The recruitment of potential participants is suspended due to the covid-19 pandemic.

The main objective of this trial is To evaluate the effect of an ankle and foot muscle strengthening program on pain, analgesic consumption, functionality, and lower limb biomechanics during gait in individuals with knee osteoarthritis.

A randomized controlled trial will be performed with 76 patients with knee osteoarthritis. The participants will be randomly assigned into either a control group (no exercises; they will keep their recommended clinical treatment) or an intervention group which will receive 8-week physical therapy exercises, three times per week, under the supervision of a physiotherapist. Every exercise has its own progression depending on the subjects' execution, increasing in intensity and difficulty.

The subjects will be evaluated in 3 different moments (Baseline, immediately after treatment and 8 weeks follow-up).

The hypothesis of this study is that the intervention group will decrease pain and medication intake, and improve functional performance, increase isometric strength of the feet and production of beneficial biomechanical changes during walking compared to the control group.

Inclusion Criteria:

• Knee osteoarthritis (KOA) based on clinical and radiological criteria of American College of Reumathology;
• KOA (Grade II and III - Radiological classification of Kellgreen and Laurence) in medial compartment of knee;
• Knee pain between 30 and 80 on the visual analogue scale;
• BMI < 35 kg/m2.

Exclusion Criteria:

• KOA isolated (Grade II and III - Radiological classification of Kellgreen and Laurence) in lateral compartment of knee;
• Lower limb strength training (3 times per week);
• Wear minimalist shoes for at least 6 hours a day and 5 days a week;
• Physical therapy in the previous 3 months;
• Having received steroid injections and hyaluronic acid intra-articular knee in previous periods of three and six months respectively;
• Previous history of surgery on knees, ankles and hips in the last 2 years;
• Neurological disease;
• Inflammatory arthritis (eg. rheumatoid arthritis);
• Asymptomatic OA of one or both knees.

All data collected during the trial will be compiled electronically. Data integrity and validity will be verified at the time of data entry (edit checks). The project manager and research assistant will regularly monitor the study datasets and make recommendations regarding necessary protocol modifications or termination of all or part of the study. Participant data that underlie the results reported in this paper will be shared after blinding (text, tables, figures, appendices), immediately following publication. In addition, the study protocol and clinical trial report (both with the planned statistical analysis) will be made available by the researchers who proposed the methodology. Requests for data or any form of analysis should be directed to glauko.ft.andre@hotmail.com or tania@ufscar.br. Requesters will be asked to sign a data access agreement.

Participant data that underlie the results reported in this paper will be shared after blinding (text, tables, figures, appendices), immediately following publication.

Requests for data or any form of analysis should be directed to glauko.ft.andre@hotmail.com or tania@ufscar.br. Requesters will be asked to sign a data access agreement.