Anatomical Adaptations in Baseball Pitchers

Baseball pitchers present with a unique profile, which allows them to throw baseballs with high speed and accuracy. From Little League pitchers who are just learning to throw consistent strikes to professional pitchers who regularly hurl 100 mile-per-hour fastballs, this throwing motion offers rehab specialists a look at a highly specific anatomical adaptation.

How Does the Body Adapt to Pitching?

One specific adaptation observed in pitchers is humeral head retrotorsion. We believe that this occurs in young throwers when their growth plates are still open, generally between the ages of 10 and 12 years old.

Throwing a baseball puts the shoulder joint at its end range of motion with every throw, and this helps the humeral head to actually rotate backward, so to speak. Because the growth plates are still open at this age, the repeated stresses from throwing create a permanent osseous adaptation. Numerous studies have shown that this occurs in overhand baseball pitchers, and it’s also been observed in athletes who excel in other sports as well, such as team handball.

This concept is well-established, and it needs to be understood if a rehab specialist is to effectively treat a baseball pitcher.

What Is the Result of This Adaptation?

The extra retrotorsion from pitching allows the glenohumeral joint to gain more external rotation (ER). One theory as to why this occurs is that this ER gain allows the pitcher to gain more lay back, known biomechanically as “the late cocking phase.” This in turn aids in improving a pitcher’s velocity, which is necessary for a pitcher to play at a competitive level.

In general, there’s a fine line between the mobility and stability needed to be an effective pitcher. The pitcher’s shoulder needs to be mobile enough to gain sufficient lay back while remaining stable enough to keep the humeral head centered in the glenoid.

This means that the main goal of the exercises we perform on the baseball pitcher is to maintain joint stability. This will hopefully minimize the chances of getting injured and keeping the pitcher on the field for as long as possible.

Common Injuries in Pitchers

As a rehab specialist, you need to be able to devise a program that enhances strength, maintains range of motion, and allows pitchers to stay in the game.

Some of the potential injuries we commonly see in baseball pitchers include:

A program that focuses on dynamic stability, especially of the rotator cuff, is usually emphasized. You can read more about this in a previous post, in which a return-to-sport program for a baseball pitcher with a rotator cuff strain is outlined.

Clinicians who want to better understand the anatomy and biomechanics involved in the baseball pitching motion should complete this course. In it, the unique profile of the baseball pitcher is presented. These concepts will help clinicians better understand and deliver a quality plan of care, along with an evidence-based approach to some of most common baseball injuries. Furthermore, they can develop a general treatment regimen that allows rehabilitation specialists to evaluate and treat baseball pitchers with much more confidence.

  1. Chant, C. B., Litchfield, R., Griffin, S., et al. (2007). Humeral head retroversion in competitive baseball players and its relationship to glenohumeral rotation range of motion. Journal of Orthopaedic Sports Physical Therapy, 37(9): 514-20.
  2. Crockett, H. C., Gross, L. B., Wilk, K. E., et al. (2002). Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. American Journal of Sports Medicine, 30(1): 20-6.
  3. Greenberg, E. M., Lawrence, J. T., Fernandez-Fernandez, A, et al. (2017). Humeral retrotorsion and glenohumeral motion in youth baseball players compared with age-matched nonthrowing athletes. American Journal of Sports Medicine, 245(2): 454-461.
  4. Reagan, K. M., Meister, K., Horodyski, M. B., et al. (2002). Humeral retroversion and its relationship to glenohumeral rotation in the shoulder of college baseball players. American Journal of Sports Medicine, 30(3): 354-60.
  5. Osbahr, D. C., Cannon, D. L., Speer, K. P. (2002). Retroversion of the humerus in the throwing shoulder of college baseball pitchers. American Journal of Sports Medicine, 30(3): 347-53.