Visual Processing and Interference Performance Influences on Knee Angular Impulse in ACLR Individuals: A Cognitive-Biomechanical Analysis of Drop-Jumps

Background: Visual processing speed and cognitive interference control play crucial roles in athletic movements and anterior cruciate ligament (ACL) injury risk. The relationship between these specific cognitive functions and biomechanical performance following ACL reconstruction (ACLR) remains poorly understood. Given this, we aim to investigate cognitive performance differences between ACLR individuals and matched controls during drop-jump tasks and examine knee angular impulse patterns and their relationship to cognitive function. Methods: Thirty-two females (16 anterior cruciate ligament reconstruction, 16 controls; age 20±1 years) completed cognitive assessments including the Stroop Color and Word Test, Trail Making Test, Digit Span Memory Test, and visual/auditory reaction time tests. Participants performed drop-jumps under four conditions: standard, choice, visual-cued, and audio-cued. Knee angular impulse was calculated for eccentric, concentric, and net phases during landing. Binomial logistic regression identified cognitive predictors distinguishing groups, followed by factorial analyses of variance to assess knee angular impulse differences. Spearman's rank correlation coefficients examined relationships between cognitive performance measures and knee angular impulse phases. Results: Three cognitive predictors distinguished groups: cognitive interference score, visual simple reaction time, and visual complex reaction time (χ²(3)=55.090, p < 0.001). The ACLR group demonstrated faster (shorter) visual reaction times, but impaired interference control compared to controls. ACLR participants showed significantly lower eccentric knee angular impulse compared to controls (p = 0.003, Cohen's d=-0.37), while audio-cued conditions produced higher eccentric knee angular impulse than standard and choice conditions. Despite distinct cognitive profiles, minimal correlations emerged between group-distinguishing cognitive variables and eccentric knee angular impulse, suggesting parallel rather than integrated adaptations. Discussion: ACLR individuals exhibit distinct cognitive-biomechanical profiles characterized by enhanced reactive capabilities alongside reduced interference control and persistent protective movement strategies. Results support incorporating cognitive assessment and training into ACL rehabilitation protocols.