Do you remember the first curveball you ever saw? It happened for me when I was 9 years old playing in the opening game of the 10u NABF World Series in South Haven, Mississippi. Of course, I thought we were the best 10u team in the world, and there was a 100% chance we would win it all. Then, in the third pitch of our opening game against the Memphis Redbirds, our leadoff hitter froze. The pitch wasn’t straight. Watching from the on deck circle, my jaw dropped as I saw the ball fall from our batter’s chin to his knees, at least it did in my mind. The opposing pitcher proceeded to throw hammer after hammer and completely shut us down. After the toughest game I had ever played, I quickly realized we weren’t the best 10u team in the world.
While we were distraught by our loss, most of my team’s parents were even more dismayed, not so much by the result, but by the number of curveballs thrown by the opposing pitcher. Throughout the remainder of the tournament, all I remember hearing from my team’s parents was non-stop criticism of the other team’s coach for allowing his pitcher to throw a curveball. The discussion became heated. “That kid is going to blow out his arm before high school!” Followed by, “Curveballs are dangerous. No 10-year-old kid should ever throw anything but a fastball and a change up.” And of course the classic, “My kid won’t throw a curveball until he can shave, and I didn’t shave until 17!” One parent then said he had the perfect compromise before proceeding to demonstrate a different grip that he said would, “…make the ball curve but wouldn’t torque the elbow,” which of course every kid wanted to learn right away.
I suspect my first experience with a curveball was not dramatically different than yours. The problem in my story is that no child or parent really knew if throwing curveballs at such a young age would cause injury.
Unfortunately, however, neither did the American Sports Medicine Institute led by Dr. James Andrews, who despite having conducted no clinical research to measure the amount of torque throwing a curveball placed on the arm, recommended in 2002 that kids should not throw breaking pitches before they turn 13 (1).
While the medical community has yet to identify a clear cause of UCL tears, thankfully, over the past decade, science has definitively answered whether throwing a curveball increases the risk of a UCL tear. However, for reasons that we can only speculate, these facts are rarely presented.
So…what are the facts?
As a review, we know that the UCL, and most commonly the anterior bundle of medial ulnar collateral ligament, tears when the medial ulnar collateral ligament and its primary supporting structures (the humeroulnar joint and the flexor pronator muscles) cannot withstand the valgus torque placed on the elbow when throwing. It has been well documented that as velocities increase, so do torques on the arm (2, 3). Although the increase of torque is not perfectly linear and can vary from to pitcher to pitcher, barring any mechanical changes, every pitcher will experience an increase in the amount of torque placed on the elbow as velocity increases. This explains why harder throwers are at a greater risk for UCL tears (2).
As for kids throwing curveballs, for nearly 2 decades coaches and clinicians in search of a simple answer to a complex problem of youth and teen elbow injuries hypothesized that breaking pitches were the culprit. This was based on their belief that curveballs subjected the elbow to greater stresses than a fastball. Proponents of this theory asserted that throwing breaking pitches required a contortion of the wrist and forearm, thereby placing excessive stress on the UCL. Predictably, the masses embraced the hypothesis because they finally had an answer.
Even today, this myth permeates the baseball community such that whenever a kid tears his UCL, it’s quite likely you’ll hear parents, coaches and perhaps even a physician say it was because the kid threw too many curveballs. Well, they are wrong. Over the past 15 years, numerous research studies have proven that throwing a curveball places less torque on the elbow than a fastball (4). In 2011, even the American Sports Medicine Institute, the same entity that in 2002 advised against allowing anyone under the age of 13 to throw curveballs, did a 10 year follow up study and concluded there was absolutely no relationship between elbow injury and throwing curveballs at a young age (5).
In fact, most studies have found that curveballs actually place less valgus torque on the elbow than a fastball. In a 2006 study performed at the American Institute of Sports Medicine, it was proven that amongst college pitchers, elbow torques on average were 6% lower when throwing curveballs vs fastballs (4). Then, in 2009, Dr. Carl Nissen and his research team did a similar comparison of stresses amongst adolescent players and found that on average fastballs produce 11% greater torque on the elbow than curveballs (6).
So, while it is true that breaking pitches may be more difficult for kids to throw, and they certainly follow the “win now” mantra of so many parents and coaches, breaking pitches are far from the root cause of UCL tears. With proper instruction, there is no reason youth players should avoid curveballs. But this does speak to the importance of video, technology, and a coach that truly understands pitching mechanics. With the tools of today’s game, coaches can pick up on mechanical differences when throwing various pitches and nip them in the bud while players are still young, creating a fantastic base for success in the future.
In review, when it comes to elbow injuries, we know for a fact that curveballs are not the issue. The amount of torque placed on the elbow is the issue.
While I may have provided you with more information regarding kids and curveballs than you ever cared to know, my primary purpose in this post is NOT to encourage kids to throw more curveballs. Rather, the purpose is to make the point that in its quest to find a solution to the dramatically increasing rate of UCL tears amongst youth and teenage players, the baseball and medical communities have been quick to blame anyone or anything for the cause of the problem, and in most instances, with little to no compelling evidence.
It is important to keep in mind that the real culprit, as stated above, is excessive valgus torque on the elbow. Monitoring these torque and workloads becomes increasingly important. Therefore, tracking throws, measuring torque, staying on a steady throwing schedule are essential to maintaining elbow health and safety. If you wish to further discuss methods of monitoring throwing workloads, please feel free to reach out.
Thank you,
Adam Moreau, MBA, CSCS
Director of Player Development and Recruiting Coordinator
Eckerd College
419-250-7243
References
1. Risk Factors for Shoulder and Elbow Injuries in Adolescent Baseball Pitchers. Samuel J. Olsen II, MD, Glenn S. Fleisig, PhD, Shouchen Dun, MS, Jeremy Loftice, and James R. Andrews, MD. 2006. From the American Sports Medicine Institute, Birmingham, Alabama
2. Fastball Velocity and Elbow-Varus Torque. JS Slowik, KT Aune, AZ Diffendaffer, EL Cain, JR Dugas, GS Fleisig. Journal of Athletic Training. March 2019
3. The Relationship of Throwing Arm Mechanics and Elbow Varus Torque: Within-subject variation for professional baseball pitchers across 82,000 throws. CL Camp, TG Tubbs, GS Fleisig, JS Dines, DM Dines, DW Altcheck B Dowling. American Journal of Sports Medicine. 2017.
4. Kinetic Comparison Among the Fastball, Curveball, Change-up, and Slider in Collegiate Baseball Pitchers. Glenn S. Fleisig, PhD, David S. Kingsley, Jeremy W. Loftice, Kenneth P. Dinnen, MS, Rajiv Ranganathan, Shouchen Dun, MS, Rafael F. Escamilla, PhD, and James R. Andrews, MD. From the American Sports Medicine Institute, Birmingham, Alabama. 2006.
5. Risk of Serious Injury for Young Baseball Pitchers A 10-Year Prospective Study. Glenn S. Fleisig, PhD, James R. Andrews, MD, Gary R. Cutter, PhD, Adam Weber, BS, Jeremy Loftice, BS, Chris McMichael, MPH, Nina Hassell, MPH, and Stephen Lyman, PhD. Investigation performed at the American Sports Medicine Institute, Birmingham, Alabama. 2011.
6. A Biomechanical comparison of the fastball and curveball in adolescent baseball pitchers. Carl W. Nissen, M Westell, S Ounpuu, M Patel, M Solomito, J Tate. American Journal of Sports Medicine. August 2009.
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