A periodized training attenuates thigh intermuscular fat and improves muscle quality in patients with knee osteoarthritis: results from a randomized controlled trial

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/m(2) 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.