A new study published in the journal Pediatrics looked at children and young adults, ages 11-22, who visited the emergency room with repeat concussions.
Those who suffered a concussion in the past year took twice as long to recover, typically 24 days compared to 12 days for kids with no history of concussions. Sports concussions accounted for almost two-thirds of those in this study.
Experts say those kids should not get back into the game until a doctor gives them the okay.