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Objective: To investigate change in shoulder rotation strength from preseason to midseason during a competitive season in youth elite handball players without shoulder problems., Design: Prospective cohort study., Methods: Players (n = 292, 45% female, 14-18 years of age) without shoulder problems from Danish youth elite handball clubs were assessed in the preseason and midseason. We measured isometric shoulder strength using handheld dynamometry in internal rotation (IR) and external rotation (ER) in supine, with the shoulder abducted 90° in neutral rotation and in 30° of IR. The primary outcome was the change in corresponding ER/IR ratio., Results: The mean ER/IR ratios increased from preseason to midseason in neutral rotation (male player difference, 0.02; 95% confidence interval [CI]: -0.01, 0.06; female player difference, 0.05; 95% CI: 0.01, 0.09) and in 30° of IR (male player difference, 0.15; 95% CI: 0.11, 0.20; female player difference, 0.12; 95% CI: 0.07, 0.17). The change in ER/IR ratio may be explained by an increase in ER strength in female players and a decrease in IR strength in male players. The amount of change in ER/IR ratio over the season was greater than individual measurement error metrics for 45% to 66% of the players., Conclusion: Shoulder rotation strength ratios changed during a competitive season in Danish youth elite handball players. J Orthop Sports Phys Ther 2020;50(7):381-387. doi:10.2519/jospt.2020.9183 .

Generalised Joint Hypermobility including shoulder hypermobility (GJHS) in swimmers is considered an intrinsic risk factor for shoulder injuries. The aim was to investigate the association of GJHS with shoulder strength, fatigue development and muscle activity during swimming-related shoulder rotations. Totally, 38 competitive swimmers (aged 13-17 years) participated, 19 were competitive swimmers with GJHS and 19 were age, sex and club matched swimmers without GJHS. Concentric isokinetic force in medial and lateral rotations were measured at 60°/s (5 repetitions) and 180°/s (10 repetitions). Electromyographic activity was measured from upper trapezius, lower trapezius, serratus anterior, infraspinatus and pectoralis major muscles. Swimmers with GJHS produced significantly lower peak torque (0.53 vs. 0.60 Nm/kg; p = .047) and maximum work (0.62 vs. 0.71 J/kg; p = .031) than controls during medial rotation (60°/s). Swimmers with GJHS showed significantly larger isokinetic fatigue at 180°/s (0.321 J/repetition; p = .010), and tendencies to lower levels of muscle activity in infraspinatus (20%, p = .066) and pectoralis major (34%, p = .092) at 60°/s during medial rotation. Young competitive swimmers with GJHS, despite no formal diagnosis, displayed strength and fatigue deficits in medial rotation, potentially inherent with greater risk of shoulder injury. Whether GJHS swimmers benefit from medial rotation strengthening is an important topic for future studies., (Copyright © 2018 Elsevier Ltd. All rights reserved.)