Introduction: Persistent hindfoot pains are very common and prevalent complaints in the Brazilian population. One of the treatments recommended for these conditions in the literature is the use of insoles. However, to use this resource it is necessary that the individual wear closed shoes and this is an obstacle to treatment in cities with hot climate. Thinking about an alternative treatment, the customized slippers with the corrective elements of the insoles can be an alternative to increase adherence to this type of treatment. Objective: To compare different types of hindfoot elements in insoles adapted in slippers in individuals with persistent hindfoot pain.

Methodology: This is a protocol for a controlled, randomized, blinded clinical trial. Eighty participants with persistent hindfoot pain will be evaluated and randomized into two intervention groups: insoles adapted to flip-flops and flip-flops with sham insole. The evaluations will be carried out at baseline (T0), after six (T6) and twelve weeks (T12) of the use of flip-flops, in addition to the follow-up that will be carried out four weeks after the end of the intervention (T16). The primary outcome will be pain, using the Numerical Pain Scale and the secondary outcomes will be: foot function, using the Foot Function Index questionnaire, functional capacity in walking, using the Six-Minute Walk Test and pain catastrophizing using the Scale. of Pain Catastrophizing. Statistical analysis: Data will be analyzed by T-student, Mann-Whitney and repeated measures ANOVA tests and will be analyzed by intention to treat. Ethics and disclosure: This protocol was approved by the Ethics Committee of UFRN/FACISA (number 4,018,821). The results of the study will be disseminated to participants and submitted to a peer-reviewed journal and scientific meetings.

Inclusion Criteria:

• Individuals of both sexes, aged 18 to 65 years;
• Persistent heel pain for at least three months based on self-reported criteria: heel pain accompanying the first steps in the morning, after a period of inactivity, and/or during prolonged weight-bearing;
• Pain intensity between 3 and 8 points, according to the Numerical Rating Scale (NRS) [22];
• Individuals who can wear flip-flop sandals for at least four hours per day for 12 weeks.

Exclusion Criteria:

• Clinical diagnosis of neuropathic pain or neurodegenerative disorders, persistent heel pain due to rheumatic conditions, and previous ankle and foot surgeries;
• Physical therapy treatment in the last three months;
• Corticosteroid injection into feet in the last six months;
• inability to answer study-related questionnaires;
• Individuals scheduled to travel in the next six months.

there is not a plan to make individual participant data (IPD) available to other researchers