Effects of neuromuscular-cognitive training on ACL injury risk factors in female volleyball athletes with dynamic knee valgus: Protocol for a randomized controlled trial

BACKGROUND: Female volleyball athletes are at high risk of non-contact anterior cruciate ligament (ACL) injuries, particularly during high-impact activities such as single-leg landings after a spike or rapid directional changes. These movements often occur under cognitively demanding conditions, including split attention, fast decision-making, and responses to unpredictable stimuli, which can impair neuromuscular coordination and exacerbate motor deficits, such as dynamic knee valgus (DKV). Although neuromuscular training programs exist, many have not been specifically tailored for female volleyball athletes or integrated cognitive demands mimicking real-game scenarios. OBJECTIVE: This study protocol describes a planned randomized controlled trial designed to evaluate the effects of an eight-week neuromuscular-cognitive training protocol in reducing risk factors for ACL injury among female volleyball players with DKV. METHODS: This study protocol describes a two-arm, parallel-group randomized controlled trial that will assess an eight-week neuromuscular-cognitive training program for female volleyball players aged 18-23 with clinically confirmed DKV and competitive experience. Participants will be randomly assigned to either an experimental group that will receive integrated neuromuscular-cognitive training or a control group that will receive standard neuromuscular training without cognitive components. The intervention will combine sport-specific motor tasks with cognitive challenges aimed at improving neuromuscular control and decision-making during dynamic movements. The primary outcome will be single-leg landing kinematics under cognitive and non-cognitive conditions. Secondary outcomes will include cortical brain activity, lower limb muscle activation, single-leg balance, muscle strength, and knee joint proprioception. Additional measures will involve participant feedback on training intensity and satisfaction. DISCUSSION: If effective, this protocol will provide evidence for integrating cognitive training into ACL injury prevention programs for female volleyball athletes. By examining the interaction between cognitive load and neuromuscular control under sport-specific conditions, this study may contribute to a better understanding of cognitive and neuromuscular mechanisms involved in injury prevention and inform future preventive strategies in sports medicine.