In this chapter, the following terms have the meanings indicated. Terms Defined. “Concussion” means a type of traumatic brain injury (TBI) causing an immediate and usually short-lived change in mental status or an alteration of normal consciousness resulting from a bump, blow, jolt, shaking, or spinning of the head or body. “Graduated return to play protocols” means the progressive return to play stages included in the Policies and Programs on Concussions for Public Schools and Youth Sport Programs (Maryland State Department of Education, updated through December 2012). “Return to play” means participation in a non-medically supervised practice or athletic competition after a period of exclusion. “School personnel” means those directly responsible for administering or coaching interscholastic athletic program within a school or county and those employees of the school or school system with overall responsibility for student-athletes’ academic performance and medical well-being. “Student-athlete” means a student participating in any try-out, practice, or contest of a school team. “Youth sports program” means a program organized for recreational athletic competition instruction for participants who are younger than 19 years old.