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Concussion Characteristics in High School Football by Helmet Age/Recondition Status, Manufacturer, and Model: 2008-2009 Through 2012-2013 Academic Years in the United States Christy L. Collins, Lara B. McKenzie, Amy K. Ferketich, Rebecca Andridge, Huiyun Xiang and R. Dawn Comstock Am J Sports Med published online February 23, 2016 DOI: 10.1177/0363546516629626 The online version of this article can be found at: http://ajs.sagepub.com/content/early/2016/02/22/0363546516629626
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Concussion Characteristics in High School Football by Helmet Age/Recondition Status, Manufacturer, and Model 2008-2009 Through 2012-2013 Academic Years in the United States Christy L. Collins,*y PhD, Lara B. McKenzie,z§k PhD, Amy K. Ferketich,k PhD, Rebecca Andridge,{ PhD, Huiyun Xiang,zk PhD, MD, and R. Dawn Comstock,#** PhD Investigation performed at the Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA Background: Football helmets used by high school athletes in the United States should meet the National Operating Committee on Standards for Athletic Equipment performance standards. Despite differences in interior padding and exterior shells, all football helmets should provide comparable protection against concussions. Yet, debate continues on whether differences in the rates or severity of concussions exist based on helmet age/recondition status, manufacturer, or model. Purpose: To investigate whether high school football concussion characteristics varied by helmet age/recondition status, manufacturer, and model. Study Design: Descriptive epidemiological study. Methods: High school football concussion and helmet data were collected from academic years 2008-2009 through 2012-2013 as part of the National High School Sports-Related Injury Surveillance Study. The certified athletic trainers of participating schools submitted athlete-exposure (AE) and injury information weekly. Results: Participating schools reported 2900 football concussions during 3,528,790 AEs for an overall rate of 8.2 concussions per 10,000 AEs. Concussion rates significantly increased from 2008-2009 through 2012-2013 overall (P = .006) as well as in competition (P = .027) and practice (P = .023). Characteristics of concussed football players (ie, mean number of symptoms, specific concussion symptoms, symptom resolution time, and time until return to play) were similar among players wearing new helmets when compared with reconditioned helmets. Fewer players wearing an old/not reconditioned helmet had concussion symptoms resolve within 1 day compared with players wearing a new helmet. Despite differences in the manufacturers and models of helmets worn by all high school football players compared with players who sustained a concussion, the mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play were similar for concussions sustained by football players wearing the most common helmet manufacturers and models. Conclusion: Overall, for new and reconditioned football helmets, the most common helmet manufacturers and models on the market today appear to provide high school football players with similar protection against concussions. Clinical Relevance: Concussions can have serious acute and long-term effects. An understanding of concussion patterns in high school athletes can drive targeted preventive measures, including improvements to and/or better use of protective equipment, to reduce the incidence and/or severity of sports-related concussions. Keywords: concussion; football; helmet; adolescent
High school sports play an important role in the adoption and maintenance of a physically active lifestyle among millions of adolescents in the United States (US). Participation in high school sports has grown rapidly from approximately 4.0 million athletes in academic years 1971-1972 to 7.8
The American Journal of Sports Medicine, Vol. XX, No. X DOI: 10.1177/0363546516629626 Ó 2016 The Author(s)
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million in 2013-2014.12 In addition to helping youth maintain a healthy weight, regular physical activity has been shown to increase strength, endurance, and flexibility; improve psychological well-being and self-esteem; reduce depression and anxiety; and improve academic performance.2,9,21 While the health benefits of a physically active lifestyle including participating in sports are undeniable, high school athletes are at risk of sports-related injuries as a certain endemic level of injury can be expected among participants of any physical activity. Injury prevention in this population is often overlooked as sports-related injuries are thought to be unavoidable; however, the morbidity, mortality, and disability caused by high school sports-related injuries can be reduced through the development of evidence-based prevention strategies. A concussion is a common sports injury in the US, with approximately 1.6 million to 3.8 million recognized sportsrelated concussions occurring annually.1,5,6,10,17 Because of the ongoing neurocognitive development that occurs throughout adolescence, concussions can have severe acute and long-term complications in young athletes.1,17 While historically, helmets were designed to prevent skull fractures rather than concussions, a protective effect for which they are now thought essential, helmets have been effective in reducing the direct external transfer of force through the skull to the brain by spreading forces over a greater surface area.4 All football helmets used by high school athletes are required to meet performance standards developed by the National Operating Committee on Standards for Athletic Equipment (NOCSAE)15,16; therefore, despite differences in interior padding and exterior shells, all football helmets should provide similarly acceptable protection against concussions. Yet, debate continues on whether differences in the rates or severity of concussions exist based on helmet age/recondition status, manufacturer, or model. The majority of studies that have compared the effectiveness of different types of football helmets in protecting against concussions have used linear impact testing in the laboratory.7,18,22,23 Only a few prior epidemiological studies have investigated concussion incidence and/or outcomes in athletes wearing various helmets.3,11,19 One recent prospective cohort study conducted in Wisconsin found no difference in the incidence of sports-related concussions by helmet age/recondition status or helmet manufacturer.11 In contrast, another previous study of high school football
athletes found a difference in the incidence of concussions for new Riddell versus standard helmets; however, this study also found no difference in concussion symptoms, symptom resolution time, or return to play by the type of helmet worn.3 In a third study utilizing data from the Helmet Impact Telemetry System, which uses helmet-mounted accelerometers to collect head impact data and assess the frequency and severity of those impacts,8 among collegiate football athletes, there was a significant difference in the rate of concussions among players wearing a Riddell VSR4 helmet compared with a Riddell Revolution helmet.19 Because of the limited number of epidemiological studies examining differences in the rates or severity of concussions by the type of helmet worn and the conflicting results of these studies, more research is needed to determine if there are differences in the risk and patterns of concussions by the type of helmet worn. The objective of this study was to investigate whether high school football concussion characteristics vary by helmet age/recondition status, manufacturer, or model.
METHODS Participants This study was approved by the institutional review board at Nationwide Children’s Hospital. Data from the National High School Sports-Related Injury Surveillance Study from the 2008-2009 through 2012-2013 academic years were used. Since the 2005-2006 academic year, this longitudinal surveillance study has monitored injuries among US high school athletes. Schools with a certified athletic trainer (AT) who provided care for high school athletes and had a valid email address, identified using the National Athletic Trainers’ Association (NATA) membership lists, were eligible to participate in the study. An email sent to the school’s AT introduced the study and invited them to participate. Among all schools with an AT who expressed interest in participating, a 3-stage sampling methodology was used to select study schools. In the first stage, all schools were categorized into 8 sampling strata by geographic location (Northeast, Midwest, South, and West)20 and school size (enrollment 1000 or .1000 students). Participant schools were then randomly selected from each substratum to obtain 100 study schools to report
*Address correspondence to Christy L. Collins, PhD, OhioHealth Research and Innovation Institute, 3545 Olentangy River Road, NMB Suite 310, Columbus, OH 43214, USA (email: [email protected]). y OhioHealth Research and Innovation Institute, Columbus, Ohio, USA. z Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA. § Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio, USA. k Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, Ohio, USA. { Division of Biostatistics, College of Public Health, The Ohio State University, Columbus, Ohio, USA. # Department of Epidemiology, Colorado School of Public Health, University of Colorado Denver, Aurora, Colorado, USA. **Pediatric Emergency Medicine, School of Medicine, University of Colorado Anschutz, Aurora, Colorado, USA. The content of this report is solely the responsibility of the authors and does not necessarily represent the official views of the Centers for Disease Control and Prevention. One or more of the authors has declared the following potential conflict of interest or source of funding: This study was funded by the National Operating Committee on Standards for Athletic Equipment. The content of this report was also funded in part by the Centers for Disease Control and Prevention (grants R49/CE000674-01 and R49/CE001172-01). The authors also acknowledge the generous research funding contributions of the National Federation of State High School Associations.
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for each of the 9 sports included in the original National High School Sports-Related Injury Surveillance Study (boys’ football, boys’ and girls’ soccer, girls’ volleyball, boys’ and girls’ basketball, boys’ wrestling, boys’ baseball, and girls’ softball). In the second stage, all schools not selected in the first stage that offered any of the more rarely offered sports included in the expansion of the National High School Sports-Related Injury Surveillance Study (girls’ gymnastics, girls’ field hockey, boys’ and girls’ lacrosse, boys’ ice hockey, and boys’ volleyball) were selected for the convenience sample in an attempt to obtain as large a sample as possible that reported for these more rarely offered sports. In the third stage, a random sample of all schools not selected in the first or second stage that offered the remaining sports of interest (boys’ and girls’ track and field, boys’ and girls’ swimming and diving, and boys’ and girls’ cross country and cheerleading) were selected in an attempt to ensure at least 100 schools were reporting for each of the sports. This 3-step sampling methodology resulted in a large, nationally dispersed convenience sample of US high schools. Although the number of high schools participating varied each year, on average, approximately 200 US high schools across the country participated annually. The National High School Sports-Related Injury Surveillance Study gathered data via the Internet-based surveillance system High School Reporting Information Online (RIO). Participating ATs, who acted as the school’s reporter, received a weekly email throughout the study period reminding them to enter their school’s data into the High School RIO surveillance system. ATs completed reports that included exposure information (number of competitions and practices) and the number of reportable injuries sustained by athletes of each sport that was currently in session at their school. For each reportable injury, the AT completed an injury report that collected detailed information about the injured player (age, year in school, etc), the injury (site, type, severity, etc), the injury event (position played, phase of play, etc), and the use of protective equipment (manufacturer/model of helmet; use of protective eyewear, mouthguards, knee/ankle braces, and/or tape, etc). The Internet-based surveillance tool provided ATs with the ability to view and update reports as needed (need for surgery, days until resuming play, etc). To reduce loss to follow-up, reporters who repeatedly failed to log on to complete the weekly exposure and injury reports or who had errors with their reporting were contacted by the study staff and either reminded to report, asked to correct errors, or assessed for their willingness to continue participating in the study. In addition to collecting data on the use of protective equipment within the Internet-based surveillance system, ATs participating in the National High School Sports-Related Injury Surveillance Study were asked to complete a helmet inventory form annually during the 2008-2009 through 2012-2013 academic years. The helmet inventory form collected data on the manufacturer and model of helmets being worn by all athletes participating in boys’ football, baseball, ice hockey, and lacrosse and girls’ softball and whether the helmets were new or old (ie, not new that season) and, if old, if they had been reconditioned.
Measures An ‘‘athlete-exposure’’ (AE) was defined as 1 athlete participating in 1 practice or competition in which he or she was exposed to the possibility of an athletic injury. Exposure was expressed in 3 parts: (1) number of practices (the sum of the number of athletes at each practice during the past week), (2) number of competitions (the sum of the number of athletes at each competition during the past week), and (3) number of total AEs (the sum of the number of practices and number of competitions during the past week). An ‘‘injury’’ was defined as (1) occurring as a result of participation in an organized high school competition or practice; (2) requiring medical attention by a team physician, certified AT, personal physician, or emergency department/urgent care facility; and (3) resulting in restriction of the high school athlete’s participation for 1 days beyond the day of injury or any fracture, concussion, or dental injury regardless of whether it resulted in restriction of the student-athlete’s participation.
Statistical Analysis Data were analyzed using SPSS (version 22; IBM Corp). Injury rates were calculated as the ratio of case counts per 10,000 AEs and were compared using rate ratios (RRs) with 95% CIs. Injury proportions were compared using injury proportion ratios (IPRs) and corresponding 95% CIs. Following is an example of an IPR calculation: 0
1 No: of concussions sustained while B C wearing a reconditioned helmet in B C B C B which all symptoms resolved within 1 day C B C B C Total No: of concussions B C @ A sustained while wearing IPR ¼
0
a reconditioned helmet
1 No: of concussions sustained while B C B wearing a new helmet in which all C B C symptoms resolved within 1 day B C B C B C Total No: of concussions B C @ A sustained while wearing a new helmet
An RR or IPR .1.00 suggests a risk association, while an RR or IPR \1.00 suggests a protective association. 95% CIs not including 1.00 were considered statistically significant. The mean number of concussion symptoms by helmet age/recondition status, manufacturer, and model was compared using analysis of variance and x2 tests. Linear regression was used to assess rates of concussion over time. Statistical significance was set at P \ .05.
RESULTS Football-Related Concussions During the 2008-2009 through 2012-2013 academic years, schools participating in the National High School Sports-
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TABLE 1 Characteristics of Football-Related Concussions by Age/Recondition Status of Helmets Worn by High School Football Players Who Sustained a Concussion Age/Recondition Status of Football Helmeta
No. of concussion symptoms, mean 6 SD Specific concussion symptoms, % Headache Dizziness/unsteadiness Difficulty in concentration Confusion/disorientation Sensitivity to light/visual disturbance Drowsiness Nausea Amnesia Sensitivity to noise Irritability Tinnitus Loss of consciousness Hyperexcitability Symptom resolution time, % \15 min .15 min to \1 h 1 h to \1 d 1 d to \1 wk 1 wk to 1 mo .3 wkb .1 mob Time until return to play, % \1 wk 1 to 3 wk .3 wk Medical disqualification for season Otherc
Overall (N = 2900)
New (n = 606)
Old/Reconditioned (n = 1412)
Old/Not Reconditioned (n = 126)
4.52 6 2.31
4.63 6 2.25
4.50 6 2.26
4.17 6 2.26
93.2 75.0 59.8 50.1 39.8 31.0 30.9 22.7 21.6 11.0 10.6 3.4 2.7
91.9 77.9 64.0 57.1 41.4 28.9 29.4 26.2 21.3 10.7 6.8 4.5 2.6
93.2 75.0 61.3 50.1 38.8 30.9 29.5 21.7 20.3 11.3 12.7 3.0 2.3
96.8 71.4 43.7 42.9 41.3 20.6 38.1 19.8 24.6 7.1 8.7 2.4 0.0
2.9 4.8 12.4 49.5 26.7 2.7 1.1
2.8 4.5 16.6 45.1 27.1 2.8 1.0
3.7 5.7 12.6 49.4 25.2 2.3 1.0
1.6 3.2 9.7 54.8 30.6 0.0 0.0
40.2 35.6 6.2 4.2 13.8
38.6 36.8 6.1 3.7 14.7
38.5 37.3 6.4 4.4 13.5
46.8 34.7 4.8 1.6 12.1
a
Age/recondition status of helmet was unknown/not reported for 756 concussions (26.1%). Categories for symptom resolution time changed slightly in the 2011-2012 academic year. c Includes ‘‘athlete chooses not to continue,’’ ‘‘athlete released from team,’’ ‘‘other,’’ and ‘‘unknown.’’ b
Related Injury Surveillance Study reported 2900 football concussions during 3,528,790 AEs for an overall rate of 8.2 concussions per 10,000 AEs. Of the 2900 footballrelated concussions, 1696 (58.5%) were sustained in competition and 1204 (41.5%) in practice. Concussion rates were higher in competition (28.7 per 10,000 competition AEs) than in practice (4.1 per 10,000 practice AEs) (RR, 7.0; 95% CI, 2.5-19.7). Of all football-related injuries reported from 2008-2009 through 2012-2013 (N = 13,795), concussions accounted for 21.0%. Concussion rates significantly increased from 2008-2009 through 2012-2013 overall (P = .006) as well as in both competition (P = .027) and practice (P = .023). Concussed athletes reported a mean (6SD) of 4.52 6 2.31 concussion symptoms (Table 1). The most commonly reported concussion symptoms included headache (93.2%), dizziness/unsteadiness (75.0%), and difficulty in concentration (59.8%) (Table 1). Overall, 20.1% of concussed athletes had all concussion symptoms resolve within 1 day, and 69.6% had all symptoms resolve within 1 week. Moreover,
40.2% of athletes returned to play in less than 1 week (Table 1); 6.2% of athletes took more than 3 weeks to return to play, and 4.2% were medically disqualified for the season (Table 1).
Characteristics of Helmets Worn by High School Football Players Who Sustained a Concussion Nearly all helmets (92.7%) worn by high school football players who sustained a concussion had an NOCSAE seal or a seal imprinted on the helmet that declared that it met the requirements of performance tests when it was manufactured or recertified (0.6% did not have an NOCSAE seal; 6.8% were unknown). The majority of helmets (84.8%) were not modified or changed from the original manufactured specifications (2.9% were modified; 12.4% were unknown). Among the small proportion of helmets that were modified, the most common modifications were regarding chin cup covers (53.0%), chin straps (30.1%), eye shields/visors (13.3%), and face shields (7.2%). Most
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helmets worn by high school football players who sustained a concussion were initially fit by a coach (71.3%), followed by an AT (15.0%), a helmet company representative (8.0%), a team/school equipment manager (2.8%), or by the athletes themselves (0.8%) (2.0% were unknown). ATs reported that, in their opinion, the helmet fit correctly at the time of the injury among 84.6% of concussions sustained by football players (the helmet did not fit correctly among 3.2%; appropriate fit was unknown among 12.3%). A larger proportion of helmets that did not fit correctly were fitted by the coach (80.5%) compared with helmets that did fit correctly at the time of the injury (70.9%) (IPR, 1.14; 95% CI, 1.02-1.26). Damage to the helmet occurred in only 0.8% of reported concussions. The most commonly reported types of damage were chipped/ scratched paint (n = 9, 40.9%), dented/broken face masks (n = 4, 18.2%), cracked helmets (n = 3, 13.6%), and broken clips (n = 2, 9.1%). Overall, most football helmets worn by concussed athletes at the time of the injury were not new during the season in which the concussion was sustained (53.0%) (20.9% of helmets were new; age of helmet was unknown/not reported for 26.1% of concussions). The majority of helmets that were not new during this season had been reconditioned (91.8%). There was no significant difference in the mean number of concussion symptoms by age/recondition status of the football helmet (F = 2.29; df = 2; P = .101) (Table 1). In general, specific concussion symptoms, symptom resolution time, and time until an athlete returned to play were similar for concussions sustained by football players wearing new helmets and football players wearing helmets that had been reconditioned (Table 1). However, a smaller proportion of football players wearing helmets that had not been reconditioned had all concussion symptoms resolve in less than 1 day (14.5%) compared with football players wearing new helmets (23.9%) (IPR, 0.61; 95% CI, 0.39-0.95). Among all high school football athletes, the most commonly worn helmets were manufactured by Riddell (60.7%) and Schutt (38.1%) (Table 2). Similarly, among high school football athletes who sustained a concussion, the most commonly worn helmets were manufactured by Riddell (67.5%) and Schutt (28.4%). However, a larger proportion of football players who sustained a concussion were wearing a Riddell helmet (67.5%) compared with all football players (60.7%) (IPR, 1.11; 95% CI, 1.08-1.15) (Table 2). Conversely, a larger proportion of all football players wore a Schutt helmet (38.1%) compared with football players who sustained a concussion (28.4%) (IPR, 1.34; 95% CI, 1.26-1.43). For all manufacturers, the majority of helmets that were not new during the season in which the player sustained a concussion had been reconditioned (Adams: 85.7%; Rawlings: 100.0%; Riddell: 88.7%; Schutt: 88.0%; Xenith: 59.1%). Similarly, for all 5 manufacturers, the majority of football-related concussions were associated with head-tohead contact (Adams: 66.7%; Rawlings: 55.6%; Riddell: 70.4%; Schutt: 65.6%; Xenith: 70.4%), the most common position of the head during contact was head up (Adams: 46.9%; Rawlings: 66.7%; Riddell: 44.8%; Schutt: 44.0%; Xenith: 53.7%), and the most common direction of impact
TABLE 2 Manufacturers of Helmets Worn by All High School Football Players Compared With Those Worn by Concussed Athletesa All Athletes Manufacturer, n (%) Adams 241 (1.0) Rawlings 0 (0.0)a Riddell 14,510 (60.7) Schutt 9116 (38.1) Xenith 36 (0.2) Total,b n (%) 23,903 (100.0)
Concussed Athletes
35 9 1723 725 60 2552
(1.4) (0.4)a (67.5) (28.4) (2.4)a (100.0)
a There are small discrepancies between the All Athletes and Concussed Athletes columns because data from the All Athletes column came from those schools returning a helmet inventory survey, while data from the Concussed Athletes column came from High School Reporting Information Online injury reports. b Percentages do not sum to 100.0% because of rounding.
during contact was from the front (Adams: 46.9%; Rawlings: 88.9%; Riddell: 45.3%; Schutt: 45.3%; Xenith: 50.0%). The mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play were similar for concussions sustained by football players wearing the most common helmet brands, Riddell and Schutt (Table 3). Although there was a relatively small number of athletes wearing Xenith helmets (n = 60), when comparing concussions that occurred while wearing helmets made by Riddell, Schutt, and Xenith, there was a significant difference in the mean number of concussion symptoms (F = 7.79; df = 2; P \ .001), with more symptoms being reported by athletes wearing a Xenith helmet (Table 3). Additionally, a larger proportion of athletes wearing a Xenith helmet sustained specific concussion symptoms including amnesia, difficulty in concentration, and sensitivity to light/visual disturbance compared with athletes wearing a Riddell or Schutt helmet. A greater proportion of athletes wearing a Xenith helmet had a medical disqualification for the season (11.5%) compared with athletes wearing a Riddell (4.1%) (IPR, 2.80; 95% CI, 1.27-6.14) or Schutt helmet (4.1%) (IPR, 2.84; 95% CI, 1.23-6.54). More specifically, the most common helmet models worn by all athletes as well as concussed athletes were Riddell Revolution and Schutt DNA (Table 4). However, a larger proportion of football players who sustained a concussion were wearing a Riddell Revolution helmet (63.4%) compared with all football athletes (51.7%) (IPR, 1.23; 95% CI, 1.19-1.27) (Table 4). Conversely, a smaller proportion of football players who sustained a concussion were wearing a Schutt DNA helmet (7.9%) compared with all football athletes (10.6%) (IPR, 0.75; 95% CI, 0.64-0.87). In general, the mean number of concussion symptoms, specific concussion symptoms, and time until return to play were similar by helmet model (Table 5). For the most common helmet models, approximately 20% to 27% of concussion symptoms resolved in less than 1 day (Riddell Revolution: 20.1%; Riddell Revolution Speed: 26.3%; Schutt DNA: 27.1%; Schutt Air: 24.0%) except for Schutt Air XP, for which only
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TABLE 3 Characteristics of Football-Related Concussions by Helmet Manufacturer Helmet Manufacturer
No. of concussion symptoms, mean 6 SD Specific concussion symptoms, % Headache Dizziness/unsteadiness Difficulty in concentration Confusion/disorientation Sensitivity to light/visual disturbance Drowsiness Nausea Amnesia Sensitivity to noise Irritability Tinnitus Loss of consciousness Hyperexcitability Symptom resolution time, % \15 min .15 min to \1 h 1 h to \1 d 1 d to \1 wk 1 wk to 1 mo .3 wka .1 moa Time until return to play, % \1 wk 1 to 3 wk .3 wk Medical disqualification for season Otherb
Adams (n = 35)
Rawlings (n = 9)
Riddell (n = 1723)
Schutt (n = 725)
Xenith (n = 60)
4.46 6 2.11
3.67 6 2.87
4.43 6 2.22
4.52 6 2.40
5.60 6 2.34
94.3 71.4 62.9 40.0 42.9 17.1 42.9 17.1 28.6 11.4 17.1 0.0 0.0
100.0 88.9 22.2 33.3 22.2 33.3 22.2 0.0 22.2 0.0 11.1 11.1 0.0
92.8 74.7 59.7 50.7 38.1 29.5 29.9 22.8 19.2 10.6 8.9 3.8 2.6
93.5 74.6 57.7 49.4 41.8 32.4 30.1 20.8 23.4 10.6 12.3 2.6 2.6
95.0 76.7 80.0 60.0 58.3 41.7 31.7 41.7 43.3 18.3 8.3 3.3 1.7
0.0 5.9 17.6 50.0 23.5 0.0 2.9
0.0 0.0 12.5 12.5 75.0 0.0 0.0
2.5 5.0 13.9 48.8 26.3 2.4 1.1
4.3 5.3 11.9 48.7 25.9 3.0 0.9
2.0 3.9 2.0 49.0 35.3 5.9 2.0
48.6 31.4 0.0 5.7 14.3
37.5 25.0 37.5 0.0 0.0
41.0 35.8 6.1 4.1 13.0
39.2 35.4 7.0 4.1 14.2
23.1 40.4 3.8 11.5 21.2
a
Categories for symptom resolution time changed slightly in the 2011-2012 academic year. Includes ‘‘athlete chooses not to continue,’’ ‘‘athlete released from team,’’ ‘‘other,’’ and ‘‘unknown.’’
b
13.3% of concussion symptoms resolved in less than 1 day (x2(4) = 12.49; P = .014) (Table 5).
TABLE 4 Common Helmet Models Worn by All High School Football Players Compared With Those Worn by Athletes Who Sustained a Concussion
DISCUSSION
All Athletesa
This study, the largest epidemiological study to date to evaluate concussion outcomes in US football athletes wearing helmets of various ages/recondition statuses, manufacturers, and models, found no differences in concussion characteristics among players wearing new and reconditioned helmets or the most common helmet manufacturers and models. Only a few prior epidemiological studies have investigated concussion incidence and outcomes in athletes wearing different types of helmets3,11,19 as opposed to comparing helmet impact testing in the laboratory.7,18,22,23 As helmet technology continues to improve, so will helmet testing technology. However, it is crucial that researchers continue to conduct epidemiological studies to determine if laboratory testing results translate to on-the-field experiences of athletes. While helmet ratings based on laboratory testing are important, they alone should not drive decision making by school athletic directors, football coaches,
Manufacturer and model, n (%) Riddell Revolution 10,698 (51.7) Riddell Revolution Speed 1525 (7.4) Schutt DNA 2200 (10.6) Schutt Air 1114 (5.4) Schutt Air XP 938 (4.5)
Concussed Athletes
1376 142 172 126 151
(63.4) (6.5) (7.9) (5.8) (7.0)
a
Only helmet models worn by 4.5% of all athletes are included.
parents, or athletes as they select which helmets will be worn. Laboratory testing and ratings based on such testing must be coupled with population-based epidemiological studies to fully understand how different manufacturers and models of helmets truly perform in the field. Such epidemiological studies are the only way to evaluate concussion outcomes including concussion rates and severity by the type of helmet worn.
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TABLE 5 Characteristics of Football-Related Concussions by Helmet Model Helmet Model
No. of concussion symptoms, mean 6 SD Specific concussion symptoms, % Headache Dizziness/unsteadiness Difficulty in concentration Confusion/disorientation Sensitivity to light/visual disturbance Drowsiness Nausea Amnesia Sensitivity to noise Irritability Tinnitus Loss of consciousness Hyperexcitability Symptom resolution time, % \15 min .15 min to \1 h 1 h to \1 d 1 d to \1 wk 1 wk to 1 mo .3 wka .1 moa Time until return to play, % \1 wk 1 to 3 wk .3 wk Medical disqualification for season Otherb
Riddell Revolution (n = 1376)
Riddell Revolution Speed (n = 142)
Schutt DNA (n = 172)
Schutt Air (n = 126)
Schutt Air XP (n = 151)
4.48 6 2.24
4.37 6 2.08
4.58 6 2.54
4.48 6 2.40
4.95 6 2.44
93.2 74.9 60.2 52.2 39.5 29.0 30.0 23.3 20.1 10.9 9.0 3.6 2.2
87.3 72.5 62.0 52.1 38.7 30.3 24.6 26.1 17.6 7.7 7.0 5.6 4.9
92.4 72.7 57.6 53.5 40.1 36.0 30.8 19.8 20.9 13.4 14.0 3.5 2.9
92.9 79.4 61.9 44.4 42.9 34.1 25.4 17.5 22.2 9.5 12.7 3.2 2.4
96.7 86.1 60.9 53.6 48.3 33.8 35.8 25.2 27.2 7.9 13.0 2.0 4.6
2.2 4.4 13.5 49.3 26.9 2.6 1.1
1.5 5.1 19.7 43.1 27.7 2.2 0.7
7.4 3.7 16.0 45.1 22.8 4.3 0.6
2.5 5.0 16.5 47.1 26.4 1.7 0.8
1.4 2.8 9.1 54.5 30.1 2.1 0.0
39.9 36.4 5.8 4.2 13.8
41.6 35.0 10.2 2.2 10.9
46.8 28.8 5.8 2.6 16.0
34.1 35.8 8.9 7.3 13.8
33.1 44.4 5.6 1.4 15.5
a
Categories for symptom resolution time changed slightly in the 2011-2012 academic year. Includes ‘‘athlete chooses not to continue,’’ ‘‘athlete released from team,’’ ‘‘other,’’ and ‘‘unknown.’’
b
Utilizing helmet data from 2900 concussions sustained by US high school football players, we found that concussion characteristics (ie, mean number of symptoms, specific concussion symptoms, symptom resolution time, and time until return to play) were similar for players wearing new helmets and reconditioned helmets. This finding is consistent with results of a recent prospective cohort study conducted in Wisconsin in 34 high schools in 2012 and 18 high schools in 2013, which found no difference in the incidence of sports-related concussions by helmet age/recondition status.11 The NOCSAE and the National Athletic Equipment Reconditioners Association strongly recommend that football helmets be reconditioned/recertified every year; however, as of 2015, only the state of California required helmets to be reconditioned on an annual basis.13,14 Reconditioning schedules vary across schools, with some high schools reconditioning their helmets every year and others reconditioning their helmets every other year.14 Only a small proportion (4.3%) of concussed athletes in this study were wearing an old/not reconditioned helmet; however, fewer football players wearing an old/not reconditioned helmet had concussion symptoms that resolved
within 1 day compared with players wearing a new helmet. All helmets, new or reconditioned, should be checked regularly for damage that could impact their effectiveness in preventing brain injuries and skull fractures. Future research is needed to determine if requiring helmet reconditioning to be done on a yearly basis could help reduce the negative effects of concussions and improve outcomes for concussed high school athletes. There were small but significant differences in the manufacturers and models of helmets worn by all football players, as reported by the helmet inventory survey, compared with those football players who sustained a concussion, as reported using the High School RIO Internet-based injury surveillance system. A larger proportion of football players who sustained a concussion were wearing a Riddell helmet (67.5%), compared with all football players (60.7%), and more specifically a Riddell Revolution helmet (63.4% and 51.7%, respectively). Conversely, a larger proportion of all football players wore a Schutt helmet (38.1%), compared with football players who sustained a concussion (28.4%), and more specifically a Schutt DNA helmet (10.6% and 7.9%, respectively). Although concussion incidence rates
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for each manufacturer/model of helmets investigated in this study could not be directly calculated, these findings appear to conflict with the results of a recent study, which found no difference in the incidence of concussions by helmet manufacturer.11 However, they do appear to be consistent with 2 other previous studies that found differences in the rate of concussions by helmet manufacturer and/or model.3,19 Despite differences in the manufacturers and models of helmets worn by all high school football players compared with players who sustained a concussion, the mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play were similar for concussions sustained by football players wearing the most common helmet brands, Riddell and Schutt. There were differences in concussion characteristics among athletes wearing a Xenith helmet compared with Riddell and Schutt helmets; however, only a very small proportion of concussed athletes were wearing a Xenith helmet (2.4%). To our knowledge, there has been only 1 other study that investigated concussion symptoms by the helmet manufacturer/model.3 That study, which compared athletes wearing a Riddell Revolution helmet to those wearing a standard NOCSAE-approved helmet in 2006, also found no difference in concussion symptoms, symptom resolution time, or return to play by the type of helmet worn.3 Additional research is needed to further support findings of no differences in concussion characteristics by helmet manufacturer and/or model among helmets that meet testing standards,15 especially as newer helmet models become more popular and helmet technology continues to advance. The Summation of Tests for the Analysis of Risk (STAR) system was developed to evaluate the relative performance of different helmet manufacturers/models based on linear acceleration in laboratory drop tests and head impact exposures of collegiate football players.18 Using the STAR system, helmets are rated from 1 through 5 stars, with more stars reportedly providing a better relative reduction in the concussion risk compared with fewer stars. For example, 5 stars indicates the best available protection against concussions, while 3 stars indicates good protection, and 1 star indicates marginal protection. As the STAR system currently only evaluates adult helmets and there may be differences between head impact exposures among adults and youth,24 STAR ratings of adult helmets should not be used to inform decisions on which youth helmets are purchased and/or worn.
Limitations The limitations of this study are largely limitations of the National High School Sports-Related Injury Surveillance Study. First, only schools with a NATA-affiliated AT were eligible to participate. Although this inclusion criterion may limit the generalizability of results, it ensured that medically trained professionals documented injuries, thereby increasing the data quality and consistency. Second, AEs were based on units of participation rather than time. While time-based AEs may be more precise, because of the large study population, it was not feasible for ATs to submit time-based reports for every athlete under their care. Third, although this study captured the
number of helmets distributed to football players and the age/recondition status, manufacturer, and model of those helmets, we were unable to capture data on AEs by helmet age/recondition status, manufacturer, or model. It is possible that old/not reconditioned helmets were more commonly distributed to younger, less experienced players or to players who rarely have playing time during competitions. Fourth, not all schools that participated in the National High School Sports-Related Injury Surveillance Study returned a helmet inventory. Therefore, there were small discrepancies between the helmet brands worn by all athletes and the helmet brands worn by concussed athletes. Fifth, participating ATs were only able to report injuries of which they were aware; therefore, data from this surveillance system likely underestimate the actual number of injuries sustained by high school athletes. Furthermore, concussions not reported and/or treated by the AT may have different symptoms or outcomes than concussions that were reported and/or treated by the AT. Finally, this study was observational; therefore, there was the potential for confounding and/or bias as helmets were not distributed in a random fashion. For example, younger, less experienced players may have been more likely to be wearing an old/not reconditioned helmet and also more likely to sustain a concussion or athletes who had previously sustained a concussion may have been more likely to be wearing a certain manufacturer/model of helmet. Data on prior concussions were not collected. Despite these limitations, this study is the largest epidemiological study to date to evaluate concussion outcomes in US football athletes wearing helmets of various ages/ recondition statuses, manufacturers, and models.
CONCLUSION Overall, for new and reconditioned football helmets, the most common helmet manufacturers and models on the market today appear to provide US high school football players with similar protection in terms of the mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play. However, as helmet technologies evolve and new models come onto the market, continued research is needed to further investigate potential differences in the protection that these helmets offer. Future research must include both laboratory testing and ratings based on such testing as well as population-based epidemiological studies to fully understand how different manufacturers and models of helmets truly perform in the field. REFERENCES 1. Buzzini SR, Guskiewicz KM. Sport-related concussion in the young athlete. Curr Opin Pediatr. 2006;18(4):376-382. 2. Centers for Disease Control and Prevention. The Association Between School-Based Physical Activity, Including Physical Education, and Academic Performance. Atlanta: Centers for Disease Control and Prevention; 2010. 3. Collins M, Lovell MR, Iverson GL, Ide T, Maroon J. Examining concussion rates and return to play in high school football players
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wearing newer helmet technology: a three-year prospective cohort study. Neurosurgery. 2006;58(2):275-286. Conidi FX. Helmets, sensors, and more: a review. Pract Neurol. 2015;15(2):32-36. Faul M, Xu L, Wald MM, Coronado VG. Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations and Deaths, 2002–2006. Atlanta: Centers for Disease Control and Prevention; 2010. Gessel LM, Fields SK, Collins CL, Dick RW, Comstock RD. Concussions among United States high school and collegiate athletes. J Athl Train. 2007;42(4):495-503. Gwin JT, Chu JJ, Diamond SG, Halstead PD, Crisco JJ, Greenwald RM. An investigation of the NOCSAE linear impactor test method based on in vivo measures of head impact acceleration in American football. J Biomech Eng. 2010;132(1):011006. Jadischke R, Viano DC, Dau N, King AI, McCarthy J. On the accuracy of the Head Impact Telemetry (HIT) System used in football helmets. J Biomech. 2013;46(13):2310-2315. Janssen I, Leblanc AG. Systematic review of the health benefits of physical activity and fitness in school-aged children and youth. Int J Behav Nutr Phys Act. 2010;7:40. Langlois JA, Rutland-Brown W, Wald MM. The epidemiology and impact of traumatic brain injury. J Head Trauma Rehabil. 2006;21: 375-378. McGuine TA, Hetzel S, McCrea M, Brooks MA. Protective equipment and player characteristics associated with the incidence of sportrelated concussion in high school football players: a multifactorial prospective study. Am J Sports Med. 2014;42(10):2470-2478. National Federation of State High School Associations. 2013-14 High School Athletics Participation Survey. http://www.nfhs.org/ParticipationStatics/PDF/2013-14_Participation_Sur vey_PDF.pdf. Accessed September 29, 2014. National Federation of State High School Associations. 2013 NFHS Football Rules Book. Indianapolis, Indiana: National Federation of State High School Associations; 2013.
14. National Operating Committee on Standards for Athletic Equipment. FAQs. http://nocsae.org/about-nocsae/faqs/#eight. Accessed October 4, 2014. 15. National Operating Committee on Standards for Athletic Equipment. Standard performance specification for new manufactured football helmets. http://nocsae.org/wp-content/files_mf/1396898424ND002 13m13MfrdFBHelmetsStandardPerformance.pdf. Accessed October 15, 2014. 16. National Operating Committee on Standards for Athletic Equipment. Standard performance specification for recertified manufactured football helmets. http://nocsae.org/wp-content/files_mf/1412194157 ND00411m14RecertFBHelmetsStandardPerformance.pdf. Accessed October 15, 2014. 17. Patel DR, Greydanus DE. Neurologic considerations for adolescent athletes. Adolesc Med. 2002;13(3):569-578. 18. Rowson S, Duma SM. Development of the STAR evaluation system for football helmets: integrating player head impact exposure and risk of concussion. Ann Biomed Eng. 2011;39(8):2130-2140. 19. Rowson S, Duma SM, Greenwald RM, et al. Can helmet design reduce the risk of concussion in football? J Neurosurg. 2014; 120(4):919-922. 20. United States Census Bureau. Census regions and divisions of the United States. http://www.census.gov/geo/maps-data/maps/pdfs/ reference/us_regdiv.pdf. Accessed January 19, 2014. 21. United States Department of Health and Human Services. Physical Activity Guidelines Advisory Committee Report. Washington, DC: United States Department of Health and Human Services; 2008. 22. Viano DC, Pellman EJ, Withnall C, Shewchenko N. Concussion in professional football: performance of newer helmets in reconstructed game impacts, part 13. Neurosurgery. 2006;59(3):591-606. 23. Viano DC, Withnall C, Halstead D. Impact performance of modern football helmets. Ann Biomed Eng. 2012;40(1):160-174. 24. Virginia Tech Institute for Critical Technology and Applied Science. Frequently asked questions. http://www.sbes.vt.edu/pdf/helmet_faq.pdf. Accessed December 10, 2014.
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Concussion Characteristics in High School Football by Helmet Age/Recondition Status, Manufacturer, and Model: 2008-2009 Through 2012-2013 Academic Years in the United States Christy L. Collins, Lara B. McKenzie, Amy K. Ferketich, Rebecca Andridge, Huiyun Xiang and R. Dawn Comstock Am J Sports Med published online February 23, 2016 DOI: 10.1177/0363546516629626 The online version of this article can be found at: http://ajs.sagepub.com/content/early/2016/02/22/0363546516629626
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On behalf of: American Orthopaedic Society for Sports Medicine
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Concussion Characteristics in High School Football by Helmet Age/Recondition Status, Manufacturer, and Model 2008-2009 Through 2012-2013 Academic Years in the United States Christy L. Collins,*y PhD, Lara B. McKenzie,z§k PhD, Amy K. Ferketich,k PhD, Rebecca Andridge,{ PhD, Huiyun Xiang,zk PhD, MD, and R. Dawn Comstock,#** PhD Investigation performed at the Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA Background: Football helmets used by high school athletes in the United States should meet the National Operating Committee on Standards for Athletic Equipment performance standards. Despite differences in interior padding and exterior shells, all football helmets should provide comparable protection against concussions. Yet, debate continues on whether differences in the rates or severity of concussions exist based on helmet age/recondition status, manufacturer, or model. Purpose: To investigate whether high school football concussion characteristics varied by helmet age/recondition status, manufacturer, and model. Study Design: Descriptive epidemiological study. Methods: High school football concussion and helmet data were collected from academic years 2008-2009 through 2012-2013 as part of the National High School Sports-Related Injury Surveillance Study. The certified athletic trainers of participating schools submitted athlete-exposure (AE) and injury information weekly. Results: Participating schools reported 2900 football concussions during 3,528,790 AEs for an overall rate of 8.2 concussions per 10,000 AEs. Concussion rates significantly increased from 2008-2009 through 2012-2013 overall (P = .006) as well as in competition (P = .027) and practice (P = .023). Characteristics of concussed football players (ie, mean number of symptoms, specific concussion symptoms, symptom resolution time, and time until return to play) were similar among players wearing new helmets when compared with reconditioned helmets. Fewer players wearing an old/not reconditioned helmet had concussion symptoms resolve within 1 day compared with players wearing a new helmet. Despite differences in the manufacturers and models of helmets worn by all high school football players compared with players who sustained a concussion, the mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play were similar for concussions sustained by football players wearing the most common helmet manufacturers and models. Conclusion: Overall, for new and reconditioned football helmets, the most common helmet manufacturers and models on the market today appear to provide high school football players with similar protection against concussions. Clinical Relevance: Concussions can have serious acute and long-term effects. An understanding of concussion patterns in high school athletes can drive targeted preventive measures, including improvements to and/or better use of protective equipment, to reduce the incidence and/or severity of sports-related concussions. Keywords: concussion; football; helmet; adolescent
High school sports play an important role in the adoption and maintenance of a physically active lifestyle among millions of adolescents in the United States (US). Participation in high school sports has grown rapidly from approximately 4.0 million athletes in academic years 1971-1972 to 7.8
The American Journal of Sports Medicine, Vol. XX, No. X DOI: 10.1177/0363546516629626 Ó 2016 The Author(s)
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million in 2013-2014.12 In addition to helping youth maintain a healthy weight, regular physical activity has been shown to increase strength, endurance, and flexibility; improve psychological well-being and self-esteem; reduce depression and anxiety; and improve academic performance.2,9,21 While the health benefits of a physically active lifestyle including participating in sports are undeniable, high school athletes are at risk of sports-related injuries as a certain endemic level of injury can be expected among participants of any physical activity. Injury prevention in this population is often overlooked as sports-related injuries are thought to be unavoidable; however, the morbidity, mortality, and disability caused by high school sports-related injuries can be reduced through the development of evidence-based prevention strategies. A concussion is a common sports injury in the US, with approximately 1.6 million to 3.8 million recognized sportsrelated concussions occurring annually.1,5,6,10,17 Because of the ongoing neurocognitive development that occurs throughout adolescence, concussions can have severe acute and long-term complications in young athletes.1,17 While historically, helmets were designed to prevent skull fractures rather than concussions, a protective effect for which they are now thought essential, helmets have been effective in reducing the direct external transfer of force through the skull to the brain by spreading forces over a greater surface area.4 All football helmets used by high school athletes are required to meet performance standards developed by the National Operating Committee on Standards for Athletic Equipment (NOCSAE)15,16; therefore, despite differences in interior padding and exterior shells, all football helmets should provide similarly acceptable protection against concussions. Yet, debate continues on whether differences in the rates or severity of concussions exist based on helmet age/recondition status, manufacturer, or model. The majority of studies that have compared the effectiveness of different types of football helmets in protecting against concussions have used linear impact testing in the laboratory.7,18,22,23 Only a few prior epidemiological studies have investigated concussion incidence and/or outcomes in athletes wearing various helmets.3,11,19 One recent prospective cohort study conducted in Wisconsin found no difference in the incidence of sports-related concussions by helmet age/recondition status or helmet manufacturer.11 In contrast, another previous study of high school football
athletes found a difference in the incidence of concussions for new Riddell versus standard helmets; however, this study also found no difference in concussion symptoms, symptom resolution time, or return to play by the type of helmet worn.3 In a third study utilizing data from the Helmet Impact Telemetry System, which uses helmet-mounted accelerometers to collect head impact data and assess the frequency and severity of those impacts,8 among collegiate football athletes, there was a significant difference in the rate of concussions among players wearing a Riddell VSR4 helmet compared with a Riddell Revolution helmet.19 Because of the limited number of epidemiological studies examining differences in the rates or severity of concussions by the type of helmet worn and the conflicting results of these studies, more research is needed to determine if there are differences in the risk and patterns of concussions by the type of helmet worn. The objective of this study was to investigate whether high school football concussion characteristics vary by helmet age/recondition status, manufacturer, or model.
METHODS Participants This study was approved by the institutional review board at Nationwide Children’s Hospital. Data from the National High School Sports-Related Injury Surveillance Study from the 2008-2009 through 2012-2013 academic years were used. Since the 2005-2006 academic year, this longitudinal surveillance study has monitored injuries among US high school athletes. Schools with a certified athletic trainer (AT) who provided care for high school athletes and had a valid email address, identified using the National Athletic Trainers’ Association (NATA) membership lists, were eligible to participate in the study. An email sent to the school’s AT introduced the study and invited them to participate. Among all schools with an AT who expressed interest in participating, a 3-stage sampling methodology was used to select study schools. In the first stage, all schools were categorized into 8 sampling strata by geographic location (Northeast, Midwest, South, and West)20 and school size (enrollment 1000 or .1000 students). Participant schools were then randomly selected from each substratum to obtain 100 study schools to report
*Address correspondence to Christy L. Collins, PhD, OhioHealth Research and Innovation Institute, 3545 Olentangy River Road, NMB Suite 310, Columbus, OH 43214, USA (email: [email protected]). y OhioHealth Research and Innovation Institute, Columbus, Ohio, USA. z Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, Columbus, Ohio, USA. § Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio, USA. k Division of Epidemiology, College of Public Health, The Ohio State University, Columbus, Ohio, USA. { Division of Biostatistics, College of Public Health, The Ohio State University, Columbus, Ohio, USA. # Department of Epidemiology, Colorado School of Public Health, University of Colorado Denver, Aurora, Colorado, USA. **Pediatric Emergency Medicine, School of Medicine, University of Colorado Anschutz, Aurora, Colorado, USA. The content of this report is solely the responsibility of the authors and does not necessarily represent the official views of the Centers for Disease Control and Prevention. One or more of the authors has declared the following potential conflict of interest or source of funding: This study was funded by the National Operating Committee on Standards for Athletic Equipment. The content of this report was also funded in part by the Centers for Disease Control and Prevention (grants R49/CE000674-01 and R49/CE001172-01). The authors also acknowledge the generous research funding contributions of the National Federation of State High School Associations.
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Concussions in High School Football by Type of Helmet 3
for each of the 9 sports included in the original National High School Sports-Related Injury Surveillance Study (boys’ football, boys’ and girls’ soccer, girls’ volleyball, boys’ and girls’ basketball, boys’ wrestling, boys’ baseball, and girls’ softball). In the second stage, all schools not selected in the first stage that offered any of the more rarely offered sports included in the expansion of the National High School Sports-Related Injury Surveillance Study (girls’ gymnastics, girls’ field hockey, boys’ and girls’ lacrosse, boys’ ice hockey, and boys’ volleyball) were selected for the convenience sample in an attempt to obtain as large a sample as possible that reported for these more rarely offered sports. In the third stage, a random sample of all schools not selected in the first or second stage that offered the remaining sports of interest (boys’ and girls’ track and field, boys’ and girls’ swimming and diving, and boys’ and girls’ cross country and cheerleading) were selected in an attempt to ensure at least 100 schools were reporting for each of the sports. This 3-step sampling methodology resulted in a large, nationally dispersed convenience sample of US high schools. Although the number of high schools participating varied each year, on average, approximately 200 US high schools across the country participated annually. The National High School Sports-Related Injury Surveillance Study gathered data via the Internet-based surveillance system High School Reporting Information Online (RIO). Participating ATs, who acted as the school’s reporter, received a weekly email throughout the study period reminding them to enter their school’s data into the High School RIO surveillance system. ATs completed reports that included exposure information (number of competitions and practices) and the number of reportable injuries sustained by athletes of each sport that was currently in session at their school. For each reportable injury, the AT completed an injury report that collected detailed information about the injured player (age, year in school, etc), the injury (site, type, severity, etc), the injury event (position played, phase of play, etc), and the use of protective equipment (manufacturer/model of helmet; use of protective eyewear, mouthguards, knee/ankle braces, and/or tape, etc). The Internet-based surveillance tool provided ATs with the ability to view and update reports as needed (need for surgery, days until resuming play, etc). To reduce loss to follow-up, reporters who repeatedly failed to log on to complete the weekly exposure and injury reports or who had errors with their reporting were contacted by the study staff and either reminded to report, asked to correct errors, or assessed for their willingness to continue participating in the study. In addition to collecting data on the use of protective equipment within the Internet-based surveillance system, ATs participating in the National High School Sports-Related Injury Surveillance Study were asked to complete a helmet inventory form annually during the 2008-2009 through 2012-2013 academic years. The helmet inventory form collected data on the manufacturer and model of helmets being worn by all athletes participating in boys’ football, baseball, ice hockey, and lacrosse and girls’ softball and whether the helmets were new or old (ie, not new that season) and, if old, if they had been reconditioned.
Measures An ‘‘athlete-exposure’’ (AE) was defined as 1 athlete participating in 1 practice or competition in which he or she was exposed to the possibility of an athletic injury. Exposure was expressed in 3 parts: (1) number of practices (the sum of the number of athletes at each practice during the past week), (2) number of competitions (the sum of the number of athletes at each competition during the past week), and (3) number of total AEs (the sum of the number of practices and number of competitions during the past week). An ‘‘injury’’ was defined as (1) occurring as a result of participation in an organized high school competition or practice; (2) requiring medical attention by a team physician, certified AT, personal physician, or emergency department/urgent care facility; and (3) resulting in restriction of the high school athlete’s participation for 1 days beyond the day of injury or any fracture, concussion, or dental injury regardless of whether it resulted in restriction of the student-athlete’s participation.
Statistical Analysis Data were analyzed using SPSS (version 22; IBM Corp). Injury rates were calculated as the ratio of case counts per 10,000 AEs and were compared using rate ratios (RRs) with 95% CIs. Injury proportions were compared using injury proportion ratios (IPRs) and corresponding 95% CIs. Following is an example of an IPR calculation: 0
1 No: of concussions sustained while B C wearing a reconditioned helmet in B C B C B which all symptoms resolved within 1 day C B C B C Total No: of concussions B C @ A sustained while wearing IPR ¼
0
a reconditioned helmet
1 No: of concussions sustained while B C B wearing a new helmet in which all C B C symptoms resolved within 1 day B C B C B C Total No: of concussions B C @ A sustained while wearing a new helmet
An RR or IPR .1.00 suggests a risk association, while an RR or IPR \1.00 suggests a protective association. 95% CIs not including 1.00 were considered statistically significant. The mean number of concussion symptoms by helmet age/recondition status, manufacturer, and model was compared using analysis of variance and x2 tests. Linear regression was used to assess rates of concussion over time. Statistical significance was set at P \ .05.
RESULTS Football-Related Concussions During the 2008-2009 through 2012-2013 academic years, schools participating in the National High School Sports-
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TABLE 1 Characteristics of Football-Related Concussions by Age/Recondition Status of Helmets Worn by High School Football Players Who Sustained a Concussion Age/Recondition Status of Football Helmeta
No. of concussion symptoms, mean 6 SD Specific concussion symptoms, % Headache Dizziness/unsteadiness Difficulty in concentration Confusion/disorientation Sensitivity to light/visual disturbance Drowsiness Nausea Amnesia Sensitivity to noise Irritability Tinnitus Loss of consciousness Hyperexcitability Symptom resolution time, % \15 min .15 min to \1 h 1 h to \1 d 1 d to \1 wk 1 wk to 1 mo .3 wkb .1 mob Time until return to play, % \1 wk 1 to 3 wk .3 wk Medical disqualification for season Otherc
Overall (N = 2900)
New (n = 606)
Old/Reconditioned (n = 1412)
Old/Not Reconditioned (n = 126)
4.52 6 2.31
4.63 6 2.25
4.50 6 2.26
4.17 6 2.26
93.2 75.0 59.8 50.1 39.8 31.0 30.9 22.7 21.6 11.0 10.6 3.4 2.7
91.9 77.9 64.0 57.1 41.4 28.9 29.4 26.2 21.3 10.7 6.8 4.5 2.6
93.2 75.0 61.3 50.1 38.8 30.9 29.5 21.7 20.3 11.3 12.7 3.0 2.3
96.8 71.4 43.7 42.9 41.3 20.6 38.1 19.8 24.6 7.1 8.7 2.4 0.0
2.9 4.8 12.4 49.5 26.7 2.7 1.1
2.8 4.5 16.6 45.1 27.1 2.8 1.0
3.7 5.7 12.6 49.4 25.2 2.3 1.0
1.6 3.2 9.7 54.8 30.6 0.0 0.0
40.2 35.6 6.2 4.2 13.8
38.6 36.8 6.1 3.7 14.7
38.5 37.3 6.4 4.4 13.5
46.8 34.7 4.8 1.6 12.1
a
Age/recondition status of helmet was unknown/not reported for 756 concussions (26.1%). Categories for symptom resolution time changed slightly in the 2011-2012 academic year. c Includes ‘‘athlete chooses not to continue,’’ ‘‘athlete released from team,’’ ‘‘other,’’ and ‘‘unknown.’’ b
Related Injury Surveillance Study reported 2900 football concussions during 3,528,790 AEs for an overall rate of 8.2 concussions per 10,000 AEs. Of the 2900 footballrelated concussions, 1696 (58.5%) were sustained in competition and 1204 (41.5%) in practice. Concussion rates were higher in competition (28.7 per 10,000 competition AEs) than in practice (4.1 per 10,000 practice AEs) (RR, 7.0; 95% CI, 2.5-19.7). Of all football-related injuries reported from 2008-2009 through 2012-2013 (N = 13,795), concussions accounted for 21.0%. Concussion rates significantly increased from 2008-2009 through 2012-2013 overall (P = .006) as well as in both competition (P = .027) and practice (P = .023). Concussed athletes reported a mean (6SD) of 4.52 6 2.31 concussion symptoms (Table 1). The most commonly reported concussion symptoms included headache (93.2%), dizziness/unsteadiness (75.0%), and difficulty in concentration (59.8%) (Table 1). Overall, 20.1% of concussed athletes had all concussion symptoms resolve within 1 day, and 69.6% had all symptoms resolve within 1 week. Moreover,
40.2% of athletes returned to play in less than 1 week (Table 1); 6.2% of athletes took more than 3 weeks to return to play, and 4.2% were medically disqualified for the season (Table 1).
Characteristics of Helmets Worn by High School Football Players Who Sustained a Concussion Nearly all helmets (92.7%) worn by high school football players who sustained a concussion had an NOCSAE seal or a seal imprinted on the helmet that declared that it met the requirements of performance tests when it was manufactured or recertified (0.6% did not have an NOCSAE seal; 6.8% were unknown). The majority of helmets (84.8%) were not modified or changed from the original manufactured specifications (2.9% were modified; 12.4% were unknown). Among the small proportion of helmets that were modified, the most common modifications were regarding chin cup covers (53.0%), chin straps (30.1%), eye shields/visors (13.3%), and face shields (7.2%). Most
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helmets worn by high school football players who sustained a concussion were initially fit by a coach (71.3%), followed by an AT (15.0%), a helmet company representative (8.0%), a team/school equipment manager (2.8%), or by the athletes themselves (0.8%) (2.0% were unknown). ATs reported that, in their opinion, the helmet fit correctly at the time of the injury among 84.6% of concussions sustained by football players (the helmet did not fit correctly among 3.2%; appropriate fit was unknown among 12.3%). A larger proportion of helmets that did not fit correctly were fitted by the coach (80.5%) compared with helmets that did fit correctly at the time of the injury (70.9%) (IPR, 1.14; 95% CI, 1.02-1.26). Damage to the helmet occurred in only 0.8% of reported concussions. The most commonly reported types of damage were chipped/ scratched paint (n = 9, 40.9%), dented/broken face masks (n = 4, 18.2%), cracked helmets (n = 3, 13.6%), and broken clips (n = 2, 9.1%). Overall, most football helmets worn by concussed athletes at the time of the injury were not new during the season in which the concussion was sustained (53.0%) (20.9% of helmets were new; age of helmet was unknown/not reported for 26.1% of concussions). The majority of helmets that were not new during this season had been reconditioned (91.8%). There was no significant difference in the mean number of concussion symptoms by age/recondition status of the football helmet (F = 2.29; df = 2; P = .101) (Table 1). In general, specific concussion symptoms, symptom resolution time, and time until an athlete returned to play were similar for concussions sustained by football players wearing new helmets and football players wearing helmets that had been reconditioned (Table 1). However, a smaller proportion of football players wearing helmets that had not been reconditioned had all concussion symptoms resolve in less than 1 day (14.5%) compared with football players wearing new helmets (23.9%) (IPR, 0.61; 95% CI, 0.39-0.95). Among all high school football athletes, the most commonly worn helmets were manufactured by Riddell (60.7%) and Schutt (38.1%) (Table 2). Similarly, among high school football athletes who sustained a concussion, the most commonly worn helmets were manufactured by Riddell (67.5%) and Schutt (28.4%). However, a larger proportion of football players who sustained a concussion were wearing a Riddell helmet (67.5%) compared with all football players (60.7%) (IPR, 1.11; 95% CI, 1.08-1.15) (Table 2). Conversely, a larger proportion of all football players wore a Schutt helmet (38.1%) compared with football players who sustained a concussion (28.4%) (IPR, 1.34; 95% CI, 1.26-1.43). For all manufacturers, the majority of helmets that were not new during the season in which the player sustained a concussion had been reconditioned (Adams: 85.7%; Rawlings: 100.0%; Riddell: 88.7%; Schutt: 88.0%; Xenith: 59.1%). Similarly, for all 5 manufacturers, the majority of football-related concussions were associated with head-tohead contact (Adams: 66.7%; Rawlings: 55.6%; Riddell: 70.4%; Schutt: 65.6%; Xenith: 70.4%), the most common position of the head during contact was head up (Adams: 46.9%; Rawlings: 66.7%; Riddell: 44.8%; Schutt: 44.0%; Xenith: 53.7%), and the most common direction of impact
TABLE 2 Manufacturers of Helmets Worn by All High School Football Players Compared With Those Worn by Concussed Athletesa All Athletes Manufacturer, n (%) Adams 241 (1.0) Rawlings 0 (0.0)a Riddell 14,510 (60.7) Schutt 9116 (38.1) Xenith 36 (0.2) Total,b n (%) 23,903 (100.0)
Concussed Athletes
35 9 1723 725 60 2552
(1.4) (0.4)a (67.5) (28.4) (2.4)a (100.0)
a There are small discrepancies between the All Athletes and Concussed Athletes columns because data from the All Athletes column came from those schools returning a helmet inventory survey, while data from the Concussed Athletes column came from High School Reporting Information Online injury reports. b Percentages do not sum to 100.0% because of rounding.
during contact was from the front (Adams: 46.9%; Rawlings: 88.9%; Riddell: 45.3%; Schutt: 45.3%; Xenith: 50.0%). The mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play were similar for concussions sustained by football players wearing the most common helmet brands, Riddell and Schutt (Table 3). Although there was a relatively small number of athletes wearing Xenith helmets (n = 60), when comparing concussions that occurred while wearing helmets made by Riddell, Schutt, and Xenith, there was a significant difference in the mean number of concussion symptoms (F = 7.79; df = 2; P \ .001), with more symptoms being reported by athletes wearing a Xenith helmet (Table 3). Additionally, a larger proportion of athletes wearing a Xenith helmet sustained specific concussion symptoms including amnesia, difficulty in concentration, and sensitivity to light/visual disturbance compared with athletes wearing a Riddell or Schutt helmet. A greater proportion of athletes wearing a Xenith helmet had a medical disqualification for the season (11.5%) compared with athletes wearing a Riddell (4.1%) (IPR, 2.80; 95% CI, 1.27-6.14) or Schutt helmet (4.1%) (IPR, 2.84; 95% CI, 1.23-6.54). More specifically, the most common helmet models worn by all athletes as well as concussed athletes were Riddell Revolution and Schutt DNA (Table 4). However, a larger proportion of football players who sustained a concussion were wearing a Riddell Revolution helmet (63.4%) compared with all football athletes (51.7%) (IPR, 1.23; 95% CI, 1.19-1.27) (Table 4). Conversely, a smaller proportion of football players who sustained a concussion were wearing a Schutt DNA helmet (7.9%) compared with all football athletes (10.6%) (IPR, 0.75; 95% CI, 0.64-0.87). In general, the mean number of concussion symptoms, specific concussion symptoms, and time until return to play were similar by helmet model (Table 5). For the most common helmet models, approximately 20% to 27% of concussion symptoms resolved in less than 1 day (Riddell Revolution: 20.1%; Riddell Revolution Speed: 26.3%; Schutt DNA: 27.1%; Schutt Air: 24.0%) except for Schutt Air XP, for which only
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TABLE 3 Characteristics of Football-Related Concussions by Helmet Manufacturer Helmet Manufacturer
No. of concussion symptoms, mean 6 SD Specific concussion symptoms, % Headache Dizziness/unsteadiness Difficulty in concentration Confusion/disorientation Sensitivity to light/visual disturbance Drowsiness Nausea Amnesia Sensitivity to noise Irritability Tinnitus Loss of consciousness Hyperexcitability Symptom resolution time, % \15 min .15 min to \1 h 1 h to \1 d 1 d to \1 wk 1 wk to 1 mo .3 wka .1 moa Time until return to play, % \1 wk 1 to 3 wk .3 wk Medical disqualification for season Otherb
Adams (n = 35)
Rawlings (n = 9)
Riddell (n = 1723)
Schutt (n = 725)
Xenith (n = 60)
4.46 6 2.11
3.67 6 2.87
4.43 6 2.22
4.52 6 2.40
5.60 6 2.34
94.3 71.4 62.9 40.0 42.9 17.1 42.9 17.1 28.6 11.4 17.1 0.0 0.0
100.0 88.9 22.2 33.3 22.2 33.3 22.2 0.0 22.2 0.0 11.1 11.1 0.0
92.8 74.7 59.7 50.7 38.1 29.5 29.9 22.8 19.2 10.6 8.9 3.8 2.6
93.5 74.6 57.7 49.4 41.8 32.4 30.1 20.8 23.4 10.6 12.3 2.6 2.6
95.0 76.7 80.0 60.0 58.3 41.7 31.7 41.7 43.3 18.3 8.3 3.3 1.7
0.0 5.9 17.6 50.0 23.5 0.0 2.9
0.0 0.0 12.5 12.5 75.0 0.0 0.0
2.5 5.0 13.9 48.8 26.3 2.4 1.1
4.3 5.3 11.9 48.7 25.9 3.0 0.9
2.0 3.9 2.0 49.0 35.3 5.9 2.0
48.6 31.4 0.0 5.7 14.3
37.5 25.0 37.5 0.0 0.0
41.0 35.8 6.1 4.1 13.0
39.2 35.4 7.0 4.1 14.2
23.1 40.4 3.8 11.5 21.2
a
Categories for symptom resolution time changed slightly in the 2011-2012 academic year. Includes ‘‘athlete chooses not to continue,’’ ‘‘athlete released from team,’’ ‘‘other,’’ and ‘‘unknown.’’
b
13.3% of concussion symptoms resolved in less than 1 day (x2(4) = 12.49; P = .014) (Table 5).
TABLE 4 Common Helmet Models Worn by All High School Football Players Compared With Those Worn by Athletes Who Sustained a Concussion
DISCUSSION
All Athletesa
This study, the largest epidemiological study to date to evaluate concussion outcomes in US football athletes wearing helmets of various ages/recondition statuses, manufacturers, and models, found no differences in concussion characteristics among players wearing new and reconditioned helmets or the most common helmet manufacturers and models. Only a few prior epidemiological studies have investigated concussion incidence and outcomes in athletes wearing different types of helmets3,11,19 as opposed to comparing helmet impact testing in the laboratory.7,18,22,23 As helmet technology continues to improve, so will helmet testing technology. However, it is crucial that researchers continue to conduct epidemiological studies to determine if laboratory testing results translate to on-the-field experiences of athletes. While helmet ratings based on laboratory testing are important, they alone should not drive decision making by school athletic directors, football coaches,
Manufacturer and model, n (%) Riddell Revolution 10,698 (51.7) Riddell Revolution Speed 1525 (7.4) Schutt DNA 2200 (10.6) Schutt Air 1114 (5.4) Schutt Air XP 938 (4.5)
Concussed Athletes
1376 142 172 126 151
(63.4) (6.5) (7.9) (5.8) (7.0)
a
Only helmet models worn by 4.5% of all athletes are included.
parents, or athletes as they select which helmets will be worn. Laboratory testing and ratings based on such testing must be coupled with population-based epidemiological studies to fully understand how different manufacturers and models of helmets truly perform in the field. Such epidemiological studies are the only way to evaluate concussion outcomes including concussion rates and severity by the type of helmet worn.
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Concussions in High School Football by Type of Helmet 7
TABLE 5 Characteristics of Football-Related Concussions by Helmet Model Helmet Model
No. of concussion symptoms, mean 6 SD Specific concussion symptoms, % Headache Dizziness/unsteadiness Difficulty in concentration Confusion/disorientation Sensitivity to light/visual disturbance Drowsiness Nausea Amnesia Sensitivity to noise Irritability Tinnitus Loss of consciousness Hyperexcitability Symptom resolution time, % \15 min .15 min to \1 h 1 h to \1 d 1 d to \1 wk 1 wk to 1 mo .3 wka .1 moa Time until return to play, % \1 wk 1 to 3 wk .3 wk Medical disqualification for season Otherb
Riddell Revolution (n = 1376)
Riddell Revolution Speed (n = 142)
Schutt DNA (n = 172)
Schutt Air (n = 126)
Schutt Air XP (n = 151)
4.48 6 2.24
4.37 6 2.08
4.58 6 2.54
4.48 6 2.40
4.95 6 2.44
93.2 74.9 60.2 52.2 39.5 29.0 30.0 23.3 20.1 10.9 9.0 3.6 2.2
87.3 72.5 62.0 52.1 38.7 30.3 24.6 26.1 17.6 7.7 7.0 5.6 4.9
92.4 72.7 57.6 53.5 40.1 36.0 30.8 19.8 20.9 13.4 14.0 3.5 2.9
92.9 79.4 61.9 44.4 42.9 34.1 25.4 17.5 22.2 9.5 12.7 3.2 2.4
96.7 86.1 60.9 53.6 48.3 33.8 35.8 25.2 27.2 7.9 13.0 2.0 4.6
2.2 4.4 13.5 49.3 26.9 2.6 1.1
1.5 5.1 19.7 43.1 27.7 2.2 0.7
7.4 3.7 16.0 45.1 22.8 4.3 0.6
2.5 5.0 16.5 47.1 26.4 1.7 0.8
1.4 2.8 9.1 54.5 30.1 2.1 0.0
39.9 36.4 5.8 4.2 13.8
41.6 35.0 10.2 2.2 10.9
46.8 28.8 5.8 2.6 16.0
34.1 35.8 8.9 7.3 13.8
33.1 44.4 5.6 1.4 15.5
a
Categories for symptom resolution time changed slightly in the 2011-2012 academic year. Includes ‘‘athlete chooses not to continue,’’ ‘‘athlete released from team,’’ ‘‘other,’’ and ‘‘unknown.’’
b
Utilizing helmet data from 2900 concussions sustained by US high school football players, we found that concussion characteristics (ie, mean number of symptoms, specific concussion symptoms, symptom resolution time, and time until return to play) were similar for players wearing new helmets and reconditioned helmets. This finding is consistent with results of a recent prospective cohort study conducted in Wisconsin in 34 high schools in 2012 and 18 high schools in 2013, which found no difference in the incidence of sports-related concussions by helmet age/recondition status.11 The NOCSAE and the National Athletic Equipment Reconditioners Association strongly recommend that football helmets be reconditioned/recertified every year; however, as of 2015, only the state of California required helmets to be reconditioned on an annual basis.13,14 Reconditioning schedules vary across schools, with some high schools reconditioning their helmets every year and others reconditioning their helmets every other year.14 Only a small proportion (4.3%) of concussed athletes in this study were wearing an old/not reconditioned helmet; however, fewer football players wearing an old/not reconditioned helmet had concussion symptoms that resolved
within 1 day compared with players wearing a new helmet. All helmets, new or reconditioned, should be checked regularly for damage that could impact their effectiveness in preventing brain injuries and skull fractures. Future research is needed to determine if requiring helmet reconditioning to be done on a yearly basis could help reduce the negative effects of concussions and improve outcomes for concussed high school athletes. There were small but significant differences in the manufacturers and models of helmets worn by all football players, as reported by the helmet inventory survey, compared with those football players who sustained a concussion, as reported using the High School RIO Internet-based injury surveillance system. A larger proportion of football players who sustained a concussion were wearing a Riddell helmet (67.5%), compared with all football players (60.7%), and more specifically a Riddell Revolution helmet (63.4% and 51.7%, respectively). Conversely, a larger proportion of all football players wore a Schutt helmet (38.1%), compared with football players who sustained a concussion (28.4%), and more specifically a Schutt DNA helmet (10.6% and 7.9%, respectively). Although concussion incidence rates
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for each manufacturer/model of helmets investigated in this study could not be directly calculated, these findings appear to conflict with the results of a recent study, which found no difference in the incidence of concussions by helmet manufacturer.11 However, they do appear to be consistent with 2 other previous studies that found differences in the rate of concussions by helmet manufacturer and/or model.3,19 Despite differences in the manufacturers and models of helmets worn by all high school football players compared with players who sustained a concussion, the mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play were similar for concussions sustained by football players wearing the most common helmet brands, Riddell and Schutt. There were differences in concussion characteristics among athletes wearing a Xenith helmet compared with Riddell and Schutt helmets; however, only a very small proportion of concussed athletes were wearing a Xenith helmet (2.4%). To our knowledge, there has been only 1 other study that investigated concussion symptoms by the helmet manufacturer/model.3 That study, which compared athletes wearing a Riddell Revolution helmet to those wearing a standard NOCSAE-approved helmet in 2006, also found no difference in concussion symptoms, symptom resolution time, or return to play by the type of helmet worn.3 Additional research is needed to further support findings of no differences in concussion characteristics by helmet manufacturer and/or model among helmets that meet testing standards,15 especially as newer helmet models become more popular and helmet technology continues to advance. The Summation of Tests for the Analysis of Risk (STAR) system was developed to evaluate the relative performance of different helmet manufacturers/models based on linear acceleration in laboratory drop tests and head impact exposures of collegiate football players.18 Using the STAR system, helmets are rated from 1 through 5 stars, with more stars reportedly providing a better relative reduction in the concussion risk compared with fewer stars. For example, 5 stars indicates the best available protection against concussions, while 3 stars indicates good protection, and 1 star indicates marginal protection. As the STAR system currently only evaluates adult helmets and there may be differences between head impact exposures among adults and youth,24 STAR ratings of adult helmets should not be used to inform decisions on which youth helmets are purchased and/or worn.
Limitations The limitations of this study are largely limitations of the National High School Sports-Related Injury Surveillance Study. First, only schools with a NATA-affiliated AT were eligible to participate. Although this inclusion criterion may limit the generalizability of results, it ensured that medically trained professionals documented injuries, thereby increasing the data quality and consistency. Second, AEs were based on units of participation rather than time. While time-based AEs may be more precise, because of the large study population, it was not feasible for ATs to submit time-based reports for every athlete under their care. Third, although this study captured the
number of helmets distributed to football players and the age/recondition status, manufacturer, and model of those helmets, we were unable to capture data on AEs by helmet age/recondition status, manufacturer, or model. It is possible that old/not reconditioned helmets were more commonly distributed to younger, less experienced players or to players who rarely have playing time during competitions. Fourth, not all schools that participated in the National High School Sports-Related Injury Surveillance Study returned a helmet inventory. Therefore, there were small discrepancies between the helmet brands worn by all athletes and the helmet brands worn by concussed athletes. Fifth, participating ATs were only able to report injuries of which they were aware; therefore, data from this surveillance system likely underestimate the actual number of injuries sustained by high school athletes. Furthermore, concussions not reported and/or treated by the AT may have different symptoms or outcomes than concussions that were reported and/or treated by the AT. Finally, this study was observational; therefore, there was the potential for confounding and/or bias as helmets were not distributed in a random fashion. For example, younger, less experienced players may have been more likely to be wearing an old/not reconditioned helmet and also more likely to sustain a concussion or athletes who had previously sustained a concussion may have been more likely to be wearing a certain manufacturer/model of helmet. Data on prior concussions were not collected. Despite these limitations, this study is the largest epidemiological study to date to evaluate concussion outcomes in US football athletes wearing helmets of various ages/ recondition statuses, manufacturers, and models.
CONCLUSION Overall, for new and reconditioned football helmets, the most common helmet manufacturers and models on the market today appear to provide US high school football players with similar protection in terms of the mean number of concussion symptoms, specific concussion symptoms, symptom resolution time, and time until return to play. However, as helmet technologies evolve and new models come onto the market, continued research is needed to further investigate potential differences in the protection that these helmets offer. Future research must include both laboratory testing and ratings based on such testing as well as population-based epidemiological studies to fully understand how different manufacturers and models of helmets truly perform in the field. REFERENCES 1. Buzzini SR, Guskiewicz KM. Sport-related concussion in the young athlete. Curr Opin Pediatr. 2006;18(4):376-382. 2. Centers for Disease Control and Prevention. The Association Between School-Based Physical Activity, Including Physical Education, and Academic Performance. Atlanta: Centers for Disease Control and Prevention; 2010. 3. Collins M, Lovell MR, Iverson GL, Ide T, Maroon J. Examining concussion rates and return to play in high school football players
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