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Opportunities for Prevention of Concussion and Repetitive Head Impact Exposure in College Football Players : A Concussion Assessment, Research, and Education (CARE) Consortium Study

  • 1 Department of Neurosurgery, Medical College of Wisconsin, Milwaukee
  • 2 Department of Biomedical Engineering, Virginia Tech, Blacksburg
  • 3 School of Public Health-Bloomington, Department of Epidemiology and Biostatistics, Indiana University, Bloomington
  • 4 Department of Psychiatry, Indiana University School of Medicine, Indianapolis
  • 5 Michigan Concussion Center, University of Michigan, Ann Arbor
  • 6 UCLA Steve Tisch BrainSPORT Program, Department of Neurosurgery, University of California at Los Angeles
  • 7 UCLA Steve Tisch BrainSPORT Program, Department of Pediatrics, University of California at Los Angeles
  • 8 Department of Family Medicine and Orthopedic Surgery, University of California at Los Angeles
  • 9 John A. Feagin Jr Sports Medicine Fellowship, Keller Army Hospital Military Academy, West Point, New York
  • 10 Department of Physical Medicine and Rehabilitation, Uniformed Services University, Bethesda, Maryland
  • 11 Air Force Academy, Colorado
  • 12 Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill
  • 13 Department of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin, Madison
  • 14 Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee
  • Editorial Who Will Protect the Brains of College Football Players? Christopher J. Nowinski, PhD; Robert C. Cantu, MD JAMA Neurology

Question   Where might there be opportunities to do the greatest good toward reducing overall concussion incidence and head impact exposure (HIE) in collegiate football?

Findings   In this cohort study, concussion incidence and HIE were disproportionately higher in the preseason than the regular season, and most concussions and HIE occurred during football practices.

Meaning   These findings point to specific areas where public policy, education, and other prevention strategies could be targeted to make the greatest overall reduction in concussion incidence and HIE in college football, which has important implications for protecting the safety and health of collegiate football players.

Importance   Concussion ranks among the most common injuries in football. Beyond the risks of concussion are growing concerns that repetitive head impact exposure (HIE) may increase risk for long-term neurologic health problems in football players.

Objective   To investigate the pattern of concussion incidence and HIE across the football season in collegiate football players.

Design, Setting, and Participants   In this observational cohort study conducted from 2015 to 2019 across 6 Division I National Collegiate Athletic Association (NCAA) football programs participating in the Concussion Assessment, Research, and Education (CARE) Consortium, a total of 658 collegiate football players were instrumented with the Head Impact Telemetry (HIT) System (46.5% of 1416 eligible football players enrolled in the CARE Advanced Research Core). Players were prioritized for instrumentation with the HIT System based on their level of participation (ie, starters prioritized over reserves).

Exposure   Participation in collegiate football games and practices from 2015 to 2019.

Main Outcomes and Measures   Incidence of diagnosed concussion and HIE from the HIT System.

Results   Across 5 seasons, 528 684 head impacts recorded from 658 players (all male, mean age [SD], 19.02 [1.25] years) instrumented with the HIT System during football practices or games met quality standards for analysis. Players sustained a median of 415 (interquartile range [IQR], 190-727) recorded head impacts (ie, impacts) per season. Sixty-eight players sustained a diagnosed concussion. In total, 48.5% of concussions (n = 33) occurred during preseason training, despite preseason representing only 20.8% of the football season (0.059 preseason vs 0.016 regular-season concussions per team per day; mean difference, 0.042; 95% CI, 0.020-0.060; P  = .001). Total HIE in the preseason occurred at twice the proportion of the regular season (324.9 vs 162.4 impacts per team per day; mean difference, 162.6; 95% CI, 110.9-214.3; P  < .001). Every season, HIE per athlete was highest in August (preseason) (median, 146.0 impacts; IQR, 63.0-247.8) and lowest in November (median, 80.0 impacts; IQR, 35.0-148.0). Over 5 seasons, 72% of concussions (n = 49) (game proportion, 0.28; 95% CI, 0.18-0.40; P  < .001) and 66.9% of HIE (262.4 practices vs 137.2 games impacts per player; mean difference, 125.3; 95% CI, 110.0-140.6; P  < .001) occurred in practice. Even within the regular season, total HIE in practices (median, 175.0 impacts per player per season; IQR, 76.0-340.5) was 84.2% higher than in games (median, 95.0 impacts per player per season; IQR, 32.0-206.0).

Conclusions and Relevance   Concussion incidence and HIE among college football players are disproportionately higher in the preseason than regular season, and most concussions and HIE occur during football practices, not games. These data point to a powerful opportunity for policy, education, and other prevention strategies to make the greatest overall reduction in concussion incidence and HIE in college football, particularly during preseason training and football practices throughout the season, without major modification to game play. Strategies to prevent concussion and HIE have important implications to protecting the safety and health of football players at all competitive levels.

  • Editorial Who Will Protect the Brains of College Football Players? JAMA Neurology

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McCrea MA , Shah A , Duma S, et al. Opportunities for Prevention of Concussion and Repetitive Head Impact Exposure in College Football Players : A Concussion Assessment, Research, and Education (CARE) Consortium Study . JAMA Neurol. 2021;78(3):346–350. doi:10.1001/jamaneurol.2020.5193

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Lights Out: Concussion Research, the National Football League, and Employer Duty of Care

  • First Online: 01 January 2022

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football concussion research paper

  • Lucia Trimbur 3  

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This chapter looks at the epic struggle between the National Football League (NFL) and social actors concerned about football, brain injury, and chronic traumatic encephalopathy (CTE). In particular, it analyzes the registers in which the NFL, on the one hand, and research scientists who work with players and their families, on the other, have situated their evidence and arguments. I argue that though both sides have strong investments in either proving or minimizing the football-concussion-CTE connection, what has been missing from the debate is any conception or even language of labor: how players are workers, how the football field is their worksite, and how athletes should be afforded attendant occupational health protections to reduce risk of injury.

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Because the focus of this paper is on the National Football League (NFL), which right now is exclusively male, I look at concussion, CTE, and male American football players. There are an increasing number of women taking up the sport and their rigor and commitment often matches that of their male counterparts. Future research will need to take into account their experiences.

Other brain injuries include scalp abrasions, contusions, and lacerations; skull fractures; and brain contusions and lacerations (Omalu, 2008 , p. 9).

The National Football League was not the only level of play that saw early career ends. Between the 2013 and 2015 season, at least 26 players in competitive Division 1 NCAA programs left the sport because of concussions (Bella, 2015 ).

Much is still unknown about the causes of CTE and scientists do not know why people with similar histories of brain trauma have different outcomes. There are cases of people who experienced repetitive brain injury and did not develop CTE. And the disorder has never been found in someone who only had one concussion. Why one develops CTE and another does not is still unclear (Concussion Legacy Foundation, 2019 ).

Omalu’s work has come under fire by researchers in the field and pieces such as “From Salesman to Scientist” published on January 22, 2020, in The Washington Post , question the validity of his scientific conclusions. I am in no position to evaluate his findings but I do not believe that CTE would be on the world stage if Omalu had not examined Mike Webster’s brain and researched its pathology.

Anti-black racism and xenophobia no doubt affected the reception of Omalu’s work as he was born in Nigeria and migrated to the US in 1994.

Pellman was not only skeptical of concussion, he was also skeptical of people who suffered them. He suggested, “Veterans clear more quickly than rookies. … They can unscramble their brains a little faster, maybe because they’re not afraid after being dinged. A rookie won’t know what’s happened to him and will be a little panicky. The veterans almost expect the dings. You have to watch them, though, because vets will try to fool you. They memorize the answers. They’ll run off the field staring at the scoreboard” (Coates, 2013 ).

Several of these articles were rejected by peer reviewers and editors and later were disavowed by the journal as well as some of the authors (Union of Concerned Scientists, 2017 ).

American Association of Neurological Surgeons. (2019). Sports-related head injury. https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Sports-related-Head-Injury

Baugh, C., Kiernan, P. T., Kroshus, E., Daneshvar, D. H., Montenigro, P. H., McKee, A. C., & Stern, R. A. (2015, March 1). Frequency of head-impact-related outcomes by position in NCAA division I collegiate football players. Journal of Neurotrauma., 32 (5), 314–326.

Article   Google Scholar  

Bella, T. (2015). No man’s land: When concussions force a college football player to retire. AlJazeera America . http://america.aljazeera.com/watch/shows/america-tonight/articles/2015/12/1/casey-cochran-ncaa-football-concussions-retire.html

Belson, K. (2017). For Ravens’ John Urschel, Playing in the N.F.L. no longer adds up. New York Times . https://www.nytimes.com/2017/07/27/sports/football/john-urschel-baltimore-ravens-retires-nfl-cte-study.html

Block, J. (2016). We shouldn’t be surprised when NFL players retire early anymore. Huffington Post . https://www.huffpost.com/entry/dbrickashaw-ferguson-nfl-early-retirement-no-surprise_n_5707c4d5e4b0c4e26a2273fa

Bonesteel, M. (2017). Troy Aikman says he has no memory of playing in the 1994 NFC championship game. Washington Post . https://www.washingtonpost.com/news/early-lead/wp/2017/02/03/troy-aikman-says-he-has-no-memory-of-playing-in-the-1994-nfc-championship-game/

CNN Library. (2018). NFL concussion fast facts. CNN.com . https://www.cnn.com/2013/08/30/us/nfl-concussions-fast-facts/index.html

Coates, T-N. (2013). The NFL’s response to brain trauma: A brief history. The Atlantic . https://www.theatlantic.com/entertainment/archive/2013/01/the-nfls-response-to-brain-trauma-a-brief-history/272520/

Concussion Legacy Foundation. (2019). What is CTE? concussionfoundation.org .

Fainaru, S., & Fainaru-Wada, M. (2013). League of Denial. PBS: Frontline.

Google Scholar  

Freeman, K. (2018). Conversations with Ken: Dr. Ann McKee. Questrom School of Business, Boston University. https://www.youtube.com/watch?v=uPOtweXTSdY

Goldman, T. (2019). Exciting games help to propel NFL TV ratings higher. NRP: Morning Edition .

Harwood, J. (2019). Andrew Luck’s retirement stunned the NFL- and left behind a big message for the game. NPR: On Point . https://www.wbur.org/onpoint/2019/08/30/andrew-luck-retirement

Leavy, J. (2012). The woman who would save football. Grantland.com . http://grantland.com/features/neuropathologist-dr-ann-mckee-accused-killing-football-be-sport-only-hope/

Mez, J., et al. (2017). Clinicopathological evaluation of chronic traumatic encephalopathy in players of American football. Journal of the American Medical Association., 318 (4), 360–370.

Morris, A. (2019). Poor students more likely to play football, despite brain injury concerns. NPR: All Things Considered .

National Football League. (2007). NFL outlines for players steps taken to address concussions. NFL.com . http://www.nfl.com/news/story/09000d5d8017cc67/article/nfl-outlines-for-players-steps-taken-to-address-concussions

Omalu, B. (2008). Play hard, die young: Football dementia, depression, and death . Neo-Forenxis Books.

Omalu, B. (2017). Truth doesn’t have a side: My Alarming discovery about the danger of contact sports . Zondervan.

Tarzi, C., Tarzi, G., Walker, M., Saarela, O., & Cusimano, M. D. (2020). Medical Assessment of head collision events in elite women’s and men’s soccer. Journal of the American Medical Association., 323 (3), 275–276.

Union of Concerned Scientists. (2017). The NFL tried to intimidate scientists studying the link between pro football and traumatic brain injury. https://www.ucsusa.org/resources/nfl-tried-intimidate-scientists-studying-link-between-pro-football-and-traumatic-brain

Wells, M. (2019). Luck retires, calls decision ‘hardest of my life.’ ESPN.com . https://www.espn.com/nfl/story/_/id/27456682/luck-retires-calls-decision-hardest-my-life

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Trimbur, L. (2021). Lights Out: Concussion Research, the National Football League, and Employer Duty of Care. In: Wagg, S., Pollock, A.M. (eds) The Palgrave Handbook of Sport, Politics and Harm. Palgrave Macmillan, Cham. https://doi.org/10.1007/978-3-030-72826-7_7

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football concussion research paper

Media Center 2/1/2021 5:19:00 PM

CARE Consortium finds higher incidence of concussion, head impact exposure during football preseason and practice

New research from ncaa-funded study shows restructuring preseason and practice protocols may reduce concussions.

The latest findings from the Concussion Assessment, Research and Education Consortium show that disproportionately higher concussion rates and head impact exposure in college football occur during the preseason and practice — not regular-season games.

The largest and most comprehensive clinical study of concussion and head impact exposure in history, the CARE Consortium is funded by the NCAA and U.S. Department of Defense with broad aims to enhance the health and safety of NCAA student-athletes and military service members. It also serves as a valuable resource for youth sports participants and society at large.

"As a higher education association, we believe strongly in the power of research to inform decision-making and with it drive action," NCAA President Mark Emmert said. "The NCAA and its members have supported this monumental study to help answer many of the questions around the diagnosis, treatment and prevention of concussions. These latest findings provide new information for our members to modify rules while continuing education efforts for college athletes across the country."

Researchers conducted this phase of the study using head impact sensor technology that measures head impact frequency, location and magnitude. Researchers found that across six Division I football programs from 2015 to 2019, almost half of the reported concussions and two-thirds of reported head impact exposure across all players occurred during preseason training.

"We are optimistic that the most recent CARE Consortium research findings will not only arm physicians and scientists with even better data on the prevalence and mechanisms of concussion and head impact exposure outside of regular-season play, but also shed light on the importance of better prevention and protection methods," NCAA Chief Medical Officer Brian Hainline said.

Hainline indicated the study results will be presented to the NCAA Football Oversight Committee at its next meeting in March.

"The Football Oversight Committee is keenly focused on making the sport as safe as possible," said Shane Lyons, West Virginia University director of athletics and committee chair. "We plan to translate important, emerging research data into policies and recommendations that further our focus on football safety." 

While a sport-related concussion is an inherent risk in all contact and collision sports, the NCAA and its Sport Science Institute remain leaders in championing student-athlete well-being.

Launched in 2014, the CARE Consortium involves participants on 30 campuses across the country, including most of the nation's military academies.

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Concussion in soccer: a comprehensive review of the literature

Affiliations.

  • 1 Department of Neurosurgery, University of Alabama at Birmingham, 1813 6th Ave S #516, Birmingham, AL 35233, USA.
  • 2 Department of Neurosurgery, Mayo Clinic, 4500 San Pablo Rd S, Jacksonville, FL 32224, USA.
  • 3 Department of Neurosurgery, Brigham & Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA.
  • PMID: 33005435
  • PMCID: PMC7506470
  • DOI: 10.2217/cnc-2020-0004

Sports-related concussion has been examined extensively in collision sports such as football and hockey. However, historically, lower-risk contact sports such as soccer have only more recently garnered increased attention. Here, we review articles examining the epidemiology, injury mechanisms, sex differences, as well as the neurochemical, neurostructural and neurocognitive changes associated with soccer-related concussion. From 436 titles and abstracts, 121 full texts were reviewed with a total of 64 articles identified for inclusion. Concussion rates are higher during competitions and in female athletes with purposeful heading rarely resulting in concussion. Given a lack of high-level studies examining sports-related concussion in soccer, clinicians and scientists must focus research efforts on large-scale data gathering and development of improved technologies to better detect and understand concussion.

Keywords: football; repetitive subconcussive head impact; soccer; sport injuries; sport-related concussion; traumatic brain injury.

© 2020 James Mooney.

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  • Christopher J Nowinski 1 , 2 ,
  • http://orcid.org/0000-0002-7986-6493 Hye Chang Rhim 3 ,
  • Ann C McKee 1 , 4 , 5 ,
  • Ross D Zafonte 3 , 6 ,
  • David W Dodick 7 ,
  • Robert C Cantu 1 , 2 , 8 ,
  • Daniel H Daneshvar 3 , 6
  • 1 Boston University Alzheimer’s Disease Research and CTE Centers , Boston University Chobanian & Avedisian School of Medicine , Boston , MA , USA
  • 2 Concussion Legacy Foundation , Boston , MA , USA
  • 3 Department of Physical Medicine and Rehabilitation , Harvard Medical School , Boston , MA , USA
  • 4 Department of Neurology , Boston University Chobanian & Avedisian School of Medicine , Boston , MA , USA
  • 5 Department of Pathology , Boston University Chobanian & Avedisian School of Medicine , Boston , MA , USA
  • 6 Mass General Brigham Spaulding Rehabilitation , Boston , MA , USA
  • 7 Department of Neurology , Mayo Clinic , Rochester , Minnesota , USA
  • 8 Cantu Concussion Center , Emerson Hospital , Concord , MA , USA
  • Correspondence to Dr Daniel H Daneshvar, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA; ddaneshvar{at}mgh.harvard.edu

https://doi.org/10.1136/bjsports-2023-107413

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  • Brain Concussion

Concussion is a traumatic brain injury (TBI) defined by the presence of transient signs and symptoms related to alterations in brain function due to biomechanical force. 1 2 However, not every such force results in acute signs or symptoms, and recent research seeks to better understand the sequelae of both forces and injuries that are subclinical. The term ‘subconcussive’ has emerged to refer to both subclinical head acceleration events (HAEs) and injuries (as defined by clinical, biomarker and/or neuroimaging changes). We believe that this term can be misleading in both instances and should be replaced.

When referring to impacts, the prefix ‘sub’ implies lower magnitude HAEs than those that cause a diagnosed concussion. However, sensor studies show that many HAEs are associated with greater head acceleration than impacts that result in a diagnosed concussion. We suggest replacing subconcussive with the more agnostic term ‘non-concussive’.

When referring to injuries, the term subconcussive is a contradiction. If a concussion is a TBI, a subconcussive event implies no injury occurred. However, impacts that do not result in diagnosed concussions are sometimes associated with evidence of neurological injury, including functional changes that do not meet criteria for concussive symptoms, biomarker changes and structural changes evident on neuroimaging. 3 There is increasing evidence that these injuries are associated with long-term sequelae. 4 5 Researchers are misusing ‘subconcussive’ when referring to these injuries without overt clinical signs or symptoms. For the reasons detailed below, we suggest replacing subconcussive when referring to injury with ‘subclinical TBI’.

Hits of greater magnitude than concussive HAEs may not cause symptoms

With the arrival of football helmet accelerometers, researchers hoped to identify HAE magnitude thresholds that would characterise concussion. Unfortunately, there is no such threshold. A study of 319 college football players reported that peak linear and rotational accelerations were not correlated with symptom frequency, severity score or any symptom. 6 In a study of 283 348 impacts from 185 college football players, Mihalik et al found that the positive predictive value of sensor data for identifying concussion at any threshold was less than 2%, despite conservatively adjusting for undiagnosed injuries. 7

Stemper et al studied 511 college football players who experienced 424 059 head impacts. They sustained 4589 head impacts with greater linear and rotational acceleration than the mean accelerations for concussed athletes, and 249 160 head impacts with greater linear and rotational acceleration than the lowest magnitude concussive impact. 9

While the football helmet accelerometers are susceptible to measurement errors and peak linear and rotational acceleration may not best capture concussion risk, these studies highlight that ‘subconcussive’ impacts are frequently associated with greater head acceleration than concussive impacts. The term ‘non-concussive’ better captures this range of impacts and reveals that a meaningful proportion of these impacts are ‘high acceleration non-concussive’. More recently, instrumented mouthguards have been developed to quantify head acceleration, and future studies using these devices may further substantiate this claim. 10–12

HAEs without symptoms may result in injury

There is growing evidence that some non-concussive impacts sometimes cause subclinical, or silent, TBI, which may cause occult deficits and disease. Acutely, HAEs without symptoms of concussion have been associated with increasing biomarkers of neuroinflammation, suggesting possible neurological injury. 3 Imaging studies have demonstrated that repetitive head impacts in the absence of symptomatic concussion are associated with functional impairment and structural damage to the integrity of brain structures including white matter changes, cortical thinning and volume loss. 3 Over time, athletes sustaining non-concussive HAEs may also be at higher risk of concussion. 9 13

In the long-term, cumulative exposure to non-concussive impacts may increase the risks of neurodegenerative disease including amyotrophic lateral sclerosis (ALS) 5 and chronic traumatic encephalopathy (CTE). 4 Duration of exposure to non-concussive HAEs has been described as being higher in professional football players with ALS compared with those without, 5 and in predicting both CTE status and severity whereas concussion does not. 4

If these HAEs have acute and long-term sequelae, they should be identified as separate from, but not necessarily less than, concussion, as the word ‘subconcussive’ may imply. The observation that some non-concussive impacts can have clinical implications is unsurprising given the widely accepted evidence that subclinical injury can lead to neurological deficits in other disease processes, such as how some ischaemic events can lead to subclinical cerebrovascular disease that can accumulate and eventually manifest as dementia and cognitive decline. 14 Introducing a ‘subclinical’ classification to TBI brings TBI in line with other neurological diseases. 15

Recommendations

The term ‘subconcussive’ should be retired when referring to both impacts and injuries ( table 1 ). We recommend using ‘non-concussive’ to describe HAEs that do not result in a diagnosed concussion. Research-to-date suggests that while some non-concussive HAEs are harmless, others may cause injury associated with changes in brain function, biomarkers and imaging. The absence of symptoms following an HAE does not indicate that no injury occurred, but rather that no injury occurred to a salient network; it is possible that damage occurred in an area that is not responsible for conscious processes. It is also possible that sensory obtundation has occurred in some individuals exposed to TBI, further weakening the link between TBI and symptoms. In addition, we anticipate there are differences in how individuals respond to the same head impact based on unique differences in brain anatomy, premorbid risk factors and comorbid conditions, which can lead to differences in subsequent injury risk. Moreover, given the wide range of HAE magnitudes and potential negative consequences associated with repetitive concussive and non-concussive HAEs, individual-based metrics considering an athlete’s cumulative impact history are important in preventing subsequent injury and long-term sequelae. By changing the nomenclature, we hope to add specificity and clarity to the growing conversation exploring non-concussive impacts on subclinical TBI and neurological outcomes.

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Current and proposed impact and injury terminology

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  • Schneider KJ , et al
  • Silverberg ND ,
  • Iverson GL , ACRM Mild TBI Definition Expert Consensus Group and the ACRM Brain Injury Special Interest Group Mild TBI Task Force
  • Mainwaring L ,
  • Ferdinand Pennock KM ,
  • Mylabathula S , et al
  • Daneshvar DH ,
  • Baucom ZH , et al
  • Alosco ML , et al
  • Stemper BD , et al
  • Mihalik JP ,
  • Lynall RC ,
  • Wasserman EB , et al
  • Campolettano ET ,
  • Gellner RA ,
  • Smith EP , et al
  • Stemper BD ,
  • Harezlak J , et al
  • Weaving D ,
  • Al-Dawoud M , et al
  • Weaving D , et al
  • Bussey MD ,
  • Romanchuk J , et al
  • Seifert J ,
  • Vermeer SE ,
  • den Heijer T , et al
  • Jiménez-Balado J ,
  • Corlier F ,
  • Habeck C , et al

Contributors All authors participated in conceptualisation, writing original draft and reviewing and editing.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests CN is the cofounder and chief executive officer of the Concussion Legacy Foundation; reported non-financial support (travel reimbursement) from the NFL Players Association as a member of the Mackey-White Health & Safety Committee, WWE and AEW (All Elite Wrestling); and serves as an advisor and options holder for Oxeia Biopharmaceuticals, PreCon Health and StataDx outside the submitted work. ACM is a member of the Mackey-White Committee of the National Football League Players Association. RZ receives royalties from Oakstone for an educational CD (Physical Medicine and Rehabilitation: A Comprehensive Review) and from demosMedical, part of Springer Publishing, for serving as coeditor of the text Brain Injury Medicine and serves on the Scientific Advisory Board of Oxeia Biopharma, BioDirection, ElMINDA and Myomo. He is also PI on a grant entitled the Football Players Health Study at Harvard University, which is funded by the National Football League Players Association (NFLPA) and evaluates patients for the MGH Brain and Body TRUST Center, sponsored in part by the NFLPA, and serves on the Mackey-White Health and Safety Committee. DWD reports consulting for AYYA Biosciences, Abbvie, Allergan, Amgen, Atria Health, Biohaven, CapiThera, Cerecin, Ceruvia Lifesciences LLC, Cooltech, Ctrl M, Eli Lilly and Co, GSK, Impel, Lundbeck, Nocira, Novartis, Perfood, Pfizer, Praxis, Revance, Satsuma, Theranica and WL Gore; payment or honoraria for lectures/presentations/educational events for Abbvie, Allergan, Amgen, Biohaven, Eli Lilly and Co, Lundbeck, Pfizer, Novartis and Teva. He participates on a data safety monitoring Board or advisory board for Abbvie, Allergan, Amgen, Biohaven, Eli Lilly, Lundbeck and Novartis. He reports honoraria for Academy for Cambridge University Press, Continued Healthcare Learning, Clinical Care Solutions, CME Outfitters, Curry Rockefeller Group, DeepBench, Global Access Meetings, KLJ Associates, Majallin LLC, Medlogix Communications, Miller Medical Communications, MJH Lifesciences, Oxford University Press, Vector Psychometric Group, WebMD Health/Medscape and Wolters Kluwer. He reports research support from the American Migraine Foundation, Department of Defense, Henry Jackson Foundation, National Institutes of Health, Patient Centered Outcomes Research Institute (PCORI) and Sperling Foundation. He reports leadership or a fiduciary role in other boards, societies, committees or advocacy groups (paid or unpaid) for the American Brain Foundation, American Migraine Foundation and International Headache Society Global Patient Advocacy Coalition. He reports stock options/shareholder/patents/board of directors for AYYA Biosciences (options), Atria Health (options), Aural Analytics (options), Epien (options/board), ExSano (options), Healint (options), King-Devick Technologies (options/board), Man and Science (options), Matterhorn (shares/board), Nocira (options), Ontologics (shares/board), Precon Health (options/ board), Second Opinion/Mobile Health (options), Theranica (options). He reports patent 17189376.1-1466:vTitle: Botulinum Toxin Dosage Regimen for Chronic Migraine Prophylaxis (non-royalty bearing); patent application submitted: Synaquell (Precon Health). RCC reported royalties from Houghton Mifflin Harcourt; compensation for expert legal opinion to the National Collegiate Athletic Association and National Hockey League; consults for the Concussion Legacy Foundation; is senior advisor and paid consultant to the NFL Head Neck & Spine Committee; is a member of the Mackey-White Committee of the National Football League Players Association; is vice president of National Operating Committee on Standards for Athletic Equipment and chair scientific advisory committee and cofounder of Medical Director Concussion Legacy Foundation; and is on the Medical Science Committee for the National Collegiate Athletic Association Student-Athlete Concussion Injury Litigation. DHD serves as an expert witness in legal cases involving brain injury and concussion and serves as an advisor and options holder for StataDx outside the submitted work.

Provenance and peer review Not commissioned; externally peer reviewed.

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IMAGES

  1. Football Concussion

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  2. Recovery Time Among Athletes with Concussion

    football concussion research paper

  3. NFL concussion research: Report identifies new flaws in studies

    football concussion research paper

  4. (PDF) Epidemiology of Concussion in Collegiate and High School Football

    football concussion research paper

  5. (PDF) ORIGINAL RESEARCH PAPER SURVEY OF CONCUSSION KNOWLEDGE OF WOMEN

    football concussion research paper

  6. Concussion Information

    football concussion research paper

COMMENTS

  1. Concussions in the National Football League: A Current ...

    Background: Significant attention has been directed toward the immediate and long-term effects of sport-related concussions on athletes participating in contact sports, particularly football. The highest level of football, the National Football League (NFL), has received significant attention and criticism regarding player management and safety after mild traumatic brain injury (mTBI).

  2. Epidemiology of Concussion in the National Football League, 2015-2019

    Results: A total 1302 concussions were identified from 2015 to 2019 among 1004 players. Of these, 80% occurred in NFL games. The average annual incidence of in-season game concussions changed over the study period, from 230.7 per season (2015-2017) to 177.0 per season (2018-2019); this represented a 23% decrease in game settings ( P < 0.01).

  3. Top-100 Most-Cited Sports-Related Concussion Articles Focus on

    This finding is similar to many other dynamic fields where research continues to rapidly evolve. 13, 15, 19 In contrast, our analysis shows that among the top-100 cited sports concussion papers, the latest was published in 2017. It is reasonable to believe that articles published in the last 3 to 5 years, although impactful in the field, have ...

  4. Short-term Outcomes Following Concussion in the NFL: A Study of Player

    The NFL and NFL Players Association have focused on earlier intervention and diagnosis to minimize and mitigate the long-term structural changes in the brain associated with NFL football play. 12 Research has often focused on the clinical and radiographic evidence of NFL-related concussions and earlier diagnosis of its pathophysiology of ...

  5. Special Issue on Concussion Biomechanics in Football

    This special issue is focused on the biomechanics of concussion in football. These papers are timely given increased public awareness concerning concussions in recent years, which has led to a push for more research in the area. Repetitive head impact exposure leading to long-term neurocognitive deficits is particularly concerning, with ...

  6. PDF Special Issue on Concussion Biomechanics in Football

    Special Issue on Concussion Biomechanics in Football (published online 3 November 2020) This special issue is focused on the biomechanics of concussion in football. These papers are timely given increased public awareness concerning concussions in recent years, which has led to a push for more research in the area.

  7. Football Concussions: Effects, Evaluation and Prevention

    concussion research because it is a contact heavy sport with many head on collisions. Many football players' lives and their families are affected, so it is important to research concussions. Concussions are common understated injuries, however, concussions related to football have gained more attention from society recently. Football related

  8. Opportunities for Prevention of Concussion and Repetitive Head Impact

    Design, Setting, and Participants In this observational cohort study conducted from 2015 to 2019 across 6 Division I National Collegiate Athletic Association (NCAA) football programs participating in the Concussion Assessment, Research, and Education (CARE) Consortium, a total of 658 collegiate football players were instrumented with the Head ...

  9. Concussions in the National Football League:

    The highest level of football, the National Football League (NFL), has received significant attention and criticism regarding player management and safety after mild traumatic brain injury (mTBI). Several review articles have reported data related to concussion in the NFL, but a succinct review and synthesis of data regarding NFL concussions is ...

  10. Epidemiology of Concussion in the National Football League, 2015-2019

    A total 1302 concussions were identified from 2015 to 2019 among 1004 players. Of these, 80% occurred in NFL games. The average annual incidence of in-season game concussions changed over the study period, from 230.7 per season (2015-2017) to 177.0 per season (2018-2019); this represented a 23% decrease in game settings (P < 0.01).Practice concussions fluctuated across the years of the study ...

  11. Lights Out: Concussion Research, the National Football League, and

    Because the focus of this paper is on the National Football League (NFL), which right now is exclusively male, I look at concussion, CTE, and male American football players. ... Concussion Research, the National Football League, and Employer Duty of Care. In: Wagg, S., Pollock, A.M. (eds) The Palgrave Handbook of Sport, Politics and Harm ...

  12. CARE Consortium finds higher incidence of concussion, head impact

    The latest findings from the Concussion Assessment, Research and Education Consortium show that disproportionately higher concussion rates and head impact exposure. ... "The Football Oversight Committee is keenly focused on making the sport as safe as possible," said Shane Lyons, West Virginia University director of athletics and committee ...

  13. Concussion in soccer: a comprehensive review of the literature

    Abstract. Sports-related concussion has been examined extensively in collision sports such as football and hockey. However, historically, lower-risk contact sports such as soccer have only more recently garnered increased attention. Here, we review articles examining the epidemiology, injury mechanisms, sex differences, as well as the ...

  14. 'Subconcussive' is a dangerous misnomer: hits of greater magnitude than

    Concussion is a traumatic brain injury (TBI) defined by the presence of transient signs and symptoms related to alterations in brain function due to biomechanical force.1 2 However, not every such force results in acute signs or symptoms, and recent research seeks to better understand the sequelae of both forces and injuries that are subclinical. The term 'subconcussive' has emerged to ...

  15. Concussion in soccer: a comprehensive review of the literature

    Here, we review articles examining the epidemiology, injury mechanisms, sex differences, as well as the neurochemical, neurostructural and neurocognitive changes associated with soccer-related concussion. From 436 titles and abstracts, 121 full texts were reviewed with a total of 64 articles identified for inclusion.

  16. Concussion in soccer: a comprehensive review of the literature

    Sports-related concussion has been examined extensively in collision sports such as football and hockey. However, historically, lower-risk contact sports such as soccer have only more recently garnered increased attention. Here, we review articles examining the epidemiology, injury mechanisms, sex differences, as well as the neurochemical, neurostructural and neurocognitive changes associated ...

  17. Five ways to kick off the concussion debate without stopping the game

    But concussion needs to be urgently and successfully addressed. In elite rugby union, the current rate of 10 to 15 concussions per 1000 playing hours , at least one concussion every 2½ games, is ...