Comparative Effects of Progressive TheraBand Throwing Load Versus Conventional Stretching on Posterior Shoulder Tightness, Internal Rotation Deficit, and Tendon Load Tolerance in Volleyball Players: A Randomized Controlled Trial

Abstract

Background: Despite widespread clinical adoption of stretching interventions for Glenohumeral Internal Rotation Deficit (GIRD) management in overhead athletes, evidence supporting long term GIRD correction and recurrent injury prevention remains limited. Conversely, little empirical evidence exists characterizing how progressive resistance loading affects posterior shoulder tightness resolution, internal rotation deficit correction, and critically, tendon load tolerance adaptation in volleyball-specific populations.

Objective: This randomized controlled trial compared the efficacy of 12-week progressive TheraBand throwing load training versus conventional stretching protocols on posterior shoulder tightness, GIRD correction rates, tendon load tolerance indices, and recurrent shoulder pain incidence at 12-month follow-up in collegiate volleyball players.

Methods: Sixty-eight male collegiate volleyball players (age 20.5±1.8 years) with documented posterior shoulder tightness and GIRD were randomized to intervention (progressive TheraBand throwing load, n=34) or control (conventional stretching program, n=34). Primary outcomes included cross-body adduction ROM, horizontal adduction ROM, internal rotation ROM, and GIRD correction rates. Secondary outcomes included tendon load tolerance index (composite measure incorporating strength symmetry, eccentric control, and functional task performance), pain severity (VAS), disability (DASH), rotator cuff strength ratios (ER/IR), and critically, recurrent shoulder pain incidence during 12-month follow-up. Return-to-play readiness and patient satisfaction were assessed.

Results: TheraBand group demonstrated substantially superior outcomes across primary measures. Cross-body adduction ROM improved 79% from baseline 10.3±3.2 cm to 18.4±2.8 cm versus stretching group 22% improvement (10.8±3.5 to 13.2±3.1 cm; p<0.001, Cohen's d=1.68). Horizontal adduction ROM improved 53% in TheraBand group (34.2° to 52.3°) versus 16% in stretching group (35.1° to 40.8°; p<0.001, d=1.52). Internal rotation ROM improved 25% in TheraBand group (57.8° to 72.1°) versus 6% in stretching group (58.6° to 61.9°; p<0.001, d=1.24). Most critically, GIRD correction rates (achieving GIRD<10°) were 91.2% in TheraBand group versus 32.4% in stretching group (p<0.001). Tendon load tolerance index increased 89% in TheraBand group (41.3 to 78.2) versus 18% in stretching group (40.8 to 48.3; p<0.001, d=2.56 [very large effect]). Recurrent shoulder pain incidence at 12-month follow-up was 11.8% in TheraBand group versus 44.1% in stretching group (p=0.001) - a 73% relative reduction in re-injury rate. Return-to-play achievement was faster in TheraBand group (4.2±1.8 weeks versus 9.6±2.4 weeks; p<0.001). Pain reduction was 82% in TheraBand group versus 22% in stretching group. Patient satisfaction with TheraBand was 88.2% versus 64.3% with stretching.

Conclusion: Progressive TheraBand throwing load training substantially outperforms conventional stretching protocols for posterior shoulder tightness resolution, GIRD correction sustainability, and critically, long-term injury prevention in volleyball players. The superior tendon load tolerance adaptation achieved through load-based rehabilitation explains the markedly lower recurrent pain incidence, supporting evidence-based paradigm shift from traditional stretching-first approaches toward load-based precision rehabilitation for overhead athletes with SIRD. These findings challenge decades of stretching-focused practice and provide compelling evidence for load-based rehabilitation protocols integrating progressive throwing mechanics.

Keywords: Glenohumeral Internal Rotation Deficit – GIRD; Posterior Shoulder Tightness; Stretching; Progressive Loading; Theraband; Tendon Adaptation; Load Tolerance; Volleyball; Overhead Athletes; Recurrent Injury Prevention

Citation

Safrin N, Muthukrishnan P. Comparative Effects of Progressive TheraBand Throwing Load Versus Conventional Stretching on Posterior Shoulder Tightness, Internal Rotation Deficit, and Tendon Load Tolerance in Volleyball Players: A Randomized Controlled Trial. WebLog J Musculoskelet Disord. wjmd.2026.a2807. https://doi.org/10.5281/zenodo.18463926