Concussion Symptomatology by Symptom Resolution Time in US High School Athletes: Findings From the National Athletic Treatment, Injury and Outcomes Network High School Surveillance Program (NATION-SP).

Context: Concussions incurred during high school athletics are a significant health concern, and studies examining concussions with a symptom resolution time (SRT) of 15 to 28 days have been limited.

Objective: To compare concussions that had an SRT of 15 to 28 days with concussions that had an SRT of greater than 28 days among US high school athletes.

Design: Descriptive epidemiology study.