A randomized controlled trial has suggested that following a concussion, young athletes who resume aerobic exercise relatively early, with an intensity that does not aggravate the symptoms, may recover faster, in comparison with stretching.

Researchers suggested that clinicians must prescribe exercise to promote recovery in patients with a concussion. The study included 118 adolescent athletes, 13-18 years of age, who had a sport-related concussion in the previous 10 days. A total of 61 participants were randomized to individualized subsymptom-threshold aerobic exercise, while 57 were assigned to stretching exercise, for a duration of at least 20 minutes a day for up to 4 weeks. 

A larger proportion of participants randomized to stretching failed to recover by 4 weeks, compared to those assigned to aerobic exercise (32% vs. 21%). Additionally, the median time to full recovery was 19 days for the stretching group compared to 14 days for the aerobic exercise group… (Medscape)