Research Review #5: Following Little League Baseball Pitch Count Recommendations is Protective against Tommy John Surgery

Erickson BJ, Chalmers PN, Axe MJ, Romeo AA. Exceeding pitch count recommendations in Little League Baseball increases the chance of requiring Tommy John surgery as a professional baseball pitcher. Am J Sports Med. 2017;5(3):1-6. doi:10.1177/2325967117695085.


Elbow injuries in youth baseball pitchers are on the rise.  Pitchers between the ages of 15 and 19 years old are showing the greatest increase in ulnar collateral ligament (UCL) reconstruction surgeries.  Research has identified several risk factors for UCL injury including pitch volume, pitch velocity, pitching year-round, pitching with fatigue, geography, sports specialization, and loss of shoulder range of motion.  In 2007, Little League baseball changed its innings limit recommendations to a pitch count limitation in order to combat the negative effects of pitching with fatigue.  The long-term effects of these changes have not been extensively studied to date.


The purpose of this study was to investigate the percentage of Little League World Series (LLWS) pitchers who progressed to professional baseball, the percentage of UCL injuries among these pitchers, and to determine the effects of exceeding Little League pitch count recommendations on injury rates.

Study Population & Research Methods

 LLWS pitchers from all countries who participated in 2001 to 2009 were retrospectively studied from Little League performance database.   Pitchers were divided into those who did and did not exceed the 2007 pitch count limitations.  A database of all major and minor league pitchers was then used to identify former LLWS pitchers.  Next, these pitchers were then searched using a public database to determine if they underwent UCL reconstruction.

Key Results

  •  10% (62/638) of pitchers from the LLWS went on to play major or minor league baseball
  • 90% (56) of these professionals played in the minors, and 10% (6) went on to play in the majors
  • 33% (1/3) of LLWS pitchers who pitched in the majors required UCL reconstruction
  • 8% (2/25) of LLWS pitchers who pitched in the minors required UCL reconstruction
  • No pitchers from the LLWS who played professionally as a non-pitcher required UCL reconstruction
  • All LLWS pitchers who underwent UCL reconstruction pitched prior to the institution of the 2007 pitch count limitations
  • 50% (2/4) of LLWS pitchers who exceeded pitch count limitations required UCL reconstruction
  • 7% (1/58) of LLWS pitchers who did not exceed pitch count limitations required UCL reconstruction
  • 1% of LLWS players who exclusively pitched required UCL reconstruction, no player who pitched and played another position in the LLWS required UCL reconstruction.

 Study Limitations

  •  Overestimation or underestimation of injury cannot be ruled out based on method on search methods used
  • For those pitchers where age could not be determined, a pitch count limit of 95 pitches per week was used.
  • LLWS pitchers from the last few years may not have yet progressed to professional baseball (i.e., 2008 or 2009)
  • It is possible that some LLWS pitchers who underwent UCL reconstruction never progressed to professional baseball.

Practical Implications & Additional Thoughts

Fifty percent of LLWS pitchers who exceeded pitch count recommendations and pitched professionally eventually required UCL reconstruction.  Only 1.7% who did not exceed pitch count recommendations required UCL reconstruction.  No LLWS pitcher after pitch count limitations was instituted in 2007 has progressed to undergo UCL reconstruction.  Also, no LLWS pitcher who also played another position required UCL reconstruction.  These findings support the protective role of following pitch count recommendations in Little League and diversifying positions played.

These results are encouraging given the rate at which UCL injuries are occurring in youth, college, and professional pitchers.  Hopefully, coaches and parents increase their support and adherence to youth pitching guidelines.  However, research suggests many youth baseball coaches are deficient in their knowledge of pitch count recommendations or do not follow them2.  If any meaningful long-term changes in injury rates are to occur, parents and coaches need to take the lead.

Diversifying positions played, or not exclusively pitching at a young age is important for mature athletes.  This minimizes the risk of pitching with fatigue and subsequent injury.  This is consistent with the research against early sports specialization.  Adhering to pitch count guidelines and exposing young athletes to multiple positions and sports helps manage workload.  This also improves overall movement pattern development which many young athletes lack today.  Following pitch count recommendations, diversifying positions played and sports played not only reduces injury risk but also improves overall athleticism.


  1. Erickson BJ, Nwachukwu BU, Rosas S, et al. Trends in medial ulnar collateral ligament reconstruction in the United States: A retrospective review of a large private-payer database from 2007 to 2011. Am J Sports Med. 2015;43(7):1770-1774. doi:10.1177/0363546515580304.
  2. Fazarale JJ, Magnussen RA, Pedroza AD, Kaeding CC. Knowledge of and compliance with pitch count recommendations: A survey of youth baseball coaches. Sport Heal A Multidiscip Approach. 2012;4(3):202-204. doi:10.1177/1941738111435632.


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