Interacting constraints and the emergence of postural behavior in ACL-deficient subjects

In this study, the authors examined how task, informational, and sensorimot or system constraints influence postural control. Postural behavior of subj ects with fn = 15) and without (n = 15) a key sensorimotor system constrain t, anterior cruciate ligaments (ACLs) in I knee, was examined during 1- and 2-legged stance with and without vision. Postural control was assessed on a commonly used postural sway meter and on a dynamic stabilometer. Data on postural sway characteristics were obtained for 30 s under 6 different cond itions: standing, with eyes open and closed, on both legs, on the injured l eg, and on the noninjured leg. The interaction of task, informational, and sensorimotor constraints was observed only on the dynamic stabilometer and not the postural sway meter. Vision was the most important informational co nstraint on postural central for subjects on the dynamic stabilometer, part icularly for the ACL-deficient group standing an the injured leg. Under mor e static task constraints,ACL deficiency did not prove a significant disadv antage, because vision was confirmed as a significant source of exproprioce ptive information. The results support the functionality of using dynamic t asks such as a stabilometer in assessing postural behavior of subjects with sensorimotor system constraints.