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Pitching Injuries: Risk Factors

50/50 chance pitcher will suffer elbow or shoulder pain during career

If your child is a pitcher, he/she has about a fifty-fifty chance of experiencing pain in his/her elbow or shoulder during his/her baseball career. Not surprisingly, baseball has been the most widely studied youth sport in the United States.

Here's what the studies have identified as risk factors for overuse injuries:

Baseball pitcher in stretch position

2001

A 2001 study in the journal Medicine, Science, Sports & Exercise1 found that athletes who pitched with a tired arm were 6 times more likely to suffer from elbow pain and 4 more times more likely to have shoulder pain than those who did not have a tired arm.

2002

A 2002 study in the American Journal of Sports Medicine2 found that roughly half of the 476 youth pitchers studied (47%) reported elbow or shoulder pain at least once over the course of two seasons, although most of the pain was considered mild (i.e. without loss of time in games or practices).

The study identified the following risk factors for injury:

  • 50 plus pitches in a game: For each additional 25 pitches thrown after reaching the 50 pitch count, the percentage of pitchers experiencing pain increased. 
  • 75 pitches in a game: The risk of shoulder pain was 2 and a half times greater for pitchers who threw more than 75 pitches per game
  • More than 600 pitches in a season: The risk of elbow pain was 3 1/2 times greater for pitchers throwing more than 600 pitches per season 
  • Pitching with tired arm: For pitchers who self-reported pitching while tired, the risk of elbow pain was 6 times greater and the risk of shoulder pain increased four-fold.
  • Throwing breaking pitches: Youth baseball pitchers who threw curve-balls or sliders were at an increased risk of elbow and shoulder pain [Note: while two recent biomechanical studies suggest that throwing a curveball actually puts less stress on the elbow and shoulder than throwing fastballs, some experts, such as world-reknowned orthopedic surgeon Dr. James Andrews of the American Sports Medicine Institute (ASMI), still believe throwing curveballs at an early age can be dangerous.  The 2011 position statement on overuse injuries3 issued by the National Athletic Trainers' Association urges "caution" in allowing younger pitchers to throw curveballs.] 

Elbow pain was related to:

  • increased age
  • decreased height
  • increased body mass index (BMI)
  • increased cumulative (season-long) pitch counts
  • arm fatigue
  • decreased self-perceived performance
  • concurrent participation in weightlifting program
  • participation in additional baseball leagues.  

Shoulder pain was associated with:

  • increased number of pitches thrown in games
  • increased cumulative pitch counts
  • pitching with tired arm
  • decreased perceived self-performance. 

2006

A 2006 study in the American Journal of Sports Medicine4 found that overuse was the overriding factor in the development of arm pain among pitchers in youth baseball. That study found that:

  • Pitchers who averaged more than 80 pitches per appearance were nearly 4 times more likely to require arm surgery;
  • Pitchers who pitched competitively more than 8 months per year were 5 times more likely to require surgery; and
  • By age 20, those who pitched on a regular basis with a tired arm were an astounding 36 times more likely to have an elbow or shoulder injury requiring surgery.
  • Those who suffered an injury also were more likely to:
    • start at another position before pitching (e.g. inadequate warm up; a relief pitcher needs to throw 25 fastballs before taking the mound)
    • throw fastballs faster than 85 mph (4 times more likely to be injured); and
    • participate in a greater number of showcases (multi-day, high-level events in which athletes participate in multiple games within a short period of time).

2010

A 2010 study by researchers at ASMI reported in the American Journal of Sports Medicine5 found that:

  • Pitchers who pitched more than 100 innings in a calendar year were 3.5 times more likely to be so seriously injured as to require elbow or shoulder surgery or retirement due to injury.
  • Playing catcher appeared to double or triple a pitcher's risk of serious injury, although the sample size of the study was not sufficient to establish that this trend was statistically significant; but that
  • The cumulative risk of serious injury to a pitcher over 10 years was relatively low (5%).

2011

A 2011 study6 reported in the American Journal of Sports Medicine suggests that pitchers in warm-weather climates are increased risk for injury because of the excessive time they dedicate to pitching in a calendar year. 

Other studies

Other studies have found that:

  • 26% of youth players and 58% of high school pitchers experience elbow pain; and
  • 29% of 9- to 19-year-old boys experience shoulder pain (according to one study and between 32% and 35% in two other studies (38% in a 2010 study of high school pitchers)

More Tommy John surgeries

The epidemic of arm injuries suffered by youth baseball pitchers is reflected in the dramatic increase in the number of shoulder and so-called Tommy John elbow (ulnar) ligament-transplant operations performed by Dr. James Andrews at ASMI:

  • 9 Tommy John elbow operations from 1995 to 1998
  • 65 over the next four years
  • 224 from 2003 to 2008
  • 2001-2002: total of 13 shoulder operations on teens
  • Over next 6 years, 241

Three main risk factors

Research by the ASMI and others points to three principal risk factors for injury to youth baseball pitchers: overuse (number of pitches during a game, season, and a year), poor pitching mechanics, and poor physical fitness/physical conditioning.

  1. Most baseball arm injuries are not the result of a single traumatic event. Instead, injuries are believe to be due to the cumulative effect of microscopic trauma from the repetitive act of pitching. Overuse occurs throughout the course of a single game, season, or year in the developing baseball player. 
  2. Poor pitching mechanics has been suggested as a possible risk factor for injury, but such a link has yet to be shown in biomechanical or clinical studies.
  3. Poor physical fitness/physical conditioning.

Of the three, experts seem to agree that the number of pitches thrown coupled with the lack of appropriate rest periods are the greatest contributor to the increasing incidence of pitcher arm injuries.  The 2010 ASMI study5 suggests that it is the number of innings (greater than 100 in a calendar year) that puts pitchers at greatest risk of serious injury. Likewise, the 2011 study6 reported in the American Journal of Sports Medicine suggests that pitchers in warm-weather climates are increased risk for injury because of the excessive time they dedicate to pitching in a calendar year.

Don't ignore pain

Because both arm fatigue and decreased self-perceived performance are risk factors for both elbow and shoulder pain, the bottom line message for parents and athletes: pain should not be ignored, because it is often the first indicator of an overuse problem.2


1. Lyman S, Fleisig GS, Waterbor JW, et al. Longitudinal study of elbow and shoulder pain in youth baseball pitchers. Med Sci Sports Exerc. 2001;33(11):1803-1810.

2. 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.

3. Valovich McLeod TC, Decoster LC, Loud KJ, Micheli LJ, Parker JT, Sandrey MA, White C.  National Athletic Trainers' Association Position Statement: Prevention of Pediatric Overuse Injuries.  J Ath. Tr. 2011;46(2):206-220.

4. Olsen SJ 2nd, Fleisig GS, Dun S, Loftice J, Andrews JR. Risk factors for shoulder and elbow injuries in adolescent baseball pitchers. Am. J Sports Med. 2006;34(6):905-912.

5. 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.

6.Kaplan KM, Jobe FW, Morrey BF, Kaufman KR, Hurd WJ. Comparison of Shoulder Range of Motion, Strength, and Playing Time in Uninjured High School Baseball Pitchers Who Reside in Warm- and Cold-Weather Climates.Am. J Sports Med.2011; 39(2): 320-328.

Posted March 15, 2011

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