RESUMO
OBJECTIVE: To analyze the influence of a 14-week periodized circuit training (CT) protocol on thigh intermuscular fat and muscle quality (force per unit area of lean tissue) in patients with knee osteoarthritis (KOA). DESIGN: Randomized controlled trial METHODS: Sixty-one selected participants with KOA grades 2 and 3, 40-65 years old, and BMI < 30 kg/m2 were randomized into three groups: CT, conventional strength training (ST), and educational protocol (EP). The CT and ST protocols consisted of 14-week training protocols conducted 3 times a week. The CT group performed exercises stratified as light, moderate, and intense, arranged progressively in a circuit model. The ST group performed conventional strength exercises, and the EP group participated in lectures twice a month about healthy lifestyles. Baseline and follow-up (week 0 and week 14) evaluations were conducted for thigh intermuscular fat (computed tomography), knee extension maximal isometric voluntary contraction (MIVC), and muscle quality (knee extension MIVC/muscle mass cross-sectional area). RESULTS: Only the CT group presented significant reductions in thigh intermuscular fat (p = 0.003) and significantly lower values in week 14 compared with the EP (p = 0.032). Both trained groups presented significant increases in muscle mass area (p=0.002 for CT and p=0.008 for ST) and increments in knee extension MIVC (p=0,033 for CT nd p=0.019 for ST) in week 14 compared with the EP and increases in muscle quality (p = 0.004 and 0.042). CONCLUSION: It can be concluded that a 14-week periodized CT protocol attenuates thigh intermuscular fat and improves muscle quality in patients with KOA. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02761590; https://clinicaltrials.gov/ct2/show/NCT02761590Key Pointsâ¢Fourteen weeks of periodized circuit training attenuates thigh intermuscular fat in patients with knee osteoarthritis.â¢Circuit training is as effective as strength training for improving muscle mass, strength, and quality.
