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Thursday

25Feb2010

Another post about Brandon McCarthy

Thursday, February 25, 2010 at 7:00AM |

If you're a betting man, you should know that the odds are good that this won't be my last article featuring the mechanics and health of the Texas Rangers starting pitcher Brandon McCarthy.

As my favorite subject, his mechanics have spent a lot of time on my computer monitor playing forward and backward, in slow motion, and in still shots. As a result, I have a small tendency to see a little bit of McCarthy in just about every pitcher. Every once in a while I run into a pitcher whose mechanics have a lot in common with him.

Meet University of Texas at Dallas junior Marvin Prestridge.

In light of recent mechanical changes, Prestridge doesn't look much like McCarthy does these days [Edit: this may not actually be true since I haven't seen high-speed video of McCarthy's new mechanics], but when I pulled up the video I shot of McCarthy last spring, the similarities were striking. The angles aren't quite the same, so you may have to use a little imagination in places.

McCarthy (left) and Prestridge (right) at the top of their leg kicks.

They don't look too similar at the top of their leg kicks, but they appear to have a similar degree of reverse rotation (turning their backs to the plate). McCarthy is more compact, and Prestridge lifts his knee much higher.

McCarthy and Prestridge at hand-break.

At hand-break, their mechanics are starting to run together. McCarthy sits a little lower on his back leg. Prestridge breaks his hands much closer to his body.

McCarthy and Prestridge right before their forearms start to turn over.

Before foot plant, this is the frame where their elbows stop moving upward and backward (toward 1B), and their arms begin external rotation. You can clearly see McCarthy's inverted W and that Prestridge's arm is below shoulder level with an extended elbow. Both pitchers have their arms well behind their shoulders.

I much prefer Prestridge's method of picking up the baseball to McCarthy's method from last spring. As a part of the changes he has made to his mechanics over the past 9 months or so, McCarthy's current pick-up features a full arm swing that positions his pitching arm much like Prestridge's arm.

McCarthy and Prestridge at foot plant.

By the time they hit foot plant, there's only one evident difference between the two: Prestridge is pulling his glove arm back toward second base. McCarthy's glove arm is essentially dead weight, while Prestridge's arm helps create additional rotational force through his shoulders.

McCarthy and Prestridge at peak elbow height just before elbow extension.

Again, the only difference is the glove arm action and position, though it appears that Prestridge has a greater degree of trunk tilt toward 1B.

McCarthy and Prestridge at full arm extension just prior to release.

At this point, the pitchers are literally inches away from letting go of the baseball. Prestridge is able to reach a little more toward vertical, thanks to his 1B-side trunk tilt.

McCarthy and Prestridge after primary arm deceleration.

After release, the pitching arm continues internal rotation while the body tries to keep the arm from flying out of socket. This frame attempts to capture the moment where internal rotation stops.

What's clear in this frame is that McCarthy's arm continued to fly forward, winding up closer to his head than to his chest. Prestridge's arm, on the other hand, is still essentially at shoulder level. This is the most significant difference between the two deliveries.

With McCarthy's arm positioned like this, the head of his humerus is placed in an anatomically questionable position while his rotator cuff applies extreme compressive force at the glenohumeral joint, driving the humerus awkwardly into the scapula.

Prestridge's arm is in a more natural position at this point, and as a result, I do not view his mechanics as risky despite their on-the-surface similarity to McCarthy's old, problematic mechanics.

McCarthy and Prestridge after complete deceleration of the arm.

McCarthy and Prestridge during the recovery stage after their follow-throughs.

You can follow Marvin Prestridge's season here: University of Texas at Dallas Baseball.

[Edit: For reference, here's a link to the video I shot of McCarthy at spring training in 2009.]

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Saturday

07Nov2009

2009 Texas Rangers Win-Curve Revisited

Trip Somers |

Saturday, November 7, 2009 at 4:00PM |

Back in January, I stumbled my way through a brief study of the relationship between Texas Rangers wins and attendance. The end result was the following graph. The yellow dot on the graph marks the 2008 attendance level, and the red dot marks the 2008 win level.

2009 Attendance Prediction. For a full description, read the original article (link at top).The Texas Rangers won 87 games in 2009, and the 2009 attendance numbers for Major League Baseball were compiled by Maury Brown in early October.

The model I prepared says that 87 wins should be worth an average attendance of 27,958. According to the data gathered and prepared for the Brown article, the average attendance of Texas Rangers home games in 2009 was 27,641. A difference of only 317 attendees per game translates to an overshot of only +1.15%.

As much as I would like to pat myself on the back for this, I have to acknowledge the extreme amount of luck involved with the startling accuracy of my prediction.

My model came with a sizable standard error attached to it: 2,646 attendees per game. You don't need to be a statistician to recognize how large that is or the uncertainty that it projects. I addressed this briefly in the comments of the original article:

The line in the graph marks the raw estimate based on the information provided by the model. At any given point on the line, the standard error says that the attendance level could be 2,646 higher or lower than the line.

With the reason for the 2008 drop off in question, it is probably unreasonable to expect that attendance will simply rebound to the 2006 or 2007 level. For this reason, I expect that actual attendance will fall somewhere below the line but within 2,646 attendees per game.

The luck of this season will definitely narrow the standard error of the 2010 model. Look for the 2010 model some time in February as the new season approaches.

If you haven't read the original article (or if you're into economics and data modeling) and you have 10-15 minutes to kill, I suggest giving it a read: Texas Rangers Win-Curve Part I: Wins vs Attendance.

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Wednesday

26Aug2009

Thoracic Outlet Syndrome: a Texas Rangers epidemic

Trip Somers |

Wednesday, August 26, 2009 at 7:00AM |

Kenny Rogers (2001). Hank Blalock (2007). John Rheinecker (2008). Matt Harrison (2009). Jarrod Saltalamacchia (2009). These are the five major leaguers from the Texas Rangers who have been diagnosed with thoracic outlet syndrome in recent history.

Aaron Cook (2004). Kip Wells (2006). Jeremy Bonderman (2008). Noah Lowry (2009). These are the four major leaguers from all other teams who have been diagnosed with thoracic outlet syndrome in recent history. [Note: There may be more, but there aren't many. This is all I could find.]

Texas Rangers 5, Everyone Else 4. The Texas Rangers also had a minor leaguer diagnosed with thoracic outlet syndrome - pitcher John Hudgins (2005).

The definition of an epidemic, according to Wikipedia, is "when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is 'expected,' based on recent experience."

Recent experience tells us that roughly 10 players have been diagnosed with TOS in the past 9 years. More than half of those players belong(ed) to a very specific population: the Texas Rangers.

Compression of the brachial plexus is a key symptom of TOS. Click for full-sized view.Thoracic outlet syndrome (TOS) is fairly common in overhead athletes like swimmers and baseball players. The overhead movement of the arm changes the orientation of the clavicle (collar bone) in such a manner that it may compress the brachial plexus (the nerve bundle the leads into the arm from the neck) and/or the subclavian artery and vein against the first rib.

The compression usually leads to numbness or pain in the affected arm, but it can also lead to blood clots like it did with Aaron Cook in 2004.

Undiagnosed TOS can have very serious health implications. In Cook's case, a clot broke away from the compression site in his shoulder and traveled to his lungs resulting in a pulmonary embolism.

Diagnosis is clearly very important when it comes to TOS. The Texas Rangers, however, have experienced quite a large number of TOS cases in recent years. Here's a brief look at a few reasons why this may be the case.

Access to expert opinion

Dr. Gregory Pearl, of Texas Vascular Associates, is a well-respected vascular surgeon who happens to live in the Metroplex. Dr. Pearl was involved with the TOS cases for Rogers, Blalock, Harrison, and Saltalamacchia - and likely Hudgins and Rheinecker as well. This relationship history and his proximity to the ballclub makes it far easier for Texas Rangers to be diagnosed with TOS.

Kenny Rogers provided the club with a first-hand example of what TOS can do to a pitcher's performance. When Rogers returned with an extra 4-5 mph on his fastball, Dr. Pearl was probably put on speed dial.

Throwing mechanics

Putting pressure on the brachial plexus? Click for full-sized image.Pitchers are a high risk group for TOS compared to position players because of the quantity and intensity of their throws but also because of the way they turn their heads toward the plate. With the previous image in mind, take a look at Matt Harrison.

When the head and neck turn away from the compression site, the brachial plexus and subclavian blood vessels are pulled into the narrowing gap between the rib and clavicle.

For low intensity throws where the head doesn't turn, TOS is less of a concern.

Training methods

Of particular note are position players Hank Blalock and Jarrod Saltamacchia, each of whom had TOS in his throwing shoulder. To discount their mechanics entirely would be foolish, but I found no reports of TOS diagnosis in any other position player. This suggests, perhaps incorrectly, that something behind the scenes has made a significant contribution.

Weight lifting can produce stress far in excess of what an intense throw can produce, but it's practically impossible to properly perform any exercise and cause thoracic outlet compression at the same time. When bad form enters the equation, though, all bets are off.

Dynamic exercises may contribute an intertial element in a manner similar to that of throwing a baseball. Even these, when performed properly, aren't likely to be significant contributors. As with weight lifting, if they are not performed correctly, they become a risk for TOS and a number of other potential problems.

If training is to blame, it's likely a series of exercises rather than a single one that results in thoracic outlet compression.

Blind, stinking luck

Not to be overlooked is random chance. It is entirely possible that the Texas Rangers have simply been unlucky. It is possible that each affected player was genetically at risk for TOS and would have been diagnosed no matter what team he was playing for. It may be nothing more than luck that has brought these players to Arlington.

So which is it?

In truth, it's most likely a combination of these factors. Given the current state of exercise science, training methods are probably the least likely to blame.

Throwing mechanics and luck combined with having a "resident" expert have likely been equally responsible for the Rangers' having lapped the rest of Major Leage baseball in thoracic outlet syndrome diagnoses.

[Historical TOS Note: David Cone and J.R. Richard, both pitchers, were also known/beleived to have suffered from thoracic outlet syndrome, but both diagnoses were well before the "Dr. Pearl era."]

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Tuesday

09Jun2009

Brandon McCarthy: Scap Load Failure

Trip Somers |

Tuesday, June 9, 2009 at 7:00AM |

Yesterday, for the second time in his 3-season stint with the Texas Rangers, Brandon McCarthy was diagnosed with a stress fracture of the scapula. With consideration to the number of muscles that move and stress the scapula when throwing a baseball, it's amazing how rarely scapular stress fractures are diagnosed in pitchers.

In 1987, Texas Rangers pitcher Edwin Correa was diagnosed with a stress fracture in his scapula. Correa never again pitched in the Major Leagues.

In 2003, Kurt Ainsworth, then pitching for the San Francisco Giants, was also diagnosed with a stress fracture in his scapula. Ainsworth recovered but pitched in only 7 more games in the Majors, all in 2004.

The most detailed information that I can find on this type of injury is what I know from McCarthy's previous stress fracture and what I learned from reading "Scapular Stress Fracture in a Professional Baseball Player," a study published in the American Journal of Sports Medicine in February 2007.

The study takes a look at the injuries suffered by an unidentified right-handed Major League Baseball starting pitcher. This pitcher's mechanics were apparently a mess. Prior to his scapular stress fracture, the pitcher had been through Tommy John (ulnar collateral ligament replacement) surgery and a "transient episode of subacromial bursitis" in his shoulder. In the three years that followed his recovery from the stress fracture, this pitcher had surgery on both his elbow and shoulder, though neither was directly related to his scapula injury.

Pitcher X's stress fracture was located on the lower outside edge of the scapula bone, called the lateral border. The doctors who authored the study concluded based on the fracture's location that the likely cause of Pitcher X's stress fracture was "repetitive stress in the area of the teres minor attachment."

Repeated stress on muscles and bones causes them to grow stronger and more resilient over time. When the growth can't keep up with the stress, stress fractures occur in bones and tendonitis occurs in muscles. In the case of Pitcher X, his teres minor grew stronger at a faster rate than his scapula. Eventually, the stress fracture developed.

Muscles with origins on the scapula. Subscapularis and biceps brachii not shown. Click to enlarge.The teres minor attaches the lateral border of the scapula to the outside edge of the back of the humerus (see the diagram). It is one of the muscles of the rotator cuff, and its primary function is external rotation. The teres minor is stretched by internal rotation when the back of the humerus turns away from the scapula. It is also stretched as the humerus moves away from the scapula.

In the delivery, the rotator cuff contracts most powerfully during the follow-through as it tries to stop the arm from twisting and flying out of socket. The faster the humerus is moving away from the scapula and the greater the rate of internal rotation, the more powerful the contraction must be to maintain joint stability.

Brandon McCarthy's follow-through is a little unique in this regard. I missed it when I reviewed his mechanics last month because I wasn't looking for it. Of course, maybe I'm just seeing what I want to see. Here's the clip I used for my original analysis:

Notice that, after release, McCarthy's arm continues to move away from his scapula and towards his head. Even at 210 frames per second, it only lasts for a few frames, so look closely. You might even see his shoulder blade "hump up" a little around this time.

This high-intensity eccentric contraction stresses the teres minor muscle more than the other rotator cuff muscles because its scapular attachment is the furthest from the joint.

A reasonable outlook

Rangers general manager Jon Daniels has reportedly said that McCarthy will not pick up a baseball for several weeks. That might be a bit of an exaggeration, depending of course on the severity of the stress fracture. McCarthy himself said the pain has been there for a while and that he feels like he did in 2007.

McCarthy suffered and recovered from an injury similar to this one back in August/September 2007. I can not say how similar because I do not know the exact location and severity of either his 2007 or his 2009 stress fracture. McCarthy recovered from the 2007 injury fairly quickly and missed only a month of Major League action.

Rest is the only way to recover from a stress fracture. While the bone heals and gets stronger, the offending muscle atrophies and weakens - killing two birds with one stone. Often times, the pain will subside long before the bone fully heals, sometimes months after diagnosis. It might be that McCarthy's original stress fracture never healed.

I believe the Rangers are more or less "on the lookout" for injuries like this with McCarthy, so I feel that this injury is probably an early-stage stress fracture. They will probably keep him from throwing until scans no longer show signs of the fracture. Hopefully, this is no longer than 3 or 4 weeks.

Last month, I said that if McCarthy could stay healthy and have success with his mechanics, there was no reason to change them. I now believe there's sufficient reason to start that process. McCarthy and the Rangers need to give serious consideration to making major changes in his delivery.

[I suspect that Pitcher X is Darren Dreifort, though the article was written by doctors in Baltimore.]

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Wednesday

27May2009

Texas Rangers Prospects: Robbie Ross and Joseph Ortiz

Trip Somers |

Wednesday, May 27, 2009 at 7:00AM |

Robbie Ross. LHP, 5' 11", 185 lbs, Born: June 24, 1989. The 2008 2nd round pick of the Texas Rangers was said to have 1st round talent. Some minor signability concerns allowed Ross to slip into the early 2nd round where the Rangers selected him and eventually signed him for a reported $1.575 million signing bonus. He has yet to make his professional debut, but Ross could be in line to join the Spokane rotation in less than a month.

In a post-draft interview with Ross, Jason Cole of Scout's LoneStarDugout.com wrote the following:

Ross enters pro ball with an advanced changeup to go along with his fastball and slider. The southpaw’s fastball, as he explains in the interview, generally sits in the upper-80s, low-90s, but he has shown the ability to dial it up to 94 mph at times.

Out of the wind-up, Ross has a very high leg kick, reminiscent of Nolan Ryan's leg kick. After the kick, he starts to drift forward before sitting down on his back leg. This loads the leg very well, but it also lowers his potential release point. From lower release points, pitches take more flattened paths to the plate compared to pitches thrown from higher release points.

Ross keeps his front leg and hip closed until right before foot plant. When he lands, his center of mass almost completely stops moving forward. The momentum from his drive helps him open his hips really well and pulls his back foot forward off the rubber. I prefer this action to the foot drag seen in a lot of pitchers. (In Ross's 2008 MLB Draft Report, he is seen dragging his back leg like dead weight on his first pitch and last pitch, both presumably change ups. I did not identify any change ups within my video sample.)

Worth mentioning is the path his front foot takes toward his landing. His front leg moves in a sweeping motion. By the time his front foot plants, it is moving more toward third base than it is toward the plate. This gives him a soft landing and sort of kick-starts his hip turn as he turns his front leg to face the plate. I like the soft landing but prefer a more direct stride.

As one would expect, Ross's hip rotation leads to strong shoulder rotation. Ross maintains extremely level shoulders throughout. Because he keeps his shoulders level, his elbow moves in a sharp arc around his body. Ross picks up the ball mostly with his shoulder, but he reverse-rotates his shoulders and takes his elbow well behind his back and toward third base. All of this creates a curved path to release, resulting in the centripetal force that causes forearm flyout.

Ross's pronation seems to occur during release. This provides a degree of protection from the negative effects of forearm flyout, but at this frame rate and camera angle, it is impossible to determine whether it prevents his ulna from slamming into his humerus. I was unable to identify any sliders in my sample, so I do not know if he supinates his release for that pitch.

At foot plant, Ross's arm is nearly vertical, but active external rotation is still taking place. This creates a reverse forearm bounce where the baseball is moving toward third base and his elbow is moving toward first base. This indicates a large valgus torque in his elbow and is a risk factor for his ulnar collateral ligament.

Ross's follow-through is where things get interesting. The continuation of the centripetal force described above causes his arm to wrap slightly across his body. There is some recoil, so I have some concern for the posterior capsule of his shoulder, mainly the infraspinatus and teres minor muscle tendons.

Finally, Ross has a weird little hop-twist after everything slows down. This is probably caused by a continuation of his powerful shoulder rotation. He ends in an athletic yet awkward looking stance.

Joseph Ortiz. LHP, 5' 7", 175 lbs, Born: August 13, 1990. When Ortiz debuted with the Low A Clinton Lumberkings last season, he was only 17 years old. Definitely one of the smaller players in the league, Ortiz pitches beyond his stature. Even as one of the youngest players in the league, Ortiz's only statistical fault was a high walk rate - 4.5 per 9 innings. He struck out just over 7 batters per 9 innings and allowed just under 6.5 hits per 9 innings.

This winter, Cole compared Ortiz to former Rule V pick Fabio Castro because of their similar body types and repertoires. From Cole's scouting report:

The lefty constantly attacked hitters with his 87-91 mph fastball... hard, late-breaking slider... [and] a promising, occasionally used changeup...

Ortiz has a very compact delivery without a lot of flair or wasted movement. His stride is fairly standard, and he lands noticeably closed. His front leg sweeps like Ross, but Ortiz puts his foot down before it sweeps all the way across.

Ortiz pulls his elbow down and to the side as he flexes his trunk forward. This can help raise the release point but prevents a few trunk muscles from adding to the pitch and puts a little extra stress on his spine.

His hip rotation isn't great, and he drags his toe in the dirt pretty firmly. Ortiz flexes his trunk over his front hip, so hip rotation - or lack thereof - isn't a huge factor for him. This drives his throwing shoulder in a nearly straight line toward home plate.

Ortiz takes the ball only slightly behind his back, but noticeably drives his elbow toward first base before as he explodes toward release. This lateral movement causes forearm flyout, but Ortiz, unlike Ross, pronates late, making him more susceptible to its negative effects.

Despite his compact delivery, Ortiz has a late forearm turnover. This leads to active external rotation at his shoulder after foot-plant and creates a reverse forearm bounce where, like Ross, the ball and his elbow are moving in opposite directions.

Ortiz's arm also wraps slightly across his body, but with a more alarming recoil. Ortiz's arm appears to collide with his rib cage after the throw. The collision doesn't appear to be terribly violent, but the leverage caused by the impact can place extra stress on the posterior capsule of the shoulder where the muscles are already contracting to help decelerate the arm.

At the very end, Ortiz actually does have a little flair. Instead of a hop-twist, Ortiz's post follow-through action resembles the finish of Dr. Mike Marshall's pitchers. His shoulders and arm point at the target while his lower half turns toward second base.

This doesn't mean much for his pitches or for his health, but it's notable because it puts him in a horrible fielding position. I imagine that you'd see a lot of bunts against him in close games.

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