Acute Effects of Unplanned and Planned Hop-Landing Training on Neurocognitive Function and Knee Biomechanics.

Background: Athletes with decreased baseline neurocognitive function may experience noncontact anterior cruciate ligament (ACL) injury in unanticipated athletic situations. Many ACL injury prevention programs (IPPs) focus on improving closed-skill movements (eg, planned landing). However, the more open-skill movements (eg, unplanned reactive movements) required in unpredictable sports scenarios are commonly absent from ACL IPPs, and the acute effects of open-skill training on neurocognitive function remain unclear.

Purpose: To investigate the acute effects of unplanned versus planned training on neurocognitive function and knee biomechanics associated with ACL injury risk during the side-step cutting motion.

Study design: Controlled laboratory study.

Methods: A total of 32 adult recreational athletes (16 female, 16 male) were randomly assigned to either an unplanned training (UT) group or a control (CON) group. The UT group performed unplanned hop-landing training while the CON group performed planned hop-landing training. Both before and after the training, neurocognitive function was evaluated using the Trail Making Test-part B and Stroop Color and Word Test. Additionally, unanticipated and anticipated side-step cutting tasks were performed while 3-dimensional kinematic and kinetic data for the dominant leg were collected. Neurocognitive test scores and biomechanical variables relevant to ACL injury were analyzed using 2-way repeated-measures analysis of variance to determine the main effects of training, group, and training × group interaction.

Results: Trail Making Test-part B and Stroop Color and Word Test scores significantly improved from pre- to posttraining in both groups (P < .001 for both). There was a significant training × group interaction for peak knee abduction angle during the unanticipated side-step cutting task (pre- vs posttraining: -8.81°± 7.23° vs -7.40°± 7.24° [UT group]; -8.23°± 9.40° vs -9.99°± 9.83° [CON group]; P = .02) and for peak vertical ground-reaction force during the anticipated side-step cutting task (pre- vs posttraining: 3.86 ± 0.59 vs 4.08 ± 0.74 percentage body weight [%BW] [UT group]; 3.70 ± 0.62 vs 3.34 ± 0.62 %BW [CON group]; P = .04).

Conclusion: Study findings showed a significant training × group interaction for knee abduction angle during the unanticipated side-step cutting task with unplanned training and for vertical ground-reaction force during the anticipated side-step cutting task with planned training.

Clinical relevance: Designing ACL IPPs based on the sport type (ie, open skill or closed skill) may contribute to better preparation.