Author(s): KONISHI, M., NICHOLAS, C.C.2, TAKEMURA, M.1, CORTES, N.2,3, Institution: UNIVERSITY OF TSUKUBA, Country: JAPAN, Abstract-ID: 440

INTRODUCTION:
Anterior cruciate ligament (ACL) injuries occur frequently in open-skill (unanticipated/unplanned) sports, and poor decision-making may be a risk for noncontact ACL injury (1). While athletes experience high-level neurocognitive demands within unanticipated athletic situations, contemporary ACL injury prevention programs (IPPs) focus typically on improving closed-skill (anticipated/planned) tasks/exercises alone (e.g., planned jump landing (2)). Contrastingly, ACL IPPs that contain more unplanned tasks/exercises more characteristic of open-skill athletic situations are uncommon. Therefore, this study aimed to investigate the acute effect of unplanned versus planned hop-landing training on decision-making and knee biomechanics during unanticipated side-step cutting motions.
METHODS:
Thirty-two recreational athletes (16 female, 16 male) were assigned randomly to the unplanned training group (UT-G) or the control group (CON-G). Both groups completed dominant-leg training involving three multi-stage athletic tasks: hop-landing from a 30cm high box (HL30) + 45° side-step cutting; HL30 + sticking the landing; HL30 + forward linear running. For each task, 2 blocks × 10 trials were completed (total = 60 trials). The UT-G performed unplanned training using three randomly ordered light stimuli triggered by a wireless sensor (Swift Neo, Swift Performance, Australia): each stimulus cued specifically one of the three athletic tasks during the HL30. The CON-G performed planned training: each stimulus was presented before the HL30. During training, errors were counted for each task and designated as deviations from instructions that defined a successful trial. Error rate was calculated: number of error trials ÷ 60 total trials. Three-dimensional biomechanical data were collected from the dominant limb for all athletic tasks before and after training. Knee peak kinematic/kinetic values within 0-50% of stance phase during the unanticipated 45° side-step cutting tasks were extracted from the data. Task error rate and knee biomechanical values were analysed using a two-way repeated-measures ANOVA to determine the effects of group, training, and any interactions.
RESULTS:
There were significant interactions for group and training for task error rate (F(1.32) = 8.55, P = 0.01) and peak knee abduction angle during unanticipated side-step cutting (F(1.32) = 6.56, P = 0.02). Specifically, for the UT-G only, these variables changed beneficially after training.
CONCLUSION:
Only the UT-G improved the task error rate and knee biomechanics linked to noncontact ACL injury during unanticipated side-step cutting. Incorporating athletic tasks under neurocognitive demands into ACL IPPs may contribute to more optimal preparations for open-skill sporting environments. Future research should explore the mechanisms underlying the observed biomechanical improvements.
REFERENCES:
1) Swanik et al., Am J Sports Med, 2007
2) Huang et al., Am J Sports Med, 2020