Anterior Cruciate Ligament Reconstruction And Alterations In Biomechanical Landing-stability And Decision-making Quality During Unanticipated Jump-landings

Abstract

In team sports such as football, athletes are often required to adapt their motor plans in response to unpredictable/unanticipated visual information on the playing field under time pressure. These unanticipated movements lead to high-risk knee mechanics (landing safety decrements) which elevates injury/re-injury risk compared to pre-planned tasks. PURPOSE: To compare the magnititude of landing safety decrements ('unanticipated-landing costs') in athletes with and without a history of anterior cruciate ligament (ACL) reconstruction. METHODS: Matched-paired cross-sectional data from 14 ACL-reconstructed (females: n=6, mean age: 23±5 SD, BMI: 23±4 Kg/m 2 , Tegner activity score (TAS): 8±1; time since surgery: <2 years) and 14 healthy individuals (females: n=6, mean age: 26±3, BMI: 22±2 Kg/m 2 , TAS: 8±2) were analyzed. Participants performed countermovement-jumps with pre-planned or unanticipated single-leg landings on force plates. Landing kinetics (peak vertical ground reaction forces; pGRF), postural landing stability (center of pressure, time to stabilization), and decision-making quality (number of landings on wrong foot) were assessed. RESULTS: In both groups, the unanticipated condition resulted in significantly higher pGRF (ACL: 52 ± 4 vs. 56 ± 5 N/Kg, p = 0.004; Controls: 55 ± 7 vs. 59 ± 5 N/Kg, p = 0.021) and decision errors (ACL: 0 ± 0 vs. 3.2 ± 2, p = 0.001; Controls: 0 ± 0 vs. 2.1 ± 1.7, p = 0.003) compared to the pre-planned condition. The magnitude of unanticipated-landing costs did not differ significantly between groups (p>0.05) for all the outcomes assessed. CONCLUSION: Unanticipated-landing costs occurred in both groups, but their magnitude was not significantly higher in the ACL-reconstructed group. To further elucidate the ACLinjury/re-injury risk associated with unanticipated movements, future biomechanical studies measuring joint kinetics and kinematics are warranted.