The Effects of High-Intensity Resistance Training Versus Isometric Training on Quadriceps Muscle Architecture and Strength in Obese Men with Early Knee Osteoarthritis

Abstract

Background and Purpose: Exercise therapy has been extensively utilized as a nonpharmacologic therapy in clinical settings for managing knee osteoarthritis (KOA), and identifying the optimal exercise intensity is crucial to gain a sufficient training response without harmful side effects. The present study aimed to investigate the effects of high-intensity resistance training versus (HIRT) isometric training on quadriceps muscle architecture and strength in obese men with early KOA.

Methods: This study included 71 obese men over the age of 45 with primary KOA graded as 1 or 2 on the Kellgren-Lawrence scale. Participants were randomly allocated into two groups: the HIRT group (n=35) underwent 12 weeks of high-intensity resistance training (65–90% of one-repetition maximum) targeting the quadriceps, while the ISOM group (n=36) engaged in 12 weeks of quadriceps isometric training, consisting of 3 to 5 sets of 5 to 10 repetitions of 5-second unilateral knee extensions per session. Assessments included measurements of vastus lateralis muscle thickness, pennation angle, and fascicle length at rest using B-mode ultrasound. Maximal voluntary isometric contraction (MVIC) torque of the affected knee was evaluated with an isokinetic dynamometer. Knee pain and functional status were assessed using the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC).

Results: The findings of this study demonstrated that 12 weeks of HIRT resulted in more significant improvements in quadriceps muscle architecture and strength compared to isometric training in obese men with early KOA (p<0.05). Both training programs resulted in comparable significant improvements in knee pain and physical function with no significant difference between groups (p>0.05).

Conclusions: HIRT may be more effective than isometric training in improving quadriceps muscle strength and architecture among obese men with early KOA. Both HIRT and isometric training led to similarly significant improvements in knee pain and function. The findings indicate that either exercise regimen may be appropriately recommended for patients with early-stage KOA.