title: Alterations of kinetic characteristics in step up and over test in patients with anterior cruciate ligament deficiency.
abstract: The purpose of this study is to investigate the alterations of kinetic characteristics in the step up/over test in patients with acute and chronic anterior cruciate ligament (ACL) deficiency. Twenty acute, twenty chronic ACL-deficient (ACLD) patients, and forty healthy controls participated in this study. The step up/over test was performed on a clinical force platform system to obtain the following variables: movement time, lift-up index and impact index. The percentages of the indexes from the stepping leg and time of step-up and swing- over were further calculated. These variables were examined statistically by using mixed repeated measure analysis of variance to reveal the differences between groups and between limbs. Smaller lift-up forces and longer swing-over time in both ACLD groups than those in the control group were found. One exception was the lift-up index in the affected side condition of the acute ACLD group, which was not significantly different from the controls. A reduced contribution to the impact index from the affected stepping leg was also found in the acute ACLD group. The acute ACLD group showed no significant change in their step-up strategy at the affected limbs, but they may have a poorer eccentric control of the affected knees on the step and thus put a larger portion of loading onto the unaffected landing leg. Our results indicated the lift-up index, swing-over time and load- distributing strategy at impact may be important parameters in monitoring functional recovery in patients with ACL deficiency. The detected alterations in these parameters could be used as a reference to design proper rehabilitation exercises for these patients. Key pointsThe lift-up index and the time of swing-over could be important parameters for indentifying functional impairments in patients with ACL deficiency.The differences between limbs were found only in the acute ACLD group with a larger lift-up index and smaller load-distribution at impact on the affected limb.The step up/over test on the clinical force platform system could be helpful in providing a reference to design proper rehabilitation exercise and to monitor the recovery of the functional ability in patients with ACL deficiency.
authors.forename: Hsiu-Chen
authors.initials: HC
authors.lastname: Lin
authors.forename: Horng-Chaung
authors.initials: HC
authors.lastname: Hsu
authors.forename: Chia-Ming
authors.initials: CM
authors.lastname: Chang
authors.forename: Pei-Wen
authors.initials: PW
authors.lastname: Chiou
authors.forename: Tung-Wu
authors.initials: TW
authors.lastname: Lu
keywords: ACL deficiency; Knee; kinetics; locomotion; step activity