Article

To understand why subjects with chronic ankle instability (CAI) have frequent
sprains, one must study the preparation/reactions of these subjects to situations
related to ankle inversion in real life. In the present pilot study, we examined
whether subjects with CAI altered their neuromuscular control and reflex
responses during and after ankle perturbations in landing. EMG signals were
collected from the tibialis anterior (TA), peroneus longus (PL), medial
gastrocnemius (MG), and gluteus medius (GLM) of both legs in 9 subjects with CAI
and 9 subjects with intact ankles (control). A trapdoor was used to produce an
ankle inversion of 25 degrees with the left leg (control) or the affected leg
(CAI) in 0%, 50% or 100% of the landing trials. As compared to controls, subjects
with CAI had increased proactive activity in the contralateral side prior to
touchdown during landing trials with 50% (PL) and 100% (PL and MG) chance of
inversion (all, p < 0.05). The increase proactive control on the contralateral
side could be part of a strategy to smooth the impact of landing on the affected
side in subjects with CAI. Following touchdown, the CAI group showed decreased
ipsilateral short latency reflex (SLR) responses in all test conditions both in
distal (PL and MG) and in proximal muscles (GLM) on the affected side (all, p <
0.05). Finally, subjects with CAI adjusted their reflex gain differently as
compared to controls when exposed to a possible inversion. Overall, individuals
with CAI displayed different neuromuscular strategies from controls while
landing.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS