SPORT SPECIALIZATION IS A RISK FACTOR FOR OVERUSE, BUT NOT ACUTE, LOWER EXTREMITY INJURIES: A PROSPECTIVE STUDY. Issue 3 (31st March 2019) - Bell, David
BACKGROUND: Sport specialization is often associated with intense, high volume training, which may result in injury – especially overuse injuries. However, there is limited prospective research investigating these relationships. Additionally, previous research has focused on adolescents older than 12 years of age with no data available in younger cohorts, who may be more susceptible to repetitive stress. Therefore, the purpose of this study is to determine if sport specialization is associated with increased risk of overuse and acute lower extremity injuries in middle school aged athletes. METHODS: A total of 281 children (113 females (40%), age=12.1±1.2years; range 10-14 years of age) completed an online survey with their parents for 39 weeks. The study was conducted during the 2017-2018 academic year with a baseline survey conducted the first week of September. Weekly surveys were sent to respondents via Qualtrics with the final weekly survey in June of 2018. The baseline survey consisted of 1) demographic information, 2) injury history in the previous 12 months, 3) a sport specialization scale which classified individuals in low, moderate, and high levels of specialization, and 4) sport participation volume (months per year in primary sport). The weekly surveys asked participants to report and musculoskeletal injury they sustained during sport participation. Participants were included in the analysis if they completed at least 80% of the total surveys. Multivariable logistic regression analyses were utilized to examine associations between specialization category (reference category: low) and prospective injury categories, while adjusting for differences in age, sex, and previous injury history. RESULTS: Respondents reported 57 acute and 32 overuse lower extremity injuries during the observation period. Highly specialized athletes had significantly greater odds of reporting a prospective lower extremity overuse injury than subjects in the low specialization group (OR: 3.78, 1.02-12.90, p=0.03), even after adjusting for sex, age, and previous injury history. However, specialization was not a risk factor for acute lower extremity injuries (OR: 2.20, 0.72-6.77, p=0.17). CONCLUSION: Highly specialized middle school athletes are nearly 4 times greater risk of developing an overuse injury compared to low specialization athletes. Younger athletes may be more susceptible to injuries at younger ages. Thus, adolescent athletes should avoid specialization when possible.