Posted by Doug Thorburn on Thursday, June 10, 2010 at 10:35 pm

Our sequel begins where the original left off, with Stephen Strasburg having just completed foot strike …

From Foot Strike to Release Point

The sequence of events is critical after foot strike, with several mechanical elements taking place in the span of about a quarter-second. It’s extremely important that a pitcher waits until after foot strike to begin the rotation of the upper body (trunk and shoulders), as it is essential to have both feet planted to generate the forces necessary to properly execute a pitch. Premature trunk rotation is the equivalent of a hitter that starts his swing before the stride foot hits the ground (give it a try).

The longer a pitcher can delay trunk rotation, the greater he will increase his hip-shoulder separation. NPA research has found that the maximum angle between a pitcher’s GS hip and PS shoulder is a critical indicator of pitch velocity.  

Stephen Strasburg has hip-shoulder separation that is off the charts. The majority of big leaguers get between 40 and 60 degrees of maximum hip-shoulder separation, and the largest values in our database were registered by the preternatural flamethrower, Nolan Ryan.

Stras is in Nolan territory.

Players can generate hip-shoulder separation in a number of ways. Depending on their personal signature, a pitcher might rely heavily on hip rotation to get his 40 – 60 degrees of separation, as evidenced by a belt buckle that is nearly facing the plate when trunk rotation kicks in (the Roger Clemens model). On the other extreme are pitchers that rely heavily on the shoulder aspect of separation, as players like CC Sabathia will load the upper body like a power hitter before firing their bullets.

Hips rotate before shoulders, and the timing of rotation has a significant impact on hip-shoulder separation. A pitcher that fires the shoulders too soon will not allow the hips to rotate far enough, limiting the separation along with pitch velocity.

Strasburg is able to gain more precious inches on his release point by maintaining efficient mechanics after foot strike. Strong balance leads to stable posture as the right-hander prepares for the final stages of the delivery, with a spine angle that keeps the head above the center of mass.

Strasburg displays an upright, stacked upper body after foot strike, with some bend in the front knee. A pitcher that keeps a flexible front knee will be able to track the body toward the plate as the shoulders square to the target, as Strasburg demonstrates in the following photos.

One aspect that is often overlooked is the position of the glove as a pitcher moves from foot strike into release point, but Strasburg scores big points in that department. Many pitchers are taught to tuck the mitt into the body or to the hip, but there is a mechanical advantage for players like Strasburg that swivel and stabilize the glove over the front foot.

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Pitchers with a glove that stays out in front will track the body toward the glove, inching closer to the plate and extending release point distance. The benefits extend beyond the couple inches at release point, and many of the best quarterbacks perform the same action when throwing a football. Players like Joe Montana and Drew Brees swivel the non-throwing hand and stabilize it in front of the chest as they get into release point.

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Strasburg stabilizes his posture well as he gets into release point, with just a minor head tilt to the glove side as the arm snaps forward in internal rotation. We had a maxim at the NPA: “every inch of inappropriate head movement will cost two inches at release point.” Most players have some tilt of the head and shoulder line, and the average Major Leaguer has worse posture than Strasburg displays right now.

Stras does have some room for improvement, and his coordination of the rest of the delivery suggests that he could approach an ideal posture with further development. Posture is one of the first things that I notice when evaluating a pitcher, and it’s a great indicator for a pitcher’s ability to repeat his release point with good extension. Poor posture is also a potential precursor to injury, so Strasburg’s outstanding postural stabilization is a positive sign for his future health.

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Injury Risk

There have been rumblings about the injury risk associated with Strasburg’s delivery, and the evidence often cited is the similarity that he shares with Mark Prior. A longtime student of Tom House, Prior has become a symbol of the dangers inherent in pitching a baseball, an elite talent whose promising career was derailed by a barrage of injuries.

The comparison is all too convenient, given the remarkable college pedigrees, the ridiculous hype, and the San Diego roots of both hurlers. When Strasburg signed his $15.1 million contract last year, it broke the record previously held by Prior, whose $10.5 million contract was inked in 2001. Both players have even held the title of “The Greatest College Pitcher That Ever Lived.”

Strasburg does share some mechanical similarities to Prior, almost all of which are points in his favor. Both pitchers have excellent balance and posture, elite hip-shoulder separation, and incredible repetition of timing and sequencing. They both display a good stride, solid momentum, and a strong glove position. But there is one mechanical element that gets all the attention in the Strasburg-Prior comp, and that’s the dreaded “inverted W.” 

As mentioned in Stras Wars I, an “inverted W” describes the look of the pitcher’s arms if the elbows rise above the shoulder line as he gets into foot strike. Some pitching analysts postulate that there is excess force placed on the joints when shoulder abduction raises above 90 degrees, with elbows above the shoulder line. 

A number of pitchers reach or exceed the shoulder line in their delivery, particularly if they use a significant scapular load. Some break down, and some do not. Dave Stewart was as durable as any pitcher in the game during the late ’80’s, tossing over 1,000 innings from 1987-1990, all with an exaggerated “inverted W.”

Johan Santana is another example. Santana separates his hands in a low position, and brings his arms up slowly at the start of his delivery, but the photos reveal an “inverted W” as he approaches foot strike. Johan dealt with bone chips last year, though it was the first injury hiccup in his 11-year career. Santana had 5 straight seasons of 219 or more innings prior to 2009, and has a current string of 7 straight years of at least 150 innings pitched.   

 

There could be something to the “inverted W” theory, though our data at the NPA was inconclusive on the subject, and we have Prior in the database. Pinpointing causes of injury is one of the biggest challenges in mechanical evaluation, due to the sample sizes involved and the number of confounding variables in the injury equation. Injuries can be impacted by mechanics, workloads, functional strength and flexibility, genetics, and plain old luck.

Mark Prior was never taught to raise his elbows when throwing a baseball. Like all pitchers, most of Prior’s arm action is a result of personal signature, and whatever feels most comfortable. As coaches we would basically leave the throwing arm alone, because it is extremely difficult to make a mechanical adjustment that goes against a player’s natural signature. It is similar to being asked to throw off-handed, from the athlete’s standpoint. Our policy was that the throwing arm belongs to the pitcher.

Prior has taken a really bad rap for his mechanics, due to the disappointment that resulted from his meeting the fate of so many pitchers before him, despite having a delivery that had been labeled as “perfect.” The fact is that most of Prior’s injury problems had nothing to do with throwing a baseball, despite his posting some of the heaviest workloads in the Major Leagues while still sailing through the rough seas of the injury nexus.

The injuries that Prior endured were traumatic. First was the collision with Marcus Giles, a baserunning gaffe that caused damage to Prior’s shoulder in July of 2003. The injury would cost Prior his trip to the All Star game, but he only missed a few starts before coming back to the mound in early August. The then 22-year old pitched the rest of the season with no ill effects, going 10-1 with a 1.52 ERA in the 2^nd half and finishing 4^th in the majors for Pitcher Abuse Points, despite missing some time. 

In May of 2005 there was the 100+ mph line drive off the bat of Brad Hawpe that drilled Prior in the pitching elbow, resulting in a compression fracture. Again, Prior came back quickly, missing just a month before returning to the mound on June 26. Once again he ranked among the top pitchers in baseball for PAP by the end of the season, finishing with the 3^rd-highest total despite having 6 fewer starts than the other guys on the list.

Things began to fall apart in the Spring of 2006, and shoulder woes have plagued Prior ever since. A 2007 exploratory surgery by Dr. James Andrews revealed structural damage in the shoulder, and suggested that Prior may have never fully recovered from the Giles collision.

It has been almost four years since Prior’s last Major League pitch, and the primary cause of his pain is still a mystery. Maybe he came back too soon from his injuries, or perhaps his arm could not handle the extreme workloads incurred during the injury nexus. It could have been a conspiracy of factors, with a lethal combination of heavy workloads on a developing arm that was still recovering from injury during the 2003 and 2005 seasons. Perhaps the mechanics were somewhat responsible, though it’s a tribute to Prior’s mechanical efficiency that he performed as well as he did despite all of the obstacles.

I am pretty comfortable with the Prior comparison for Stephen Strasburg given all of their similarities, with the caveat that the comp is a good thing. I still look at Mark Prior’s delivery and see excellence, and Strasburg’s delivery stirs up more excitement than any pitcher I have seen since Prior was mowing down hitters five years ago.

In the final chapter of the Stras Wars trilogy, we will wrap up Strasburg’s incredible debut. Mechanics, stuff, stats, approach to hitters… it will be fun the whole family can enjoy. Coming soon to a website near you.