Exertional heat illness (EHI) is a potentially major threat to athlete health and should be a source of concern for all sports medicine clinicians (5). Most EHI cases occur during fall sports’ preseason in the month of August but are widely distributed geographically (8,10). One particularly vulnerable group is the 1.1 million high school football players in the United States, particularly during the initial days of preseason practice (1). Both the absolute number and the rate of EHI cases are much higher in football than those in other high school sports (8–10). It is estimated that more than 6500 high school football athletes are treated annually for EHI (8).
EHI is almost completely preventable given proper precautions (6), as outlined in various EHI prevention and management guidelines (1,3,4,6,15,17). However, implementation and effectiveness of policy-related EHI prevention interventions have been assessed in only one previous study, with a cross-sectional volunteer sample of 540 coaches, certified athletic trainers (ATs), and athletic directors from high schools in 26 states, conducted in 2005 (13). This study found many high schools were aware of EHI prevention strategies, but that numerous strategies were underused, including regular on-site measurement of environmental temperature and humidity and alterations of practice intensities, practice durations, and equipment configurations in response to high temperature and/or humidity (13).
In 2009, the National Athletic Trainers Association (NATA) led an effort with more than 10 organizations known as the Inter-Association Task Force (NATA-IATF). The NATA-IATF’s goals were to formulate and publish a comprehensive preseason heat acclimatization process for high school athletes and to reduce the risk of EHI by gradually introducing equipment, exercise duration, and exercise intensity across a 14-d period to help the athletes adjust to the environment (6). This was the first comprehensive set of preseason heat acclimatization guidelines with a specific timeline for high school sports programs. The National Federation of State High School Associations has a heat safety program, but the organization cannot require its members to incorporate the heat safety plan into the individual state rules. Several state high school associations have developed mandatory guidelines that meet the heat acclimatization standards of the NATA-IATF (12).
The purposes of this article were to 1) estimate the level of NATA-IATF preseason heat acclimatization guidelines use, 2) estimate prevalence of related EHI prevention strategies, and 3) examine the effect of state mandates on implementation of heat safety and related EHI prevention strategies in US high school football programs. Currently, there is no mechanism for monitoring compliance with the guidelines among high school football programs.
METHODS
Sample recruitment
We emailed study information to the 6343 NATA-affiliated ATs from across the United States that were identified by NATA as being responsible for high school sports in the 2011–2012 school year. To be eligible for inclusion, ATs had to have a valid e-mail address and be either 1) directly employed by school districts or 2) working in the high school setting via outreach for a clinic/hospital/physician practice. Those providing informed consent completed a self-administered online questionnaire. Nonrespondents received e-mail reminders on a weekly basis until the end of the data collection period (May–June 2012). Although we were interested in EHI prevention in football programs, there was no ready means to identify whether or not individual high schools sponsored football on the basis of the NATA membership list. Therefore, we surveyed all responding ATs and then eliminated schools without football programs on the basis of responses to the survey instrument.
Measuring compliance
We first reviewed the NATA-IATF preseason heat acclimatization guidelines and identified 17 specific recommendations to use as key metrics. These 17 recommendations were then grouped into six major categories. In addition to the NATA-IATF preseason heat acclimatization guidelines, we identified several related EHI prevention strategies on the basis of existing recommendations (1,7,11,14). These included policies for initiating emergency medical service (EMS) response, staff training policies, and active monitoring of environmental temperature and humidity.
We then developed an online questionnaire (http://www.qualtrics.com/) to collect data on high school football program’s compliance (as reported by AT) to the NATA preseason heat acclimatization guidelines and the related EHI prevention strategies. We defined the preseason as “the period usually 2–3 weeks prior to the first game of the regular football season, characterized by athletes participating in football-specific training, in which equipment is phased in, and football specific training and skills are conducted.” This definition excluded summer conditioning that occurred before football-specific training. In addition, ATs also had the option of writing in other EHI prevention strategies they had used that were not specifically included in the questionnaire.
The questionnaire also collected the ATs’ demographical information and experience, enrollment size and number of student athletes at their school(s) during the 2011–2012 school year, and geographic region in which each school was located, on the basis of the 2009 US Census Region Map (16). In addition, ATs provided data on each high school football program’s 2011 preseason training, including size of the preseason squad and schedule of practice sessions and rest breaks.
The questionnaire was piloted in a convenience sample of 11 ATs from two universities that currently and formally provided care to high school athletes; the questionnaire was then revised on the basis of their feedback before deployment. Copies of the instrument are available from the first author (Z. Y. Kerr).
Statistical analysis
We computed the percentage of high school football programs where ATs reported compliance with each of the 17 individual NATA-IATF recommendations and all 17 recommendations (i.e., full compliance). We also computed the percentage of high school football programs where ATs reported implementing the related EHI prevention strategies.
We compared results between ATs working in those states with and without state high school athletics association mandates to implement preseason heat acclimatization guidelines (12). The state athletic association-mandated guidelines had to be approved by the Korey Stringer Institute (KSI) as meeting the criteria set forth by the NATA-IATF preseason heat acclimatization guidelines for the state to be included in the “with mandate” category (12). State guidelines did not have to be enacted before the 2011 preseason; however, they did have to be approved before the 2011 preseason.
We also stratified analyses by school size (enrollment, <1000 or ≥1000). Statistical analyses included chi-square tests, Fisher exact tests, and independent sample t-tests. We analyzed data using SAS software (version 9.2; SAS Inc, Cary, NC). This study was approved by the Institutional Review Board at The University of North Carolina at Chapel Hill.
RESULTS
Characteristics of ATs and high schools
A total of 1583 ATs (25.0% of 6343 initially contacted) agreed to participate in the study. Of those, 1335 (85.3%) provided care to high school football athletes in the 2011–2012 school year, and 1142 (72.1%) fully completed the questionnaire. We included these 1142 in the final analysis.
Most ATs were male (51.8%), with an average age of 37.0 yr (SD = 10.2) (Table 1). More than half had more than 10 yr of experience (57.9%), but 20.8% had less than 5 yr of experience. ATs mostly worked in high schools with 2011–2012 student enrollments of more than 1000 (62.6%) and were from all 51 US jurisdictions, with the exception of Alaska and Rhode Island. The largest proportions of respondents were from Texas (11.5%), Pennsylvania (7.2%), California (5.1%), Virginia (5.1%), Ohio (4.9%), Florida (4.9%), and North Carolina (4.8%). Approximately one-third of the respondents (32.3%) worked in states with mandated heat acclimatization guidelines. The states meeting the criteria were Arizona, Arkansas, Florida, Georgia, New Jersey, North Carolina, and Texas.
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TABLE 1:
Characteristics of surveyed ATs providing care to US high school football programs in the 2011 football preseason and their high schools (n = 1142).
Compliance with NATA-IATF preseason heat acclimatization guidelines
ATs reported that their high school football program complied with an average of 10.4 (SD = 3.2) of the 17 individual NATA-IATF preseason heat acclimatization recommendations (Fig. 1). Six hundred and seventy-eight ATs (59.4%) reported compliance with 10 or more recommendations, but only 29 (2.5%) reported full compliance with all 17 (Table 2). The recommendations most complied with were as follows: “one day of complete rest after six consecutive days of practice” (96.8%); “Athletic trainer must be on-site before, during, and after all practices” (95.0%); and “no more than two practices/day” (91.5%). The South region of the United States had the highest compliance (10.2, SD = 4.2), followed by the West (9.3, SD = 4.4), Midwest (8.5, SD = 3.9), and Northeast (7.7, SD = 4.4).
TABLE 2:
Percentage of high school football programs complying with NATA-IATF preseason heat acclimatization recommendations during the 2011 preseason by presence of KSI-approved preseason heat acclimatization recommendations mandated by state’s high school athletics association and by school size.
FIGURE 1:
Distribution of high schools’ level of compliance with NATA preseason heat acclimatization guidelines during the 2011 preseason.
Several of the 17 individual recommendations had poor compliance. In 60.3% of schools, ATs reported their football program did not comply with the following recommendation: “Single-practice days consisted of practice no more than three hours in length.” In fact, 17.6% of ATs reported single practice sessions lasting more than 5 h. In addition, 51.1% reported football programs did not comply with the following recommendation: “Two practices were separated by a break of at least three continuous hours that was in a cool environment,” with 24.5% reporting breaks that were 1 h or less. Furthermore, 41.2% reported football programs did not comply with the following recommendation: “A three-hour recovery period occurred between the practices and the walk-through (or vice versa),” with 20.7% reporting no recovery period was provided.
Overall, high school football programs in states with state high school association mandates regarding EHI guideline implementation complied with more NATA-IATF preseason heat acclimatization recommendations (mean = 11.4, SD = 3.1) than high school football programs in states without mandated implementation of guidelines (mean = 10.0, SD = 3.1) (P < 0.001). This was true for most of the individual recommendations (Table 2). The recommendations with the greatest differences were as follows: “Double practice days did not occur during the first five days of formal football practice” (57.1% vs 34.8%, P < 0.001), “Two practices were separated by a break of at least three continuous hours that was in a cool environment” (60.6% vs 43.3%, P < 0.001), and “Single-practice days consisted of practice no more than three hours in length” (50.0% vs 34.6%, P < 0.001).
There was no difference in the average number of NATA-IATF preseason heat acclimatization recommendations complied with by school size (<1000 students: 10.6, SD = 3.4; ≥1000 students: 10.4, SD = 3.1; P = 0.34), and there were few differences by school size for most of the individual recommendations (Table 2).
Related EHI prevention strategies
All but four AT (99.7%) reported their high school football program implemented at least one related EHI prevention strategy (Table 3). On average, ATs reported 7.6 EHI prevention strategies implemented during the 2011 preseason (SD = 2.5; range, 0–14). The most commonly implemented EHI prevention strategies were having ice bags/cooler available (reported by 98.5% of ATs), having a policy with instructions for initiating EMS response (87.8%), having an emergency response plan enacted in school (84.0%), and training staff for recognition and treatment of heatstroke (79.7%). Approximately 83.1% of AT reported they monitored practice climate by checking environmental temperature (72.8%) and humidity (71.6%), but only 31.7% reported using a wet bulb globe thermometer. The majority of ATs who performed climate monitoring reported that they checked the environmental temperature (94.6%), humidity (72.0%), or wet bulb globe (87.5%) multiple times during a practice.
TABLE 3:
EHI prevention strategies used by NATA ATs in US high school football during the 2011 preseason by presence of KSI-approved preseason heat acclimatization recommendations mandated by state’s high school athletics association and by school size.
Additional EHI prevention strategies—beyond those listed in the survey options—were provided by 37.4% of ATs. Commonly written-in EHI prevention strategies reported by ATs were having an air-conditioned room available (8.8%), using weigh-in and weigh-out charts (3.7%), having cold/ice towels available (2.6%), and having a nearby tent or shaded area available (1.3%).
ATs from high school football programs in states with state high school association mandates regarding EHI guidelines used more related EHI prevention strategies during the 2011 preseason (mean = 8.2, SD = 2.4) than programs in states without mandates (mean = 7.4, SD = 2.4) (P < 0.001). The EHI prevention strategies with the greatest differences between states with and without mandates were as follows: “immersion tub filled with ice water prior to the start of practice” (55.3% vs 39.4%, P < 0.001), “athletes required to wear light-colored clothing during all practices” (42.2% vs 29.3%, P < 0.001), and “mist machine/water-spray available” (33.0% vs 23.0%, P < 0.001).
There was no difference in the average number of related EHI prevention strategies implemented by school size (<1000 students: 7.5, SD = 2.5; ≥1000 students: 7.7, SD = 2.4; P = 0.08), and there were few differences in specific related EHI prevention strategies implemented by school size (Table 3). However, a smaller proportion of ATs working in high schools with <1000 students used the following EHI prevention strategies: “policy with instructions for initiating EMS response” (81.8% vs 91.1%, P < 0.001), “emergency response plan enacted in school” (79.4% vs 86.8%, P = 0.001), and “immersion tub filled with ice water prior to the start of practice” (40.7% vs 47.6%, P = 0.02).
DISCUSSION
This is only the second study to report compliance with EHI prevention strategies and the first to use only AT as respondents. The prior study (13) surveyed 540 high school coaches, ATs, and athletic directors from 26 states on practices recommended by the 2005 American College of Sports Medicine youth football consensus statement on EHI and injury risk. Our study used a larger sample (n = 1142) and covered more US jurisdictions (n = 49) but was limited to schools with ATs. We focused on the NATA-IATF preseason heat acclimatization guidelines (6), the first comprehensive list of recommendations that outlined a specific acclimation timeline for sports programs to follow during the preseason.
Our findings suggest that a very low proportion (2.5%) of high school football programs fully comply with all 17 NATA-IATF preseason heat acclimatization recommendations. This is consistent with the prior study (13). This indicates that the true potential of the NATA-IATF preseason heat acclimatization guidelines has yet to be reached. Because the guidelines were published in early 2009 (6), and this study examines the 2011 preseason, there may not have been sufficient time to measure the effect of the guidelines. We also caution placing accountability for lack of compliance with NATA-IATF guidelines on any specific individual within a high school sports program, particularly the ATs in this study. Our findings indicated that in a large proportion of schools, ATs were on-site, able to modify and cancel practices on the basis of environmental conditions, and voluntarily implementing several strategies to prevent EHI. For guidelines to be most effective, all stakeholders of high school sports organizations (e.g., high schools, state high school athletic associations, the National Federation of State High School Associations, athletic directors, ATs, coaches, parents, and athletes) must collaborate to ensure proper implementation of all recommended guidelines to fully reduce the incidence and burden of EHI. Ultimately, the concerned parties must work together to get their individual state organizations to adapt and enforce the NATA-IATF recommendations. Because these guidelines are based on the best heat acclimatization evidence available and are not expensive to implement, we believe high schools will be able to work progressively toward complying with all 17.
Compared with the previous study (13), a higher proportion of football programs in our study had implemented specific EHI prevention strategies, such as using a wet bulb globe thermometer, not having back-to-back double-practice days, and training staff for recognition of exertional heatstroke. We believe the observed increases are attributable to, first, public concern around EHI-related deaths and, second, increased awareness of the importance of EHI prevention and management strategies through the growing number of published position statements (1,3,4,6,15,17). It is concerning that 16.9% of high school football programs did not monitor environmental conditions and 55.2% did not have an immersion tub filled with cold water available at practice. Better implementation of EHI prevention strategies is required if we are to continue the downward trajectory in the incidence of exertional heat events and avert further deaths (10).
We found that programs from states with mandated heat safety guidelines had greater implementation of NATA-IATF recommendations and EHI prevention strategies. Although these states’ heat recommendations were not enacted until the summer of 2012, they were approved in the prior fall/winter/spring (12). As a result, during our data collection period, ATs may have been aware of the pending enactment of such state recommendations and consequently became more rigorous in implementation of EHI prevention strategies. At the same time, according to the National Center for Catastrophic Sport Injury Research (http://www.unc.edu/depts/nccsi/), five of the seven states with mandated implementation of guidelines (Arkansas, Florida, Georgia, North Carolina, and Texas) also had recent high school heat-related deaths in 2006–2011. As a result, these deaths may have instigated a push for such legislation. Currently, we do not have information regarding the number of heat-related deaths in the following years. As a result, we cannot suggest whether the higher level of compliance in these states results in improved outcomes. Nevertheless, on the basis of our findings, we recommend that all state athletic associations should mandate implementation of NATA-IATF preseason heat acclimatization recommendations. Furthermore, we recommend that emergency action plans incorporate heat safety management recommendations.
We also found that high schools with smaller student enrollments were less likely to have a policy with instructions for initiating EMS response and to have enacted an emergency response plan. Local and state high school athletic associations should focus efforts on ensuring that smaller high schools receive adequate support to draft and implement such policies and plans. Although all programs in this study had at least one high school AT, nationwide, a disproportionate number of smaller high schools lack any AT coverage (2) and therefore may be even less likely to comply with EHI prevention recommendations and strategies.
Limitations of this study include that we received complete data from only 1142 of the 6343 ATs we contacted (18.0%). Thus, our sample may be biased, and our findings may not be generalizable to all high school football programs, particularly those high schools without AT coverage. Furthermore, our sample of NATA-affiliated ATs may be more knowledgeable and thus more likely to implement published recommendations than those ATs unaffiliated with NATA. Our rationale for limiting the survey to ATs was to maximize data quality by ensuring a sports medicine clinician provided the data. We were also unable to obtain data from high schools without ATs; data collection from high schools without ATs is recommended. The validity of our findings may also be limited by typical biases related to survey research, such as recall (our survey was conducted toward the end of the 2011–2012 school year) and social desirability bias. However, we believe the ATs—who are well trained to recognize the signs and symptoms of EHI—likely had good recall of events and practices occurring in the 2011 football preseason.
There are also critical research needs in this area. Although our study focuses on implementation of preseason heat acclimatization recommendations and related EHI prevention strategies by US high school football programs, other facets of EHI prevention have yet to be evaluated, including coach/player education and barriers to compliance. Finally, we recommend ongoing longitudinal monitoring of compliance practices utilizing this survey as a baseline.
Our findings suggest that state mandate of acclimatization recommendations confers benefits beyond those offered by the acclimatization recommendations themselves, also extending to increased use of related EHI prevention strategies. State-level mandated EHI prevention recommendations may increase compliance with recognized best practices recommendations, thereby decreasing the frequency of EHI events. States that have already enacted acclimatization recommendation mandates should also consider enacting other policies related to mandating use of wet bulb globe thermometers and immersion tubs. On the basis of the data presented in this article and our knowledge of this area, we provide Table 4 as a summary of areas identified for improvement in high school football programs to reduce the burden of EHI during the preseason. National-, state-, and local-level high school athletics associations must work with high schools to ensure that adequate resources are available to help football programs comply with NATA-IATF recommendations. Furthermore, high school athletics associations must consult additional recommendations to ensure implementation of effective related EHI prevention strategies (1).
TABLE 4:
Summary of areas for improvement to reduce the burden of EHI during the preseason.
The authors thank the staff at the NATA, particularly Ruth Riggan and Cate Brennan, and Anthony Luke, M.D., M.P.H., for their assistance in this research study.
Z. Y. Kerr was funded by the Society for Public Health Education/Centers for Disease Control and Prevention 2012 Student Fellowship in Injury/Violence Prevention and Control. All other authors have no financial relationships relevant to this article to disclose.
D. J. Casa is the chief operating officer of the KSI. There have been no involvements that might raise the question of bias in the work reported in the conclusions, implications, or opinions stated.
The authors of this article appearing in this journal are solely responsible for the content thereof; the publication of an article shall not constitute or be deemed to constitute any representation by the American College of Sports Medicine.
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