PROLONGED ANKLE BRACE APPLICATION DOES NOT AFFECT THE SPECTRAL QUALITIES OF POSTURAL SWAY

Abstract

In an attempt to prevent recuring ankle sprains, many athletes have resorted to using various external support devices over a course of a season in order to protect the ankle joint. Spectral analysis of center of pressure (COP) data allows for investigation of the relative contribution of the different sensory systems used in controlling posture. Potential long-term effects of ankle bracing on postural sway are not well known. Therefore, the purpose of this study was to determine if prolonged ankle brace application affects selected spectral qualities of medial-lateral (ML) and anterior-posterior (AP) COP during a one-legged stance. The effects of three independent variables (treatment: brace, control; frequency bin: 0–20%, 20–40%, 40–60%, 60–80%, and 80–100% of area; and time: pretest, immediately following ankle brace application, and after 1-, 2-, 3-, and 4-, days brace wearing) on mean frequency amplitude for both AP and ML COP excursions were examined. Twenty-eight healthy volunteers (22.18 ± 1.90 yrs, 173.0 ± 8.02 cm, 72.13 ± 12.13 kg) participated in this study. The first testing session consisted of 10, 20-second, trials (5 without and 5 with an ankle brace). Subjects in the brace group were instructed to wear the brace 8 consecutive hr · day−1. For all subsequent testing sessions, measurements for both groups were taken wearing an ankle brace. A significant difference was found between frequency bins at each time for the mean frequency of ML (F4,108 = 495.8, P < .0001) and AP (F4,108 = 79.751, P < .0001) COP. Mean frequency amplitudes of ML and AP COP were greater at lower frequency ranges than at higher frequency ranges during all 6 measurements (P < .05). No difference was found between the brace and control conditions (P > .05). Application of an ankle brace may not require a modification in the postural control strategy during a one-legged stance in healthy ankles.