Abstract
BACKGROUND: Current return-to-sport screening paradigms after anterior cruciate ligament (ACL) injury are inadequate as they fail to reflect cognitive-motor sports demands. This pilot study aimed to evaluate dual-task ability in individuals with ACL reconstruction (ACLR) using a novel dual-task test paradigm. Specifically, we compared (1) cognitive and motor performance between individuals with ACLR and controls, (2) hop test performance between the injured and non-injured legs within the ACLR group, and (3) performance across test-retest sessions. MATERIALS AND METHODS: Twenty sports active individuals (10 ACLR, 10 controls) performed the dual-task paradigm twice within a week, comprising a cognitive test, a dual-task drop-vertical hop test, and an upper-body hand-tapping test. All tests incorporated a visuospatial working-memory task (cognitive performance), with the latter two additionally engaging attention, decision-making, and inhibitory control (motor performance). Between-group, between-leg, and test-retest differences were analyzed using independent and paired t-tests with Cohen's d effect sizes (ESs). Test-retest reliability was examined using intraclass correlation coefficient (ICC), along with the within-person standard deviation and minimal detectable change. RESULTS: No significant differences were observed between ACLR and controls at the first test session (p = 0.09 - 0.34; ESs = 0.19-0.62 [very small-medium]), although ACLR mean performances were 3.8%-14.1% lower. At retest, ACLR performed significantly worse than CTRL for most outcomes (p = 0.01 - 0.03; ESs = 0.91-1.17 [large]) and showed smaller improvements for a hop test outcome (p = 0.04; ES = 0.97 [large]). No differences were found between ACLR legs, both groups improved across test sessions, and test-retest reliability was excellent for ACLR (ICCs = 0.74-0.97) and ranged from poor to excellent in CTRL (ICCs = 0.19-0.86). CONCLUSIONS: This pilot study demonstrates the feasibility and preliminary reliability of the dual-task paradigm, particularly within the ACLR group. Poorer cognitive, hop, and upper-body test performances and smaller test-retest improvements for the ACLR group suggest persistent dual-task deficits following injury, supporting the paradigm's utility for ecologically valid ACL rehabilitation and return-to-sport assessment.