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Pitching Biomechanics Evaluation
The American Sports Medicine Institute (ASMI) is a not-for-profit organization dedicated to improving the understanding, prevention, and treatment of sports-related injuries through research, technology-based education, and information dissemination. For two decades, ASMI has been studying the biomechanics of baseball pitching. The initial focus of these studies was to understand injury mechanisms and provide knowledge to the medical community for improving injury treatment. During the last few years, our purpose has been broadened to include injury prevention. More than 1,000 baseball pitchers from all levels have been tested at ASMI. The wealth of data has led to numerous scientific publications for physicians and others. Biomechanical pitching evaluations are available to baseball pitchers from any level, from youth to professional.

The purpose of the biomechanical pitching evaluation is to reduce the risk of injury or re-injury by addressing the efficiency of a pitcherís mechanics. If a pitcher is able to generate arm speed using his entire body, then less force and torque will be placed on his throwing arm.

To accurately measure and calculate these parameters of human motion, a biomechanics computer program was developed at ASMI. Reflective markers are first placed on some of the pitcherís anatomical landmarks (1).

The pitcherís motion is then collected by a 3D, high-speed, infrared, eight-camera Motion Analysis System (Eagle digital system, Motion Analysis Corporation, Santa Rosa, CA) that picks up the reflective markers on a computer (2, 3).

The pitching computer program is then used to calculate the kinematics (body angles, joint velocities, and timing mechanisms) and kinetics (joint forces and torques). Data from an individualís evaluation are compared to cumulative data from a set of elite pitchers previously tested by ASMI. The data is also studied by researchers at ASMI to determine the anatomic comfort of the shoulder and the elbow joints as that individual pitcher throws the baseball. The results of the biomechanical pitching evaluation are based upon the motion analysis data as well as ASMIís knowledge of biomechanics, baseball, orthopaedics, physical therapy, and strength & conditioning. You will receive a 15-page evaluation packet that includes a written evaluation with our comments concerning the efficiency of your pitching delivery and still photos taken of you during your test.

High speed video of the pitcher is also collected using a Vision Research high-speed video camera. This camera records the pitching motion at 450 frames per second (standard video is 30 frames per second) (4).

    The evaluation will last approximately an hour to an hour and a half.

    Pitchers will need to wear tennis shoes (preferably turf shoes), socks that cover the ankle, and spandex shorts. If you don't have spandex shorts, ASMI has some for you to use. Don't forget to bring your glove.

∑  For additional biomechanical evaluation options including strength & conditioning and personalized pitching instruction click here.

To find out about scheduling an evaluation and/or the cost, please contact Becky Bolt, M.S. at (205) 918-2116 or

Copyright © 2007, American Sports Medicine Institute
February 07, 2008