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Is Curveball Debate Over?

Overuse to Blame For Youth Pitching Injuries, But Sliders and Curveballs Still Risk

Little League report says pitch count limits work; warns parents travel baseball is "high risk, low reward"

Chicken or egg?

John Pinkman, the head of Pinkman Baseball Academy in Herndon, Virginia and MomsTeam's baseball expert, agrees  with Dr. Fleiseg, noting that, "as a superior pitcher increases his pitch count, it is likely that he would increase the number of curve balls thrown. While confusing semantics is always involved in throwing pitches that go crooked, as opposed to those that go straight, young pitchers are often injured due to irresponsible training and attempts to force them to use competitive skills that are more suited for older players.

In practical application, due to the small hand of a child, to make a ball spin at the proper axis of rotation to create the traditional interpretation of a curve ball, the player must forcefully twist his hand, and subsequently his elbow, in a supinated direction (counter clockwise on a right hand thrower).  Through overuse, that motion can and, very often has, caused serious repetitive micro trauma (in layman's terms, a sore arm).  Medical professionals call it a 'door knob curve,' since the motion mimics someone opening a door."

As an expert on the mechanics of pitching, Pinkman notes that, "much less discussed is the fact that many players throw fast balls with a similarly excessive and premature supination. Routinely, we clearly observe this motion in our video analysis at very slow motion (480 frames per second). This type of pitch, although nominally a fastball, also increases the risk of overuse injuries because the ball is thrown with excessive force and more often.  In the final analysis. proper training which takes into account the player's size, age and experience is the safest policy."

As Pinkman notes, "a really good pitcher, even at the elite level, strikes out about one batter per inning on average.  The remaining 66% of the outs are grounders and fly balls. In my view, far too much emphasis is placed on curve balls at an early age to increase the number of strike outs."

Prevention strategies

Regardless of whether the Little League study puts to rest the controversy over curve and other kinds of breaking balls, it is valuable in correctly focusing attention on overuse injuries as the primary cause of arm injuries to youth baseball pitchers, identifying  mandatory pitch count limits as the best prevention technique and in laying some of the blame for the increase in pitching injuries at the youth level at the feet of travel ball and showcases (which have not, until now, imposed pitch limits), and in viewing it as perhaps the biggest obstacle to injury prevention.

In terms of prevention, the study recommends:

  • Continuing and strengthening mandatory pitch count limit programs;
  • Regulating pitch counts in other youth baseball leagues (i.e. travel baseball and showcases) and at the high school level;
  • Increasing education of coaches, parents and athletes about what the study terms the "high risk and low reward" of travel ball and showcases.
  • Teaching proper pitching technique, and educating parents and athletes about its importance in injury prevention.
  • Properly stretching, warming-up, and cooling-down for pitchers, regardless of age.

Use common sense

"The practical implication [of the new study]," says ASMI's Dr. Fleiseg, "is that years of scientific study - from motion analysis in the lab to following kids on the field - support the fact that the best computer is right there on the field, in the player's head! If a pitcher is tired, he should stop pitching until the day he is fully recovered. If a pitcher has elbow or shoulder pain, shut him down until he sees a sports medicine specialist. The adults need to use "the computers in their heads" too. The coaches and parents need to be able to read the signs, and react when the player is fatigued or hurt. The data shows that following this common sense will maximize the chance for long-term success, whereas ignoring the signs will most likely lead to injury," says Fleiseg.

Study methodology

The study used three different test groups - Little League pitchers (ages 8-13); high school-aged pitchers; and college-aged pitchers. The Little League test group consisted of 410 players who were followed for four years between 2006 and 2010. The test group from the high school level was made up of 293 players who were recruited in 2007 and followed for additional years. The college test group consisted of 629 players that were followed for two years beginning in 2008.

The pitchers were surveyed each year to assess their pitching methods, techniques, pain presence and injury occurrence. The factors acquired from the surveys were then analyzed to assess which of those factors influenced pitching injury risk.

The study was commissioned by Little League Baseball and funded with a grant from the Yawkey Foundation.

UPDATE: USA Baseball and MLB's Pitch Smart program recommends that pitchers under the age of 13 avoid throwing pitches other than fastballs and change-ups, and that for pitchers ages 13 and up "can begin using breaking pitches after developing [a] consistent fastballs and change-up."

*In 2008, Little League Baseball became the first national youth baseball organization to adopt the pitch count, instead of the number of innings pitched, as the basis for its pitching rules.  For more on its pitch count and mandatory rest rules, click here.

1. The Learning Curve: Little League Seeks to Address Concerns, Answer Questions about Curveballs & Overuse (Little League International 2011). 

2.  Fleisig G, Andrews J, Cutter G, Weber A, Loftice J, McMichael C, Hassel N, Lyman S. Risk of Serious Injury for Young Baseball Pitchers: A 10-Year Prospective Study. Am J Sports Med. 2010;20(10): 1-5.

3. Lyman S, Fleisig GS, Andrews JR, Osinski ED. Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitchers. Am J. Sports Med 2002;30(4):463-468

4. Fortenbaugh D, Fleiseg G, Andrews J. Baseball Pitching Biomechanics in Relation to Injury Risk and Performance. Sports Health: A Multidisciplinary Approach 2009;1:314-320.

5.Shouchen, Dun et. al., A Biomechanical Comparison of Youth Baseball Pitches: Is the Curveball Potentially Harmful? Am J Sports Med. 2008;36(4):686-692.

6 Davis, J.T., et. al. The Effect of Pitching Biomechanics on the Upper Extremity in Youth and Adolescent Baseball Pitchers. Am J Sports Med. 2009;37(8):1484-1491.

7. Hyman, Mark, "Studies Show That the Curveball Isn't Too Stressful for Young Arms," New York Times (July 26, 2009).

Updated October 2, 2015