Soccer Injuries in Children and Adolescents

Lower Extremities

The majority of injuries among youth soccer players involve the lower extremities. The ankles and knees are the most commonly injured body parts, whereas sprains and/or strains and contusions are the most commonly reported injury types.^5,8,9,21,22 Fractures represent only approximately 3% to 10% of all injuries but up to 28% of soccer-related injuries seen in emergency departments.^7,8,10,23 Younger athletes tend to have a lower overall injury incidence but typically demonstrate similar injury locations. In a study of time-loss injuries among 417 soccer players ages 5 to 17 over a 2-year period, ankles and knees were the most commonly injured body parts (20.9% and 16.3% of all injuries, respectively), whereas sprains, contusions, and muscle injuries were the most common diagnoses (20.6%, 22.5%, and 20.6% of all injuries, respectively). Although overuse injuries are less common, they appear to be more common among female youth soccer players, with feet and/or ankles and lower legs being the most commonly injured areas among boys and girls.¹⁸ Among high school athletes, the majority of overuse injuries were less severe, with only 7.7% resulting in time loss greater than 21 days.¹⁸ Although the majority of overuse injuries involve apophysitis and tendinopathy, stress fractures are another important consideration for youth soccer athletes.

With respect to severe injuries, player-to-player contact is the most common mechanism for injuries resulting in significant time loss (>21 days)²⁴ as well as medical disqualification.¹⁶ The knees are the most commonly affected body part in season-ending injuries, and player-to-player contact is the most common mechanism for both boys and girls.¹⁶ Anterior cruciate ligament (ACL) rupture remains a significant lower-extremity injury among youth soccer players, with noncontact valgus hyperextension during rapid change of direction or deceleration as the most common mechanism.^25,26 Female soccer players appear to be at an increased risk for ACL injury compared with their male counterparts, and this has been attributed to a number of factors, including lower-limb anatomy, hormonal influences, and neuromuscular activation patterns.^25,27

Concussion

Recent data suggest that concussion rates may be increasing among youth soccer athletes, and concussion remains more common among girls than boys.^28–30 In a recent 9-year study of high school soccer players, concussion incidence was found to be 0.28 and 0.45 per 1000 athletic exposures for boys and girls, respectively. For both sexes, concussion incidence has been found to be greater during games than during practice, and concussion rates during both practices and games increased significantly during the study period.³⁰ Finally, a recent study of soccer-related injuries among 7- to 17-year-old children presenting to the emergency department revealed that concussion incidence increased nearly 1600% between 1990 and 2014.¹⁰ It is unclear, however, whether this increase in concussion rates is the result of a greater number of concussions sustained or of increased recognition and diagnosis of concussions as a result of previous education efforts.

Heading is the most common sport-specific activity during which concussions occur, although the majority of injuries are attributable to contact with another player while heading rather than contact with the ball itself.^30,31 Concussions are a result of brain acceleration after contact. Theoretically, concussion incidence could be reduced if the magnitude of horizontal head acceleration could be reduced. In addition to the mass and velocity of the player, factors that affect horizontal acceleration include the mass, size, speed, and inflation pressure of the ball. Therefore, balls that are overinflated or inappropriately large for the age and size of the athletes may increase the risk of head injury in young soccer players.³² Data are insufficient to determine if concussions or subconcussive impacts (repetitive heading or blows to the head that do not result in concussive symptoms) result in potentially detrimental long-term cognitive effects.³³

Facial and Ocular Injury

Although there are limited data regarding ocular injuries in youth soccer, a recent 10-year study among soccer players identified the incidence of eye injuries to be 1.0 and 0.8 per 100 000 athletic exposures for boys and girls, respectively.³⁴ The incidence of eye injuries was found to be higher than that in a number of other sports but lower than in wrestling, basketball, and baseball for boys and lower than in field hockey and softball for girls. The use of appropriate protective eyewear can substantially decrease the risk of ocular injuries in athletes. A recent 5-year study has revealed that among youth soccer players, lacerations were the most common facial injury, followed by contusion and fracture. The nose was the most common site of injury, and contact with an opposing player’s head or upper extremity was the most common mechanism.³⁵ Dental injuries also occur with a frequency similar to eye injuries (1.1 per 100 000 athletic exposures), with injuries occurring more commonly during competition (3.2 per 100 000) than during practice (0.3 per 100 000).³⁶

Environmental Injuries

As an outdoor sport, soccer also carries a potential risk for dehydration, exertional heat illness, and other environmental dangers. Heat illness encompasses a variety of conditions and can range from heat cramps and heat exhaustion to life-threatening heat stroke.³⁷ Although these issues may occur at any ambient temperature, the incidence increases with increasing temperature and humidity. Heat cramps are painful involuntary muscle contractions that usually occur during preseason conditioning and are treated with stretching the muscle, rest, and rehydration. Heat exhaustion is a moderate heat illness characterized by the inability to continue exercising because of cardiovascular insufficiency resulting from strenuous exercise, environmental heat stress, dehydration, and energy depletion.³⁷ Heat exhaustion typically manifests as a headache, nausea, profuse sweating, incoordination, weakness, syncope, and mildly elevated core body temperature. Heat stroke is a life-threatening condition characterized by elevated core body temperature >104°F (>40°C) resulting in central nervous system dysfunction, circulatory failure, and potential multiorgan failure.³⁷ Initial treatment of heat stroke includes immediate cooling via whole body immersion, if available, and transfer to the nearest emergency department. Guidelines to minimize risk of exertional heat illness in youth sports are applicable to soccer, particularly during hotter months and the early part of the season, when players may not be sufficiently acclimatized.³⁷

Another potential hazard for those engaging in outdoor activities is lightning. According to the National Oceanic and Atmospheric Association, lightning strikes an average of 400 people and kills 49 of these victims every year in the United States.³⁸ Although there are no specific data with respect to youth soccer, this remains a risk in all outdoor physical activities, and careful monitoring during inclement weather can identify potentially dangerous conditions so prevention strategies can be implemented.

Fatalities in Soccer

Fatalities in youth soccer are rare and have historically been attributable to blunt trauma with goalposts.^39,40 A previous study of 1.6 million emergency department visits attributable to soccer injuries from 1990 to 2003 identified 2 fatalities resulting from a brain hemorrhage and a ruptured spleen caused by blunt trauma.²⁰ The US Consumer Product Safety Commission has reported 36 previous fatalities in soccer as a result of falling goalposts since 1979 and has published specific recommendations regarding proper installation, use, and storage of goalposts to reduce the risk of injury.⁴¹

Footwear and Playing Surface

Footwear type and playing surface may affect lower-extremity injury rates. Outdoor soccer shoes are cleated and have either bladed studs or a combination of bladed and conical studs. Generally, bladed studs afford greater traction and speed; however, they may be associated with increased rates of injury. In a systematic review of 23 studies investigating the relationship between cleat-surface interaction and injury rates, Silva et al⁴² found that bladed studs were associated with an increased risk of injury related to higher pressure on the lateral foot border when compared with rounded studs. Conical studs allow for quicker release and provide a greater degree of stability because they offer more points of contact with the playing surface. Although this stabilizing feature may translate to a lower risk of injury, more in vivo studies are needed. The pattern of stud placement on cleated shoes may also affect injury rates. A study on American football revealed that shoes with longer irregular cleats placed at the peripheral margin of the sole and a number of smaller pointed cleats positioned interiorly were associated with a higher risk of ACL injuries than flat, soccer-style cleats on which the studs on the forefoot were the same height, shape, and diameter.⁴³

When artificial turf debuted, an increase in lower-extremity injuries was noted.⁴⁴ Authors of initial studies postulated that increased shoe-surface friction produced increased torque at the knee and ankle.⁴² The most recent third generation of artificial turf has longer grass-like fibers embedded in granules of sand, rubber, and/or silica and more closely mimics natural grass. Several recent studies reveal no difference in injury rates during games played on grass or turf but higher injury rates during training on grass.^45,46 In youth soccer specifically, a 2016 study revealed that players who suffered a lower-extremity injury were 2.83-fold more likely to have played on a grass surface and were 2.40-fold more likely to have worn cleats on grass in practice (versus cleats on artificial turf) compared with players who were uninjured. These researchers also found that training on grass was associated with a 2.8-fold increased risk of lower-extremity injury, but game injuries did not vary significantly when comparing artificial turf with grass.⁴⁶ This finding mirrors a similar study in adults that revealed no significant differences in the incidence of lower-extremity injuries on artificial turf or grass for male and female elite soccer players in games.⁴⁵

In the last few years, media reports have surfaced suggesting a possible relationship between playing on synthetic turf and the development of certain childhood cancers, particularly leukemia and lymphoma.⁴⁷ The basis for these media reports has been anecdotal, and to date, no epidemiological or longitudinal research regarding a causative relationship between artificial turf and neoplasia has been published.⁴⁸

Preparticipation Physical Examination

The preparticipation evaluation (PPE) is a critical opportunity for primary prevention and takes place before the athlete even touches the soccer field. Although few concrete data exist to validate its use as a screening tool, a uniformly applied PPE is generally believed to be the optimal opportunity to detect any medical conditions that may be potentially life-threatening or disabling or that may predispose the athlete to injury.⁷⁵ The PPE monograph is a collaborative effort among several national medical organizations, including the AAP, and serves as a useful tool for pediatricians regarding best practices for performing the examination.⁷⁶

For soccer players, noting any previous musculoskeletal injuries, especially lower-extremity injuries such as ankle sprains, knee injuries, or groin strains, as well as a detailed history of previous concussions or head injuries allows for rehabilitation if deficits are identified. Given that cardiac etiologies account for 56% of nontraumatic causes of sudden death in collegiate athletes,⁷⁷ noting the presence of any cardiac-related symptoms as well as a detailed family history of any cardiac conditions, especially hypertrophic cardiomyopathy, allows for further workup. As part of a complete physical examination for sport, critical areas of focus include assessment of the cardiovascular system, a baseline ocular examination, and a thorough musculoskeletal examination with special attention to the weight-bearing joints of the lower extremities.⁷⁵

Neuromuscular and Biomechanical Training

As previously mentioned, ACL injuries represent a source of significant morbidity for youth soccer players, especially girls. The reasons for the relatively high prevalence of ACL injuries in girls are likely multifactorial.²⁵ Most noncontact ACL injuries occur when landing from a jump, stopping abruptly, or quickly changing direction during deceleration. Compared with boys, girls tend to have a higher degree of internal rotation at the hip and external rotation of the tibia when decelerating or landing. Girls also have a higher tendency to land with insufficient knee and hip flexion.⁷⁸ Additionally, girls tend to have a greater degree of quadriceps activation and differences in muscle recruitment, timing, and strength, which appear to increase the risk for ACL injury. Given that these biomechanical factors represent a potentially modifiable risk factor for ACL injuries, authors of multiple studies have investigated the effectiveness of teaching proper landing and deceleration techniques, muscle strengthening and recruitment, neuromuscular warm-up, proprioception, and plyometrics.^79–81 Mandelbaum et al⁷⁹ studied the effectiveness of such a program and demonstrated a 74% to 88% reduction in ACL injury. In 2011, LaBella et al⁸¹ investigated the effects of a neuromuscular warm-up program in female athletes in Chicago public high schools and showed a 56% reduction in noncontact lower-extremity injuries and a lower ACL injury rate in the intervention group. General recommendations for strengthening programs include an emphasis on gluteal and hamstring strength and recruitment as well as core strength and trunk stabilization.⁸² Pediatricians can access a video demonstration of such ACL injury prevention exercises on the AAP Web site (https://www.aap.org/en-us/about-the-aap/aap-press-room/aap-press-room-media-center/Pages/preventingACLinjury.aspx). The Fédération Internationale de Football Association (FIFA) developed a warm-up program called “FIFA 11+” that consisted of 10 strengthening, plyometric, and proprioceptive exercises designed to decrease the frequency and severity of injuries in soccer.⁸³ Multiple studies have revealed the program to be significantly effective at decreasing the incidence of injury in male and female youth players.^80,83–86

Individual Player Monitoring

Overtraining, stress, and inadequate rest may individually or jointly contribute to risk of injuries among athletes in soccer and other youth sports.^58,87,88 As previously mentioned, an acute increase in training load has been shown to be an independent risk factor for injury in youth soccer players. Spurred by advances in development of wearable technology, individual player monitoring has exploded in popularity in the last few years.^24,89–91 Although not as prevalent as in collegiate or professional teams, youth teams, especially elite club and travel teams, are beginning to employ user-friendly wearable technologies to measure training loads, accelerations, and decelerations as well as heart rate. Many training staffs use such technologies to adjust the design, pace, and components of practice sessions in an effort to maximize performance and reduce injuries; however, there is limited research regarding the effectiveness of such technology in achieving these aims.

Because fatigue and inadequate sleep may be risk factors for injury,^60,70 multiple technologies exist for monitoring sleep, such as sensor-embedded wristbands and smart phone applications; however, there is a paucity of medical literature regarding their effectiveness, particularly in young athletes. Various studies have revealed an inverse relationship between psychological well-being and risk of injury. Steffen et al⁹² discovered that in female youth soccer players ages 14 to 16 years, the risk of injury was 70% greater among players with a high degree of perceived life stress. Many professional and collegiate programs are now using athlete self-report measures to gauge their athletes’ response to training with respect to mood, motivation, perception of well-being, and stress levels. In addition, programs are also training athletes in mindfulness skills, coping mechanisms, and stress-reduction strategies in an attempt to mitigate the effects of negative self-perception and stress. Swedish investigators conducted a randomized study in junior elite soccer players and found that 67% of the players in the intervention group who received mindfulness-based training remained injury free at the end of the season, compared with 40% in the control group.⁹³

Concussion

Eliminating all concussions from soccer is unattainable; however, implementation of prevention strategies may reduce the number and severity of concussive injuries.

All 50 states and the District of Columbia have passed concussion legislation mandating schools to develop concussion protocols and restrict participation after suffering a head injury.³³ Most are modeled after Washington State’s Lystedt Law, which mandates automatic removal from play for any suspected concussion, medical clearance before returning to sport, and education for parents, athletes, and coaches. Pediatricians and other health care providers are encouraged to familiarize themselves with the precise language and requirements in the legislation regarding concussion in their individual states.

As mentioned previously, the majority of concussions in soccer occur during the act of heading but are attributable to player-player contact, not player-ball contact.³⁰ In a recent study, contact with another player was the most common mechanism of injury in heading-related concussions among boys (68.8%) and girls (51.3%).²⁸ Because of concerns regarding heading, the US Soccer Federation unveiled an initiative aimed at reducing concussions by banning heading for children 10 years and younger and limiting the amount of heading in practice for children between the ages of 11 and 13 years.⁹⁴ More research is needed to evaluate whether this program will reduce the number of concussions in these age groups. Instructing young soccer players in proper heading techniques once the athletes demonstrate body awareness and visual tracking skills and have developed the requisite core and cervical strength is imperative. Following manufacturer recommendations for proper ball inflation and size for the age of the players also is recommended. Finally, adherence to fair-play practice and enforcement of rules may reduce the number of foul plays and dangerous contacts and may therefore reduce the risk of concussive injuries.³⁰

Current evidence is insufficient to support the uniform use of headgear or mouth guards to prevent concussion.^95,96 Mouth guards have been shown to prevent orofacial injuries; however, evidence is mixed regarding risk reduction in sports-related concussion.^95,97 The use of soft headgear has been studied more extensively in rugby, in which it has been shown to reduce superficial abrasions but not affect the overall rate of concussion.⁹⁸ In laboratory testing, by using head forms, soccer headgear has not been shown to attenuate the head impacts during simulated soccer ball heading.⁹⁹ Although Delaney et al¹⁰⁰ concluded that headgear use in youth soccer players may reduce the risk of concussion, the national governing body for soccer in the United States does not permit its members or affiliates to require the use of headgear by players.¹⁰¹ Use of padded headgear is controversial because of the paucity of rigorous medical studies as well as concern for possible increased risk of injury resulting from a false sense of security.⁹⁶

Fair Play and Rule Enforcement

Foul play, or actions that violate the rules of the game, has been associated with an increased incidence of injuries in various levels of many sports, including soccer. In a study of professional soccer players, foul play was found to be involved in 14% to 37% of all injuries.¹⁰² Peterson et al⁶⁵ studied soccer injuries over a 1-year period in different age groups and skill levels and found that 82% of players suffered at least 1 injury. Forty-six percent of the injuries were attributable to contact, and almost half of these were associated with foul play.⁶⁵ With respect purely to youth soccer, Emery et al¹⁰³ discovered that direct contact was involved in 46.2% of all injuries. Limiting foul play, penalizing dangerous behavior, and properly enforcing the rules are generally believed to reduce the risk of injury in sport. Referees, players, and spectators all have a responsibility to advocate for fair play and sportsmanship.

Protective Equipment

Shin guards are the only protective devices that are required by FIFA, the National Collegiate Athletic Association, and the US Soccer Federation.^104–106 Currently, shin guards are typically made of polypropylene and plastic composites, although some also contain fiberglass, para-aramid synthetic fibers, or copper. Although they certainly protect against leg abrasions and contusions, the role of shin guards in reducing the risk of fractures has not been fully demonstrated to date.^107,108 Nevertheless, laboratory studies indicate that shin guards significantly dissipate the forces and strain on the tibia that could cause fracture.^109,110 Appropriately sized shin guards should cover most of the anterior tibia, and the National Operating Committee for Standards in Athletic Equipment has established standards for function.¹¹¹

Dental injuries can occur in all contact sports, and soccer is no exception. Two older studies revealed that dental injuries account for 0.2% of all high school athletic injuries,^112,113 and more recent data suggest an overall incidence rate of 0.06 and 0.11 dental injuries per 10 000 athletic exposures in boys’ and girls’ high school soccer, respectively.³⁶ In all of these studies, the rate of dental injuries appears to be lower for soccer than for many other contact sports.^36,112,113 Although most studies affirm that custom-made mouth guards confer better protection than the more common “boil and bite” type, a vast majority of studies reveal that simply by wearing mouth guards, athletes can significantly decrease the frequency and severity of orofacial injuries in contact sports.^114–116

Injuries to the eye and surrounding orbit can occur in any contact or projectile sport. Traumatic ocular injuries have the potential for significant long-term morbidity. Boys account for a significantly greater proportion of injuries than girls, and the peak incidence occurs in mid-to-late adolescence. A recent study revealed that soccer accounted for almost 7% of all ocular trauma.¹¹⁷ Approximately 90% of serious eye injuries are preventable through use of appropriate protective eyewear.¹¹⁸ The AAP and the American Academy of Ophthalmology classify soccer as a moderate-risk sport and strongly recommend that all young participants wear eye protection that meets the American Society for Testing and Materials standard F803,¹¹⁹ which specifies that protective eyewear be made of polycarbonate, impact-resistant plastic and be worn by all athletes who are functionally monocular or who have a history of major eye surgery or trauma.¹¹⁹

Given that sudden cardiac arrest is the leading cause of nonaccidental death in youth and can occur with athletic activity, physicians involved with soccer organizations are encouraged to advocate for basic life-support training of coaches as well as placement of automated external defibrillators at practice and competition sites.¹²⁰

Environmental Safety

Heat and lightning pose an extrinsic risk to participants in outdoor sports. The number of heat-related injuries increased 133% from 1997 to 2006, and youth accounted for the largest proportion of those injuries.¹²¹ Additionally, recent evidence suggests that heat-related illness may be increasing with climate change.^122,123 Every year, lightning accounts for dozens of deaths in the United States, although data regarding the incidence among youth soccer participants are not available.¹²⁴ Precautions and simple strategies may reduce the risk of injury due to adverse environmental conditions.

Heat

Some primary prevention strategies for heat illness include acclimatization, activity modification, development of an emergency action plan, and hydration.³⁷ The risk of heat illness appears to be highest in deconditioned athletes at the start of the season.³⁷ Allowing athletes 7 to 14 days to acclimate their bodies to heat is essential. Several state high school organizations have formal policies regarding heat acclimatization. It is recommended that all youth teams and institutions have a policy regarding heat that incorporates an emergency action plan that addresses properly monitoring ambient weather conditions, ideally with a wet-bulb globe temperature device, and modifying training sessions in certain hot and humid conditions.³⁷ Some activity-modification strategies include limiting warm-ups, scheduling hydration and rest breaks, shortening sessions or holding them earlier or later in the day, and canceling events in case of dangerous conditions.³⁷ Although the incidence of heat illness has not been directly compared between artificial turf and natural grass surfaces, significantly elevated surface temperatures have been reported on in-filled turf fields,¹²⁵ and this may need to be considered for soccer played on turf.

Ensuring proper hydration before starting a workout and replacing fluids lost through sweating during and after exercise are important considerations for athletes.^37,126 Although fluid requirements will vary between individuals and environmental conditions, fluid intake of 300 to 750 mL/hour for 9- to 12-year-olds and 1.0 to 1.5 L/hour for adolescents is typically sufficient to offset sweat losses and reduce the risk of dehydration during intense exercise in hot conditions.³⁷ Water is generally sufficient for hydration during soccer competition, although sports drinks that contain additional electrolytes and carbohydrates may be considered during periods of prolonged, intense activity.¹²⁷ In general, caffeine and energy drinks do not play a role in proper hydration during exercise and are not recommended in children and adolescents.¹²⁷

Lightning

Primary prevention of lightning injuries requires careful monitoring of weather conditions. Strategies for prevention of lightning injuries by the Centers for Disease Control and Prevention include having venue-specific emergency action plans, suspending activities when thunder and lightning are present (typically within 6 miles), and moving athletes and spectators to shelters designated specifically for lightning.¹²⁸ Activities may resume 30 minutes after the last strike of lightning is seen (or at least 5 miles away) and after the last sound of thunder is heard.^38,128,129

Footwear, Playing Surface, and Field Conditions

Some studies in soccer athletes indicate that shoes with bladed cleats improve performance during changes of direction but may increase the torque and rotational movements on the ankle and knee joints, which may theoretically lead to injury; however, most studies reveal no increased rate of injury when comparing cleat type.⁴² General recommendations for soccer footwear include ensuring that the shoe fits properly, that the laces are fastened completely, and that the cleat type is appropriate for the surface of play. Although practicing on artificial turf may be associated with a decreased injury risk compared with natural grass, injury rates during games appear to be similar between the 2 surfaces.^45,46 Regardless of the playing field type, players as well as coaches and referees may consider checking the condition of the field before playing to identify potential hazards, remove any debris, fill any divots or holes, and assess for areas of poor water drainage. The US Consumer Product Safety Commission recommends that movable soccer goals be securely anchored to the ground and only used on level playing fields and that no one climbs or hangs from a post.⁴¹