Abstract
Wearing a helmet and mouthguard are mandatory for adolescent (ages 14–18) tackle football (American football) players. Coaches are usually responsible for fitting player helmets despite many organizations not mandating/providing training. This structure may create a significant concern for player safety, as 60% of adolescent players wear a poor fitting helmet and wearing a poor fitting helmet may be associated with a higher risk of concussion. We conducted a cross-sectional survey to examine Canadian adolescent tackle football coaches’ current helmet fitting procedures and their beliefs towards the effectiveness of helmets and mouthguards for injury prevention. Amongst the 101 coaches from three leagues, most coaches (51%–88%) believed that wearing a mouthguard could protect against concussions, dental injuries, and/or other orofacial injuries. Helmet fitting procedures were highly variable within and between teams, with coaches using between 1 and 7 criteria. Despite 78%–92% of coaches believing that wearing a proper fitting helmet could protect against concussion and/or reduce its severity, 31%–96% of coaches who fit helmets have never received any training. Lack of formal helmet fit training was reported as the largest barrier to fitting helmets, which supports that tackle football organizations should take immediate action to provide coaches with formal helmet fit training.
Introduction
Over 2.6 million children and adolescents (under 18 years old) participate in tackle football (American football) each year in North America.1,2 Unfortunately, tackle football has the second highest concussion rate amongst all adolescent collision sports (0.9 concussions/1000 athletic exposures), following rugby, and has the highest game-related concussion rate (2.5 concussions/1000 game exposures).3,4 Concussion prevention avenues include policy/rule changes, training strategies, and correct use of personal protective equipment.3,4 As adolescent tackle football players are mandated to wear a mouthguard and hard-shell helmet, initiatives relating to personal protective equipment would be important to improve player safety.
Current evidence suggests that wearing a mouthguard is protective against concussion (28% lower risk with use in ice hockey) and dental/orofacial injuries (58% lower risk with use across multiple sports).5–7 For helmets, a prior study found no association between concussion risk and current helmet brands, helmet ages, and helmet manufacturer recertification status in tackle football players; 8 however, having a properly fitted helmet (meeting ≥15 of 16 standardized items, 12 specific to fit) was associated with a 63% lower odds of concussion (relative to a poor fit score of meeting ≤14 of 16 items) for youth ice hockey players aged 11–17 years. 9 Moreover, adolescent tackle football players (ages 14–18) who sustained a concussion experienced significantly more symptoms and had a longer recovery if a team trainer identified them as having a poor fitting helmet (without using standardized criteria) at the time of concussion. 10 Prior reports suggest that nearly 60% of adolescent tackle football players wear a poor fitting helmet, demonstrating an urgent need to improve player helmet fit and optimize helmet-related concussion prevention.11–13
Within many tackle football organizations, teams commonly lend helmets to players and rely on coaches to ensure that the helmets are in good condition and fit properly. Coaches regularly coordinate this process and despite the potential significance on player safety, many organizations do not mandate helmet fit training nor provide coaches with training. We previously co-developed a 12-item tackle football-specific helmet fit checklist (with additional helmet condition and player appraisal of fit criteria) with tackle football team personnel (i.e., coaches, equipment managers, athletic therapists) to support coach helmet fit education. 11 However, no prior study has examined whether coaches have received helmet fit training, their current processes for fitting helmets, sources for helmet education, and whether coaches believe helmets and mouthguards are effective for injury prevention. Therefore, the objective of this study was to describe Canadian adolescent tackle football coaches’ helmet fit experience, procedures for fitting helmets, sources for helmet knowledge, and beliefs regarding helmet and mouthguard effectiveness for injury prevention.
Methods
Study design and participants
We conducted a cross-sectional study within a larger quasi-experimental helmet fit training intervention that was part of the SHRed Concussions (
Procedures
Coaches from teams enrolled in the SHRed Concussions research program were recruited to participate in this study. Upon providing consent, coaches were presented with a questionnaire that included demographic information, current helmet fitting procedures, and personal beliefs regarding the effectiveness of helmets and mouthguards for injury prevention. Based on the broader quasi-experimental study that implemented a helmet fit training intervention, the questionnaire was completed either at the start of the season (i.e., Calgary club and Québec City high school) or at least 30 days into the 9-week season (i.e., Calgary high school), prior to any intervention training to reflect the coaches’ current knowledge.
Collected demographic information included age, sex, and tackle football specific information (e.g., coaching and playing experience, injury and concussion history, coaching role on the team, prior helmet fit training, role in fitting helmets). Coaches were then asked in an open-ended question “how do you fit a football helmet?” and were provided with a blank page (and a scribe, if needed) to record their current fitting procedures. Written responses were reviewed separately by two authors (ATK – English speaking, CAS – French and English speaking) and coded into specific categories that coaches reported using (e.g., assessing if the helmet shell fits snug, the chin strap fits snug, the helmet is comfortable for players). Categories included items from our previously developed helmet fit checklist 11 and if other criteria were presented (e.g., measure head size/circumference), additional categories were included. Responses between the two authors were compared, and if there were disagreements, a third author (DL – French and English speaking) reviewed and made a final decision for categorizing the responses. Lastly, coaches were asked about their beliefs regarding the role that helmets and mouthguards play for injury prevention (e.g., if helmet fit is protective against concussion, the same for mouthguards), which helmet brand they prefer and why, and their sources for helmet knowledge. The response options included ‘multiple choice’ and ‘select all that apply’ formats with an option to report “other” where applicable. All study materials were created in English and translated into French with review from two Francophone team members (DL, CG) to ensure translation quality.
Statistical analyses
We did not complete an a priori sample size calculation. As this study was descriptive and exploratory, we opted to recruit as many coaches as possible from teams participating within the SHRed Concussions research program, with at minimum, a head coach or coach-equipment manager who were tasked with fitting helmets for each team. Data were described using frequencies (with proportions) or medians [with interquartile ranges (IQRs)] stratified for each league (Calgary high school, Calgary club, Québec City high school). We opted to stratify our results in case there would be specific recommendations for different tackle football organizations (e.g., Football Alberta versus Football Québec, Calgary high school versus Calgary club). A frequency-weighted scatter plot was created to display the number of helmet fit criterion reported by coaches, stratified by league and team.
Results
Responses were collected from 101 coaches, which included 43 coaches from 11 Calgary high school teams spanning 8 schools [3–9 coaches per school; both junior (ages 13–15) and senior (ages 13–18 years) divisions], 31 coaches from 8 Calgary club teams [1–9 coaches per team; single division (ages 13–17 years)], and 27 coaches from 9 Québec City high school teams spanning 6 schools [2–11 coaches per school; both cadet (junior; ages 13–15 years) and juvenile (senior; ages 13–18) divisions]. At minimum, the primary helmet fit coach/equipment manager for each team participated.
Demographics
Within all leagues, nearly all coaches were male (91%–100% of coaches) and were youngest in Québec City (median = 29 years, range: 21–59 years) and Calgary (median = 36 years, range: 17–67 years) high school leagues, and oldest in the Calgary club league (median = 48 years, range: 17–67 years) (Table 1). Coaches reported between one and three roles on a team, with most being a head coach (17%–43% of coach responses), an offensive coordinator (19%–35% of coach responses), and/or a defensive coordinator (19%–36% of coach responses). Most coaches had been coaching for at least three years (70%–87% of coaches) and 90%–93% had played tackle football (87%–89% had played for ≥3 years and 59%–84% had played in adulthood). There were similar prevalences of lifetime football-related histories of concussions (63%–70% of coaches) and non-concussion injuries (e.g., orofacial, neck, musculoskeletal; 64%–78% of coaches) amongst coaches in each league (Table 1).
Coach demographics.
Notes. There were no missing data.
The 101 coaches recorded 115 coaching roles within the team (with coaches selecting between 1 and 3 roles).
The sample was restricted to the 92 coaches who reported playing football.
Helmet fitting and prior training information
Nearly all coaches from Québec City (93% of coaches) reported that they had or would be fitting helmets for the current season, compared with the 52% of coaches within Calgary club and 42% within Calgary high schools (Table 2). Across all coach responses, 75% reported never receiving helmet fit training, ranging from 96% of coaches from Québec City high school teams, 76% from Calgary high school teams, and 58% from Calgary club teams (Table 2). Amongst only coaches who reported fitting helmets, 31%–96% had never received any training (Table 2). Of those who had received training, the training was most commonly provided by either an equipment manager (46%–57%), football administration (0%–23%), or an equipment manufacturer representative (0%–50%). In most cases, coaches who received training were not provided with formal criteria (27%–100%) or were unsure if formal criteria were provided (0%–18%) (Table 2).
Helmet fitting and prior training information.
Notes. There were no missing data.
The 25 coaches who received helmet fit training recorded 29 responses for who provided their prior helmet fit training (with coaches making between 1 and 3 selections).
Coaches’ current helmet fitting procedures
When asked the open-ended question “how do you fit a football helmet?”, 85 coaches (84%) provided information. The 16 coaches (16%) who did not provide information (13 Calgary high school coaches and 3 Calgary club coaches) reported that they did not know how to fit a helmet (7 coaches, 44%), that they did not fit helmets (7 coaches, 44%), or left the section blank (2 coaches, 12%).
The most commonly reported criteria included considerations for the helmet shell's fit (73%–96% of coaches), the chin strap's fit (43%–85% of coaches), and the cheek-pads’ fit (23%–52% of coaches) (Table 3). Other prominent items included considering a player's feeling of comfort/fit (27%–43% of coaches) and the helmet's positioning on the forehead (7%–32% of coaches) (Table 3). Additional items that were not included in our previously developed helmet fit checklist included measuring the player's head size/circumference (4%–20% of coaches), trying different helmet brands (0%–4% of coaches), and ensuring the helmet is positioned correctly on the head (no information for how this was determined; 0%–4% of coaches) (Table 3). The remaining items in our checklist were reported by <10% of coaches, with ensuring unrestricted neck movement and considerations for the facemask's distance from the chin not reported by any coaches (Table 3).
Coach description of criteria used in current helmet fitting procedures.
Notes. Responses were collected as an open paragraph and then categorized separately by two members of the research team (with agreement in categorization) for describing specific criteria. Values within the table display the prevalence of coaches who reported using each criterion. Sixteen coaches did not provide any criteria (13 Calgary high school coaches and 3 Calgary Club coaches).
Represent additional criterion not from our previously developed checklist (Kolstad et al., 2022). 11
Coach helmet beliefs/perspectives.
Notes. There were no missing data.
The 101 coaches recorded 123 responses for barriers to fitting helmets (with coaches making between 1 and 3 selections).
The 101 coaches recorded 115 responses for best brand (with coaches making between 1 and 3 selections).
The 101 coaches recorded 328 responses for why a helmet brand is preferable (with coaches making between 1 and 10 selections).
The 101 coaches recorded 159 responses to learning about helmets (with coaches making between 1 and 6 selections).
Coach helmet and mouthguard beliefs/perspectives for injury prevention.
Notes. There were no missing data.
When comparing the number of criteria reported, Figure 1 displays a frequency-weighted scatter plot for individual coaches, stratified by team/school and league. The median number of criteria reported was 3 for both Calgary (IQR: 2, range: 1–7) and Québec City (IQR: 2, range: 1–5) high school coaches, and 2 for the Calgary club coaches (IQR: 1.5, range: 1–6) (Figure 1 and Table 3). There are 55 data points within the figure and the number of coaches per data point (i.e., the frequency of coaches reporting the same number of criteria per team) ranged from 1–3 coaches for Calgary high schools (68% of data points had a single coach), 1–4 coaches for Calgary club (63% of data points had a single coach), and 1–6 coaches for Québec City high schools (65% of data points had a single coach) (Figure 1).
The number of helmet fit/condition criteria reported by individual coaches (stratified by team) for each league.
Coach helmet beliefs/perspectives
Assessment of coaches’ helmet-related beliefs using ‘select all that apply’ question formats (denominator is the number of coach responses to account for multiple selections) found that 89%–93% of coaches reported at least one barrier to fitting helmets, with lack of formal training as the most common barrier (41%–62% of coach responses), followed by lack of equipment to fit helmets and high costs of equipment (13%–31% of coach responses), and lack of coaches to fit helmets (15%–17% of coach responses) (Table 4). Moreover, 68%–75% of coaches reported that there is either not enough helmet fit information available (39%–56% of coaches) or that they were not sure if enough information was available (18%–35% of coaches) (Table 4). The most common sources for learning about helmets included Football Canada (21%–26% of coach responses), generic internet search/advertisements (11%–28% of coach responses), and helmet manufacturers (18%–21% of coach responses), while 11%–16% of coaches were unsure where they learn about helmets (Table 4).
Most coaches preferred the Riddell helmet brand (53%–67% of coach responses), followed by Schutt (10%–21% of coach responses), and Vicis (3%–23% of coach responses). Moreover, 0%–28% of coach responses either had no helmet brand preference (0%–19% of coach responses) or were unsure of a preferred brand (0%–8% of coach responses) (Table 4). The main reasons for favouring a helmet brand included its impact technology (12%–20% of coach responses), the helmet's comfort (13%–16% of coach responses), and being easy to fit (13%–16% of coach responses) (Table 4). Favouring a helmet brand based on providing the most protection against concussion or severe head injury was found in 10%–13% of coach responses (Table 4).
Coach helmet and mouthguard beliefs/perspectives for injury prevention
Most coaches believed that wearing a helmet (regardless of fit) could protect against sustaining a concussion (52%–70% of coaches) (Table 5). Most coaches also believed that wearing a properly fitted helmet could protect against sustaining a concussion (78%–93% of coaches) and experiencing a more severe concussion (84%–92% of coaches) (Table 5). For mouthguards, most coaches believed that wearing a mouthguard could protect against sustaining a concussion (67%–77% of coaches), dental injuries (77%–88% of coaches), and orofacial (e.g., lip) injuries (51%–63% of coaches) (Table 5).
Discussion
To our knowledge, this was the first study to examine adolescent tackle football coaches current helmet fitting procedures and beliefs for helmet and mouthguards. As tackle football has amongst the highest adolescent sport-specific concussion rates and approximately 60% of players are estimated to be wearing a poor fitting helmet,4,11,12 this study provides an important perspective for future helmet fit and mouthguard education initiatives.
We found most coaches believed that wearing a mouthguard could protect against sustaining a concussion (67%–77% of coaches), dental injuries (77%–88% of coaches), and orofacial injuries (51%–63% of coaches). Evidence from a meta-analysis demonstrated that collegiate and youth ice hockey players who wore a mouthguard had a 28% lower concussion rate.5,6,17 It is interesting that 12%–49% of coaches did not believe that wearing a mouthguard could protect against dental and/or orofacial injuries despite meta-analyses demonstrating a 58% lower risk for these injuries when wearing a mouthguard. 7 As youth tackle football leagues mandate mouthguard use, perhaps more education about the benefits of wearing a mouthguard is warranted. We were surprised to find that a higher proportion of coaches believed wearing a mouthguard (equipment that sits in the mouth) could protect against a concussion (67%–77% of coaches) than wearing a helmet (equipment that covers the head, regardless of fit; 52%–70% of coaches). We are unsure why this was found when evidence demonstrating that wearing a mouthguard for concussion protection is relatively recent and extensive literature has demonstrated that wearing a helmet is effective for reducing head injuries (albeit most studies are not specific to concussion).5,18 Perhaps these findings reflect interpretations from media messaging that indicates helmets are for the prevention of moderate and severe traumatic brain injuries and not for concussion prevention.19,20 However, as the most coaches agreed that wearing a properly fitted helmet could protect against sustaining a concussion (78%–93% of coaches) and reduce the severity of a concussion (84%–92%), perhaps coaches believed that helmet-based concussion prevention could only be achieved if the helmet is worn properly. Wearing a proper fitting helmet was associated with a 63% lower concussion odds in youth ice hockey players and a shorter concussion recovery (with less symptoms experienced) in adolescent tackle football players.9,10 It is concerning that 58%–96% of coaches (31%–96% who reported fitting helmets) had never received any helmet fit training, and that lack of training was reported as the main barrier for fitting helmets (followed by lack of helmets, equipment, and high costs for helmets and helmet parts). The main sources that coaches used to learn about helmets included Football Canada, helmet manufacturers, and internet searches/advertisements; however, 68%–74% of coaches believed there was not enough helmet fitting information available or were unsure if enough information was available. These results suggest that tackle football organizations are not actively training coaches to fit helmets but are relying on coaches to acquire information themselves (if at all). This is further supported by football administrations leading less than 25% of the helmet fit training sessions that coaches had received.
Aside from available helmet manufacturer fitting guidelines 14 and developed checklists,11–13,15,16 the USA Football's Heads Up Football program and the American Pop Warner little scholar program take active roles in coach safety training through comprehensive educational modules that includes fitting protective equipment (including helmets), proper tackle training, and other safety components of safety.21,22 Unfortunately, it is unclear whether the helmet fitting components within these programs are adhered to by coaches and if players within the programs have better fitting helmets than players not in the programs. Therefore, adherence with helmet fit training programs should be explored in future research.
Across leagues, we found coaches reported a median of 2–3 criterion within their helmet fitting procedures, which is lower than the number of items used within Riddell helmet manufacturer guidelines (7 criteria), the National Athletic Trainers’ Association guideline (10 criteria), and checklists developed within prior research studies (7–17 criteria).11–16 We also found a high variability in the number of criteria reported by coaches on the same team, which may affect the consistency of proper helmet fit amongst players within a single team. Twelve of 17 items (71% of items) from our developed criteria were completed by ≤10% of coaches across all 3 cohorts, which suggests that a training module with our checklist (most comprehensive checklist to date) is needed. The most common criteria used by coaches included considerations for a snug fitting helmet shell (79%–96% of coaches), a snug fitting chin strap (43%–85% of coaches), snug fitting cheek pads (21%–52% of coaches), the player's perception of comfort/fit (25%–43% of coaches), and the helmet's positioning on the forehead (7%–30% of coaches). Although coaches are considering these items, prior research has indicated that the most problematic criteria for tackle football players are “the helmet shell positioned 1–2 finger widths above the eyebrows” (25%–43% of players met this item), “the helmet shell fits snug” (48%–73% of players met this item), and “the chin strap fits snug” (53%–88% of players met).11–13,15 These findings suggest that standardizing procedures for assessing helmet fit items needs improvement amongst coaches.
Unfortunately, few coaches provided specific information for how they would assess each criterion, but rather included generic information such as “ensuring proper positioning on the forehead” or that the helmet is “snug on the head”. We suspect that there would be even more variability in helmet fitting procedures if each coach had provided their specific process for assessing each criterion. For example, coaches who provided their processes for assessing if the helmet shell fits snug ranged from ensuring there is “no bouncing of the shell”, “no jiggling on the head”, determining if the “forehead skin moves while twisting the facemask”, to ensuring that one finger-width can fit between the helmet shell and the player's head at the front, back, and sides of the helmet. As these procedures for assessing the same criteria are quite variable, it is unknown whether the standards for determining if the helmet shell fits snug or not would be consistent. Moreover, one coach reported they ensure one finger-width can fit between the cheek pads and the player's face, which although shows that they are considering the fit of the cheek pads, their procedure would actually indicate a poor fit. Equipment manufacturer guidelines and developed checklists suggest that the cheek pads should be snug against the cheeks so that a playing card (much thinner than a finger-width) is unable to fall out.11,14,16 These results support immediate action for tackle football organizations to provide coaches with formal helmet fit training and standardized criteria to harmonize fitting procedures.
We stratified our results to descriptively display the similarities and differences by each league, in case there would be specific recommendations for different tackle football organizations (e.g., Football Alberta versus Football Québec, Calgary high school versus Calgary club). The main discrepancies included 93% of Québec City coaches reported fitting helmets (compared with 42%–52% in Calgary high school and club), the majority of Calgary club coaches (69%) who fitted helmets had received prior helmet fit training (compared with 39% of Calgary high school and 4% of Québec City high school coaches), and that formal helmet fit criteria was provided to the majority of Calgary high school coaches (55%) compared with Calgary club (23%) and Québec City (0%). Regardless, the patterns of responses for helmet fitting procedures, beliefs for helmet information, and beliefs for helmet and mouthguards’ effectiveness against injury were similar between leagues; and therefore, the interpretations of our findings and recommendations are relevant for all leagues.
Despite our findings of inconsistent helmet fitting procedures amongst coaches, it is important to note that tackle football's reliance on coaches to fit and manage helmets is unique and may be more effective for player safety than other helmeted sports that rely on individual players/families to oversee helmet fit (e.g., ice hockey, ringette, lacrosse). A responsibility hierarchy for child and adolescent safety developed by Emery, Hagel, and Morrongiello (2006) proposes that the most effective injury prevention initiatives are endorsed and driven by government and sport organizations, rather than individual agents (i.e., players, parents, and coaches) (Figure 2). 23 Although the current structure of tackle football leagues rely on coaches to fit helmets, there is significant opportunity for national, provincial, and local tackle football organizations to support this responsibility by providing formal training modules and detailed instructions with standardized criteria to coaches. Moreover, educational resources provided to players, parents, and coaches that include the importance of wearing a mouthguard to protect against concussion and orofacial injuries, and wearing a proper fitting helmet for head injury (and concussion) protection would be important for knowledge mobilization. Additional actions by organizations could include policy that requires all players to wear a properly fitted helmet during gameplay (e.g., a snug helmet shell, snug chin strap, coverage of the occipital bone) or incur sanctions by officials. Although there would be additional training and enforcement considerations for officials, a similar policy is already in place that mandates the use of mouthguards for child and adolescent players. 24
Responsibility hierarchy for player safety specific to helmet fitting contexts in select sports [adapted from Emery, Hagel, and Morrongiello (2006)]. 23
Overall, the structure of many tackle football leagues creates a unique and important opportunity for organizations to implement evidence-informed training to harmonize helmet fitting procedures amongst coaches. Our results suggest that there are significant gaps and barriers to coach helmet fitting that may affect player safety. Further development, implementation, and examination of a helmet fit training intervention on coach helmet fit knowledge and behaviours, and incidence rates of concussion amongst players is warranted.
Limitations
We acknowledge several limitations within this study. First, as our description of helmet fit processes and beliefs were based on self-reported responses from teams working with the SHRed Concussions study, there is a potential for social desirability bias amongst respondents. This may have led coaches to overestimate the importance that they place on helmet fit (especially for concussion prevention) and the comprehension they reported using for their helmet fitting processes (e.g., coaches reporting more criteria than they actually would use). One method to address this limitation would be for the research team to observe coaches while they fit helmets and document the criteria and procedures being used; however, this would likely result in altered behaviours (i.e., coaches assessing more comprehensively under research team scrutiny). Although the severity and influence of this potential bias on study findings is difficult to determine, this would not affect our conclusions that greater educational resources should be provided to coaches by tackle football organizations.
Second, as we only recruited coaches from teams participating within the SHRed Concussions program, we were limited in both our recruitment sample size and in representation of coaches across all Canadian provinces and within the United States. However, as we included multiple leagues and teams from two Canadian provinces and the patterns of results were similar across the leagues, we believe that the results are likely generalizable to many tackle football settings. Nevertheless, future work should engage coaches from multiple settings within Canada and the United States (e.g., younger leagues, girls leagues), especially with representation of rural communities.
Finally, we assumed that the reported helmet fit criteria are correct and useful for determining proper fit. However, as many coaches did not report specific information for how they assess each criterion, we were not able to compare and contrast their current procedures against manufacturer guidelines and previously developed helmet fit checklists.11–15 Therefore, we are likely overestimating the comprehension of coach helmet fitting procedures.
Conclusion
This study demonstrated a significant gap in helmet fit education for Canadian adolescent tackle football coaches, with current helmet fitting procedures being highly variable within teams and not comprehensive compared with previously developed checklists and helmet manufacturer guidelines. Although most coaches believed that wearing a properly fitted helmet was protective against concussion and concussion severity, lack of formal helmet fit training was the most prominent barrier. Our findings suggest that tackle football organizations should take immediate action by creating formal helmet fit training modules and providing coaches with standardized criteria to support optimal helmet fitting.
Footnotes
Acknowledgements
We acknowledge the support of the National Football League's Play Smart Play Safe Scientific Advisory Board, Alberta Innovates, Canadian Institutes of Health Research, and the Alberta Children's Hospital Research Institute (Alberta Children's Hospital Foundation). Ash Kolstad holds a Canadian Institutes of Health Research Frederick Banting and Charles Best Doctoral Scholarship, a Killam Laureates Pre-Doctoral Award, and the UCalgary Eyes High Doctoral Recruitment Scholarship. Carolyn Emery is a Deputy Editor for British Journal of Sports Medicine, was a member of the Expert Panel for the 6th International Conference on Concussion in Sport and holds a Canada Research Chair (Tier 1) in Concussion and research funding from the Canadian Institutes of Health Research, International Olympic Committee, World Rugby, National Football League Play Smart Play Safe Program, and Canada Foundation for Innovation. The University of Calgary Sport Injury Prevention Research Centre is one of the International Olympic Committee Research Centres for the Prevention of Injury and Protection of Athlete Health.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was part of the larger SHRed Concussions Research program which was investigator-initiated as part of a grant competition supported by the National Football League/Football Research, Inc.; funding decisions were made by an independent Scientific Advisory Board.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.