Article

Subjects with CAI (chronic ankle instability) are slower in activating their leg
muscles when shifting weight (from double to single leg stance; DLS and SLS). We
examined if these delays are associated with longer transition/stabilization
times. This was tested by analyzing the center of pressure (COP) trajectory data
(1) in the DLS phase before onset of transition, (2) in the quasi-stable phase of
the SLS, immediately after the transition phase but before time to stabilization
(TTS) and (3) in the SLS phase after TTS. Data were recorded from 20 subjects
with CAI and 20 controls. The TTS was longer for the CAIs than for controls (3.25
vs. 2.28 s in EO and 3.41 vs. 2.51 s in EC; p<0.001). Similarly, the time of
transition (TTR) was prolonged in CAIs (1.48 vs. 1.14 s in EO and 1.53 vs. 1.20 s
in EC; p<0.05). These prolonged periods came in parallel with an increase in the
ML sway in the quasi-stable phase (mean displacement 2.20 vs. 1.75 cm in EO; 3.37
vs. 2.62 cm in EC; significant for EC p<0.05). The TTR in CAIs was positively
correlated with time onsets of the adductor longus muscle during transitions with
EC (R=0.51, p=0.03). The findings support the use of a weight-shifting paradigm
for the evaluation of balance control in CAI. Specifically, we underscore the
transition phase and quasi-stable phase of the SLS as promising time windows for
documenting balance control deficits in CAI.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS