August 3, 2015 • BaseballSports Medicine

SportsMed: Understanding baseball injuries

About 15 million people play baseball each year in the United States. Six million of these players are children in grades eight or below.

A significant number of these ballplayers incur elbow injuries of some sort. The dominant arm is usually affected; the cause is repetitive pitching.

PitcherAn increasing number of young baseball players are suffering elbow injuries. Pitchers are most affected. A prospective longitudinal study of about 500 youth pitchers aged 9 to 14 showed that the incidence of serious elbow or shoulder injuries for pitchers was 5 percent. The researchers defined a “serious” injury as one that required surgery or retirement from baseball. The risk factor that showed the strongest correlation to sustaining such an injury was amount of pitching.

Players injured in youth baseball usually report pitching more times per game, more innings per game and more months per year than non-injured players do (assuming all others variables are kept relatively constant). Pitching in competition for more than eight months a year increases the odds of a young pitcher requiring surgery by five times.

Averaging more than 80 pitches per game leads to a fourfold increase in the likelihood of surgery. Surgery becomes 36 times more likely if pitchers regularly throw with a fatigued arm. The risk of serious shoulder and elbow injury triples for those who pitch more than 100 competitive innings in a calendar year. Moreover, high school and Little League pitchers’ risk of elbow injuries increased if they also pitched in showcases or for travel teams.

The apparent surge in elbow injuries in youth baseball is believed to be due to the increased amount of pitching in this setting. Various factors — including more extensive schedules, the temptation to throw breaking pitches, parents who continually push their children and even passion for the game — have directly or indirectly led to the increase in serious elbow and shoulder injuries. Participation on travelling teams, in addition to high school and local leagues, has led to much more protracted schedules than those that were common for players of previous generations. These days, it is not unusual for a young baseball player to play more than eight consecutive months or to play more than 70 games in a year.

Pitchers from warm climates appear to be more prone to throwing-related injuries than their counterparts from cold climates. This may be due to the fact that young athletes in warm climates are able to play baseball for more months each year. There are also indications that this disadvantage makes it slightly more difficult for young baseball players in warm climates to progress to the highest levels of the game.

As a pitcher throws, the pelvis rotates as the upper trunk faces the target, and the abducted arm externally rotates at the shoulder. The maximum varus torque is about 50 percent absorbed by the elbow’s ulnar collateral ligament (UCL) as elbow valgus opening is prevented at the moment of maximum external rotation. This is why repetitive pitching can cause the UCL to tear, either completely or partially. Despite the fact that young players transmit less force across the upper extremities than more mature players do, the underdeveloped muscles, open epiphyses and more compliant connective tissue of the typical player in the former group may lead to not only a tear of the UCL but also a bony avulsion at the growth plate near the insertion/origin of the UCL’s anterior bundle.

On the other side of the elbow, avascular necrosis, osteochondritis dissecans and osteochondral chip fractures may result from repeated compression of the humeral capitellum and the radial head. At the posteromedial elbow, the constant elbow extension and elbow varus torque produced by pitching may cause impingement, chondromalacia, loose bodies and osteophytes. Furthermore, the risk of injury is exacerbated by young pitchers’ inconsistent biomechanics.

Upper extremity injuries affect a large number of competitive baseball players each year. These injuries may lead to retirement from the game, decreased quality of life due to difficulty performing everyday activities and surgery. They may also lead to prolonged absences from baseball.

For example, it takes 12 to 18 months to recover from UCL reconstruction, one of the most commonly performed surgeries in baseball.

Shoulder and elbow injuries and surgery result in decreased quality of life. Shoulder and elbow pain in high school baseball pitchers are associated with difficulties performing tasks at school and at home. These ailments can also involve significant financial costs. One study showed that the average direct medical cost of such injuries was $466, and the total cost — including reduced quality of life and average value of a day’s work for the injured athlete and family members — was around $8,000.

This suggests that research on injury prevention in baseball is sorely needed. Improper pitching techniques, suboptimal physical characteristics and unsafe participation practices contribute to injuries. Research could help to identify and ameliorate these risk factors.

Age-specific pitch counts and rest periods have been promulgated by the USA Baseball Medical Society and Little League Baseball to protect pitchers from injuries caused by overuse. Strengthening and stretching exercises to address scapular kinematics, humeral retrotorsion, shoulder strength, and shoulder and trunk range of motion have been shown to help in the treatment of shoulder and elbow injuries. However, studies on prevention are less robust.

Professional, collegiate, and high school pitchers are now watched more carefully based on recommendations from USA Baseball. If a league is unwilling or unable to enact pitch count limits for some valid reason, that league is advised to limit the number of batters a pitcher faces. However, studies do show that pitch limitations are a better choice than batter limitations for accurately monitoring and controlling the risk of overuse.

Breaking pitches such as curveballs and sliders have been shown to lead to an increased risk of elbow and shoulder pain, so in order to reduce the risk of future overuse injuries, young pitchers are now discouraged from throwing these.

Because a youth pitcher usually stays in the game at another position after pitching, the player is eligible to return to the mound later in the game. However, it is not a good idea from a health and safety perspective to have a starting pitcher come back in and finish a game. After physical activity, a cool-down period is recommended for muscles, tendons and ligaments, similar to the way a player requires a warm-up period.

Participation in showcases is also not recommended. Showcases are meant to give young players the opportunity to display their skills to scouts at higher levels of baseball. These events often occur near the end of the players’ season when they are fatigued and require rest and recovery. Moreover, young pitchers’ tendencies to overthrow at these events further increase the risk of serious injury. Showcases may also be scheduled long after a player’s league ends. Attempting to throw hard again without adequate preparation after such a layoff puts a pitcher at greater risk.


Fleisig, G.S., & Andrews, J.R. (2012). Prevention of elbow injuries in youth baseball pitchers. Sports Health: Multidisc Appr. 1941738112454828.

Oyama, S. (2012). Baseball pitching kinematics, joint loads, and injury prevention. J Sport Health Sci, 1(2), 80-91.

USA Baseball Medical and Safety Advisory Committee Guidelines. (2006).

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