Kinematic adjustments of the ankle joint complex on different unstable surfaces

Abstract

INTRODUCTION: There are few studies approaching the bodily reactions of healthy individuals while performing exercises on unstable surfaces, although the training effects – exercise chronic effects - are well studied. OBJECTIVE: The goal of this study is to describe the ankle and rear foot region osteoarticular kinematic during this interaction. METHODS: Eighteen volunteers participated in the study. The ankle region osteoarticular displacement was studied in three different surfaces: AIREX® Balance-pad, BOSU® and Ground (control). Statistical analysis was performed using ANOVA and Tukey test, considering a significance level of 0.05. RESULTS: The position of the ankle joint in the sagittal plane was greater in the BOSU® than in the AIREX® (p < 0.001) and ground (p < 0.001). The ankle was close to the neutral position in the AIREX® and on the ground. With BOSU, the dorsiflexion was accentuated. Considering the frontal plane, there was no difference in the rear foot position. Moreover, the variability in the ankle region position in sagittal and frontal planes was higher in BOSU® than AIREX® (p < 0.001) and ground (p < 0.001). The mean frequency of the ankle position in the sagittal plane was greater in the BOSU® than on the ground (p < 0.001), and, in frontal plane, the rear foot frequency displacement was largest in the BOSU® than in the AIREX® (p < 0.001) and on the ground (p < 0.001). CONCLUSION: There were observed differences in ankle region postural control strategies in the BOSU® condition when compared with the other surfaces tested. The ankle and rear foot oscillations increase and there is a greater dorsiflexion for the postural control under the most unstable condition - BOSU.