Traumatic brain injury (TBI) remains one of the most frequently occurring public health issues and is the number one cause of death and disability among children of 19 years old and under. There has been a rapid emergence of experimental Repeat TBI (RTBI) models to address concerns observed clinically, including axonal injury, inflammatory responses, cognitive impairments, and long-term risk for neurodegenerative diseases. The goal of these injury device modifications is to model concussive or mTBI. Knowledge of developmental profiles of the specific outcome measures in a given species is important for interpretation of TBI-induced effects. The incidence of TBI across all age groups has shown peaks in early development and adolescence. Adolescence is a developmental period characterized by hormonal changes that are necessary for time-sensitive development of permanent brain structures, cognition, and behavioral function. Chronic pathology model produces detectable changes in axonal injury with RTBI in the visual system and cerebellum that is used to examine adolescent TBI therapeutic interventions.