Determine the effect of neck muscle fatigue on dynamic visual acuity in healthy young adults

[Purpose] The aim of this study was to determine whether neck muscle fatigue affects dynamic visual acuity in healthy young participants. [Subjects and Methods] This study was a double-blinded, prospective, randomized, controlled trial. Thirty healthy young subjects (ages 21 to 30 years) participated in the study. Participants were randomly divided into an experimental group (n=15) and a control group (n=15). The experimental group performed an exercise designed to induce neck muscle fatigue and the control group preformed non-fatiguing sham exercises. [Results] There were significant differences in mean dynamic visual acuity between the two groups (0.26±0.11 LogMar versus 0.003±0.02 LogMar). Subjects in the experimental group showed a significant decline in their dynamic visual acuity compared with the control group. Dynamic visual acuity strongly correlated with neck muscle fatigue (r = 0.79). No significant differences in joint position error were observed between the two groups and no significant correlations between joint position error and neck muscle fatigue were observed (r = 0.23). [Conclusion] The results of this study suggest that neck muscle fatigue negatively impacts dynamic visual acuity. Although not statistically significant, cervical spine proprioception as measured by the joint position error in the experimental group was diminished after fatigue.