Asymmetry of Single-Leg Vertical Hop Performance and Biomechanics in Adolescent Athletes With Anterior Cruciate Ligament Reconstruction.

OBJECTIVE

To assess single-leg vertical hop (SLVH) symmetry in adolescent athletes with anterior cruciate ligament reconstruction (ACLR), comparing injured to uninjured limbs.

DESIGN

Retrospective cohort study.

METHODS

Nineteen patients (15 female; mean age=16.3 years; mean=9.2 months post-ACLR) underwent three-dimensional motion analysis during SLVH. Hop performance and biomechanics were compared between ACLR and contralateral limbs using Wilcoxon signed rank tests.

RESULTS

Hop height was significantly lower for the ACLR limb compared with the contralateral side (P = .028), with a median limb symmetry index (LSI) of 92.3%. Biomechanical variables demonstrated asymmetry, including peak knee and ankle flexion angles, peak knee flexion moment, total power generation, total power absorption, and percent power absorption contributed by the knee (all P ≤ .037) even in participants who achieved hop height symmetry (LSIheight ≥90%).

CONCLUSION

Adolescent athletes in late-stage rehabilitation post-ACLR had interlimb asymmetry of biomechanics during the SLVH, indicating deficiencies of their ACLR limb and decreased readiness for return to sport. JOSPT Open 2026;4(3):321-327. Epub 18 May 2026. doi:10.2519/josptopen.2026.0199.