ESPN – Sport Science
I recently watched an ESPN video entitled “Sport Science: Aroldis Chapman,” in which the mechanics of the 105 mph pitcher were examined. Although the torque Chapman generates on his elbow and shoulder are extraordinary, his separation of lower and upper body are to me, astonishing. As pointed out by Tom Howes, the typical pitcher averages 50 degrees of separation between shoulder and hip turn. Chapman generates 65 degrees!
I note this because the exact point on the human body which feels the brunt of this force is the rectus aponeurotic plate. This is the point which attaches structures to the pubic bone. The two main muscles are the rectus abdominus, and the adductor longus. Other structures like the inguinal ligament, the conjoint tendon, and the pectineus muscle are also involved. Simply put, this one point of attachment bears the load of this extraordinary force. Unfortunately, when this structure is injured, it may not heal without appropriate rest and physical therapy. In some cases, it cannot heal, and requires surgery. I see a large contingent of ball players in my practice, many of them pitchers. After watching videos like these, I am not surprised.