Article

Knowledge about the non-linear dynamical pattern of postural sway may provide
important insights into the adaptability (flexibility) of human postural control
in response to everyday stresses imposed on the body. A commonly used non-linear
tool, i.e. recurrence quantification analysis, was chosen to investigate the
effect of prior anterior cruciate ligament injury on the deterministic pattern of
postural sway under different conditions of postural and cognitive difficulty. In
double leg stance, as postural difficulty increased from open-eyes to closed-eyes
and rigid-surface to foam-surface, the centre of pressure regularity
(%determinism) increased as well. In comparison to healthy counterparts, subjects
with prior anterior cruciate ligament injury produced more regularity when
maintaining balance on their injured leg. Also, for both the double and single
leg stance balance conditions, the performance of a secondary cognitive task (a
backward digit span task) caused less center of pressure regularity than the
single postural task, which suggests that both study populations required the
same amount of cognitive involvement for maintaining balance. Center of pressure
dynamic patterns exhibited by the anterior cruciate ligament deficient patients
were more regular than those of the healthy controls indicating "complexity loss"
and may be indicative of the reduced adaptability (flexibility) of a balance
system to sudden perturbations.
CI - Copyright 2010 Elsevier B.V. All rights reserved.

Langue : ANGLAIS