*2.2. Sample Size*

The sample size was calculated with software from Unidad de Epidemiología Clínica y Bioestadística. Complexo Hospitalario Universitario de A Coruña. Universidade A Coruña (www.fisterra.com) to detect a significant difference in the deviation of the axes of IMTT and PPH during static and dynamic test wearing high heels versus barefoot similar in another study with 15 recruited subjects [34] where hallux dorsiflexion decreased while wearing high heels from 26.6 ± 2.33◦ to 22.5 ± 1.62◦ in barefoot condition with 80% statistical power. Here, β = 20% with a 95% interval of confidence and α = 0.05 using a 2-tailed test. Thus, at least 61 participants were required. Furthermore, assuming a loss to follow up rate of 15%, at least 71 participants were included in the study. However, recruited 80 subjects.
