Circuit Training on Knee Osteoarthritis Patients

Introduction: The increase in intermuscular adipose tissue (IMAT) can contribute to muscle weakness and consequently on progression of knee OA. The prescription of exercise protocols has been used as a treatment strategy to minimize some of the bouts. Circuit training (CT) involves the combination of strength training and aerobic in the same session and has shown benefits in body composition and physical function. But the literature is unclear with respect to the influences of CT in the concentration of IMAT in the population with knee OA. Objective: To investigate the influence of a 14-week CT protocol in body composition and thigh IMAT concentration as well as cartilage degradation indicators and systemic inflammation and its impact on quality of life in patients with knee OA.

This study presents a randomized controlled trial design. They will be selected 40 participants diagnosed with knee OA grades II and III, aged 40 and 65 years and BMI \<30 kg / m2 were randomly divided into two groups: participants underwent training (trained group - TG) and not subjected to training ( untrained group - NTG). The participants trained group will undergo a periodized CT protocol of 14 weeks load progression, 3 times a week, with sessions last 15 minutes in the first weeks and will arrive 35 minutes in final weeks, and added 10 minutes between heating and cooling down. All subjects will conduct pre and post CT variables: IMAT thigh (computed tomography); body composition (Dual-energy X-ray absorptiometry - DXA), inflammatory biomarker concentrations: IL-1β, IL-6, IL-10, TNF-α, leptin and adiponectin and joint degradation biomarkers (uCTX-II and sCOMP), performance tests functional (six-minute walk, 30 seconds chair stand test and stair climb test), muscle strength (maximum voluntary isometric contraction - MVIC), WOMAC and KOOS questionnaires, and catastrophizing pain scale. During the training protocol, uCTX-II variables, sCOMP and MVIC will also be evaluated. To compare the groups will be applied the unpaired t-test. When found significant main effects, the Bonferroni test will be used to identify the statistically significant differences. To compare the collections times (pre, during and post TC) for uCTX-II variables, sCOMP and MVIC will be held repeated measures ANOVA with post hoc Bonferroni, and the WOMAC variables, KOOS, DXA, IMAT, functional testing and inflammatory cytokines (pre and post CT) will be held the paired t test. A significance level of 5% (p ≤ 0.05) will be adopted.

Eligibility Criteria:
Inclusion Criteria:

* aged between 40 and 65
* sedentary
* radiographically and clinically diagnosed with knee OA

Exclusion Criteria:

* performed physical therapy or exercise protocol up to 6 months prior to the beginning of the evaluations of this study
* previous knee surgeries
* previous history of trauma to the lower limb
* corticosteroid infiltration in knees in the 30 days prior to baseline
* prosthesis (partial or total) hip or knee arthritis
* use of chondroprotective
* cognitive deficits that compromise the understanding of tests and exercises
* body mass index (BMI) ≥30 kg / m²
* heart disease uncontrolled
* history of muscle injuries severe (above grade I)
* motor deficits due to neuromuscular disease
* cardiac pacemaker use
* chronic diseases
* impaired renal function, or any other medical condition that makes it impossible to participate in this study.