Sport Specialization and Increased Injury Frequency in Youth Baseball Players: A Prospective Study

Abstract

Context Sport specialization is thought to be a primary contributor to the throwing-related injury risk in youth baseball players. Objective To (1) establish arm-injury incidence in a cohort of male youth (9–12 years old) baseball players and (2) examine sport specialization and the frequency of arm injuries in the same cohort. Design Cohort study. Setting Greenville, South Carolina, youth baseball programs and tournaments. Patients or Other Participants A total of 159 asymptomatic youth baseball players (age = 11.1 ± 1.1 years) were physically assessed and then were prospectively followed for 6.7 ± 1.5 months. Main Outcome Measure(s) Athlete demographics and playing and injury histories were initially recorded. Athlete-exposures and presence of arm injury were prospectively tracked. All injuries were physically confirmed by a licensed physical therapist. Results Youth players demonstrated an arm-injury incidence rate of 2.22 per 1000 athlete-exposures. Parents and players underestimated sport-specialization status based on the standard research definition (self versus research based: 31% versus 83%, respectively; P = .001). The frequency of arm injuries was higher in specialized players (100%) than in nonspecialized players (80%, P = .03) but did not differ between pitchers and position players (13.2% each, P = 1.00). Conclusions Sport specialization was associated with throwing-related arm injuries in a small cohort of youth baseball players. It is concerning that 57.9% of parents and specialized players were unaware of the athletes' status. Larger studies with longer follow-up periods are needed to further evaluate injury-risk profiles in physically developing youth populations.

Prevalence and Consequences of Sport Specialization Among Little League Baseball Players

“…Both findings are behaviors commonly reported by highly specialized athletes that have been linked with injury. 3,11,36 This relationship with injury, however, was not found in the present study. 14,25,30 The second key finding of this study was that specialization was associated with worse throwing arm health.…”

“…Our results are in agreement with the many studies that have identified sport specialization as a risk factor for overuse injury among large cohorts of athletes from multiple sports 4,12,14,18,27,28,30 and also with the few studies that have specifically examined baseball players. 3,11,35 Arnold et al 3 prospectively followed youth baseball players, aged 9 to 12 years, who self-classified as specialized or nonspecialized and found that the frequency of arm injuries was greater among specialized players compared with nonspecialized players. 3 Similarly, sport specialization was associated with previous upper extremity overuse injury history and lower YTS score in a sample of 551 high school baseball players.…”

“…3,11,35 Arnold et al 3 prospectively followed youth baseball players, aged 9 to 12 years, who self-classified as specialized or nonspecialized and found that the frequency of arm injuries was greater among specialized players compared with nonspecialized players. 3 Similarly, sport specialization was associated with previous upper extremity overuse injury history and lower YTS score in a sample of 551 high school baseball players. 29 Several retrospective surveys of professional baseball players have similarly found that players who specialized early in baseball (ie, prior to high school) were more likely to sustain injuries during their professional careers.…”

Early Sport Specialization Linked to Throwing Arm Function and Upper Extremity Injury History in College Baseball Players

“…3 In a recent study of youth baseball players younger than 13 years, 83% of players met the study's criteria to be considered specialized in baseball, and those who were specialized reported a higher frequency of throwing-related arm injuries compared with players who were not specialized. 2 Similarly, in another recent study of high school baseball players, 52% of players met the study's criteria of being highly specialized, and those who were highly specialized reported greater rates of upper extremity overuse injuries in the previous year and poorer subjective throwing arm function. 14 Evidence suggests that adolescent baseball specialization may be associated with short-term negative effects on upper extremity health during players' adolescent baseball careers 2,14 ; however, the long-term effects of early baseball specialization on upper extremity health are not well-understood.…”

“…13 Sport specialization, defined as year-round intensive training in a single sport while excluding other sports, 7 is a popular trend among youth baseball players. 2 The high-volume training, repetitive tissue stresses, and limited rest associated with sports specialization could play a role in the high rates of noncontact and overuse upper extremity injuries we have observed in college baseball players. A recent meta-analysis suggests that high and moderate sport specialization during adolescence is associated with a greater risk for overuse injury across diverse sports.…”