Fewer US Adolescents Playing Football and Public Health: A Review of Measures to Improve Safety and an Analysis of Gaps in the Literature.

Physical activity during adolescence is associated with positive health outcomes, yet only 26% of US middle and high school students report daily physical activity. Moreover, the number of high school students playing a sport is declining, with the largest decline in football. One reason for this decline in playing football may be increased attention to the risk of head injury. For public health, the decline is alarming because football offers a physical activity opportunity for millions of young people every year. In response, efforts have been made to institute measures to enhance the safety of football. The objective of this topical review was to review these measures and the data supporting their effectiveness. We conducted a search of scientific literature supplemented by a web search to identify safety measures. We used the Indiana University library electronic database, PubMed, and web browser searches with specific search terms. In addition to peer-reviewed studies, we searched news stories and reports from sport-related organizations. We summarized the measures and evaluations of effectiveness and categorized the measures by type (game rules, practice guidelines, equipment innovations, strategic initiatives) and target age group (elementary/middle school, high school, college, professional). We found that attempts are being made to improve the safety of football at all levels. However, many measures lack scientific evidence to support their effectiveness. Therefore, researchers need to systematically evaluate safety measures. By implementing evidence-based interventions, we can balance the public health risk of playing football versus the public health risk of continued declines in participation.

Playing Rule Article Eight Decreases the Rate of Sport Related Concussion in NFL Players Over Two Seasons.

OBJECTIVES: The objectives of this study were to determine if rule article 8 significantly reduced (1) the rate of concussions sustained by NFL players during regular season games, (2) the average games missed secondary to concussion injury, and (3) the number of players placed on the injury reserve for sport-related concussions (SRC). METHODS: This study was a retrospective review of all NFL players who were placed on the publically available injury reports for a concussion from the 2016-2017 to 2019-2020 regular seasons. Player's date of injury was cross-referenced with an absence of statistics from the respective games for which they were ruled out to ensure accuracy. With article 8 taking effect starting with the 2018-2019 season, players were assigned to a pre- or postrule cohort based on date of injury for purposes of injury rate comparison. Injury rates were calculated per 1000 athletic exposures (AE). Relative risk (RR) with 95% confidence intervals (CI) compared injury rates between the two cohorts. Average number of games missed and number of players placed on injury reserve (IR) per year were also calculated. Continuous variables were statistically compared using two-tailed t-test, while categorical variables were compared using Chi-squared test. Statistical significance was set at P ≤ 0.05. RESULTS: There was a 40% decrease in the SRC rate when comparing the post- to the pre-article-8 cohort (3.3 vs 5.5/1000 AEs, respectively; RR 0.60; 95% CI 0.50-0.73). There was no significant difference in average games missed per concussion or percentage of players placed on the IR due to SRC between the two cohorts. CONCLUSIONS: The rate of SRC over the past two NFL seasons following the enactment of playing rule article 8 has significantly decreased when compared with the two seasons prior. The average games missed per concussion and the number of players placed on the IR due to SRC has not significantly changed under playing rule article 8.

Updated Return-to-Play Recommendations for Collision Athletes After Cervical Spine Injury: A Modified Delphi Consensus Study With the Cervical Spine Research Society.

BACKGROUND: Previous studies have attempted to establish return-to-play (RTP) guidelines in collision sport athletes after cervical spine injury; however, recommendations have been limited by scant high-quality evidence and basic consensus survey methodologies. OBJECTIVE: To create relevant clinical statements regarding management in collision sport athletes after cervical spine injury, and establish consensus RTP recommendations. METHODS: Following the modified Delphi methodology, a 3 round survey study was conducted with spine surgeons from the Cervical Spine Research Society and National Football League team physicians in order to establish consensus guidelines and develop recommendations for cervical spine injury management in collision sport athletes. RESULTS: Our study showed strong consensus that asymptomatic athletes without increased magnetic resonance imaging (MRI) T2-signal changes following 1-/2- level anterior cervical discectomy and fusion (ACDF) may RTP, but not after 3-level ACDF (84.4%). Although allowed RTP after 1-/2-level ACDF was noted in various scenarios, the decision was contentious. No consensus RTP for collision athletes after 2-level ACDF was noted. Strong consensus was achieved for RTP in asymptomatic athletes without increased signal changes and spinal canal diameter >10 mm (90.5%), as well as those with resolved MRI signal changes and diameter >13 mm (81.3%). No consensus was achieved in RTP for cases with pseudarthrosis following ACDF. Strong consensus supported a screening MRI before sport participation in athletes with a history of cervical spine injury (78.9%). CONCLUSION: This study provides modified Delphi process consensus statements regarding cervical spine injury management in collision sport athletes from leading experts in spine surgery, sports injuries, and cervical trauma. Future research should aim to elucidate optimal timelines for RTP, as well as focus on prevention of injuries.

Normative Reference Values for High School-Aged American Football Players.

McKay, BD, Miramonti, AA, Gillen, ZM, Leutzinger, TJ, Mendez, AI, Jenkins, NDM, and Cramer, JT. Normative reference values for high school-aged American football players. J Strength Cond Res 34(10): 2849-2856, 2020-The purpose of the present report was to provide test- and position-specific normative reference values for combine test results based on a large, nationally representative sample of high school-aged American football players in their freshman, sophomore, and junior classes. Cross-sectional anthropometric and performance data were obtained from 12 different high school American football recruiting combines between March 7, 2015, and January 9, 2016, across the United States. Subjects included a sample (n = 7,478) of high school-aged American football athletes in their junior (n = 3,779), sophomore (n = 2,514), and freshman (n = 1,185) classes. The database included combine date, school state, position, class, height, body mass (BM), 40-yard dash, pro-agility, 3-cone, vertical jump, broad jump, and power push-up. Each player self-classified their American football positions as defensive back, defensive end, defensive linemen, linebacker, offensive linemen, quarterback, running back, tight end (TE), or wide receiver. Test- and position-specific normative values were generated by aggregating data from freshman, sophomore, and junior classes. Mean differences were found among classes for all positions and all measurements (p ≤ 0.05), except for TE BM (p > 0.05). Greater differences for all variables were observed from freshman to sophomore classes than from sophomore to junior classes. These normative reference values may provide realistic comparisons and evaluations in performance for young American football players, parents, and coaches with collegiate football aspirations. High school strength and conditioning professionals should use these norms to set attainable goals and reward accomplishments for young football players.

Parents' Perspectives Regarding Age Restrictions for Tackling in Youth Football.

BACKGROUND: In ice hockey and soccer, age restrictions exist for body checking and heading because of injury risk. There are currently no age restrictions for tackling in youth football. METHODS: We surveyed a nationally representative sample of US parents regarding their support for age restrictions on tackling in football with responses of "yes," "no," and "maybe." We then generated regression models, attempting to predict support for age restrictions in tackling using demographic variables, parent perceptions of the risk of concussion in youth football, and the intensity of football support. All analyses were stratified by sex given effect modification. RESULTS: There were 1025 parents who completed the survey (52% response rate; 56% female sex). The majority (61%) supported age restrictions for tackling, and an additional 24% indicated they maybe would support age restrictions. For female respondents, a greater perceived risk of tackle football (odds ratio [OR] 3.83; 95% confidence interval [CI] 1.06-13.83) and greater educational attainment (OR 3.97; 95% CI 1.61-9.80) were associated with greater odds of supporting age restrictions for tackling. For male respondents, having a child 6 to 12 years old was associated with greater odds of maybe supporting age restrictions for tackling (OR 2.34; 95% CI 1.19-4.62). CONCLUSIONS: A majority of US parents across sexes would support age restrictions for tackling in football. This information should inform discussions when guidelines about tackling in youth football are revisited.

Alcohol management practices in community sporting clubs: Validation of an online self-report tool.

INTRODUCTION AND AIMS: Those involved in organised sport have a high risk of excessive alcohol consumption and alcohol-related harm, the implementation of alcohol management practices have been proven to reduce these risks. Measuring alcohol management practice implementation by sporting clubs is impeded by a lack of valid tools. The aim of this study was to determine the validity of online self-report of alcohol-management practices by community football clubs via comparison with observational methods. DESIGN AND METHODS: A cross-sectional study was undertaken with a sample of community football clubs within Australia. The implementation of 12 alcohol management practices was collected via: (i) an online survey; and (ii) observational audit at a clubs home ground. The prevalence of implementation of alcohol management practices for both data collection methods was calculated as was percent agreement and Kappa/Prevalence Adjusted and Bias Adjusted Kappa (PABAK) statistics. RESULTS: Data were collected from 58 football clubs. For both assessment methods, implementation prevalence was greater than 80% for 6 of the 12 alcohol management practices. A total of 75% (n = 9) of practices had at least 70% agreement between the online and observation methods of assessment. Kappa/PABAK scores ranged from -0.08 (poor agreement) to 0.97 (almost perfect agreement). DISCUSSION AND CONCLUSION: The online survey provided valid measure of assessing some but not all alcohol management practices in community sporting clubs. The validity of the measure may be improved by enhancements to the manner in which the self-report data are collected.

Impact of the national prevention policy and scrum law changes on the incidence of rugby-related catastrophic cervical spine injuries in French Rugby Union.

BACKGROUND AND AIMS: Catastrophic cervical spine injuries are rare in rugby union but require close monitoring. The aim of this study was to analyse the incidence of severe cervical spine injuries and determine the impact of a national prevention programme and new scrum rules implemented by the French Rugby Union. METHODS: A prospective study was performed between 2006 and 2013 including all players affiliated to the French Rugby Union. All cervical spine injuries resulting in death, tetraplegia or a permanent neurological deficit were included. Prevention programmes were implemented from 2007 to 2013 and a change in scrum rules in 2010. To measure the impact of rule changes, results between 2006-2010 and 2010-2013 were compared using a Poisson regression. RESULTS: Altogether, 31 injuries were observed and the mean annual incidence was 1.6 per 100 000 players. There were significantly more injuries in senior players compared to junior players (3.5 vs 0.6 per 100 000 players; CI 95% (2.1 to 4.9) vs (0.1 to 1.0)). Incidence decreased from 1.8 in 2006 to 1.0 per 100 000 players in 2013 (p<0.0001). After 2010, there were significantly fewer injuries during scrums (p=0.02). In contrast, there were significantly more injuries in backs during 2010-2013 compared to 2006-2010 (p=0.003). CONCLUSIONS: The incidence of catastrophic cervical spine injuries has declined in French Rugby Union. The implementation of specific prevention programmes and scrum law changes has notably resulted in a decrease in scrum injuries in forwards. This prospective study should be continued to monitor the future progression of injuries and adapt prevention programmes accordingly.

Non-sanctioning of illegal tackles in South African youth community rugby.

OBJECTIVES: The tackle event in rugby union ('rugby') contributes to the majority of players' injuries. Referees can reduce this risk by sanctioning dangerous tackles. A study in elite adult rugby suggests that referees only sanction a minority of illegal tackles. The aim of this study was to assess if this finding was similar in youth community rugby. DESIGN: Observational study. METHODS: Using EncodePro, 99 South African Rugby Union U18 Youth Week tournament matches were coded between 2011 and 2015. All tackles were coded by a researcher and an international referee to ensure that laws were interpreted correctly. The inter- and intra-rater reliabilities were 0.97-1.00. A regression analysis compared the non-sanctioned rates over time. RESULTS: In total, 12 216 tackles were coded, of which less than 1% (n=113) were 'illegal'. The majority of the 113 illegal tackles were front-on (75%), high tackles (72%) and occurred in the 2nd/4th quarters (29% each). Of the illegal tackles, only 59% were sanctioned. The proportions of illegal tackles and sanctioning of these illegal tackles to all tackles improved by 0.2% per year from 2011-2015 (p<0.05). CONCLUSIONS: In these youth community rugby players, 59% of illegal tackles were not sanctioned appropriately. This was better than a previous study in elite adult rugby, where only 7% of illegal tackles were penalised. Moreover, the rates of illegal tackles and non-sanctioned illegal tackles both improved over time. However, it is critical that referees consistently enforce all laws to enhance injury prevention efforts. Further studies should investigate the reasons for non-sanctioning.

Head Impact Exposure in Youth Football: Comparing Age- and Weight-Based Levels of Play.

Approximately 5,000,000 athletes play organized football in the United States, and youth athletes constitute the largest proportion with ∼3,500,000 participants. Investigations of head impact exposure (HIE) in youth football have been limited in size and duration. The objective of this study was to evaluate HIE of athletes participating in three age- and weight-based levels of play within a single youth football organization over four seasons. Head impact data were collected using the Head Impact Telemetry (HIT) System. Mixed effects linear models were fitted, and Wald tests were used to assess differences in head accelerations and number of impacts among levels and session type (competitions vs. practices). The three levels studied were levels A (n = 39, age = 10.8 ± 0.7 years, weight = 97.5 ± 11.8 lb), B (n = 48, age = 11.9 ± 0.5 years, weight = 106.1 ± 13.8 lb), and C (n = 32, age = 13.0 ± 0.5 years, weight = 126.5 ± 18.6 lb). A total of 40,538 head impacts were measured. The median/95th percentile linear head acceleration for levels A, B, and C was 19.8/49.4g, 20.6/51.0g, and 22.0/57.9g, respectively. Level C had significantly greater mean linear acceleration than both levels A (p = 0.005) and B (p = 0.02). There were a significantly greater number of impacts per player in a competition than in a practice session for all levels (A, p = 0.0005, B, p = 0.0019, and C, p < 0.0001). Athletes at lower levels experienced a greater percentage of their high magnitude impacts (≥ 80g) in practice, whereas those at the highest level experienced a greater percentage of their high magnitude impacts in competition. These data improve our understanding of HIE within youth football and are an important step in making evidence-based decisions to reduce HIE.

Safety regulation in professional football: Empirical evidence of intended and unintended consequences.

In response to increasing public awareness and negative long-term health effects of concussions, the National Football League implemented the "Crown-of-the-Helmet Rule" (CHR). The CHR imposes penalties on players who initiate contact using the top of the helmet. This paper examines the intended effect of this policy and its potential for unintended consequences. We find evidence supporting the intended effect of the policy- a reduction in weekly concussion reports among defensive players by as much as 32% (34% for all head and neck injuries), but also evidence of an increase in weekly lower extremity injury reports for offensive players by as much as 34%.

Tackling in Youth Football.

American football remains one of the most popular sports for young athletes. The injuries sustained during football, especially those to the head and neck, have been a topic of intense interest recently in both the public media and medical literature. The recognition of these injuries and the potential for long-term sequelae have led some physicians to call for a reduction in the number of contact practices, a postponement of tackling until a certain age, and even a ban on high school football. This statement reviews the literature regarding injuries in football, particularly those of the head and neck, the relationship between tackling and football-related injuries, and the potential effects of limiting or delaying tackling on injury risk.

Predicting higher selection in elite junior Australian Rules football: The influence of physical performance and anthropometric attributes.

OBJECTIVES: To develop a physiological performance and anthropometric attribute model to predict Australian Football League draft selection. DESIGN: Cross-sectional observational. METHODS: Data was obtained (n=4902) from three Under-18 Australian football competitions between 2010 and 2013. Players were allocated into one of the three groups, based on their highest level of selection in their final year of junior football (Australian Football League Drafted, n=292; National Championship, n=293; State-level club, n=4317). Physiological performance (vertical jumps, agility, speed and running endurance) and anthropometric (body mass and height) data were obtained. Hedge's effect sizes were calculated to assess the influence of selection-level and competition on these physical attributes, with logistic regression models constructed to discriminate Australian Football League Drafted and National Championship players. Rule induction analysis was undertaken to determine a set of rules for discriminating selection-level. RESULTS: Effect size comparisons revealed a range of small to moderate differences between State-level club players and both other groups for all attributes, with trivial to small differences between Australian Football League Drafted and National Championship players noted. Logistic regression models showed multistage fitness test, height and 20 m sprint time as the most important attributes in predicting Draft success. Rule induction analysis showed that players displaying multistage fitness test scores of >14.01 and/or 20 m sprint times of <2.99 s were most likely to be recruited. CONCLUSIONS: High levels of performance in aerobic and/or speed tests increase the likelihood of elite junior Australian football players being recruited to the highest level of the sport.

Improving the diffusion of safety initiatives in community sport.

OBJECTIVES: The "Mayday Safety Procedure" (MSP) is included in the Australian Rugby Union (ARU) Medical and Safety Recommendations and the mandatory SmartRugby training for coaches. Previous research indicates that translating the Mayday Safety Procedure into practice among community rugby coaches is challenging. This study investigated whether Mayday Safety Procedure translation could be enhanced by systematically planning and implementing a range of theory-informed and context-specific diffusion strategies. DESIGN: A controlled before-and-after study. METHODS: Coaches of senior community rugby teams in five zones in New South Wales (Australia) were invited to complete a questionnaire about their Mayday Safety Procedure knowledge and practice at the end of the 2010 and 2011 rugby seasons. During 2011, coaches in the intervention zone were exposed to a range of strategies to promote Mayday Safety Procedure diffusion which were planned by following Step 5 of the Intervention Mapping protocol. Coaches in the other four zones were exposed to usual strategies to promote Mayday Safety Procedure diffusion. RESULTS: Using the RE-AIM evaluation framework, statistically significant improvements were found among intervention zone coaches in: knowledge of most Mayday Safety Procedure key criteria; the number of coaches recognising their zone policy requiring them to train players in the Mayday Safety Procedure; frequency of provision of Mayday Safety Procedure training to players; coach perceptions of the quality of Mayday Safety Procedure training for players; and in confidence that referees could implement the Mayday Safety Procedure during a game if required. CONCLUSIONS: The findings suggest that the translation of injury prevention policy into community practice can be enhanced by developing and implementing a theory-informed, context-specific diffusion plan, undertaken in partnership with key stakeholders.

Fuzzy logic and its application in football team ranking.

Fuzzy set theory and fuzzy logic are a highly suitable and applicable basis for developing knowledge-based systems in physical education for tasks such as the selection for athletes, the evaluation for different training approaches, the team ranking, and the real-time monitoring of sports data. In this paper, we use fuzzy set theory and apply fuzzy clustering analysis in football team ranking. Based on some certain rules, we propose four parameters to calculate fuzzy similar matrix, obtain fuzzy equivalence matrix and the ranking result for our numerical example, T 7, T 3, T 1, T 9, T 10, T 8, T 11, T 12, T 2, T 6, T 5, T 4, and investigate four parameters sensitivity analysis. The study shows that our fuzzy logic method is reliable and stable when the parameters change in certain range.

Influence of playing standard on the physical demands of junior rugby league tournament match-play.

OBJECTIVES: To investigate the physical demands on junior rugby league players competing at three different standards of tournament match-play. DESIGN: Cross-sectional study. METHODS: Sixty junior rugby league players (mean ± SD age, 16.7 ± 0.7 years) participated in this study. Players were either competing in Division 1, Division 2, or Division 3 teams of the Confraternity carnival. Global positioning system (GPS) analysis was completed during 17 matches (totalling 139 appearances). RESULTS: Division 1 and 2 players covered significantly (p=0.001) greater distance per minute of match play than Division 3 players (83.0 ± 12.3m/min and 81.5 ± 6.9 m/min vs. 73.3 ± 9.8m/min). The greater total distance at the higher competitive standard was achieved through greater (p=0.001) distances at low speeds, with Division 1 players also covering more (p=0.038) high speed running than Division 3 players. Expressed relative to playing time, the number of total collisions was lower (p=0.001) in Division 3 players. Division 2 players engaged in more (p=0.034) repeated high-intensity effort bouts than Division 3 players. Significant decrements in total (p=0.005) and low speed distances (p=0.006) were found, with Division 3 players showing the largest reductions in performance. CONCLUSIONS: These findings demonstrate that both the average intensity and the repeated high-intensity effort demands of junior rugby league tournament match-play are greater at higher playing standards. Sport scientists and conditioning staff can use these data to plan appropriate training sessions to allow players to tolerate match-play demands, and recover from the demands of competition.

Return to play guidelines cannot solve the football-related concussion problem.

BACKGROUND: High school football players are the single largest cohort of athletes playing tackle football, and account for the majority of sport-related concussions. Return to play guidelines (RTPs) have emerged as the preferred approach for addressing the problem of sport-related concussion in youth athletes. METHODS: This article reviews evidence of the risks and effects of football-related concussion and subconcussive brain trauma, as well as the effectiveness of RTPs as a preventative measure. Literature review utilized PubMed and Google Scholar, using combinations of the search terms "football,""sports,""concussion,""Chronic Traumatic Encephalopathy,""athlete,""youth," and "pediatric." Literature review emphasized medical journals and primary neuroscientific research on sport-related concussion and concussion recovery, particularly in youth athletes. RESULTS: Sport-related concussion is a significant problem among student athletes. Student athletes are more vulnerable to concussion, and at risk of neurocognitive deficits lasting a year or more, with serious effects on academic and athletic performance. RTPs do little to address the problem of sport-related concussion or the chronic damage caused by subconcussive brain trauma. CONCLUSIONS: Emphasizing RTPs as the solution to the concussion problem in tackle football risks neglecting genuine reforms that would prevent concussions. More effective concussion prevention is needed. Eliminating tackling from school football for youth under 16 is recommended to reduce concussions. Additional modifications to football are recommended to enhance safety and reduce brain trauma at all levels of play.

Global positioning system data analysis: velocity ranges and a new definition of sprinting for field sport athletes.

Global positioning system (GPS) technology has improved the speed, accuracy, and ease of time-motion analyses of field sport athletes. The large volume of numerical data generated by GPS technology is usually summarized by reporting the distance traveled and time spent in various locomotor categories (e.g., walking, jogging, and running). There are a variety of definitions used in the literature to represent these categories, which makes it nearly impossible to compare findings among studies. The purpose of this work was to propose standard definitions (velocity ranges) that were determined by an objective analysis of time-motion data. In addition, we discuss the limitations of the existing definition of a sprint and present a new definition of sprinting for field sport athletes. Twenty-five GPS data files collected from 5 different sports (men's and women's field hockey, men's and women's soccer, and Australian Rules Football) were analyzed to identify the average velocity distribution. A curve fitting process was then used to determine the optimal placement of 4 Gaussian curves representing the typical locomotor categories. Based on the findings of these analyses, we make recommendations about sport-specific velocity ranges to be used in future time-motion studies of field sport athletes. We also suggest that a sprint be defined as any movement that reaches or exceeds the sprint threshold velocity for at least 1 second and any movement with an acceleration that occurs within the highest 5% of accelerations found in the corresponding velocity range. From a practical perspective, these analyses provide conditioning coaches with information on the high-intensity sprinting demands of field sport athletes, while also providing a novel method of capturing maximal effort, short-duration sprints.