Context

A growing number of high-school–aged athletes participate on club sport teams. Some, but not all, state concussion laws apply to both interscholastic and private sport organizations. However, concussion education, management plans, and knowledge have not been examined in club coaches who coach high school-aged athletes.

Objective

To determine if differences in concussion education, management plans, and knowledge exist between high school coaches and coaches of club sport teams.

Design

Cross-sectional study.

Setting

Online survey.

Patients or Other Participants

A total of 769 coaches (497 high school coaches, 272 club coaches coaching high school-aged athletes; 266 women [34.6%], 503 men [65.4%]) completed an anonymous online questionnaire.

Main Outcome Measure(s)

The questionnaire consisted of demographic and team information, requirements for concussion-education and -management plans, and concussion knowledge.

Results

High school coaches were more likely than club coaches to report that their organizing bodies or leagues required them to receive concussion-education information (97.4% versus 80.4%; P < .001) and that their organizing bodies or leagues had a concussion-management plan (94.0% versus 70.2%; P < .001). High school coaches were more likely than club coaches to correctly agree that most concussions resolve in 7 to 10 days (48.6% versus 40.1%; P = .02) and disagree that loss of consciousness is required to diagnose a concussion (87.1% versus 80.9%; P = .02).

Conclusions

Club coaches were less likely to be aware of requirements for concussion-education and -management plans from their parent organizations and scored lower on specific concussion-knowledge questions than high school coaches despite the same education requirements across groups under their state concussion laws. These results raise concerns regarding the proper management of concussions in club sports and suggest a need for greater oversight and enforcement of state laws in the club sport setting.

Key Points
  • Fewer club than high school coaches were aware of concussion-education requirements from their organizing bodies or leagues despite being located in states with concussion laws that mandated concussion education for both interscholastic sports and private sport organizations.

  • Club coaches had less concussion knowledge and were less likely to be aware of whether their league or organization had a concussion-management plan.

  • These results raise concerns regarding the proper management of concussions in club sports and suggest a need for greater oversight and enforcement of state laws in the club sport setting.

  • Greater attention to club sport enforcement of concussion laws and efforts in concussion education may be needed to address gaps in concussion knowledge between high school and club coaches.

During the 2017–2018 school year, almost 8 million adolescents participated in high school sports.1  With an increase in sport specialization among youth athletes, more adolescents may be choosing to join non–school-affiliated club teams with the goals of training year-round and earning college scholarships.2,3  In 1 study,4  nearly half of high school athletes reported that they participated on a club team not affiliated with their high school team. In a survey5  of collegiate athletes, approximately 90% of soccer, basketball, and volleyball players had participated in their sport on both high school and club teams before college.

For high school and club athletes, injuries, such as concussions, pose health risks. An estimated 1.1 to 1.9 million sport- and recreation-related concussions occur annually in youths aged ≤18 years.6  The Centers for Disease Control and Prevention defined a concussion as “a type of traumatic brain injury caused by a bump, blow, or jolt to the head or by a hit to the body that causes the head and brain to move quickly back and forth.”7  All 50 states and Washington, DC, have passed laws regarding concussions in youth sports.8  The state laws for concussion-management plans and coach concussion education for high school teams and other youth sport organizations, as obtained from a review of each state's concussion legislation, are provided in Table 1. All states except Georgia require high school coaches to receive educational materials or undergo training about concussions. Fewer than half of state concussion laws extend the same requirements to club sport coaches. Concussion recognition and proper management are important aspects of concussion education for coaches, who can play a key role in recognizing these injuries and removing injured athletes from play.9,10  Continuing to play while experiencing concussion symptoms has been associated with prolonged recovery, increased risk of incurring a second concussion, and a greater likelihood of a poor outcome after the injury.11,12  Coaches with greater knowledge of concussions may be better able to identify athletes experiencing concussion symptoms and guide them to appropriate medical personnel.1315 

Table 1

State Law Requirements for Concussion Education for Coaches and Concussion-Management Plansa in Schools or School Districts and Other Youth Sport Organizations

State Law Requirements for Concussion Education for Coaches and Concussion-Management Plansa in Schools or School Districts and Other Youth Sport Organizations
State Law Requirements for Concussion Education for Coaches and Concussion-Management Plansa in Schools or School Districts and Other Youth Sport Organizations

The role of coaches in concussion recognition, athlete concussion reporting, and proper management of the injury is especially critical when an athletic trainer (AT) or other medical professional with concussion training is not available. In a recent study,16  approximately 65% of high school coaches and 39% of club coaches stated that an AT was present at competitions most or all of the time. Only 30% of high school coaches and 8% of club coaches indicated that ATs were present at most or all practices.16  If an AT was not responsible for immediate medical care at either a practice or competition, both high school and club coaches most frequently acknowledged that this responsibility was theirs.16  Therefore, coaches must be able to recognize concussion symptoms and understand the appropriate steps to take if they suspect an athlete has sustained a concussion. The purpose of our study was to evaluate whether differences in concussion education, concussion-management plans, and concussion knowledge existed between high school coaches and coaches of club sport teams consisting of high school-aged athletes.

METHODS

Participants

The procedures for this study have been described previously.16  Briefly, coaches were eligible if they served as head or assistant coaches for basketball, volleyball, or soccer teams in a high school setting or club setting with high school-aged athletes in the 12 months before the study. These sports have high rates of participation in both the high school and club team settings.1  Coaches received emailed invitations to complete an anonymous online survey (Qualtrics Inc, Provo, UT). During the survey, coaches were instructed to identify their primary sport coaching responsibility, which was defined as the coaching opportunity most important to them and the one they would choose if restricted to a single sport. Respondents gave consent to participate by completing the survey, and the study was approved by the institutional review board at the University of Wisconsin-Madison.

Survey email distribution in this study has been described previously.16  Briefly, the Michigan High School Athletic Association assisted with email distribution to high school coaches. Given the difficulty in recruiting club coaches from Michigan alone, club coach recruitment was extended to 3 additional states within the Midwest. Club coach email addresses were also gathered from club sport organizations in Illinois, Minnesota, and Wisconsin. These states have similar concussion-education laws as those in Michigan.

We sent 11 248 emails and received 1156 responses, for a response rate of 10.3%. Surveys that were started but never finished were not included in this analysis. Thus, the overall effective response rate was 6.8% (769 completed questionnaires), with response rates of 17.4% (497 completed questionnaires, 2852 emails sent) for high school coaches and 3.2% (272 completed questionnaires, 8396 emails sent) for club coaches. About one-third of our sample identified as female (n = 266, 34.6%).

Questionnaire

Questions for this study were part of a larger questionnaire used to examine emergency preparedness factors, medical coverage, emergency-care training requirements, and sport specialization. Questions examined in the present study composed 3 sections: (1) demographics and teams coached, (2) requirements for concussion-education and concussion-management plans from the coach's organizing body or league, and (3) concussion-knowledge questions. Specific questions of interest for this study are presented in Tables 2 through 4.

Table 2

Comparative Demographics of High School and Club Sport Coaches

Comparative Demographics of High School and Club Sport Coaches
Comparative Demographics of High School and Club Sport Coaches

State concussion laws were obtained from individual state government Web sites and databases through June 28, 2019. We examined the laws for requirements regarding concussion education and training for coaches, a concussion-management plan for each institution or organization, and whether these mandates applied only to schools or also to other sport organizations.

A modified version of the index designed by Chrisman et al17  was used to measure general concussion knowledge among high school and club sport coaches. We adapted 5 of the original statements from this index for use in our survey: “Most concussions (>80%) resolve within 7 to 10 days,” “It is safe for a player to go back into the game if concussion symptoms last less than 15 minutes,” “After having a concussion, an athlete has a higher risk of getting a second concussion,” “Loss of consciousness is required to diagnose a concussion,” and “Returning to play while having symptoms of a concussion can slow recovery.” Responses to the questions were scored on a 7-item Likert-type scale, ranging from 1 (strongly disagree) to 7 (strongly agree).

Statistical Analysis

Likert-scale responses were reduced to binary variables to indicate the answer for each question. This allowed us to analyze the coaches' actionable beliefs about the items rather than their confidence levels in their responses. Somewhat agree, agree, and strongly agree were grouped into an agree category, whereas somewhat disagree, disagree, and strongly disagree were grouped into a disagree category. Agree was the correct answer for 3 of the 5 questions, and disagree was the correct answer for 2 questions (Table 4). Neither agree nor disagree was considered incorrect for all questions and grouped with the incorrect response (either the agree or disagree category) for each question.

Table 3

High School and Club Sport Coaches' Awareness of Receiving Concussion-Education and Concussion-Management Plans

High School and Club Sport Coaches' Awareness of Receiving Concussion-Education and Concussion-Management Plans
High School and Club Sport Coaches' Awareness of Receiving Concussion-Education and Concussion-Management Plans
Table 4

Concussion Knowledge Between High School and Club Sport Coaches

Concussion Knowledge Between High School and Club Sport Coaches
Concussion Knowledge Between High School and Club Sport Coaches

Demographic data were summarized as frequencies with proportions (in percentages) and means with standard deviations. Chi-square analyses were calculated to compare differences in demographic factors between groups, except for age, which was compared using an independent t test. Chi-square analyses were also conducted to compare the frequency of responses to all concussion questions between high school and club coaches. To determine whether demographic differences between high school and club coaches influenced their awareness of concussion-education requirements, concussion-management plans, or concussion knowledge, we performed secondary χ-square analyses to compare responses based on the sport coached and education level. We used SPSS (version 25.0; IBM Corp, Armonk, NY) for all analyses. The α level was set at .05.

RESULTS

Several demographic factors differed between high school and club coaches (Table 2). Basketball coaches were more likely to identify as high school coaches (high school = 40.8% versus club = 32.0%), whereas volleyball (high school = 30.6% versus club = 38.2%) and soccer (high school = 28.6% versus club = 29.8%) coaches were more likely to identify as club coaches. More high school than club coaches reported that they had earned a graduate or professional degree (48.3% versus 31.3%), and more club than high school coaches reported they had earned an associate or 2-year college degree (17.6% versus 8.5%) or a bachelor's or 4-year degree (46.0% versus 36.4%). Awareness of whether their parent organizations had a concussion-management plan differed among basketball, volleyball, and soccer coaches, with soccer coaches most likely to report that their parent organizations had a concussion-management plan (basketball = 84.5%, volleyball = 81.3%, soccer = 91.9%; χ24 = 14.9, P = .005; see Supplemental Table 1). The requirements for concussion education and concussion knowledge did not differ based on sport coached (P > .05; see Supplemental Table 2). No differences were found in responses to any concussion questions based on coach education level (P > .05; see Supplemental Tables 3 and 4).

More high school than club sport coaches reported that they were required to receive educational information about concussions from their organizing bodies or leagues (97.4% versus 80.4%; χ22 = 64.3, P < .001; Table 3). Similarly, high school coaches were more likely than club coaches to report that their organizing bodies or leagues had a concussion-management plan (94.0% versus 70.2%; χ22 = 84.6, P < .001).

More high school than club coaches correctly agreed that most concussions resolve in 7 to 10 days (48.6% versus 40.1%; χ21 = 5.1, P = .02; Table 4). However, fewer than half of all respondents answered this question correctly (45.6%, n = 350/768). Additionally, more high school than club coaches correctly disagreed with the statement, “Loss of consciousness is required to diagnose a concussion” (87.1% versus 80.9%; χ21 = 5.3, P = .02). High school and club coaches did not differ in their responses to the 3 additional concussion-knowledge questions.

DISCUSSION

We found a difference between high school and club sport coaches for concussion knowledge, as well as awareness of requirements for concussion-education and -management plans. Compared with high school coaches, fewer club coaches reported that they were required to receive concussion education. Club sport coaches in Illinois, Michigan, Minnesota, and Wisconsin were surveyed in this study, and these states' concussion laws require or encourage (Illinois) concussion education for coaches in any youth sport organization, including those not affiliated with public or private schools. However, 17% fewer club than high school coaches knew whether their organizing bodies or leagues required them to receive concussion education. Several factors could have contributed to this finding. It is possible that the organizing bodies or leagues were not aware that the laws in these states applied to their organizations, were poorly communicating the requirement for concussion education to their coaches, or were not enforcing or complying with the laws within their organizations. Previous authors18  have suggested that the lack of a formal compliance or enforcement mechanism in state concussion laws was a barrier to effective implementation. Interscholastic athletic associations, departments of education, or both may be providing greater oversight and enforcement of these laws within high schools, whereas a lack of similar oversight or ineffective enforcement for club sport organizations may result in downstream consequences that contributed to our findings. Additional research is needed to explain why fewer club coaches were aware of their concussion-education requirements.

More high school than club coaches answered concussion-knowledge questions correctly in this study, which may be related to the coaches' lack of awareness of their leagues' requirements. Investigators1315  have proposed that coaches with greater concussion knowledge may be more likely to identify a concussed athlete, appropriately remove that athlete from play, and ensure that the athlete receives proper medical care and clearance before returning to play. As shown in Table 1, concussion education or training is required only for coaches in club or other youth sport organizations in 20 states (42%) and Washington, DC. Four additional states encourage concussion education for non–school-affiliated youth sports organizations, and another 3 states require concussion education for outside organizations using school or other public facilities. Given the rise in sport specialization and club sport participation in recent years2,3  and the responsibility that club coaches have in their athletes' medical care,16  it is concerning that club sport coaches are held to a different standard regarding concussion education and knowledge than those who coach high school athletes.

As with concussion education, fewer club sport coaches reported that their organizing bodies or leagues had a concussion-management plan. A total of 94.0% of high school coaches said their school had a concussion-management plan, whereas only 70.2% of club coaches reported the same. All state concussion laws discuss the appropriate management of a concussion. However, among all states and Washington, DC, only 18 (35.3%) required schools or school districts to create their own concussion-management plan, and only 5 (9.8%) required non–school-affiliated youth sports organizations to have their own plan (Table 1). One additional state encouraged youth organizations to have their own plan, and 2 others had this requirement only for organizations using school or other public facilities. Of the 4 states in this study, only Illinois required schools to have a concussion-management plan, whereas none of the states required that of club sport organizations. Researchers should investigate whether having a concussion-management plan influences high school and club coach concussion knowledge and the proper management of concussions in their athletes.

High school coaches (48.6%) correctly agreed with the statement, “Most concussions (>80%) resolve within 7 to 10 days,” more frequently than club coaches (40.1%). Notably, fewer than half of all coaches responded to this statement correctly, whereas at least 80% of coaches responded correctly to all other concussion-knowledge statements. This timeline is primarily based on research published in the 1990s and early 2000s,19  but more recent authors19,20  have suggested the average recovery time may be longer than originally thought (ie, within 1 month of injury). It is possible that some coaches answered this question based on their personal experience with concussed athletes who had a longer average recovery time. More concerning is that some coaches may be allowing their athletes to return to play prematurely, especially in settings without an AT, leading them to underestimate the average recovery time.16  Researchers should further investigate what coaches believe is the average time to recovery from concussions and return to play and the reasoning behind their estimates.

For decades, loss of consciousness (LOC) has not been required for a concussion diagnosis.21  However, more club (19.1%) than high school (12.9%) coaches indicated that they believed LOC was necessary for a concussion to be diagnosed. These values are consistent with studies13,14,22  of youth sports coaches' concussion knowledge. In 2007, Valovich McLeod et al23  found that 42% of youth sport coaches believed that a concussion only occurs when an athlete experiences LOC. Mandated concussion education may have resulted in improved coach knowledge regarding LOC and concussions over the past decade. The fact that 12.9% to 19.1% of coaches overall still subscribed to this common misconception is troubling. Given that most concussions do not result in LOC, this misconception may lead to concussions going undiagnosed, particularly when an AT is not present and the coach is responsible for the team's medical care.

High school and club coaches differed on some, but not all, of their answers to the concussion-knowledge questions, which may be due to receiving information from sources other than formal concussion-educational materials. Mrazik et al22  observed that coaches most often obtained concussion information from magazines and newspapers, whereas the internet was the second most frequent source. Information about removal from play and same-day return to play has been a focus of concussion laws, as well as media coverage about concussions.24  Short-term and long-term consequences of poor concussion management have also received media attention over the past decade.24  Media coverage could be responsible for the lack of difference in responses to these questions despite fewer club coaches reporting that they received concussion education from their organizing bodies or leagues. It is also possible that some club coaches currently or previously coached a high school sport and received concussion education in that setting. We did not obtain information about previous or concurrent coaching roles in this study.

Coaches play an important role in setting the culture and expectations for safety and reporting among their teams.9,20,25,26  Several researchers10,27  have suggested that approximately half of concussed athletes continue to play while experiencing symptoms without reporting their injury. Continuing to play with a concussion can have serious consequences, including an increased risk that the vulnerable brain will sustain a second concussion, resulting in the athlete's experiencing prolonged recovery from the original injury, delayed return to play, and persistent difficulties in the classroom.11,12  Numerous factors can influence an athlete's decision not to disclose the injury, including not wanting to let the coach down, perceiving pressure from the coach to continue playing, or perceiving that the coach did not support reporting of the injury.15,26,28,29  Chrisman et al29  examined barriers to reporting concussion symptoms through interviews with high school athletes. Some players stated that their coaches set clear expectations and made them comfortable reporting concussion symptoms, whereas other players reported negative experiences or pressures not to disclose the injury. Of particular interest to us, 1 female soccer player reported that she began perceiving pressure to play through symptoms when she joined her club team. Coaches' concussion knowledge may affect their attitudes and beliefs toward concussion reporting, which in turn can influence the reporting culture of the teams that they coach.25  This raises important concerns, given our results about the lack of education and knowledge reported by club sport coaches.

Two demographic characteristics differed between the high school and club coaches: sport coached and educational attainment. Sport coached only influenced coach awareness of their parent organizations requiring a concussion-management plan, and the educational level did not influence responses to any concussion questions. Concussion rates were higher in soccer than in basketball and volleyball.30  The higher concussion rate may have resulted in more soccer leagues developing and distributing concussion-management plans to coaches.

Our study had several limitations. Because of the geographic distribution and response rate, it is possible that our results are not generalizable. Budget constraints restricted our recruitment of high school coaches to only 1 state. Recruitment of high school coaches from 1 state and club coaches from several states may have influenced the findings regarding concussion management, education, and knowledge. All states from which club sport coaches were recruited have similar concussion laws requiring education of coaches from non–school-affiliated sport organizations, but enforcement of these regulations may vary across these states. Club coaches may have also received concussion education from sources other than their current organizing bodies or leagues. Moreover, club coaches may have coached high school teams previously or concurrently and received concussion education in that setting. Future researchers should address additional sources of information, as well as other factors that may influence concussion education and management in the club sport setting.

Given that many athletes see club sports as a key to college recruitment2  and consistent with the perception of increased pressure to play through an injury on club teams observed by Chrisman et al,29  coaches in the club sport environment may add to pressure promoting nondisclosure of concussion symptoms. Adequate concussion knowledge does not always reflect attitudes toward concussion-management or concussion-reporting behaviors.28  However, we only addressed concussion education and knowledge among high school and club sport coaches. Investigators should examine coaches' attitudes and intentions toward concussion management and the effect on team reporting culture between high school and club sport teams.

CONCLUSIONS

Fewer club than high school coaches were aware of concussion education and requirements by their organizing bodies or leagues despite all being located in states with concussion laws that mandate concussion education for both interscholastic sports and private sport organizations. Similarly, club coaches displayed less concussion knowledge and were less likely to be aware of whether their leagues or organizations had a concussion-management plan. These results raise concerns regarding the proper management of concussions in club sports and suggest the need for greater oversight and enforcement of state laws in the club sport setting. Greater attention to club sport enforcement of concussion laws and efforts in concussion education may be needed to address gaps in concussion knowledge between high school and club coaches.

REFERENCES

REFERENCES
1. 
High school sports participation increases for 29th consecutive year
.
National Federation of State High School Associations Web site
.
2. 
Difiori
JP,
Benjamin
HJ,
Brenner
JS,
et al.
Overuse injuries and burnout in youth sports: a position statement from the American Medical Society for Sports Medicine
.
Br J Sports Med
.
2014
;
48
(4)
:
287
288
.
3. 
McGuine
TA,
Post
EG,
Hetzel
SJ,
Brooks
MA,
Trigsted
S,
Bell
DR.
A prospective study on the effect of sport specialization on lower extremity injury rates in high school athletes
.
Am J Sports Med
.
2017
;
45
(12)
:
2706
2712
.
4. 
Post
EG,
Bell
DR,
Trigsted
SM,
et al.
Association of competition volume, club sports, and sport specialization with sex and lower extremity injury history in high school athletes
.
Sports Health
.
2017
;
9
(6)
:
518
523
.
5. 
Results from the 2015 GOALS study of the student-athlete experience
.
Paper presented at: NCAA Convention; January 14, 2016; San Antonio, TX
.
6. 
Bryan
MA,
Rowhani-Rahbar
A,
Comstock
RD,
Rivara
F
;
Seattle Sports Concussion Research Collaborative. Sports- and recreation-related concussions in US youth
.
Pediatrics
.
2016
;
138
(1)
:
e20154635
.
7. 
Heads up concussion: a fact sheet for youth sports coaches
.
Centers for Disease Control and Prevention Web site
.
https://www.cdc.gov/headsup/pdfs/youthsports/coaches_engl.pdf. Published 2015. Accessed December 18, 2019.
8. 
Parsons
JT,
Baugh
C.
The evolving landscape of policies, rules, and law in sport-related concussion
.
In:
Hainline
B,
Stern
RA,
eds.
Sports Neurology: Handbook of Clinical Neurology Series. Vol 158
.
San Diego, CA
:
Elsevier Inc;
2018
:
257
267
.
9. 
Parker
EM,
Gilchrist
J,
Schuster
D,
Lee
R,
Sarmiento
K.
Reach and knowledge change among coaches and other participants of the online course: “concussion in sports: what you need to know.”
J Head Trauma Rehabil
.
2015
;
30
(3)
:
198
206
.
10. 
Rivara
FP,
Schiff
MA,
Chrisman
SP,
Chung
SK,
Ellenbogen
RG,
Herring
SA.
The effect of coach education on reporting of concussions among high school athletes after passage of a concussion law
.
Am J Sports Med
.
2014
;
42
(5)
:
1197
1203
.
11. 
Prins
ML,
Alexander
D,
Giza
CC,
Hovda
DA.
Repeated mild traumatic brain injury: mechanisms of cerebral vulnerability
.
J Neurotrauma
.
2013
;
30
(1)
:
30
38
.
12. 
Carson
JD,
Lawrence
DW,
Kraft
SA,
et al.
Premature return to play and return to learn after a sport-related concussion: physician's chart review
.
Can Fam Physician
.
2014
;
60
(6)
:
e310
,
e312
e315
.
13. 
Guo
D,
Verweel
L,
Reed
N.
Exploring gaps in concussion knowledge and knowledge translation among coaches of youth female hockey
.
Clin J Sport Med
.
2019
;
29
(6)
:
486
493
.
14. 
Nanos
KN,
Franco
JM,
Larson
D,
Mara
K,
Laskowski
ER.
Youth sport-related concussions: perceived and measured baseline knowledge of concussions among community coaches, athletes, and parents
.
Mayo Clin Proc
.
2017
;
92
(12)
:
1782
1790
.
15. 
Kerr
ZY,
Register-Mihalik
JK,
Marshall
SW,
Evenson
KR,
Mihalik
JP,
Guskiewicz
KM.
Disclosure and non-disclosure of concussion and concussion symptoms in athletes: review and application of the socio-ecological framework
.
Brain Inj
.
2014
;
28
(8)
:
1009
1021
.
16. 
Post
EG,
Schaefer
DA,
Biese
KM,
et al.
A comparison of emergency preparedness between high school coaches and club sport coaches
.
J Athl Train
.
2019
;
54
(10)
:
1074
1082
.
17. 
Chrisman
SP,
Schiff
MA,
Rivara
FP.
Physician concussion knowledge and the effect of mailing the CDC's “Heads Up” toolkit
.
Clin Pediatr (Phila)
.
2011
;
50
(11)
:
1031
1039
.
18. 
Lowrey
KM,
Morain
SR.
State experiences implementing youth sports concussion laws: challenges, successes, and lessons for evaluating impact
.
J Law Med Ethics
.
2014
;
42
(3)
:
290
296
.
19. 
McCrory
P,
Meeuwisse
W,
Dvořák
J,
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
(11)
:
838
847
.
20. 
Chrisman
SP,
Lowry
S,
Herring
SA,
et al.
Concussion incidence, duration, and return to school and sport in 5- to 14-year-old American football athletes
.
J Pediatr
.
2019
;
207
:
176
184
.
21. 
Scharf
R.
When is a head injury concussion?
Can Fam Physician
.
1980
;
26
:
948
951
.
22. 
Mrazik
M,
Bawani
F,
Krol
AL.
Sport-related concussions: knowledge translation among minor hockey coaches
.
Clin J Sport Med
.
2011
;
21
(4)
:
315
319
.
23. 
Valovich McLeod TC, Schwartz C, Bay RC
.
Sport-related concussion misunderstandings among youth coaches
.
Clin J Sport Med
.
2007
;
17
(2)
:
140
142
.
24. 
Bird
H.
What parents should know about concussions
.
Chicago Parent Web site
.
https://www.chicagoparent.com/learn/health-fitness/parents-guide-to-concussions/. Published March 12, 2019. Accessed December 18, 2019.
25. 
Kroshus
E,
Baugh
CM,
Hawrilenko
MJ,
Daneshvar
DH.
Determinants of coach communication about concussion safety in US collegiate sport
.
Ann Behav Med
.
2015
;
49
(4)
:
532
541
.
26. 
Baugh
CM,
Kroshus
E,
Daneshvar
DH,
Stern
RA.
Perceived coach support and concussion symptom-reporting: differences between freshmen and non-freshmen college football players
.
J Law Med Ethics
.
2014
;
42
(3)
:
314
322
.
27. 
Baugh
CM,
Meehan
WP,
Kroshus
E,
McGuire
TG,
Hatfield
LA.
College football players less likely to report concussions and other injuries with increased injury accumulation
.
J Neurotrauma
.
2019
;
36
(13)
:
2065
2072
.
28. 
Register-Mihalik
JK,
Guskiewicz
KM,
McLeod
TC,
Linnan
LA,
Mueller
FO,
Marshall
SW.
Knowledge, attitude, and concussion-reporting behaviors among high school athletes: a preliminary study
.
J Athl Train
.
2013
;
48
(5)
:
645
653
.
29. 
Chrisman
SP,
Quitiquit
C,
Rivara
FP.
Qualitative study of barriers to concussive symptom reporting in high school athletics
.
J Adolesc Health
.
2013
;
52
(3)
:
330
335
.
30. 
O'Connor
KL,
Baker
MM,
Dalton
SL,
Dompier
TP,
Broglio
SP,
Kerr
ZY.
Epidemiology of sport-related concussions in high school athletes: National Athletic Treatment, Injury and Outcomes Network (NATION), 2011–2012 through 2013–2014
.
J Athl Train
.
2017
;
52
(3)
:
175
185
.

Supplementary data