Decreased external rotation strength is a risk factor for overuse shoulder injury in youth elite handball athletes

Purpose Overuse shoulder injuries are common in youth handball, but research is limited. The purpose of this study was to identify pre-season risk factors associated with overuse shoulder injuries in this population. Methods One-hundred and thirty-eight (70 boys and 68 girls) youth elite players (age 14.1 +/- 0.8 years, height 175.2 +/- 8.2 cm, weight 64.0 +/- 9.6 kg) completed a pre-season screening protocol. Passive glenohumeral range of motion and maximum external (ER) and internal rotation (IR) strength were measured with a manual goniometer and a hand-held dynamometer. Scapular dyskinesia and maximum throwing velocity were also assessed. Players completed standardised questionnaires over the 2017-2018 season and reported any overuse shoulder symptoms. Results Decreased isometric and eccentric ER strength was identified as a risk factor for overuse shoulder injury, both for absolute (OR 10.70, 95% CI 1.2-95.6, p = 0.034) and normalised ER strength (OR 1.2, 95% CI 1.0-1.4, p = 0.015) and the ER:IR strength ratio (OR 1.2, 95% CI 1.1-1.5, p = 0.012). ER gain of more than 7.5 degrees (p = 0.025) and GIRD of more than 7.5 degrees (p = 0.014) were identified as risk factors for overuse shoulder injury in girls. Scapular dyskinesia (OR 1.1, n.s.) and maximum throwing velocity did not seem to contribute to injury risk. The average response rate was 63%. Conclusion In elite youth handball, deficits in ER strength is a risk factor for overuse shoulder injury for both sexes; ER gain and GIRD are only risk factors for girls. Focused pre-season assessments may aid the identification of risk factors for shoulder overuse injuries and the application of specific programmes to reduce risk