Pitching Motion Analysis

There are certain aspects of the throw which will give a better understanding of the throwing motion.  I have used Kerry Wood and Roger Clemens to show differences in delivery.  I regard Clemens and Mariano Rivera to have excellent mechanics which have allowed them to pitch over a long period of time.  Kerry Wood’s arm problems are well documented.

In the stride phase Clemens’ shoulder angle has his lead arm shoulder higher than his throwing arm shoulder and his head remains behind his crotch.  His throwing arm fingers have moved to the top of the ball, palm facing down, allowing for an easy move into the throwing position.  Clemens’ humerus is pointing toward second base in this phase of the throw.  Wood has his lead arm shoulder slightly lower than his throwing arm shoulder with his head slightly ahead of his crotch.  His throwing arm palm is facing first base which tends to drive the elbow up ahead of the hand while trying to get in a throwing position.

At front foot contact (FFT)  Clemens’ throwing arm is in a good throwing position, which I believe is critical, with his head still slightly behind his crotch, his hips almost open but his shoulders still relatively closed to the plate.  My experience in working with young pitchers is that if their throwing arm is not in a throwing position, (elbow the same height as the shoulder flexed 90 degrees, with the humerus, upper arm, pointed toward second base,) at FFT it leads to many different mechanical problems in the cocking and acceleration phase of the throw. I also believe a key to ease of external rotation (ER) in the throwing shoulder is the lumbar or thoracic extension of the back at this point of the delivery.  I also am coming to believe that this extension for ER takes some pressure off

of the medial part of the elbow during acceleration.  Wood does not have his arm in a good throwing position, has his head slightly in front of his crotch, and has his throwing arm (TA) elbow slightly higher than his TA shoulder.

At full cocking phase both pitchers have good ER, have tucked their lead arm, and have their chest out over their knee with their head still slightly behind their front knee.  From this angle it would appear that their throwing motions are similar.

However, during the acceleration phase of the delivery it appears that Wood still has extension in his back and his elbow has moved in front of his head.  This puts additional strain on the ulnar collateral ligament (UCL). Clemens has started to bow his back but has not taken his elbow past his head.  Note both pitchers back foot has turned over and are off the ground.

At release Clemens has strided directly toward the plate, with head moving toward the plate and the front knee is still bent.  Wood’s stride is across his body (toward third base) showing that his hips are not completely square to the plate and his resultant follow through shows lack of balance.  Both pitchers have their shoulders relatively level at release and their eyes are parallel to the ground. 

Note: All pictures taken from "Right View Pro" video