Spare the Arm II: Mechanics

This (Part 1) overview of pitching injuries made the claim that focus on the arm may increase the chances of injury when it takes emphasis off the entire athlete. Pitching is a total body effort, and we often need to look beyond the sore shoulder and elbow to get to the root of the issue.

The first strike against pitchers is having optimistic expectations with the traditional "do it like it's been done" of preparation. Overlooking mechanics and accepting advice on mechanics are two more related paths to an injured arm.

2. Ignore mechanics

The less common error is to just go pitch without giving much thought to mechanics. Since higher level pitchers are usually coached ad nauseum, "mechanical neglect" occurs more often in younger athletes. Athletes who think bench pressing 350 or some other training secret is the answer to a mediocre fastball should also give more attention to mechanics.

It's rare that a 14-year old intuitively generates high force with the legs and efficiently transfers it to the arm. At this level, coaches and parents describe vague notions of mechanics, often referring to the shoulder, elbow, or "the core." Again, little attention is given to numerous details down the kinetic chain.

Greater velocity comes from applying more force to the ball over a greater range of motion. But no amount of weight training or conditioning will bring about the skilled coordination that allows an athlete to safely achieve that end result. In fact, the combination of great foundational power with relatively low skill (in any sport) is a great recipe for injury.
Big bench; probably not hitting 90 mph.
See It

High speed video is needed to capture everything that happens so quickly during pitch delivery. Instructors should understand normative values(1) and be able identify outliers that may lead to injury or suboptimal arm speed.

For example, anterior shoulder pain often comes from late "opening" of the trunk toward home plate during delivery. Opening late may come from decreased rotation and extension range of motion in the spine or hips. Insufficient loading of the back leg can also cause mistiming of hip and trunk rotation.

A detailed analysis of angles and forces at each joint is beyond the scope of this review, but suffice to say that there's a lot you can miss without the aid of a camera and sound mechanical instruction.

If It Ain't Broke?

Knowing what's happening mechanically is one thing, but when do you actually try to change a pitchers mechanics?

Do you change mechanics in order to achieve greater throwing velocity? Sometimes. How much force can the athlete generate? How is his flexibility? If he can't vertical jump 20 inches or achieve near 90 degrees of hip flexion during a straight leg raise, for example, then mechanics may not be the main issue. Put the glove down for a while and hit the gym.

Do we fix him?
Mechanical "tweaks" are often good and even essential when there's pain. An athlete with medial elbow pain who shows well below 90 degrees of shoulder abduction during the late cocking phase should probably try some torso tilt with a higher arm slot (so long as there are no ROM limitations in the trunk or legs). Careful though, because more shoulder abduction tends to spare the elbow but increases strain on the shoulder (2).

3. Accepting Advice

The down side of instruction.

Do not blindly accept everything from the local baseball "expert" (including me). Not all advice from baseball instructors, trainers, and physical therapists is good advice. When did your instructor or trainer change from the dumb jock stereotype to a well read critical thinker? Just like making it to the pros does not make one a great teacher, the nuances of pitching are not required material for medical license exams.

A few common pieces of plain bad advice include:

"Stay tall then fall."
"Always throw down the mound."
"Keep the elbow up."
"First throw strikes."

[If you want a young pitcher to aim the ball with horrible short-arm mechanics instead of gradually learning from the feedback of cutting it loose in a total body effort, tell him to "settle down and throw strikes."]

Throwing Downhill

Official looking poster, but the guy along the bottom has serious mechanical issues.

Approaching Why

Mechanical faults in pitchers are usually more than just bad habit. Why are the shoulders opening too soon? Why does the front knee collapse when trying to increase stride length? Is your coach or instructor able to assess and correct the impairments that cause poor movement patterns? When the athlete is lacking in range of motion or the strength is takes to produce, stabilize, and control appropriate forces, pitching lessons are not the answer.

In summary, pitchers should not put all their eggs in one basket. Mechanics only go so far without correct training, and training only goes so far without attention to applying correct mechanics.

Instructors should avoid being too rigid with athletes of any age. They should know how to assess and correct potential problems, but appreciate that pitching is an art. There is great value in one athlete's natural rhythm, and it's good to remember the limits of what the literature says should be happening.

Whatever the case, do you get the feeling that it's ideal when sports medicine guys and hardcore baseball guys (coaches, instructors, etc.) team up (3)?
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1) Matsuo T, Fleisig GS, Zheng N, Andrews JR. Simulated influence of shoulder abduction and lateral trunk tilt on peak elbow varus torque for college baseball pitchers. Journal of Applied Biomechanics 22:93-102, 2006.

2) Whitley, R. Baseball throwing mechanics as they relate to power and performance. Journal of Sports Science and Medicine (6) 1-20, 2007.

3) Gorinski, RW. Plug for gowags training center. If you didn't get the hint already 2010.

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