Postural Control Performance at Different Levels of Task Difficulty in Individuals With Haemophilia

INTRODUCTION: Haemophilia is a congenital bleeding disorder caused by a deficiency of clotting factors VIII and IX. As a result, it leads to joint and muscle impairments that affect postural control performance. OBJECTIVE: To investigate postural control performance in different types of tasks in individuals with haemophilia. METHODS: 19 people with haemophilia (HG) and 16 without haemophilia (CG) were invited to perform postural tasks in the following conditions: bipedal stance on a firm surface with eyes open (BSFO) and eyes closed (BSFC); bipedal stance on an unstable surface with eyes open (BSUO) and eyes closed (BSUC); semi-tandem stance on a firm surface with eyes open (STFO) and closed (STFC); and semi-tandem stance on an unstable surface with eyes open (STUO) and eyes closed (STUC). RESULTS: Differences between the groups were found only in the STUC condition, in which the haemophilia group (HG) showed lower values of peak in the anteroposterior direction (PEAK_AP) (0.35 Hz | 1.29 Hz) and 80% power frequency in the mediolateral direction (FREQ80_ML) (0.48 Hz | 1.61 Hz) than the control group (CG) (p ≤ 0.001). CONCLUSION: People with haemophilia showed less sway compared to healthy individuals in the frequency variable under the condition of a reduced base of support (semi-tandem), on an unstable surface (foam) and with eyes closed. The variables that showed interactions were mainly frequency and velocity. Predominantly, the interactions between groups and conditions occurred in variables in the anteroposterior direction, whose main balance-maintenance strategies involve the ankle and hip.