Injury Surveillance in Early Specialized Adolescent Competitive Swimmers: A 4-Year Prospective Study

Introduction: The aim of this study was to quantify the injury incidence among early specialized adolescent swimmers. Methods: Ninety-seven adolescent swimmers were recruited and prospectively studied from January 2021 to March 2025. Injuries were defined as time loss (TL), for withdrawal of more than 1 day, and non-time loss (NTL). The incidence rate and incidence rate ratios (IRR) were calculated for sex, body part, severity (TL/NTL), and history of injury (new/recurrent). Each characteristic was verified based on 95% confidence intervals (CI). Age of peak height velocity (APHV) was estimated, and chronological and biological ages at injury onset were calculated. Unpaired t -tests were used to compare age at injury onset between sexes. Chi-square tests were used to compare injuries that occurred before and after APHV. Results: Incidence rates (per 1000 athlete hours) were 0.868 overall, 0.643 in males, and 1.042 in females. IRRs were 1.62 for female:male (95% CI, 1.09–2.41) and 3.11 for NTL:TL (95% CI, 2.02–4.80). The IRR for recurrent injuries was 3.67 (95% CI, 1.62–8.29) for female:male. Chronological age at onset did not differ significantly between sexes, whereas biological age was significantly lower in males (−0.88 ± 1.4 vs 0.9 ± 1.77, P < 0.001; Cohen’s d = 1.093). Shoulder injuries were most common for females but not males. Ankle injuries had high incidence rates before APHV, whereas lumbar injuries had high incidence rates after APHV. Conclusions: The most frequent injuries were in the shoulder and were NTL injuries. Sex differences were demonstrated in incidence rates, recurrence of injuries, and biological ages at onset. Also, the most common injury sites differed before and after APHV. Future studies focusing on sex and age differences will be required for swimming injury prevention among adolescent swimmers.