A Review of Sport-related Concussion – Part 1: Introduction and Prevention

By Dr. Shawn Halvorson, DC, CCSP

With the recent concussion injury of NDSU legend and current Eagles QB Carson Wentz, along with a few high school athletes presenting with similar injuries in our clinic, it’s a great time to review some good information for parents and athletes to know about concussions. Most of the information presented is from the Concussion In Sports Group Berlin Consensus Paper (2017), unless otherwise noted.1

The information presented will be disbursed in three separate parts. I’ve underlined certain parts that the general public may have misconceptions about.

What is a concussion?

A sport-related concussion (SRC) is a traumatic brain injury induced by biomechanical forces. Several common features that may be utilized in clinically defining the nature of a concussive head injury include:

► It may be caused either by a direct blow to the head, face, neck, or elsewhere on the body with an impulsive force transmitted to the head.

► It typically results in the rapid onset of short-lived impairment of neurological function that resolves spontaneously. However, in some cases, signs and symptoms evolve over a number of minutes to hours.

► It may result in neuropathological changes, but the acute clinical signs and symptoms largely reflect a functional disturbance rather than a structural injury and, as such, no abnormality is seen on standard structural neuroimaging studies.

► SRC results in a range of clinical signs and symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive features typically follows a sequential course. However, in some cases, symptoms may be prolonged. The clinical signs and symptoms cannot be explained by drug, alcohol, or medication use, other injuries (such as cervical injuries, peripheral vestibular dysfunction, etc.) or other comorbidities (e.g. psychological factors or coexisting medical conditions). The majority of SRC do not involve loss of consciousness.

Prevention of Sport-related Concussion

“An ounce of prevention is worth a pound of cure” is as relevant today as it was when Benjamin Franklin wrote it. But how do we avoid the unpredictable and seemingly unavoidable sports head injury? The truth is, we will never be able to 100% prevent head injuries, but we can reduce their likelihood in a few ways. Research has identified certain risk factors, classified as either intrinsic or extrinsic, which lead to an increased likelihood of concussion.

Intrinsic factors are specific to the athlete and include a history of previous concussion, player weight, pre-existing symptoms (such as headaches, anxiety, and depression) and neuromuscular control.

Extrinsic risk factors are related to the environment or rules of the game. I’ll break down the extrinsic risk factors into three categories where we can try to make a difference in the incidence of concussions: rule changes, equipment, and training strategies.

Rule Changes:

Disallowing body checking in youth ice hockey showed a 64% decrease in concussion, estimated at reducing concussions by 4800 across Canada when it was implemented at a national level.2

The NFL has made significant changes to the rules in order to reduce or prevent concussions. Examples include major penalties and possible fines for hits to defenseless players and implementing rules that reduces the amount of kick returns.


Developing helmet fit criteria (e.g. chin strap fit, position of helmet, condition) in youth ice hockey. So far there are 19 total criteria. When more than 1 criteria is not met, early evidence suggests it increases the risk of concussion by double.3

Training Strategies:

Restricting contact practices in football reduced head impacts by >40%.4 Restricting contact practices in football, along with coach training (equipment, tackling technique) reduced practice concussion rates >80%.5

Neuromuscular training warm-up in youth rugby and youth soccer showed >50% reduction in concussion rates.6,7

Part 2 will cover Detection and Diagnosis of Concussion.

Part 3 will cover Team Concepts of the Treatment and Management of Concussion.


  1. McCrory P, Meeuwisse W, Aubry M, et al. Consensus statement on concussion in sport—the 5th International Conference on Concussion in Sport Held in Berlin, October 2016. Br J Sports Med 2017; 51: 838–847
  2. Black AM, Hagel BE, Palacios-Derflingher L, Schneider KJ, Emery CA. The risk of injury associated with body checking among Pee Wee ice hockey players: an evaluation of Hockey Canada’s national body checking policy change.Br J Sports Med March 2017;51(24):1767-1772 doi:10.1136/bjsports-2016-097392
  3. Gamble A, Sick S, Krolikowski M, Bigg J, Hagel BE, Emery CA. Helmet fit assessment and concussion risk in youth ice hockey players ages 11-18 years. Canadian Academy of Sport and Exercise Medicine (Halifax Canada, June 2018) Clinical J of Sport Med 2018;28(3):e75
  4. Broglio SP, Williams RM, O’Connor KL, Goldstick J. Football players’ head-impact exposure after limiting of full-contact practices. Journal of athletic training. 2016;51(7):511-8. doi:10.4085/1062-6050-51.7.04
  5. Kerr ZY, Dalton SL, Roos KG, Djoko A, Phelps J, Dompier TP. Comparison of Indiana High School Football Injury Rates by Inclusion of the USA Football “Heads Up Football” Player Safety Coach. Orthopaedic Journal of Sports Medicine. 2016;4(5):2325967116648441. doi:10.1177/2325967116648441
  6. Hislop MD, Stokes KA, Williams S, McKay CD, England ME, Kemp SPT, Trawartha G. Reducing musculoskeletal injury and concussion risk in schoolboy rugby players with a pre-activity movement control exercise programme: a cluster randomised controlled trial. Br J Sports Med 2017;51:1140–1146. doi:10.1136/bjsports-2016-097434
  7. Emery CA, Meeuwisse WH. The effectiveness of a neuromuscular prevention strategy to reduce injuries in youth soccer: a cluster randomized controlled trial. Br J Sports Med 2010;44:555-562


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