Abstract
Background and objective Posterior shoulder tightness (PST) is common in young overhead athletes and may increase the risk of shoulder injury. Cross-body and sleeper stretches are widely used, but their comparative effectiveness remains unclear. Hence, we conducted this study to address that gap in the literature Methods We performed a single-blind randomized controlled trial involving 24 adolescent baseball players (mean age 11.6 years); the participants were randomly assigned to a cross-body group (n = 12) or a combined group (cross-body plus sleeper, n = 12). Both groups performed daily stretching for three weeks. Shoulder range of motion (ROM) (internal rotation (IR), external rotation (ER), horizontal adduction (HA), and total rotation) was measured with a digital inclinometer before and after the intervention. Results Twenty-four participants completed the trial (combined: n = 12; single: n = 12). Both groups showed significant improvements in IR (combined: from 31.7° to 46.0°; single: from 26.9° to 42.0°) and HA ROM (combined: from 83.6° to 94.2°; single: from 82.9° to 91.9°). Total rotation improved significantly only in the combined group (from 104.6° to 123.9°), whereas ER did not change significantly in either group. No significant between-group differences were observed in any outcomes (p>0.05). No adverse events were reported. Post-hoc power analysis indicated that the study may have been underpowered to detect small between-group effects. Conclusions Cross-body stretching, performed alone or with sleeper stretching, is an effective approach for reducing PST in early adolescent baseball players. Level of evidence: 1b (individual randomized controlled trial).