Sample size
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A pilot sample size of 20 participants (to cover a possible dropout of 25%) was conducted by considering the post-treatment Medial-Lateral dynamic stability index as the main variable. METCALC® software (Ver. 5.43; Technische University Wien) was used to achieve a power of at least 0.8 at a significant level of α = 0.05, and an effect size of 1.49. Finally, 14 subjects (7 subjects per group) were recruited to suffice the target power.