Investigating the effects of eccentric stretching on pain, grip strength, and functional outcomes in patients with lateral epicondylopathy: a randomized controlled trial

Background: Lateral Epicondylopathy (LE) is a common musculoskeletal condition characterized by pain over the lateral elbow. Purpose: To examine the effects of eccentric stretching on pain, grip strength, and function in LE. Methods: Forty participants with LE were randomized into study and control groups. The control group received cold application, deep friction massage, and a home exercise program (three times/week for four weeks). The study group additionally performed eccentric stretching(3 sets/15 repetitions, three times/week for four weeks). Outcomes included pain, grip strength, Patient-Rated Tennis Elbow Evaluation (PRTEE), viscoelastic muscle properties, Quick Disabilities of the Arm, Shoulder, and Hand (Quick DASH), and quality of life. Clinical relevance was assessed using the smallest worthwhile change (SWC). Results: Significant Group×Time interactions were observed for grip strength (p <.001, ηp² = 0.426), lateral pinch strength (p =.014, ηp² = 0.150), and fingertip pinch strength (p =.014, ηp² = 0.149), indicating greater improvements in the study group. PRTEE-function (p <.001, ηp² = 0.443) and QuickDASH (p <.001, ηp² = 0.598) also demonstrated significant interaction effects favoring the intervention. Significant interactions were further observed for muscle tone, stiffness, and elasticity at rest (ηp² = 0.284–0.468) and for tone and stiffness during activity (ηp² = 0.151–0.257; all p ≤.013), indicating superior viscoelastic adaptations in the intervention group. No significant interaction was found for elasticity during activity (p =.322, ηp² = 0.026). Pain outcomes showed no between-group differences (all p ≥.512), although both groups demonstrated clinically meaningful reductions. Conclusion: This study demonstrates for the first time that supervised eccentric stretching provides clinically meaningful improvements in strength, function, muscle viscoelastic properties, quality of life beyond conventional physiotherapy alone in chronic LE. These findings suggest that targeting passive tissue mechanics through controlled eccentric elongation may enhance functional recovery even when pain reduction is similar. Eccentric stretching may therefore represent a valuable adjunct strategy when functional restoration rather than pain relief alone is the primary therapeutic goal.