Two 2014 studies in The American Journal of Sports Medicine suggest as much: One study, which was based on a survey of 1066 collegiate institutions, concludes that “although a large majority of respondents indicated that their school has a concussion management plan, improvement is needed.” Another paper about protective equipment at the high school level found that among 2081 players enrolled during the 2012-13 football seasons, some 206 (9%) sustained a total of 211 concussions 

http://journalistsresource.org/studies/society/public-health/sports-related-concussions-head-injuries-what-does-research-say#

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Recent work has identified deficits in dual-task gait balance control for up to 2 months following teen concussions, however how resuming of pre-injury physical activities affects recovery is unknown. Conclusions: Adolescents with concussion displayed increased center-of-mass medial/lateral displacement and velocity during dual-task walking following RTA, suggesting a regression of recovery in gait balance control. This study reinforces the need for a multi-faceted approach to concussion management and continued monitoring beyond the point of clinical recovery. 

http://journals.lww.com/acsm-msse/Abstract/publishahead/Return_to_Activity_after_Concussion_Affects.97957.aspx