The role of placebo and nocebo in the effectiveness of dynamic tape on the postural control, electrical muscle activity of selected muscles, and the performance of athletes with chronic ankle instability

This study aimed to determine the impact of placebo and placebo mentality on the effectiveness of dynamic tape on posture control, the electrical activity of selected muscles, and functional performance in athletes with chronic ankle instability.

A clinical trial, crossover design, double-blind, randomized on 32 patients. A lottery is used for randomization.

The study will take place in the sports rehabilitation laboratory at Arak University. The participants will be athletes with chronic ankle instability. They will visit the laboratory on three separate days to perform tests under three different taping expectations.

The inclusion criteria: a history of ankle sprain two or more times; a sensation of fear and instability in ankle function; a score of 24 or lower on the Cumberland Ankle Instability Tool (CAIT ≤ 24); and confirmation of ankle functional instability; no history of using dynamic tape). The exclusion criteria include a history of previous surgery on the lower limb; a history of fracture or acute injury to the musculoskeletal structures or joints of the lower limb (such as sprains, fractures, etc.) within the three months prior to the study.

We will conduct this study with one group under three different conditions, each with a different intervention: 1. The first intervention involves creating a positive expectation (placebo) about the dynamic tape. 2. The second intervention involves creating a negative expectation (nocebo) about the dynamic tape. 3. The third intervention involves creating a neutral expectation about the dynamic tape. 4. The fourth intervention: the measurement is performed in conditions without taping.

Posture control, the electrical activity of selected muscles, and functional performance

Participants are required to visit the sports science laboratory at Arak University on three separate days. Evaluations will be conducted under three conditions: positive mental induction, negative mental induction, and neutral, over three different days (sessions). The lottery is used to determine which criteria will be used to evaluate the tests in each session. At the start of the first session, the subject selects one of three different conditions through a lottery, and the tests are carried out accordingly. In the second session, a draw is conducted between the two remaining conditions. Then, in the third session, the third condition is tested.

The participants are unaware of the intervention due to their positive, negative, and neutral mental expectations. Additionally, the collected data is provided to the analysts in code form, and they are unaware of the evaluated mentalities.