Effect of Isometric Exercise on Pain and Range of Motion in Quadriceps Tendinopathy: A Case Report

Abstract

Background: Quadriceps tendinopathy is a common overuse injury in athletes, characterized by pain, limited range of motion (ROM), and functional impairment. Isometric exercise has been proposed as a physiotherapy intervention that may reduce pain through endogenous analgesic mechanisms while maintaining neuromuscular activation without excessive mechanical loading.
Objective: To evaluate the clinical effect of isometric exercise on pain reduction and ROM improvement in a patient with quadriceps tendinopathy.
Methods: This study reports a single case (n=1) of a 14-year-old female taekwondo athlete diagnosed with quadriceps tendinopathy due to overuse. The intervention consisted of a structured isometric exercise program combined with supportive exercise therapy and cryotherapy, delivered over four sessions within two weeks. Pain intensity was measured using the Numeric Rating Scale (NRS), and ROM was assessed using a goniometer.
Results: Pain intensity decreased from 2/10 (rest), 7/10 (pressure), and 6/10 (movement) to 0/10, 3/10, and 3/10, respectively, indicating a reduction of 2–4 points, exceeding the minimal clinically important difference (MCID). Knee ROM improved from −5°–110° to −2°–125° on the affected side. Lower Extremity Functional Scale (LEFS) score improved from 63/80 to 72/80, reflecting enhanced functional capacity. Anthropometric measurements indicated a slight reduction in edema.
Conclusion: Isometric exercise may be a potentially effective intervention for reducing pain and improving ROM in quadriceps tendinopathy. However, these findings are preliminary, based on a single case, and cannot be generalized. Further studies with larger samples and controlled designs are required.