Flat Arm Syndrome is an easy to visualize way of describing a severe — and, disturbingly, more and more common — type of Timing problem in baseball pitchers.

And, increasingly, position players.

Flat Arm Syndrome: Overview

My understanding of Flat Arm Syndrome helped me see the problem with Johan Santana's pitching mechanics and understand that, and why, he wasn't going to be the savior the Mets hoped he would be.

Flat Arm Syndrome is a problem because the latest research into pitching mechanics and injuries makes it clear that Timing problems are what's driving the rising incidence of Tommy John surgery and other, even more serious, problems in baseball pitchers.

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In the picture above, notice how Justin Verlander's pitching arm is UP as he goes into foot plant while Trevor Clifton's pitching arm is FLAT at foot plant.

That is a problem because, if the pitching arm is FLAT, and not UP, at foot plant, that it will increase the distance over which, and the force with which, the pitching arm will externally rotate.

Typically, that first overloads the elbow and then gets the shoulder.