The Effect of Binaural Beats Music-Based Interventions on the Autonomic Nervous System, Considering Kinesiophobia of Reinjuries and Fitness Biomarkers in Professional Athletes with Musculoskeletal Injuries: Study Protocol for a Double-Blind Randomized Controlled Trials.

Background/Objectives: This study aims to evaluate the effectiveness of binaural beats (BB) on the autonomic nervous system (ANS), kinesiophobia of reinjury and fitness biomarkers in professional athletes with chronic musculoskeletal injuries. Methods: A total of 54 athletes aged 18-25 years, engaged in open-skill sports and experiencing chronic lower-limb injuries for over three months, will be recruited. They will be randomly assigned to one of three groups: an intervention group, a placebo group, and a control group. All athletes will undergo a 15 min auditory intervention five times per week for four weeks. The intervention group will listen to BB embedded in music at high beta and gamma frequencies (30-100 Hz) with guided instructions. The placebo group will receive placebo BB within the same music framework, while the control group will listen only to the music background. Assessments will be conducted at baseline, immediately post-intervention, and at a 4-week follow-up. The primary outcomes will be kinesiophobia of reinjury, ANS function, and heart rate variability (HRV), assessed using the Tampa Scale of Kinesiophobia (TSK-17), Sympathetic Skin Response (SSR), and HRV analysis, respectively. Secondary outcomes will include sport-related anxiety and pain beliefs, assessed using the Sport Competition Anxiety Test (SCAT-15) and the Pain Beliefs and Perceptions Inventory (PBPI-16), respectively; handgrip strength, assessed using the Hand Grip Test; and fitness-related biomarkers, including maximal oxygen uptake (VO2max) and blood lactate concentration. Conclusions: These findings may provide evidence supporting BB as a complementary, non-invasive intervention to enhance psychological and physiological rehabilitation in injured athletes. Ethics and Dissemination: The study has received ethical approval and is registered on ClinicalTrials.gov. Findings will be disseminated through peer-reviewed publications, conferences, and academic presentations.