Effects of Resistance Training on Muscle Recovery Post-Surgery: A Randomized Controlled Trial

Abstract

Background/Objective: Postoperative muscle weakness significantly impairs functional recovery following orthopedic surgery. While progressive resistance training (RT) is increasingly incorporated into rehabilitation programs, robust empirical evidence regarding its clinical efficacy remains limited. This study aimed to evaluate the impact of early structured resistance training on quadriceps muscle strength, pain intensity, and functional mobility following Total Knee Arthroplasty (TKA).

Methods: A randomized controlled trial was conducted with 60 post-TKA patients allocated into two groups: an RT group (n = 30), which completed an 8-week progressive resistance exercise program (3 sessions/week), and a control group (n = 30), which received standard postoperative rehabilitation. Outcome measures included isometric quadriceps peak torque (dynamometry), pain intensity (Visual Analogue Scale [VAS]), self-reported functional status (WOMAC function subscale), and objective mobility performance (Timed Up and Go [TUG] and 30-second Sit-to-Stand tests), evaluated at baseline (week 1) and post-intervention (week 8). Group comparisons were analyzed using mixed-model repeated-measures ANOVA and Cohen’s d effect sizes.

Results: The RT group demonstrated significantly superior gains in quadriceps muscle strength compared to controls (+38.6% vs. +12.4%, p < 0.001, Cohen’s d = 1.05). Pain intensity decreased by 34.2% in the RT group versus 14.1% in the control group (p = 0.002, Cohen’s d = 0.82). Self-reported function (WOMAC) improved by 26.8% in the RT group compared to 9.7% in controls (p < 0.001, Cohen’s d = 0.94). Objective functional performance also showed marked enhancements in the RT group (TUG: −29.5%; Sit-to-Stand: +38.5%) over controls (TUG: −11.3%; Sit-to-Stand: +13.3%; p < 0.001, Cohen’s d = 0.88). No intervention-related adverse events were observed.

Conclusion: Early supervised progressive resistance training is safe, well-tolerated, and substantially enhances muscular strength, pain reduction, and functional recovery compared to standard postoperative care alone.