For athletes at any level—youth, high school, college and professional—brain trauma is a major concern. Despite increased awareness of safety measures and concussion protocol, many concussions and head injuries still go undiagnosed. In this white paper, we explain how an athlete’s reaction time is affected by brain trauma. We also explore how integrating a simple reaction time test into the course of practice and play could help determine whether an athlete should sit out or seek a doctor for a formal medical diagnosis.