Effects of acute static stretching and dynamic warm-up protocols on shoulder function in young adult male athletes with shoulder impingement syndrome:A randomized controlled crossover trial

Background: Shoulder impingement syndrome (SIS) is common among overhead athletes. Static stretching (SS) and dynamic warm-up (DW) are widely used, but their acute effects on comprehensive shoulder function in athletes with SIS are not fully understood. This study compared the acute effects of SS, DW, and a combined protocol (SS+DW) on range of motion (ROM), stability, proprioception, and strength in male athletes with SIS and healthy controls. Methods: In this randomized controlled crossover trial, 25 male athletes with SIS and 25 healthy controls performed SS, DW, and SS+DW protocols in a randomized order. Outcomes included shoulder internal rotation (IR) and external rotation (ER) ROM, Y-Balance Test (YBT) performance, joint position sense (JPS) accuracy, and isokinetic strength, measured at baseline, immediately post-intervention, and an hour follow-up. Data were analyzed using mixed-design ANOVA. Results: All protocols significantly improved IR and ER ROM (p < 0.05), with SS producing the greatest gains for the SIS group (IR +4.4°, d = 1.25; ER +3.4°, d = 1.02). For the SIS group, DW resulted in the largest improvements in YBT performance (+7.4 cm, d = 1.09; p < 0.05) and markedly enhanced JPS accuracy (error reduction of –3.8°, d = 6.66; p < 0.05). In contrast, SS increased proprioceptive error in SIS athletes (+1.2°, d = 2.91; p < 0.05). Isokinetic strength analysis showed that SS significantly reduced eccentric IR strength at 60°/s (–2.5 Nm, d = 0.69; p < 0.05), whereas DW improved concentric ER strength at 60°/s (+0.6 Nm, d = 0.13; p < 0.05). Across all outcomes, the combined protocol produced effect sizes ranging from d = 0.08 to 3.06, representing small to large effects (p < 0.05). Conclusions: The findings indicate that while all warm-ups improve ROM and stability, DW offers the most comprehensive benefits for athletes with SIS by enhancing proprioception and strength without the performance inhibition associated with SS. DW is recommended for pre-activity routines when neuromuscular readiness is critical.