Greater range of motion definitely contributes to higher velocity. The research supports this, and all you have to do is take a look at photos of hard throwing big league pitchers at max external rotation or arm lay back. 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:
-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 avg. 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 avg. internal rotation, which is why that internal rotation stretch Nathan G. mentioned is a good idea, especially after throwing to prevent tightening up.
The main thing the studies find is what’s called humeral head retroversion – basically means the head of your humerus (upper arm where it fits in your shoulder socket) has twisted slightly with the repeated stress of throwing. I’m not a doctor, but that’s my understanding of it based on all I’ve read. Sounds pretty crazy, but it’s actually a positive adaption that works in a pitcher’s favor. I know I definitely still have way more external rotation in my throwing arm than my non-throwing arm. Here are some of the studies:
-Humeral head retroversion in competitive baseball players and its relationship to glenohumeral rotation range of motion.
-Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers.
is also common to see greater external rotation as a season goes on:
-Glenohumeral rotational range of motion in collegiate overhead-throwing athletes during an athletic season.
So 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 as you will when you’re 18.
Other things to consider:
-increased flexibility and range of motion are good, but only if accompanied by increased strength and stability in the joint. If you just stretch the crap out of your arm and don’t work on strengthening the muscles around the joints you’re asking for a trip to the DL. So I would definitely incorporate a shoulder strengthening routine using light weights and/or tubing.
-another good point by Nathan G: don’t stretch too much before you throw. Recent studies have shown that overstretched muscles actually perform worse. Here are a couple recent studies relating to stretching and throwing:
-Static and Dynamic Warm-up in Upper Extremity Functional Activities
-STRETCHING REDUCES THROWING ABILITY
Eric Cressey does a great job explaining this topic, definitely worth a read - actually pretty funny too.
“Why President Obama Throws Like a Girl” - http://www.ericcressey.com/tag/optimal-shoulder-performance/page/5