Related Experiment Video
Updated: Aug 18, 2026
Early Weight-Bearing Rehabilitation Protocol After Anterior Cruciate Ligament Reconstruction
Published on: March 1, 2024
The Influence of Visual Disruption and Dual-Task Conditions on Single-Leg Vertical Hop Performance 1 to 5 Years After
Keith A Knurr1, Zach Lorbeck2, Emma Rutherford2
1Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, Badger Athletic Performance Program, University of Wisconsin-Madison, Madison, Wisconsin, and Doctor of Physical Therapy Program, University of Wisconsin-Madison, Madison, Wisconsin.
Background:
Current return-to-sport (RTS) testing after anterior cruciate ligament reconstruction (ACLR) lacks the visual and cognitive demands consistent with most sporting environments. Implementing RTS tests that challenge these systems may better assess RTS readiness, potentially reducing reinjuries. This study assessed the effects of additional visual-cognitive demands on single-leg vertical hop (VH) performance.
Hypothesis:
Visual-cognitive conditions would result in reduced hop heights, success rates, and ground reaction force (GRF) impulses for both healthy controls and participants at 1 to 5 years post-ACLR, with greater reductions in those post-ACLR.
Study Design:
Cross-sectional.
Level Of Evidence:
Level 3.
Methods:
A total of 30 ACLR and 30 healthy control participants completed 3 successful trials for each of 4 randomized VH conditions: VH, VH + stroop test (Stroop), VH + stroboscopic visual disruption (SVD), and VH + SVD + ST (Stroop-SVD). Between-conditions and between-limb differences in success rates, hop height, and GRFs were assessed using linear mixed effects models, with sex as a covariate.
Results:
Across all groups, success rates were lower in SVD (-17.1%; P < 0.01), Stroop-SVD (-20.3%; P < 0.01), and Stroop (-5.6%; P = 0.02) compared with VH (89.1%). Hop height was lower in SVD (-0.9 cm; P < 0.01) and Stroop-SVD (-1.0 cm; P < 0.01) than VH (19.6 cm). In the ACLR group, hop height was lower in the surgical limb compared with the nonsurgical limb (-1.2 cm; P < 0.01), across all test conditions.
Conclusion:
SVD and Stroop-SVD conditions resulted in reduced success rates and hop height in both groups. Although participants post-ACLR displayed surgical limb VH deficits, SVD and Stroop-SVD did not further impair ACLR group performance compared with healthy controls.
Clinical Relevance:
The VH protocol was found to be reliable and challenged participants enough to induce errors in both healthy participants and those 1 to 5 years post-ACLR.