Research on Shoulder Helps Parents Prevent “Little Leaguer’s Elbow”

By: Steve Siwy for Shoulder1

As more young pitchers visit their doctors with elbow damage, researchers are seeking to decipher the complex interplay of muscle, tendon, and bone that takes place in active joints. With better techniques for measuring the motions involved in pitching, doctors can get a better idea of what causes the most common injuries, including “Little Leaguer’s Elbow.”

When the repeated throwing motion of pitching causes a strong pull on elbow tendons and ligaments, they may begin to pull away from the bone, sometimes uprooting tiny bone fragments with them. Alternately, the stresses of repetitive throwing might compress the elbow joint to the extent that the bones grind together, also loosening bone and cartilage fragments. These sorts of injuries in young, especially pre-pubescent, pitchers can hinder normal bone development.

At centers like Connecticut Children’s Medical Center at the University of Connecticut, and the Motion Analysis Laboratory at San Diego Children’s Hospital’s Center for Human Performance, researchers are tracking, filming, and analyzing the sequence of motions comprised by a baseball pitch. Using such biomechanical analysis, doctors can offer recommendations to individual pitchers, and accumulate data about what kinds of practices might make young pitchers more prone to injury.

Traditionally, doctors have believed that elbow and other injuries are caused when young pitchers throw too many sliders and curveballs, which place more strain on developing arms, and when they throw too many pitches per game. A study by the American Sports Medicine Institute (ASMI) has found that pitchers aged 9-14 who threw sliders were 56% more likely to report elbow pain, for example, and that a 35% increase in elbow pain was reported among young pitchers who threw between 75-99 pitches a game.

Motion analysis now shows that throwing an overhand curveball using proper form actually produces less force on the arm than throwing a fastball would. What is it, then, about a curveball that makes it more likely to cause injury? According to research at the ASMI, throwing a curveball exerts different sets of muscles, and the demands a curveball places on muscles, tendons, and ligaments are apparently more likely to cause pain.

Experts agree, however, that elbow and other arm injuries are more usually a result of throwing too many pitches, rather than the wrong types. Young pitchers may stay on the mound too long, or return to the mound after having been removed previously in the game (once again exerting muscles which should be “cooling down”). Some pitchers may participate in baseball leagues nine months out of the year, or even year-round, and some may play on more than one team at a time. Any of these scenarios leads to a young pitcher throwing at full effort more often than is considered safe for a developing body. The ASMI recommends that young pitchers throw no more than 75 pitches per game and 600 pitches per season. And as Dr. Glen Fleisig of the ASMI recently told CNN, "A boy shouldn't throw a curveball until he can shave.”

As well as following guidelines to reduce the likelihood of injury, doctors say, parents and coaches should also pay attention to a young pitcher’s own assessment. A report by USA Baseball recommends that parents and coaches should immediately remove a young pitcher from a game if he/she complains of arm pain, and seek medical attention if the pain hasn’t subsided after four days.

Last updated: 14-Sep-04