The incidence of serious shoulder and elbow injuries in pitchers is 5% and increasing at an alarming rate (serious injury was defined as that requiring surgery or retirement from baseball). Inadequate rest, poor pitching mechanics, and breaking pitches have been broadly cited as the 3 most significant modifiable risk factors for pitching-related injury. Therefore, coaches and governing bodies have attempted to reduce stresses on the pitching shoulder and elbow by enforcing age- specific pitch counts, emphasizing the importance of proper mechanics, and discouraging breaking pitches in younger pitchers. Although literature is sparse, a few smaller-sample-size biomechanical studies using quantitative motion analysis have elucidated kinematic and kinetic commonalities and differences witnessed among youth, high school, collegiate, and professional pitchers in an attempt to establish “normal” pitching characteristics within various age groups.
In one of the first published comparisons of pitching mechanics among various levels of development, Fleisig and colleagues compared kinematic and kinetic parameters among 231 pitchers at the youth (10 to 15), high school (15 to 20), college (17 to 23), and professional level (20 to 30). The authors found no significant differences among levels with regard to 16 of 17 temporal and position parameters and concluded that pitchers should be taught proper adult mechanics from an early age. More recent literature has shown that youth pitchers, compared with skeletally mature pitchers, have a propensity for early trunk rotation and have reduced range of external shoulder rotation during pitching. There is limited literature comparing pitchers of different age groups with regard to pitch counts and prevalence of breaking pitches. The purpose of this study was to determine differences among healthy pitchers at different levels of competition with regard to pitching history, pitching mechanics, and prevalence of breaking pitches. We hypothesized that as pitchers aged, they would be more likely to pitch with favorable mechanics; however, they would also be more likely to throw breaking pitches and pitch with inadequate rest.