The impact of fatigue on dynamic balance in coopers athletes with chronic ankle instability

Athletes who have successfully regained high sports performance despite prior inversion injuries, and who do not have persistent symptoms, are referred to as "copers" in the literature. The aim of the study was to assess dynamic stability under fatigue in patients with chronic ankle instability in comparison to healthy controls. We conducted a case - controlled study on a group of 60 young, physically active individuals aged 29.8 ± 4.6. They were divided into 3 groups: I - unilateral ankle instability n = 14, II - bilateral ankle instability n = 15, III - no ankle instability, n = 31. All participants filled out questionnaires on the health, the FADI and FADI-S. The study protocol consisted of a dynamic stability measurements by Biodex Balance System, followed by a fatigue test, followed by the series of the same measurements. General stability index value before and value after fatigue test did not differ significantly. The differences between groups in measurements taken before fatigue test (F (2.49) = 1.59; p = 0.214; η_p² = 0.06) and after fatigue test also proved insignificant (F (2.49) = 1.28; p = 0.286; η_p² = 0.05). The incidence of structural ankle instability did not affect functional stability. "Copers" had efficient neural-muscular control in dynamic stabilography tests.