Effect of Isometric Quadriceps Exercise on Muscle Strength,Pain, and Function in Patients with Knee Osteoarthritis: A Randomized Controlled Study

[Purpose] The aim of present study was to investigate the effects of isometricquadriceps exercise on muscle strength, pain, and function in knee osteoarthritis.[Subjects and Methods] Outpatients (N=42, 21 per group; age range 40–65years; 13 men and 29 women) with osteoarthritis of the knee participated in the study. Theexperimental group performed isometric exercises including isometric quadriceps, straightleg raising, and isometric hip adduction exercise 5 days a week for 5 weeks, whereas thecontrol group did not performed any exercise program. The outcome measures or dependentvariables selected for this study were pain intensity, isometric quadriceps strength, andknee function. These variables were measured using the Numerical Rating Scale (NRS),strength gauge device, and reduced WOMAC index, respectively. All the measurements weretaken at baseline (week 0) and at the end of the trial at week 5. [Results] Inbetween-group comparisons, the maximum isometric quadriceps strength, reduction in painintensity, and improvement in function in the isometric exercise group at the end of the5th week were significantly greater than those of the control group (p<0.05).[Conclusion] The 5-week isometric quadriceps exercise program showed beneficial effects onquadriceps muscle strength, pain, and functional disability in patients withosteoarthritis of the knee.Key words: Isometric exercise, Osteoarthritis, Rehabilitation