Eight weeks of visual perturbation training effects on unanticipated cutting lower-limb biomechanics and errors in male athletes following anterior cruciate ligament reconstruction: a randomized controlled clinical trial (RCT).

backgroundAnterior cruciate ligament (ACL) tears are among the most common knee injuries, leading to joint instability, muscle weakness, and disrupted motor coordination. The neuromuscular consequences of ACL injury extend beyond the joint and surrounding musculature and also involve reorganization of the central nervous system. Current return-to-sport training protocols may not adequately restore subtle neuromuscular deficits associated with ACL injury neuroplasticity. Specifically, impaired neuromuscular control under visual or cognitive perturbations. These neuromuscular deficits are especially evident during unanticipated cutting maneuvers, which place high demands on rapid motor control and decision-making.

methodsTwenty-four ACLR male athletes who had returned to sport were randomly assigned to a visual-cognitive neuromuscular training (VCNT) group (n = 12) or the VCNT with added visual perturbation via stroboscopic glasses (VCNT-S, n = 12). The primary outcome was lower-limb biomechanics during unanticipated cutting; secondary outcomes included cutting-task cognitive error. participants performed an unanticipated cutting maneuver (30-40°change of direction guided by two taped ground lines) in a biomechanics lab before and after an 8-week intervention (3 sessions/week). The outcome assessor was blinded to group allocation.

resultsAll 24 participants (12 per group) were analyzed; no adverse events occurred. Compared with VCNT, VCNT-S showed greater reductions in involved knee abduction torque (mean difference: -0.08 Nm/kg, 95% CI: -0.14 to -0.02) and involved ground reaction force (mean difference: -0.39 BW, 95% CI: -0.55 to -0.23). VCNT-S also demonstrated greater improvements in involved knee flexion ROM (mean difference: +7.71°, 95% CI: 2.26° to 13.16°), uninvolved peak knee flexion (mean difference: +5.68°, 95% CI: 3.03° to 8.33°), and uninvolved peak hip flexion (mean difference: +7.64°, 95% CI: 3.50° to 11.78°), as well as greater reductions in involved knee abduction ROM (mean difference: -1.97°, 95% CI: -3.15° to -0.79°) and uninvolved peak knee abduction (mean difference: -2.85°, 95% CI: -5.52° to -0.18°). Cutting-task errors were reduced more in VCNT-S (-40.5% vs. -14.7%; mean difference: -25.8%, 95% CI: -47.2% to -4.4%; p = 0.02).

conclusionIncorporating visual perturbation into neuromuscular training improved lower-limb biomechanics and reduced cognitive errors during unanticipated cutting compared to standard training. These surrogate outcomes suggest potential for modifying re-injury risk factors, through direct injury endpoints were not measured.

trial registrationIranian Registry of Clinical Trials (IRCT) at https://www.irct.ir/search/result?query=IRCT20250314065070N1 , IRCT20250314065070N1, Date of Registration: 2025-06-03, (retrospective registration).