MERItest<sup>TM</sup>-A multidimensional model for functional evaluation at 6 months after ACL reconstruction.

At 6 months following anterior cruciate ligament reconstruction (ACLR), athletes transition from structured rehabilitation toward sport-specific reconditioning, a critical phase characterised by elevated re-injury risk and high variability in recovery trajectories. Yet clinical assessments at this milestone often rely on unidimensional metrics such as hop distance or limb symmetry indices (LSI), which fail to capture the complexity of functional readiness. This gap between apparent recovery and underlying neuromechanical deficits may contribute to persistently high re-injury rates, even in athletes who meet conventional return to sport criteria. The MERItest TM is presented as a structured, multidimensional evaluation framework designed to enhance clinical reasoning at the 6-month follow-up. Rather than introducing new isolated tests, it integrates three complementary domains: monoarticular isometric strength testing, three-dimensional biomechanical analysis of functional tasks (jumping, hopping and running), and psychological readiness assessment using the anterior cruciate ligament-return to sport after injury (ACL-RSI) questionnaire, into a unified interpretive model. The isometric component quantifies contractile capacity of key muscle groups, the three-dimensional biomechanical analysis captures movement strategies and intersegmental coordination under dynamic loading, and the psychological assessment contextualises motor behaviour through confidence and risk appraisal. By examining not only how much force an athlete produces, but how movement is organised and experienced, the framework enables identification of residual deficits and compensatory strategies often overlooked by performance-based testing alone. The MERItest TM proposes a shift from checklist-driven clearance decisions toward multidimensional profiling and individualised interpretation of recovery patterns, thereby supporting more informed clinical reasoning. Its

Design: balances biomechanical rigour with clinical feasibility, supporting integration in both research and specialised clinical environments. Although prospective validation is required to confirm its predictive utility, this framework reframes the 6-month evaluation as a diagnostic opportunity rather than a binary clearance checkpoint. Level of evidence Level V.