External rotation how does it work?

I’ve been researching a lot of the high velocity pitchers and recently saw a picture of CC Sabathia. His external rotation was cocked back ready to fire. My velocity is getting higher and higher but looking at my footage in slomo I noticed I don’t have any type of rotation externally with my arm. What causes this arm action? Thanks for the help really wanna work on this.

There’s a study that looked into maximum external rotation (MER) a few years ago that compared MER of > 90 mph throwers and 80 mph > throwers. The hard throwing group was able to get their arms back into 179 degrees of rotation whereas the slow group could only get 166.3 degrees.


Greater amounts of external rotation allow you to throw harder because you generate more of a stretch reflex in your internal rotators which act like springs allowing your arm to rotate forward at an incredibly fast rate.

Another reason why more external rotation allows you to throw harder is that you are creating a bigger range of motion which means that you have more time to add force – your muscles take time to build up force so by creating a bigger range of motion you give yourself a little bit of extra time to add an extra mph or two.

I’ll find the study and post the link for you this weekend.

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What causes the actual action of the arm to rotate externally in pitching mechanics? Also what makes it get to the 179 degrees point? Flexibility? strength? Hip shoulder separation?

According to ASMI:

The greater the maximum external rotation in pitching, the greater distance there is to accelerate the hand forward and consequently the greater the ball velocity.

Max ER is not something that is gained by stretching, unless you’re coming back from an injury, or have a deficit of some kind that a Dr. or PT has assessed and is treating you for. MER is a dynamic measurement that is the result of a combination of the rotational velocity of the upper trunk, the amount of rotation at the shoulder joint, the amount of movement of the shoulder blade, and the amount of extension in the upper spine (arching the back).

We’ve seen too many people out there cranking back on a pitcher’s arm, trying to improve his MER, when all they’re actually doing is stretching out the joint capsule and creating an unstable shoulder joint. If there isn’t a health issue, then you improve ER by improving the efficiency of the pitching mechanics, beginning with the hip/upper trunk separation.


Ya no health issues ever here. I figured it had something to do with your shoulder to hip separation, and your trunk out in front of your lead foot moving forward. Just seeing Aroldis and CC able to have all that force moving forward and that arm literally pointing the opposite direction almost is incredible to me.

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In a nut shell, strive for later and faster shoulder rotation.

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One thing I have noticed…and this is just from observation, not a study or anything done in a lab…is that most guys that have good external rotation have their elbow up above shoulder height at the moment of max external rotation, like in the picture above. A lot guys with a limitation tend to have a lower elbow. That low elbow position (for guys who are not true sidearm guys) creates a motion where they are “pushing” the ball. Creating a lot of external rotation in a healthy way is something I have heard very few really comment on. Stretching is a no-no unless, as Steven said, it is part of an injury recovery program.
Creating good hip shoulder separation (to me) is first a bi product of moving well and powerfully with the lower body. Good arm lay back is a bi product of good upper body rotation and good “elbow lead”. These mechanics are tricky things. One movement helps form the next.

*I am not a doctor or a PT or even an ex pitcher, just a guy in the high desert who enjoys pitching and baseball. Amateur observations for sure.

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