Associations between single-leg postural control and drop-landing mechanics in healthy women.

CONTEXT Impaired postural control in single-limb stance and aberrant drop-landing mechanics have been implicated separately as risk factors for noncontact anterior cruciate ligament (ACL) injury, but associations between these variables has not been reported. OBJECTIVE To determine whether there are associations between single-limb postural control and drop-landing mechanics. SETTING University motion-analysis laboratory. DESIGN Single-leg-landing kinematic and kinetic data were collected after participants dropped from a hang bar. Postural-control variables COP excursion and velocity were assessed during single-leg barefoot standing on a force platform. PARTICIPANTS A convenience sample of 24 healthy women. MAIN OUTCOME MEASURES Pearson product-moment correlation coefficients. RESULTS Strong associations were measured between maximal knee-abduction moment and COP excursion (r = .529, P = .003) and average COP velocity (r = .529, P = .003). Strong inverse associations were measured between minimum hip-flexion angle and COP excursion (r = -.521, P = .003) and average COP velocity (r = -.519, P = .003). CONCLUSIONS Participants with decreased postural control had higher knee-abduction moments and a more extended hip on landing, which have been implicated separately as risk factors for ACL injury. A longitudinal prospective analysis is needed to determine whether force-platform postural-control measures can identify athletes at risk for ACL injury.