External Rotation

A powerful throwing motion requires the pitcher add his upper body rotational speed to his arm speed. When these two elements of the throwing motion are combined, the result will be higher overall hand speed (and therefore, ball velocity). The way a player accomplishes the addition of these speeds is through proper timing between his torso and his arm.
Ball speed is maximized at release when the arm is utilized as a whip with the ball being at the end of the fully extended arm. In order for the ideal whip action to take place, the elbow needs be even or above the shoulder line and the ball should be above the head when the stride foot lands. These two elements provide the basis for pain free external rotation (ER) of the upper arm in the shoulder socket as described in the Arm Action page. Ideally, the elbow should to be bent slightly more than ninety degrees as shown in these pictures of Paul and Kolt.

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If this position is achieved, then when the lead hip begins to open the arm can begin the safe ER in the shoulder socket. The following pictures of Paul and Kolt show the arm beginning ER. The desired timing has ER starting when the front hip opens and before the upper body has rotated very far.

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These two movements are in the opposite direction. The front hip opens and the arm externally rotates in the shoulder. This is similar to a hitter who strides forward but takes his hands back and begins to lay the bat off. The pitcher feels the arm “catch” in  ER just like the hitter feels the bat “catch”. The desired timing is for the pitcher to be in full ER well before the shoulders are square to the target. There is a calculation in the Adding Velocities page if you are so inclined.
ER achieves a “wound spring” effect for the arm in the shoulder socket. In the Legs and Torso page we discuss the fact that the front hip opens with the shoulders closed to create the “wound spring” effect for the torso.
When the pitcher has the two “wound springs” timed properly he  will be able cause the upper body to reach maximum rotational speed and the hand to reach maximum “whip” extension (almost no bend in the elbow) simultaneously. Consequently, maximum hand speed will result. Because hand speed due to exclusively to arm speed is much faster than upper body speed (maybe as much as five times quicker) the upper body has to have a significant head start in rotation if the two elements are to reach maximum speed at the same instant. The following pictures of Paul and Kolt demonstrate the full extension associated with maximum “whip”.
The really interesting thing about throwing is that the hand is going zero velocity (or even negative) when arm is in full ER. The hand goes from zero velocity to maximum velocity during the last portion of the quarter turn of the upper body. For guys like Paul, the hand accelerates from zero to nearly 100 mph in an extremely short amount of time. And that’s the key to throwing hard. The quicker the upper body rotational speed the faster the hand speed that can be generated if the upper body, arm and hand are tightly linked.

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You can look at this series of pictures and visualize the core muscles of the body as a rotating catapult with rotational energy directed at whipping the arm and hand. The strong, chest out position allows the stomach, lower back and chest muscles to deliver the energy to the arm and hand. At the release point the arm is at full extension to maximize the length of the whip and the speed of the fingers. All aspects of a pitcher’s motion should be focused on getting the body in the ideal position to create an explosive quarter turn.
Late External Rotation
If the player is late with ER in the shoulder socket, as shown here with Max, he will still be in full ER when his upper body is square (facing) to the target.
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At this squared up point the upper body rotational speed is maximum and will tend to decrease afterward. With  Max  in full ER the pure arm speed is still zero. So, the upper body is rotating quickly and the arm isn’t helping yet. When maximum hand speed is achieved due to the arm coming out of ER, the upper body rotational speed will have reduced. If the throwing elbow is even or slightly above the throwing shoulder (as in this case with Max) when full ER occurs, there should be minimal risk of injury. However, maximum velocity will not be developed.
For Max, the difference in timing associated with late ER and a desired early ER can be as much as 6-7 mph. When his timing is really good he can throw about 97-98 mph. When he is late with ER he typically is in the 91-93 mph range. Max gets guys out extremely well at 91-93 but can have “electric” stuff at 97-98. The thing to realize is that it’s a very subtle timing difference that causes the difference in velocity.
Max can develop some additional arm speed by rapidly driving his shoulder through release, but the result is typically less than his maximum velocity. A pitcher’s upper body rotational velocity can exceed his linear shoulder velocity.
Early External Rotation (Elbow First)
The issue of early ER, and specifically a throwing motion that is “elbow first” rather than ball first, is the real crux of  how this website differs from what is most commonly taught to pitchers today. Paul and I understand that the “elbow first” throwing technique (“touch the thigh, reach for the sky”) is both easier to learn and can generate high velocity. We teach the “ball first” method because we feel that it is much safer on the shoulder and elbow. Our goal is to develop a set of throwing mechanics that allow pitchers to maintain themselves injury free for a long period of time while also creating high velocity.
In the discussions above we have emphasized that early full ER in the shoulder is needed to generate great whip action of the baseball. The “elbow first” method (shown below in the starting position for ER) will definitely develop great early ER in the shoulder.

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When you lead with the elbow with the elbow bent about 90 degrees so the ball is down at hip level, you use the dynamic weight (momentum) of the baseball in the generation of ER. The arm movement, starting from this first picture, is rapid ER of  the arm in the shoulder socket. All of these “elbow first” pictures show the elbow slightly below the shoulder line when the ER is being executed. Picture 1 above is the start with ball hanging down below the elbow. Picture 2 is 90 degrees from the start of ER. Picture 3 is 180 degrees from the start of ER. Picture 3 is the point where shoulder impingement is about to occur.
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The last picture in the sequence (below) shows that full ER in the shoulder with a low elbow causes impingement in the shoulder and either causes less than ideal external shoulder rotation (shown here) or, if full ER is achieved, causes shoulder discomfort. (This low elbow, shoulder impingement issue was described in detail in the Arm Action page.) Since the “elbow first” method creates a dynamic ER, there is quite a bit of energy going into shoulder rotation. If you have a shoulder impingement issue you will be attacking the impingement with a lot of dynamic force.

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If the elbow is even with the shoulder line the dynamic ER should not cause impingement and corresponding discomfort. However, we believe that leading the reverse arm swing with the “elbow first” and then early, dynamic ER with a low elbow is a major factor in the large numbers of shoulder and elbow injuries that occur in pitchers. Because it’s easier to learn to throw hard using an elbow first reverse swing, it is the method most generally taught.
In this following picture, Max has his elbow slightly above the ball in the reverse arm swing, but not nearly as much as a lot of hard-throwing major league pitchers and top prospects. This is an issue Max has worked on for some time but it has been a difficult issue for him to completely eliminate.

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Our caution is that if you begin to externally rotate the arm in the shoulder socket with the elbow above the baseball, you MUST insure that the elbow is even or above the shoulder when ER starts.
When a player is elbow first in his reverse arm action, throwing can be pain free until maybe fatigue or some other factor enters the picture. Most players survive throwing with an “elbow first” technique until the throwing frequency and duration is extended (examples would be Strasburg, Prior, etc). Discomfort, though, can happen in youth leagues, high school, college or in a professional season. It doesn’t take many throws with the shoulder dynamically impinged to create significant discomfort. Competitive athletes do not want to admit problems exist and they do not want to stop pitching.
There are several major league pitchers that have stayed healthy even with their elbow leading the reverse swing. If you are disciplined enough to ALWAYS get the elbow above the shoulder before starting external rotation it’s possible you can continue to throw injury free.
To conclude this discussion, a player can learn to throw hard leading with the elbow and today many instructors teach this technique. As a matter of fact, the method described in this book, with the ball leading the elbow in the reverse arm swing, is considered by most instructors as “old school.” I definitely agree it’s old school but “elbow first” is a much higher risk method than a reverse swing that leads with the ball. This isn’t to say you will never undergo an injury if you are “ball first”, but if you look at the large number of MLB pitchers that have undergone shoulder and elbow surgery recently you’ll find the majority of them are “elbow first” guys.