Effects of a single session of noninvasive auricular vagus nerve stimulation on sports performance in elite athletes: an open-label randomized controlled trial

Objectives: The purpose of this study was to investigate the efficacy of noninvasive auricular vagus nerve stimulation (AVNS) on sports performance.Methods: The intervention group (n = 30) received a single session of AVNS, while the control group (n = 30) received a single session of sham AVNS. Pre- and post-treatment isometric quadriceps muscle strength, heart rate, lower extremity balance, and grip strength were measured.Results: It was ascertained that the differences in heart rate (-0.73 pulse/min, p = 0.032) and modified Star Balance Test scores (anterior 2.72 cm, p = 0.000, posterolateral 3.65 cm, p = 0.000 and posteromedial 2.43 cm, p = 0.000) before and after AVNS were significant in subjects in the experimental group. The results of the one-way ANOVA analysis show that the differences obtained in all measurement parameters are not statistically significant (p > 0.05). Considering the partial eta squared (eta 2) obtained from the measurements, a small descriptive effect in favor of experimental group was obtained for the quadriceps strength (0.016) and anterior balance (0.054) measurements.Conclusion: This study demonstrates that a single AVNS session compared to sham AVNS shows a modest benefit though not statistically significant improvement in athletic performance. Single-use of AVNS seems not effective in improving athletic performance.