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When the rules of the game are broken: what proportion of high school sports-related injuries are related to illegal activity?
  1. C L Collins1,
  2. S K Fields2,
  3. R D Comstock1,3
  1. 1
    The Research Institute at Nationwide Children’s Hospital, Center for Injury Research and Policy, Columbus, OH, USA
  2. 2
    The Ohio State University, College of Education and Human Ecology, School of Physical Activity and Educational Services, Columbus, OH, USA
  3. 3
    The Ohio State University, College of Medicine, Department of Pediatrics and College of Public Health, Division of Epidemiology, Columbus, OH, USA
  1. Christy Collins, MA, Center for Injury Research and Policy, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205, USA; christy.collins{at}nationwidechildrens.org

Abstract

Objectives: To compare sport and gender differences in injury rates and proportions of injuries related to illegal activity and to describe the epidemiology of injuries related to illegal activity.

Design: Descriptive epidemiology study.

Setting: 100 US high schools.

Subjects: Athletes participating in nine sports: boys’ football, soccer, basketball, wrestling, and baseball plus girls’ soccer, volleyball, basketball, and softball.

Main outcome measures: Illegal activity-related injuries were analyzed using data from the 2005–06 and 2006–07 National High School Sports-Related Injury Surveillance Study.

Results: Nationally, an estimated 98 066 injuries were directly related to an action that was ruled illegal activity by a referee/official or disciplinary committee, giving an injury rate of 0.24 injuries per 1000 athletic competition-exposures. Boys’ and girls’ soccer had the highest rates of injuries related to illegal activity, and girls’ volleyball, girls’ softball, and boys’ baseball had the lowest. Overall, 6.4% of all high school sports-related injuries were related to illegal activity, with the highest proportion in girls’ basketball (14.0%), girls’ soccer (11.9%), and boys’ soccer (11.4%). A greater proportion of injuries related to illegal activity were to the head/face (32.3%) and were concussions (25.4%) than injuries not related to illegal activity (13.8% (injury proportion ratio 2.35; 95% CI 1.82 to 3.04; p<0.001) and 10.9% (injury proportion ratio 2.35; 95% CI 1.71 to 3.22; p<0.001), respectively).

Conclusions: Illegal activity is an overlooked risk factor for sports-related injury. Reducing illegal activity through enhanced enforcement of sports’ rules and targeted education about the dangers of illegal activity for players, coaches, and referees/officials may reduce sports-related injuries.

Statistics from Altmetric.com

Participation in sports is one way to maintain a physically active lifestyle; however, sports participation also places athletes at risk of injury. Each sport has a unique set of rules developed to promote fair competition and protect participants from injury by minimizing the number of unsafe acts that expose players to high-risk situations including inadvertent illegal activity or intentional acts of foul play. Thus, enforcing rules and punishing illegal activity is a risk control measure that may reduce injury rates by modifying players’ behavior.

Sports injury research has largely focused on describing patterns of injury and studying methodologies for reducing injury rates including protective equipment, coaching techniques, and athlete conditioning. Although illegal activity occurs at all levels of sport and across all cultures,1 the impact of illegal activity/foul play on sports injury rates has not been studied in detail. Prior research has examined illegal activity/foul play in individual sports including rugby,212 soccer,1323 Gaelic football,2425 hurling,26 and ice hockey,2728 with the proportion of injuries attributed to illegal activity/foul play ranging from 41% for hurling,26 33% for ice hockey,27 5%12 to 33%9 for rugby, 10%23 to 50%19 for soccer, and 6%24 to 35%25 for Gaelic football. Research investigating illegal activity/foul play in athletes across multiple sports has been limited to reviews of athletes presenting for treatment at emergency departments2930 as well as a 1-year prospective study of school children (illegal activity/foul play was identified as a major factor in athletic injuries.)31 Although some of these studies included youth,291421232731 only one focused specifically on high school age athletes.12 Differences in illegal activity among high school aged youth and populations studied in previous research may exist as a result of differences in rules, level of rule enforcement, and penalties for illegal activity.

This study’s objectives were to compare sport and gender differences in injury rates and proportions of injuries related to illegal activity across nine boys’ and girls’ high school sports and to describe the epidemiology of injuries related to illegal activity using a nationally representative sample of US high school athletes.

METHODS

RIO (Reporting Information Online), an internet-based surveillance system, was used to capture injuries sustained by US high school athletes participating in nine sports including boys’ football, soccer, basketball, wrestling, and baseball and girls’ soccer, volleyball, basketball, and softball during the 2005–06 and 2006–07 academic years. The RIO system is closely modeled on the National Collegiate Athletic Association Injury Surveillance System, which has successfully collected quality data on injuries, athletic-exposures, and risk factors since 1982 and has been used to develop preventive interventions that have had proven success in reducing injuries among collegiate athletes.32 RIO has been successfully used in several other studies.123335

As previously described,3335 all US high schools with a Board of Certification-certified and National Athletic Trainer’s Association-affiliated certified athletic trainer (ATC) with a valid email address (n = 4120 in 2005–06 and n = 3378 in 2006–07) were invited to participate in the National High School Sports-Related Injury Surveillance Study. Schools interested in participating (n = 425 in 2005–06 and n = 316 in 2006–07) were placed into one of eight sampling strata according to their high school’s US Census geographic location36 (northeast, midwest, south, and west) and enrollment size (<1000 or ⩾1000 students). Schools were randomly selected from each stratum to obtain a nationally representative study sample of 100 high schools each year. To maintain the representativeness of the study sample, if a school dropped out of the study, another school from the same stratum was randomly selected for replacement.

ATCs at participating high schools reported athletic-exposure, injury, and injury event information weekly throughout the 2005–06 and 2006–07 academic years. An athletic-exposure was defined as one athlete participating in one competition. A reportable injury was defined as one that occurred as a result of an organized high school athletic competition, required medical attention by an ATC or physician, and resulted in restriction of the athlete’s participation for 1 or more days beyond the day of injury. For each injury, the ATCs completed a detailed report that described characteristics of the injured athlete (eg, age, body mass, year in school), the injury itself (eg, body site, diagnosis, severity), and the circumstances leading to the injury (eg, general mechanism, specific activity). For injuries sustained during a competition, ATCs also reported if the injury was directly related to an action that was ruled illegal/foul play by a referee/official or disciplinary committee such as punching, tripping, or tackling in sports in which tackling is not allowed. Throughout the study, ATCs were able to view all the data they submitted and update reports as needed (eg, need for surgery, number of days until return to play). Routine data audits and internal validity checks were performed to ensure data completeness and accuracy.

Data were analyzed using SPSS software, V14.0, and Epi Info, V6.0. All rate calculations used unweighted case counts (ie, the absolute number of reported injuries). Additional analyses used national estimates with the standard errors adjusted for the sampling plan using the SPSS Complex Samples module. To calculate national estimates of the number of injuries, each reported injury was assigned a sample weight based on the inverse of the probability of the school’s selection into the study (based on the total number of US high schools in each of the eight sampling strata). Statistical analyses included the χ2 test with Yates’ correction and t tests. Rate ratios (RRs) and injury proportion ratios (IPRs) were calculated using 95% confidence intervals (CIs) and p values to assess significance (p<0.05 was considered significant). The following is an example of the RR calculation comparing the rate of girls’ soccer-related injuries sustained during competition with the rate of boys’ soccer-related injuries sustained during competition:

Embedded Image

where A  =  number of unweighted competition girls’ soccer-related injuries, B  =  number of girls’ soccer athletic competition-exposures, C  =  number of unweighted competition boys’ soccer-related injuries, and D  =  number of boys’ soccer athletic competition-exposures.

The following is an example of the IPR calculation comparing the proportion of injuries related to illegal activity in girls’ sports to boys’ sports.

Embedded Image

where E  =  national estimated number of injuries related to illegal activity in girls’ sports, F  =  national estimated total number of injuries sustained by girls, G  =  national estimated number of injuries related to illegal activity in boys’ sports, and H  =  national estimated total number of injuries sustained by boys.

This study was approved by the Nationwide Children’s Hospital’s Institutional Review Board.

RESULTS

Overall injury rates for competitions

High school athletes participating in the nine sports studied sustained 4618 injuries during 971 794 athletic competition-exposures for an injury rate of 4.75 injuries per 1000 athletic competition-exposures (table 1). Boys’ football and girls’ soccer had the highest injury rates, and boys’ baseball, girls’ softball, and girls’ volleyball had the lowest.

Table 1 Comparison of US high school sports competition injury rates, National High School Sports-Related Injury Surveillance Study, United States, 2005–07 school years

Overall, boys’ sports had a higher competition injury rate (5.81 injuries per 1000 athletic-exposures) than girls’ sports (3.11 injuries per 1000 athletic-exposures) (RR = 1.87, 95% CI 1.75 to 2.00, p<0.001). In soccer and basketball, two of the three sports played by both sexes, the injury rate was higher for girls than boys (RR = 1.25, 95% CI 1.10 to 1.42, p<0.001 and RR = 1.23, 95% CI 1.06 to 1.42, p = 0.006, respectively).

National injury data

During the 2005–06 and 2006–07 school years, 66.9% of the estimated 1 525 846 injuries that occurred nationally during competition were sustained by male competitors. The ages of injured athletes ranged from 13 to 19 years.

Rate of injuries related to illegal activity

Overall, high school athletes sustained 238 injuries that were related to illegal activity giving an injury rate of 0.24 injuries related to illegal activity per 1000 athletic competition-exposures (table 2).

Table 2 Comparison of US high school injury rates for sports injuries related to illegal activity, National High School Sports-Related Injury Surveillance Study, United States, 2005–07 school years

Boys’ and girls’ soccer had the highest rates of injury related to illegal activity, and girls’ volleyball, girls’ softball, and boys’ baseball had the lowest (table 2). Boys’ and girls’ sports had similar rates of injuries related to illegal activity.

Proportion of injuries related to illegal activity

Of all injuries, 6.4% were related to illegal activity (table 2). The highest proportion of injuries related to illegal activity was in girls’ basketball, girls’ soccer, and boys’ soccer (table 2). Girls’ softball, boys’ football, and girls’ volleyball attributed the lowest proportion of injuries to illegal activity. Overall, girls’ sports had a higher proportion of injuries related to illegal activity than boys’ sports (IPR = 1.99, 95% CI 1.46 to 2.71, p<0.001).

Characteristics of injuries related to illegal activity compared with injuries not related to illegal activity

The body parts most commonly reported as injured related to illegal activity were the head/face, ankle, and knee (table 3). A greater proportion of injuries related to illegal activity were to the head/face (32.3%) than injuries not related to illegal activity (13.8%) (IPR = 2.35; 95% CI 1.82 to 3.04; p<0.001).

Table 3 Characteristics of sports competition injuries related to illegal activity compared with other high school sports-related injuries, National High School Sports-Related Injury Surveillance Study, United States, 2005–07 school years

The most common diagnoses for injuries related to illegal activity were concussions, contusions, ligament sprains (incomplete tear), and fractures (table 3). A greater proportion of injuries related to illegal activity were concussions than those injuries not related to illegal activity (25.4% vs 10.9%; IPR = 2.35; 95% CI 1.71 to 3.22; p<0.001). In addition, a greater proportion of injuries related to illegal activity were contusions compared with other high school sports-related injuries (IPR = 1.64; 95% CI 1.24 to 2.16; p = 0.001). Conversely, a greater proportion of injuries not related to illegal activity were ligament sprains (incomplete tears) and muscle strains (incomplete tears) compared with injuries related to illegal activity (IPR = 1.62; 95% CI 1.14 to 2.29; p = 0.003 and IPR = 5.01; 95% CI 2.42 to 10.38; p<0.001, respectively).

Although most injuries related to illegal activity resulted in a time loss of less than 1 week, 8.5% resulted in a time loss of more than 21 days, and 10.5% resulted in medical disqualification for the season. Of all injuries related to illegal activity, 5.7% required surgery. Injuries related to illegal activity and those not related to illegal activity were similar with respect to time loss and need for surgery (table 3). For both groups, the most commonly injured body site that resulted in medical disqualification for the season and/or required surgery was the knee, and the most common diagnoses that resulted in medical disqualification and/or surgery were fractures and ligaments sprains (complete tears). A greater proportion of injuries related to illegal activity were attributed to contact with another player (80.1%) than injuries not related to illegal activity (56.2%; IPR = 1.43; 95% CI 1.31 to 1.56; p<0.001; fig 1).

Figure 1 Mechanism of injury for sports injuries related to illegal activity compared with other high school sports-related injuries, National High School Sports-Related Injury Surveillance Study, United States, 2005–07 school years. *Based on national estimates.

DISCUSSION

Illegal activity/foul play is a generally overlooked risk factor for sports-related injury that presents a worldwide opportunity for injury reduction through preventive interventions. Until now, there have been no nationally representative studies on the incidence of US high school sports-related injuries related to illegal activity, so there have been no reliable estimates of the magnitude of the problem. Although the 0.7–14.0% of sports-related injuries attributed to illegal activity identified in this study is generally lower than the 6%24 to 50%19 of sports-related injuries attributed to illegal activity/foul play in prior studies, illegal activity was responsible for over 10% of injuries in four of the nine sports studied. Any single risk factor directly responsible for such high proportions of high school sports-related injuries should be addressed by programs designed to prevent injuries.

Overall, we found that injuries related to illegal activity and those not related to illegal activity were similar in severity (eg, time loss and need for surgery); however, nearly one-third of injuries related to illegal activity were to the head/face and more than one-quarter of injuries related to illegal activity were concussions. Previous studies have found a similar association between head injuries/concussions and foul play,21422 including a recent study of US high school rugby injuries.12 In this study, we also found that a significantly greater proportion of injuries related to illegal activity were to the head/face or were concussions than injuries not related to illegal activity/foul play. Reducing the number of injuries attributed to illegal activity in general among US high school athletes can specifically reduce the number of injuries to the head/face and concussions. This is particularly important given the long-term effects of concussions.37

Athlete-to-athlete contact has been identified as a leading cause of sports-related injury.2578141720 22 28 Although the amount of contact varies by sport, categorization of sports as contact or non-contact is arbitrary. In this discussion, contact sports are defined as those in which athlete-to-athlete contact is expected, encouraged, and allowed in the rules (eg, boys’ football and wrestling). Non-contact sports include those in which athlete-to-athlete contact can, and often does, occur, although it is largely against the rules (eg, boys’ and girls’ soccer and basketball). This study found that a higher proportion of injuries were related to illegal activity in non-contact than contact sports. Although football had the highest competition injury rate, <2% of the injuries in football were related to illegal activity. Conversely, although boys’ and girls’ basketball had comparatively low rates of injury, ⩾10% of the injuries in these sports were related to illegal activity. In non-contact sports, acts of illegal activity may be more obvious to the referees/officials, as over 80% of injuries related to illegal activity were attributed to contact with another player.

Key points

  • Illegal activity is a generally overlooked risk factor for sports-related injury that presents an opportunity for injury reduction through preventive interventions.

  • Of the nine sports studied, over 10% of injuries in four sports were related to illegal activity. This single risk factor directly responsible for such high proportions of sports-related injuries should be addressed by injury prevention.

  • Reducing the number of injuries attributed to illegal activity in general among US high school athletes may specifically reduce the number of injuries to the head/face and concussions.

  • Attempts to reduce illegal activity/foul play including enhanced enforcement of sports’ rules as well as targeted education about the dangers of illegal activity/foul play for players, coaches, and referees may be effective in reducing rates of high school sports-related injuries.

In addition, we found in two of the three sports in which male and female competitors play by the same or similar rules (ie, soccer, basketball, and baseball/softball), girls tend to have both a slightly higher competition injury rate and a higher proportion of injuries related to illegal activity. Although these differences were not statistically significant, this finding suggests that potential gender-related physiological differences exist or that either girls commit additional or more violent fouls or referees/officials are quicker to penalize illegal activity committed by girls than that committed by boys. Referees/officials should be aware that illegal activity occurs in all sports, both contact and non-contact, as well as in sports played by both genders. Future studies are needed to further investigate potential differences in illegal activity by sport and gender.

Student athletes self-reporting injury information may be more likely to attribute injuries to illegal activity; however, because the definition of illegal activity was based on the ruling of a referee/official or disciplinary committee, this potential recall bias was reduced. Our inability to differentiate between inadvertent (unintentional) illegal activity and intentional foul play was a limitation. Although several researchers have concluded that enhanced enforcement of sporting rules may help to reduce sports-related injury rates,24710131920222728 at least one study of professional hockey players suggested that the effectiveness of enhanced rule enforcement as an injury prevention technique may be affected by differences between inadvertent illegal activity and intentional foul play.38 However, these findings may not be generalizable to high school, collegiate, or non-professional adult athletes. Future studies are needed to investigate potential differences in patterns of injuries related to inadvertent illegal activity compared with intentional foul play among different sports, genders, and levels of competition.

Other potential limitations were associated with the RIO surveillance system. Although schools were selected to be nationally representative with respect to geographic location and school size, only schools with an NATA-affiliated ATC were eligible to participate. Therefore, our results may not be generalizable to all schools in the USA. However, this potential limitation was outweighed by the quality of data provided by these medically trained professionals. ATCs also had to have access to the internet and be able to use the internet-based surveillance system in order to participate. However, internet access is generally widespread in US high schools, and ATCs were provided with a written training packet as well as a PowerPoint-based training guide. Only injuries that came to the attention of the ATC and resulted in at least 1 day of time loss were included in the study; therefore, it is possible that we actually underestimated the rate of illegal activity-related injuries. This was necessary, however, to reduce the time burden placed on the participating ATCs. In addition, there is a relative lack of clinical importance of non-time-loss injuries. Although there is a current movement to use a more quantitative time-based unit of athletic-exposure such as minutes or hours,39 it was not feasible for the reporters (high school ATCs), to be present at all athletic competitions to collect such detailed exposure data. Furthermore, we argue that every athlete is at risk of injury during every competition in which they participate. Despite these limitations, to date, this is the most comprehensive study of injuries related to illegal activity across multiple sports in a nationally representative population of high school athletes.

IMPLICATIONS FOR PREVENTION

By definition, activities ruled illegal are not supposed to occur. Thus, injuries attributed to illegal activities should be largely preventable. Attempts to reduce illegal activity/foul play including enhanced enforcement of sports’ rules as well as targeted education about the dangers of illegal activity/foul play for players, coaches, and referees/officials may be effective in reducing rates of high school sports-related injuries. Well-designed cohort studies are needed to investigate further the impact of illegal activity on sports-related injuries, to provide data from which preventive interventions can be developed, and to evaluate such interventions.

REFERENCES

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Footnotes

  • Competing interests: None.

  • Funding: This study was funded in part by the Centers for Disease Control and Prevention (CDC) grant No R49/CEOOO674-01. The content of this report is solely the responsibility of the authors and does not necessarily represent the official view of the CDC.

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