Tex. Educ. Code § 38.155

A student may not participate in an interscholastic athletic activity for a school year until both the student and the student's parent or guardian or another person with legal authority to make medical decisions for the student have signed a form for that school year that acknowledges receiving and reading written information that explains concussion prevention, symptoms, treatment, and oversight and that includes guidelines for safely resuming participation in an athletic activity following a concussion. The form must be approved by the University Interscholastic League.