*This article is adapted from a response I initially gave over at online pitching forum, letstalkpitching.com.
One thing that stands out when you watch major league pitchers is just how much whip (for lack of a better word) you see in their throwing arms. And it makes a lot of sense that greater external rotation in your throwing shoulder would contribute to higher velocity. The research supports this, and all you have to do is take a look at photos of hard throwing pitchers at max external rotation (MER) or full arm “lay back” to see it.
And if you don’t have the range of motion in your shoulder to get your forearm near parallel with the ground at MER you’re not going to get the same catapult effect in the elbow extension/acceleration phase of your throw.
But before you go stretching your arm ‘til it falls off, some things to consider:
1. How old are you and how long have you been pitching:
A good part of it is skeletal, and has to do with what’s known as Osseous Adaptation (basically bone adaptation). It depends on how much you threw/pitched in your adolescent years before your growth plates closed.
Studies have shown that both college and pro pitchers exhibit greater than average external shoulder rotation than non-throwers. The same studies also show these pitchers have greater external rotation in their throwing arms than their non-throwing arms, so it’s not just something they were born with.
At the same time, pitchers show below average internal rotation, and this tends to get worse immediately after pitching and over the course of a season. For more on this, do some research on GIRD (Glenohumeral Internal Rotation Deficit)…
GIRD has been linked to increased risk of shoulder injuries (click here for one such study), but proper stretching protocols can help improve and maintain internal range of motion in pitchers. Here is one commonly recommended post-throwing stretch for improving/maintaining internal rotation:
The Sleeper Stretch
The more I discuss with industry professionals, the more I learn that it’s all about the individual. Many, including Mike Reinold (another fantastic resource), feel that too much sleeper stretch can actually work against you. He does a great job explaining and demonstrating the stretch in this article.
2. What is Humeral Head Retroversion?
The main thing the studies find is what’s called humeral head retroversion. This basically means the head of your humerus (upper arm where it fits in your shoulder socket) has twisted slightly over the years with the repeated stress of throwing.
– Humeral head retroversion in competitive baseball players and its relationship to glenohumeral rotation range of motion (click here for the study).
– Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers (click here for the study).
I’m not a doctor (didn’t even stay at a Holiday Inn last night), but that’s my understanding based on my research and discussions with those in the medical/physical therapy fields. Sounds pretty crazy, but it’s actually a positive adaption that works in a pitcher’s favor. I know I still have way more external rotation in my throwing arm than my non-throwing arm.
3. Pitchers tend to gain external rotation over the course of a season:
Probably the best way to improve external rotation is just good old fashioned throwing… lots and lots of it (within reason, of course). Over the course a season, it’s normal for pitchers to develop greater external rotation as a result of the repetitive act of throwing.
– Glenohumeral rotational range of motion in collegiate overhead-throwing athletes during an athletic season (click here for the study).
So when you think about it, actively stretching your arm where it’s already getting loose on its own doesn’t make much sense. You’re just creating more instability in the joint, putting you at greater risk of injury.
4. Flexibility and Stability in all the right places:
Increased flexibility and range of motion are good, but only if accompanied by increased strength and stability. If you just stretch the [bleep] out of your arm and don’t work on strengthening the muscles around the joints (scapular stabilization, in particular) you’re asking for a trip to the DL.
For a better understanding, looking at Gray Cook’s joint-by-joint approach is a good starting point. An in-depth discussion goes beyond the scope of this article, but the basic premise is simple: certain joints tend to be tight and can benefit from greater flexibility; others tend to be unstable and can benefit from greater stability.
For example, we generally want flexibility in our ankles and more stability in our knees… working up the body, we want mobility in our hips, stability in our lumbar spine (lower back). In our throwing arm, greater range of motion in our shoulder is good, but we want to accompany that with stability in the scapular region.
5. You can increase total “Range of Motion” with better thoracic mobility:
The main benefit of increased external rotation is increased distance over which a pitcher can accelerate the arm into ball release (velocity = distance/time). You can also increase that distance through greater chest thrust and thoracic mobility (think of an archer pulling back on a bow).
Photo source: Jason O. Watson, US PRESSWIRE
If you’re 20 years old and have never thrown a baseball in your life, no amount of stretching is going to get you the kind of natural external rotation found in college and pro pitchers who have been throwing a baseball since they were kids. And if you’re a 13 yr old pitcher you aren’t likely to have as much external rotation in your shoulder as you will when you’re 18.