Kinetics During the Tuck Jump Assessment and Biomechanical Deficits in Female Athletes 12 Months After ACLR Surgery.

Background: Residual interlimb deficits after anterior cruciate ligament reconstruction (ACLR) can lead to functional maladaptation and increase the risk of reinjury. The tuck jump assessment (TJA) may offer a more effective evaluation of ACLR status as compared with traditional tasks owing to increased risk of altered landing mechanics, asymmetrical landing, and increased knee valgus attributed to the cyclical nature of the task. However, it remains unclear whether altered TJA kinetics resolve over time or persist through return-to-play phases of rehabilitation.

Purpose: To examine longitudinal kinetics, asymmetries, and functional performance deficits during TJA at 9 and 12 months after ACLR in female athletes at high risk of reinjury.

Study Design: Cohort study; Level of evidence, 2.

Methods: Female athletes (ACLR, n = 24; controls, n = 19; total, N = 43) performed a single trial of TJA on dual-force plates at 2 time points. The ACLR group (mean ± SD age, 16.8 ± 1.9 years) was tested at 9 and 12 months after surgery, and the control group (16.5 ± 3.6 years) was tested at similar time points. All athletes participated in similar sports and had comparable activity levels. Discrete time point analysis and statistical parametric mapping were used to identify deficits within each group.

Results: At 9 months after surgery, the ACLR group exhibited significant interlimb differences in all kinetic variables ( < .05), which persisted at 12 months with only small reductions in magnitude. As compared with controls, the ACLR group demonstrated a persistent offloading strategy in the involved limb by exhibiting larger interlimb asymmetries for a range of kinetic variables and a greater vertical ground-reaction force in the uninvolved limb during most of the stance phase at both time points ( < .001). Distinct differences in functional performance of TJA were evident at both time points, characterized by lower peak vertical ground-reaction force, peak center of mass displacement, and relative vertical leg stiffness and longer ground contact times ( < .001).

Conclusion: This study revealed that young female athletes after ACLR exhibit persistent interlimb deficits and functional maladaptations up to 12 months after surgery. The TJA identified significant biomechanical impairments to both limbs, resulting in asymmetrical loading and altered movement strategies as compared with healthy controls. Despite some improvements, athletes with ACLR continued to demonstrate offloading to the uninvolved limb, indicating incomplete neuromuscular recovery.