A Comparison of Core Muscles Onset Timing between Healthy Subjects and Subjects after Anterior Cruciate Ligament Reconstruction (ACLR) during Drop Landing Task

Most knee anterior cruciate ligament injuries happen during challenging activities like drop landing. Core muscles feedforward activity can control challenging activity and prevent injury. The aim of this study was to investigate core muscles feedforward activity in patients after ACLR and healthy group. Eleven males with ACLR, aged 18-40 years old, with at least 6-24 months after reconstruction surgery and eleven mathed males as a control group were enrolled in this study. Muscle activity of Geluteus medius, Abdominis external oblique, Quadratus lumborum and erector spine in landing was recorded in both groups. Cross hop functional test and IKDC questionnaire were completed and compared in both groups. Significance level was considered less than 0.05 for all analysis. score of IKDC subjective questionnaire and cross hop functional test in control group were significantly more than the score of patients (p≤0.000 questionnaire, p=0.039 functional test). Feedforward response time for Gluteus medius (p=0.028), Abdominis external oblique (p=0.03) and erector spine (p=0.028) in control group was significantly sooner than patients with ACLR. Quadratus lumborum was not significantly different in these two groups (p=0.191). muscles activity and their patterns in these groups observed different. Patient group did not have appropriate feedforward activity; they also demonstrated a decrease in functional test and IKDC questionnaire. These results necessitate a appropriate rehabilitation program.