Narrow Results

Analysis of knee kinematics and ground reaction forces (GRFs) is widely used to determine compensatory mechanisms of people with anterior cruciate ligament deficiency (ACLD). However, the practicality of the measurements is subject to their reliability during different trials. This study aims to determine the reliability and repeatability of knee joint rotations and GRFs in people with ACLD during stair ascent. Eight participants with unilateral ACL-deficient knees performed five trials of stair ascent with each leg. The movements were captured by VICON motion analysis system, and GRF components were recorded using force plate. Three-dimensional tibiofemoral joint rotations were calculated. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of multiple correlation (CMC) were calculated ACL-deficient legs showed lower absolute reliability during swing ($\mathrm{\text{SEM}}=1.6$–6.4) than stance phase ($\mathrm{\text{SEM}}=0.6$–2.2) for knee joint rotations. Moderate to high average measure ICCs (0.59–0.98), relative reliability, were achieved for injured and uninjured sides. The results also demonstrated high repeatability for the knee joint rotation ($\mathrm{\text{CMC}}=0.78$–0.97) and GRF ($\mathrm{\text{CMC}}=0.87$–0.99). The outcomes of this study confirmed the consistency and repeatability of the knee joint rotations and GRFs in ACL-deficient subjects. Additionally, ACL-deficient legs exhibited similar levels of reliability and repeatability compared to contralateral legs.