pediatrics
November 2015, VOLUME136 /ISSUE 5

Tackling in Youth Football

  1. COUNCIL ON SPORTS MEDICINE AND FITNESS

    Abstract

    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.

  1. Abbreviations:
    AE
    athletic exposure
    CTE
    chronic traumatic encephalopathy
  2. Introduction

    With more than 1.1 million players, American football remains one of the most popular sports for male high school athletes.1 In addition, there are approximately 250 000 youth football players 5 to 15 years of age in Pop Warner leagues alone, making football one of the most popular sports for younger athletes as well.2 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 the medical literature. Concerns about the number of head and neck injuries, especially concussions and catastrophic injuries, have led some athletes to stop playing football.3 More recently, the cumulative effects of concussions and the potential for a cumulative effect of subconcussive blows to the head, defined as those that do not cause symptoms of concussion, have been hypothesized as a causative risk factor for chronic traumatic encephalopathy (CTE). 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.46

    Others, however, have argued that football is a generally safe sport that carries with it the substantial benefits of regular exercise on health7,8 as well as social and academic outcomes911 that outweigh the risks involved, pointing out that the risk of catastrophic injury is low, that most concussions resolve within a few days or weeks, and that there are substantial limitations to the current understanding of CTE. Some have expressed concerns about limiting contact practices or delaying the age at which tackling is introduced for fear that inadequate training may lead to unintended consequences once contact is allowed, such as increased forces of impact and more concussions.

    The purpose of this statement is to review 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. For purposes of this statement, unless otherwise defined, an athletic exposure (AE) refers to 1 athlete participating in 1 game or 1 practice.

    Incidence of Injuries in Youth Football

    The most commonly injured body parts in football at all ages are the knee,1220 ankle,1221 hand,21 and back.1216 The head and neck sustain a relatively small proportion of overall injuries, ranging from 5% to 13%.1218 Fortunately, most injuries are contusions, musculotendinous strains, and ligamentous sprains.12,13,15,17,18

    Available data suggest that both the overall incidence and the severity of injuries sustained by younger football players are lower than those sustained by older players,1216,18,19,2125 although this finding is not universally consistent.21 Some studies suggest that the incidence of overall injuries in football is similar to other sports,19,21 although the incidence of serious injuries appears to be greater for football than many other team sports.21,26 Although data regarding the most common injuries sustained by football players at the professional, collegiate, and high school level are more readily available, data regarding younger players is limited. The overall incidence of injury varies between studies, depending on how an injury was defined and how data were gathered (Table 1).

    TABLE 1

    Summary of Studies Describing Incidence of Injuries in American Football

    Cumulative and Catastrophic Head and Neck Injuries in Football

    Although the risk of catastrophic injuries to the head and neck in football is low, with yearly estimates between 0.19 and 1.78 for every 100 000 participants,2729 it appears higher in football than most other team sports.28 The risk of catastrophic injury during participation in football is, however, comparable to the risk in gymnastics and lower than the risk in ice hockey.28 The risk appears lower for youth players than for high school players and lower for high school players than for college players.27,29 The annual risk of quadriplegia is approximately 0.52 per 100 000 football participants and, again, appears lower for high school football players (0.50/100 000 participants) than collegiate players (0.82/100 000 participants). Spear tackling, or leading with the crown of the helmeted head while tackling by defensive players, continues to be the predominant mechanism of injury causing quadriplegia.29

    The cumulative effects of concussion have been documented both in athletes and those outside the realm of organized sports.3034 Some former athletes who participated in sports that involve purposeful collisions and repetitive blows to the head have suffered from mood disorders, behavior problems, cognitive difficulties, gait abnormalities, headaches, and Parkinsonism later in life. At autopsy, these athletes had pathologic changes to the brain, including ventriculomegaly, cerebral atrophy, β-amyloid deposits, and phosphorylated τ deposits, an entity now commonly known as CTE.3549 These case reports and case series have led to the hypothesis that repetitive blows to the head, whether concussive or subconcussive, result in the pathologic changes noted above and that these pathologic changes are associated with certain neurobehavioral characteristics. Whether the pathologic findings are solely attributable to the blows to the head and whether the pathologic changes are significantly associated with the neurobehavioral correlates is debated because these hypotheses remain to be tested by case-control and cohort studies.5054 Some have argued that these effects may be attributable to confounding variables, such the use of drugs, alcohol, or performance-enhancing substances. It should be noted, however, that animal models of repetitive concussive brain injury have shown a decrease in cognitive function in the absence of such potential confounding variables.5557

    “Second impact syndrome” is a term used to describe a devastating brain injury associated with cerebral edema that occurs after an often minor blow to the head is sustained before full recovery from a concussion.5861 Although second impact syndrome is often associated with football, it has been observed in other sports, such as ice hockey, boxing, and skiing.58 Nearly all athletes with this diagnosis in the literature are younger than 20 years old. Given the rarity of this injury, its incidence in football is unknown. Furthermore, whether second impact syndrome is a unique entity, as opposed to cerebral edema attributable to a solitary blow to the head, remains debated.6265

    Injuries Associated With Tackling

    Injuries are common during contact and tackling in particular.14,1618 A higher proportion of injuries result from contact than noncontact mechanisms.14,16,17,23,66 Tackling, specifically, is the most common player activity at the time of injury20 and at the time of severe injury.26 Being tackled and tackling account for about half of high school and college football-related injuries.17,18 The majority of concussions result from tackling or being tackled.17 Head-to-head contact is one of the leading causes of concussions sustained by youth football players.18,23

    Badgeley et al studied the mechanisms leading to injury in a cohort of high school students playing football.17 Players in the older division had higher overall rates of injury than players in younger divisions. The leading mechanism of injury was player-to-player contact, with tackling/being tackled accounting for nearly half (46.2%) of all injuries. Similar findings have been reported in studies of youth football. In an observational cohort study of 208 Pop Warner football teams from New England, Goldberg et al reported on injuries sustained by players between the ages of 5 and 15 years that required restricted participation for more than 1 week.16 The vast majority (88%) of injuries occurred during contact with another player; 41% resulted directly from tackling. Players in the older division (Bantam) had higher overall rates of injury than players in younger divisions.

    In a community survey by Radelet et al, the incidence of injuries sustained by children ages 7 to 13 years playing football (0.15 per 1000 AEs) was similar to, and in fact slightly lower than, that of baseball (0.17 per 1000 AEs) and boys’ soccer (0.17 per 1000 AEs).21 This finding was unexpected, but the authors noted that the results may have been affected by underreporting and differences in the interpretation of the definition of injury. The percentage of injuries that were defined as serious (fractures, dislocations, and concussions) was higher in football (13%) than other sports (0%–3%). Furthermore, the frequency of injury per team per season was 5 to 7 times higher in football than in baseball, soccer, or softball. The most common method of injury was contact with another player, although the authors did not report the nature of contact; therefore, the proportion of injuries attributable to tackling as opposed to blocking or incidental person-to-person contact is unknown. As with many other studies,17,18,67 their results showed a higher rate of injuries during football games (0.43 per 1000 AEs) than practices (0.07 per 1000 AEs).21

    Head Injuries and Impacts Associated With Tackling

    The study by Badgeley et al suggests that during high school football, the majority (64.3%) of concussions occur when an athlete is tackling or being tackled,17 a finding consistent with previous work performed by some of the same investigators showing that tackling/being tackled accounted for half of all high school football injuries.18 During football played by younger athletes, Kontos et al showed that head-to-head contact was the most common mechanism of concussion, but whether head-to-head contact occurred during tackling, as opposed to blocking or incidental contact, is not discussed.23

    In a study of 42 varsity high school football players, Broglio et al used accelerometers to record head impacts resulting >14.4 g of linear acceleration and found a mean of 774 impacts per player during a single season. The mean number of impacts varied by player position, with linemen sustaining a higher number of impacts. Games were associated with a higher incidence of impacts than practices. Contact practices were associated with a higher incidence of impacts than noncontact practices.68

    In a single-season study of 7 football players aged 7 and 8 years, Daniel et al used accelerometers to record the cumulative number of impacts to the head.69 The authors examined both linear acceleration and rotational acceleration with blows to the front, side, rear, and top of the head. The average number of impacts per player was 107, with more impacts occurring during practices (59% of recorded impacts) than games (41% of recorded impacts). A greater number of high-force impacts (>95th percentile for acceleration) occurred during practices than games. The number of impacts experienced by these youth players was lower than that reported for high school and college players and more heavily weighted toward lower levels of impact. As might be expected, the number of impacts increased with increasing level of play, likely because of the increased size and strength of older players. The authors argued that restructuring practices might lead to a lower number of head impacts.69 This study was limited by a small sample size.

    Neck Injuries Associated With Tackling

    Fortunately, most neck injuries that occur during football are strains, sprains, and contusions.12,15 Cervical spine fractures and spinal cord injuries do occur, however, and some lead to permanent neurologic damage.15,16

    Catastrophic Head and Neck Injuries Associated With Tackling

    Although the rates of catastrophic injury in football are low, most of the cases that occur are sustained during tackling.29,7073 Most cases of quadriplegia occur while the injured player is making a tackle.29 A majority of brain and cervical spine injury–related fatalities result from tackling or being tackled.67,74,75

    Brain injury–related fatalities account for approximately 69% of all football fatalities.67 Subdural hemorrhages are the most common injury associated with brain injury–related fatalities; tackling and being tackled67,7476 are the most frequent activities when subdural hemorrhages occur.67 The annual incidence of catastrophic head injuries sustained by football players appears higher for high school athletes than college players (0.67 vs 0.21 per 100 000 participants).29 The majority are sustained by an athlete who is tackling or being tackled.29

    Football players are among the team sport athletes at highest risk for catastrophic cervical spine injuries.71 The annual incidence of catastrophic cervical spine injuries appears higher for collegiate players than for high school players (4.72 vs 1.10 per 100 000 participants).77 Most catastrophic cervical spine injuries occur during tackling, often when improper technique is used. Specifically, most spinal cord injuries are caused by axial loading of the cervical spine during head-down contact, often as a result of “spear tackling,” a method in which the athlete lowers his head, thereby lining up the vertebral bodies, and uses his body as a battering ram to deliver a blow to another player with the crown of his head.19,70,72,73 Fortunately, the incidence of catastrophic cervical spine injuries decreased after the banning of spear tackling in 1976.71,72 Catastrophic spine injuries still occur, however, and spear tackling remains a problem despite the ban.19,29,70,73

    The Effect of Decreasing Contact Practices on Injury Incidence

    Given the association of player-to-player contact with incidence of injury, decreasing the number of contact practices has been proposed as a method of decreasing injury risk, particularly concussions. Although the incidence of concussion is lower during practice than it is during games, there are far more practices than games. Because most impacts to the head occur during practices, decreasing the number of contact practices has been shown to decrease the overall number of head impacts that occur during the course of a season, thereby reducing the risk of any potential cumulative effects of such exposures.23,68,69,78 Some argue this may also lead to a decrease in the number of concussions.79

    Other authors, however, note that the risk of concussion is higher during games than it is during practices and argue that decreasing the number of contact practices is unlikely to reduce the number of concussions. In fact, they propose that the decrease in time spent practicing proper tackling technique may lead to an increase in the magnitude of impacts during games and an increase in the risk of concussion.23,68 Therefore, some authors have suggested that if contact practices are to be reduced as a means of decreasing overall head impact exposures, then extra emphasis should be placed on teaching appropriate tackling technique to avoid an increased risk during games.68 Other authors have also cautioned that a lack of proper training may increase risk of injury.18,24

    In a study of high school varsity football players, Broglio et al reported that limiting the number of contact practices to 1 per week would result in an 18% decrease in the number of impacts, whereas eliminating contact practices entirely would result in a 39% decrease in the number of impacts.68 That same study showed that games resulted in both a significantly higher number of impacts than practices as well as higher magnitude impacts than practices. The authors cautioned that limiting contact practices may increase the risk of high-magnitude impacts and concussions that occur during game time, especially if additional efforts are not made to teach proper tackling and techniques for safely absorbing tackles.68

    As opposed to high school and collegiate players,68 preliminary evidence suggests younger players may sustain higher magnitude impacts during practices as opposed to games.69 Thus, for younger players, limiting full contact practices while simultaneously teaching fundamental skills required for proper tackling and properly absorbing tackles may reduce the overall exposure to head impacts and high magnitude impacts. If CTE proves to be the result of cumulative impacts to the head, including subconcussive impacts, then limiting contact practices should decrease the risk of CTE.68,69,80

    A recent report from the Institute of Medicine concluded that although the concept of limiting the number of head impacts is sound, setting a limit on number of impacts or the magnitude of impacts per week or per season is without scientific basis.81

    The Effect of Delaying Tackling Until a Certain Age

    Some physicians have recently argued that because the brain is in a rapid period of development during youth, contact should be eliminated from football until a certain age.4,6 Others have argued, however, that eliminating contact at a young age would prevent young athletes from learning the skills required to tackle, absorb a tackle, and fall to the ground safely. Then, when contact is later introduced, athletes will be ill prepared and forced to learn these skills at an age where they are bigger, faster, stronger, more coordinated, and capable of delivering more forceful blows. Some have suggested that this might increase the risk of injury23 and have argued the correct contact techniques should be taught at the earliest organized level.72,81 A previous study of high school football players in Wisconsin suggested that previous tackling experience is not independently associated with the risk of sustaining a sport-related concussion.82 Further investigation into the effects of delaying the introduction of tackling until a certain age must be conducted before informed recommendations can be made.

    Although there does not appear to be any study to date showing the effect of delaying the age at which tackling is introduced to football on risk of injury, data from other sports suggest that eliminating tackling would decrease the risk of certain injuries for athletes participating at ages for which tackling would be prohibited.83,84 In a study of Canadian youth ice hockey players, Emery et al showed that the risk of injury, severe injury, concussion, and severe concussion was higher in leagues that allowed body checking than in leagues that did not allow body checking,83 confirming previous work that had demonstrated an association between body checking and the incidence of concussion.85 In a follow-up study, however, the same investigators reported that, once exposed to body checking, players who were not introduced to body checking until a later age were at significantly higher risk of severe injuries than those exposed to body checking at an earlier age.86 The risk of sport-related concussion was also higher in those previously unexposed to body checking, although the findings were not statistically significant.86 Other studies of youth ice hockey players have shown no significant difference in the incidence of injury between those exposed to body checking at differing ages. However, a previous study by MacPherson et al showed that hockey players exposed to body checking at a younger age had a significantly higher odds of suffering a checking injury than those exposed to checking at a later age.85

    Other Strategies for Reducing Injuries

    Teaching Proper Tackling Technique

    Initiating contact with the shoulder while the head is up is believed to be the safest way to tackle in football. Most experts recommend that proper technique be learned and practiced regularly as a means of reducing the risk of injury.17,18,71,72,79 A recent initiative by USA Football emphasizes keeping the head up during tackling to prevent catastrophic injuries as well as concussions, although this new coaching method needs further study.

    Rule Changes

    In addition to changing practice regimens and teaching proper tackling techniques, some have proposed changes to the rules of football as a means of reducing head and neck injuries. Indeed, the 1976 banning of spear tackling has been widely credited with reducing the numbers of cervical spinal injuries resulting in quadriplegia.7073,77,87,88 Unfortunately, spear tackling has persisted even since the 1976 rule change, and cervical spine injuries continue to occur.73,88,89 Modification and consistent enforcement of the rules may lead to a further decrease in the risk of injury, including catastrophic injuries.73,79,89

    Protective Equipment

    The introduction of helmets to football and the updating of helmet design is widely credited for playing a role in the reduction of head injuries, particularly catastrophic head injuries and brain injury–related fatalities.67,90,91 Therefore, athletes participating in football should wear undamaged, properly fitted helmets with secured chin straps. By protecting the scalp from the discomfort of blows to the vertex of the head, however, helmets are considered, in part, to have led to an increase in the number of cases of quadriplegia by encouraging the use of the head as the point of impact.92 This trend was fortunately reduced by the banning of spear tackling, as noted previously. The role of helmets in preventing concussions is less clear. Although some studies suggest that helmet design might play a role in reducing the incidence of concussion,93,94 many experts refute such a claim.82,95,96 In a recent study of more than 2000 high school football players, McGuine et al reported that helmet model had no significant effect on the incidence of sport-related concussion.82 As of now, there is little reliable evidence that concussions can be prevented or mitigated by any of the currently available helmet designs.9597

    Mouth guards are effective at reducing the incidence of dental injuries.97,98 Although some studies have suggested an effect of mouthguard type on the incidence of concussion,82,99,100 there are few reliable data suggesting that any currently available mouth guards are effective at preventing or reducing the incidence of concussion.95,96,101103

    Although there is some evidence that neck rolls and cowboy collars can reduce movement of the head and neck, there is limited evidence regarding their effect on the incidence of burners or stingers, injuries to the nerve of the upper arm that result in a burning or stinging sensation.104106 Because neck rolls limit extension of the neck, they may, theoretically, interfere with the ability of the proper head-up tackling technique.

    Neck Muscle Strengthening

    Neck muscle strengthening has been recommended by the National Athletic Trainers’ Association as a means of decreasing neck fatigue, thereby allowing for maintenance of the head-up position associated with proper tackling technique and decreasing the risk of burners and stingers.72 Furthermore, weak neck musculature has been proposed as a risk factor for concussion.107109 Acceleration of a struck object is inversely proportional to its mass. Because concussion results from a rotational acceleration of the brain, it has been suggested that increasing the effective mass of the head might result in a decreased acceleration of the brain after impact. The head becomes more firmly bonded to the rest of the body when the neck muscles are contracted, thereby increasing the effective mass of the head and decreasing the resultant acceleration after impact.109 This increase in effective mass is thought to explain the decreased risk of concussion when collisions are anticipated.108,109 Thus, by increasing cervical muscle strength, athletes might decrease their risk of concussion.108,110 Preliminary evidence supports this hypothesis.111 Other preliminary studies suggest that it may be cervical stiffness, as opposed to strength alone, that is associated with risk of injury.112

    Conclusions and Recommendations

    Most injuries sustained during participation in youth football are minor, including injuries to the head and neck. The incidences of severe injuries, catastrophic injuries, and concussion, however, are higher in football than most other team sports and appear to increase with age. Player-to-player contact results in an increase in the number of subconcussive impacts that occur during football. Concussion is associated with player-to-player contact and tackling, in particular. Severe and catastrophic injuries, particularly those of the head and neck, are associated with tackling, often when improper and illegal technique, such as spear tackling, is used. Efforts should be made to improve the teaching of proper tackling technique and enforce existing rules prohibiting the use of improper technique.

    1. Officials and coaches must ensure proper enforcement of the rules of the game. A significant number of concussions and catastrophic injuries occur because of improper and illegal contact, such as spear tackling. There is a culture of tolerance of head first, illegal hits. This culture has to change to one that protects the head for both the tackler and those players being tackled. Stronger sanctions for contact to the head, especially of a defenseless player, should be considered, up to and including expulsion from the game. The culture should change to one of zero tolerance of illegal, head-first hits.

    2. Removing tackling from football altogether would likely lead to a decrease in the incidence of overall injuries, severe injuries, catastrophic injuries, and concussions. The American Academy of Pediatrics recognizes, however, that the removal of tackling from football would lead to a fundamental change in the way the game is played. Participants in football must decide whether the potential health risks of sustaining these injuries are outweighed by the recreational benefits associated with proper tackling.

    3. The expansion of nontackling leagues for young athletes who enjoy the game of football and want to be physically active but do not want to be exposed to the collisions currently associated with the game should be considered by football leagues and organizations. This would allow athletes to choose to participate in football without tackling and its associated risks, even after the age at which tackling is introduced.

    4. Although the effect of subconcussive blows on long-term cognitive function, incidence of CTE, and other health outcomes remains unclear, repetitive trauma to the head is of no clear benefit to the game of football or the health of football players. If subconcussive blows to the head result in negative long-term effects on health, then limiting impacts to the head should reduce the risk of these long-term health problems. Thus, efforts should be made by coaches and officials to reduce the number of impacts to the head that occur during participation in football. Further research is needed in this area.

    5. Delaying the age at which tackling is introduced to the game would likely decrease the risk of these injuries for the age levels at which tackling would be prohibited. Once tackling is introduced, however, athletes who have no previous experience with tackling would be exposed to collisions for the first time at an age at which speeds are faster, collision forces are greater, and injury risk is higher. Lack of experience with tackling and being tackled may lead to an increase in the number and severity of injuries once tackling is introduced. Therefore, if regulations that call for the delaying of tackling until a certain age are to be made, they must be accompanied by coaches offering instruction in proper tackling technique as well as the teaching of the skills necessary to evade tackles and absorb being tackled. It is unclear whether such techniques and the neuromuscular control necessary for performing them can be adequately learned in the absence of contact.

    6. Although definitive scientific evidence is lacking, strengthening of the cervical musculature will likely reduce the risk of concussions in football by limiting the acceleration of the head after impact. Physical therapists, athletic trainers, or strength and conditioning specialists, with expertise in the strengthening and conditioning of pediatric athletes, are best qualified to help young football players achieve the neck strength that will help prevent injuries.

    7. Given their importance in the medical management of sport-related injuries and preliminary evidence suggesting an association between athletic trainers presence and a decreased incidence of sport-related injuries,113 efforts should be made by football teams to have athletic trainers at the sidelines during organized football games and practices.

    Lead Authors

    William P. Meehan, III, MD, FAAP

    Gregory L. Landry, MD, FAAP

    Council on Sports Medicine and Fitness Executive Committee, 2014–2015

    Joel S. Brenner, MD, MPH, FAAP, Chairperson

    Cynthia R. LaBella, MD, FAAP, Chairperson-Elect

    Margaret A. Brooks, MD, FAAP

    Alex Diamond, DO, MPH, FAAP

    Amanda K. Weiss Kelly, MD, FAAP

    Michele LaBotz, MD, FAAP

    Kelsey Logan, MD, MPH, FAAP

    Keith J. Loud, MDCM, MSc, FAAP

    Kody A. Moffatt, MD, FAAP

    Blaise Nemeth, MD, MS, FAAP

    Brooke Pengel, MD, FAAP

    William Hennrikus, MD, FAAP

    Past Council Executive Committee Members

    Rebecca Demorest, MD, FAAP

    Liaisons

    Andrew J. M. Gregory, MD, FAAP – American College of Sports Medicine

    Mark Halstead, MD, FAAP – American Medical Society for Sports Medicine

    Lisa K. Kluchurosky, MEd, ATC – National Athletic Trainers Association

    Consultants

    Gregory Canty, MD, FAAP

    Emily Hanson, ATC, CSCS

    Neeru A. Jayanthi, MD

    Staff

    Anjie Emanuel, MPH

    Footnotes

    • This document is copyrighted and is property of the American Academy of Pediatrics and its Board of Directors. All authors have filed conflict of interest statements with the American Academy of Pediatrics. Any conflicts have been resolved through a process approved by the Board of Directors. The American Academy of Pediatrics has neither solicited nor accepted any commercial involvement in the development of the content of this publication.

    • Policy statements from the American Academy of Pediatrics benefit from expertise and resources of liaisons and internal (AAP) and external reviewers. However, policy statements from the American Academy of Pediatrics may not reflect the views of the liaisons or the organizations or government agencies that they represent.

    • The guidance in this statement does not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate.

    • All policy statements from the American Academy of Pediatrics automatically expire 5 years after publication unless reaffirmed, revised, or retired at or before that time.

    • FINANCIAL DISCLOSURE: Dr. Meehan participates in research funded, in part, by the National Football League Players Association and receives compensation from ABC-Clio Publishing, Wolters Kluwer, and Springer International Publishing for his authored works. Dr. Landry has indicated he does not have a financial relationship relevant to this article to disclose.

    • POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

    References