click here to visit Eric Cressey's blog.
Seriously unbelievable. Bones get stronger after stress fractures. It's part of the healing process sometimes referred to as overcompensation (or supercompensation). Bones respond to stress and stress fractures by growing thicker, stronger, and more dense.
What is believable, though? I see a couple of possible explanations.
The original stress fracture from 2007 simply may not be healed. If this is the case, the cause is likely dietary, but it could be that the injury has never been given sufficient time to heal. Stress fractures often become pain-free well before they are actually healed.
Another explanation is that the problem is not actually a stress fracture. Soft tissue is much more susceptible to re-injury than is bony tissue, and the location of McCarthy's injury is a confluence of soft tissue that literally encapsulates the glenohumeral joint.
At this point, it looks like mechanics aren't McCarthy's real problem. If it isn't his mechanics, the culprit is one of the following: diet, strength/conditioning, and genetics.
Genetics, of course, can not be changed, but the other two can be addressed.
In addressing the diet, there are three things to watch for, and they all go hand-in-hand. The goal is improved bone density so the main focal points are calcium, vitamin D, and pH balance. I am not a dietician or a nutritionist, so I will stop short of making specific recommendations.
In addressing potential strength and conditioning issues that may be contributing to McCarthy's problems, a recently published DVD set contains just about everything anyone would ever need to know ranging from prehab and diagnosis to rehab and high performance.
[[Update: The evidence is apparently quite clear. This is, in fact, a scapular stress fracture. Someone who has seen recent video of McCarthy believes that McCarthy had fallen back into old mechanical habits.]]
Former MLB scout. Current web developer. Long-time opinion-haver.