Relationships Between Sport Specialization and Running-Related Injury Among Competitive High School Cross-Country Runners

BACKGROUND: During the past few decades, the number of participants in high school cross-country has increased. Simultaneously with its popularity has been an increased incidence of running-related injury (RRI). Limited risk factors have been examined in their relationship to RRI in this population. Of these, few studies have reported on the prevalence of sport specialization and its association with RRI among competitive high school cross-country runners. PURPOSE: The purpose of this study was to assess the prevalence of sport specialization and examine its risk association with RRI in competitive high school cross-country runners. METHODS: We prospectively followed 93 runners (35 females, 15.7±1.1y) who competed in the 2018 interscholastic cross-country season in Southern California. At baseline, all runners were injury-free and completed the study questionnaire, which included questions on whether cross-country was their primary sport, the number of months/year spent running-related training, and if they quit another sport(s) to focus on cross-country/track distance running during the past year. High (all 3 factors), moderate (2 of 3 factors) and low (0 or 1 factors) sport specialization was then determined using a widely-utilized scale. Injury occurrence data for all runners was recorded throughout the cross-country season using a standardized injury reporting system. Odds Ratio (OR) estimates and 95% confidence intervals (CIs) were used to determine the association between sport specialization and likelihood of RRI. RESULTS: Of the 93 runners, 15 (16.1%) met criteria for high sport specialization, 49 (52.7%) were classified as moderately specialized, and 29 (31.2%) runners were classified as low sport specializers. The prevalence of high sport specialization was similar between female (17.1%) and male (15.5%) runners (p=0.38). Twenty-six runners (28%) experienced a time loss RRI, with a higher percentage among female runners (37.1%) than males (22.4%) (p=0.16). Although the incidence of injury was greater among high sport specializers (40.0%) than low sport specializers (24.1%), the likelihood of RRI was not statistically significant (OR=2.10, 95% CI: 0.6-8.0; p=0.28). Similar risk associations between high sport specialization and RRI were found between female and male runners. CONCLUSIONS: Based on the existing classification method for sport specialization, these findings indicated that high sports specialization was not common among competitive high school cross-country runners in this study sample. As the incidence of RRI was almost twice as great among high sport specializers, studies assessing larger populations of high school cross-country runners are needed to better evaluate this relationship.