Getting Your Head Around Concussions in Soccer

Concussions.  They’re a big deal in the news these days.  For football players, hockey players, and even soccer players.  And especially for young soccer players.  Scary stuff.  And my teenage son is a soccer player.  So I couldn’t resist reigniting this blog with a post about concussions in soccer.   If you’ve asked yourself the question “should I be worried about my son heading the ball”, this post is for you.   We’ll start with some basic facts about the number of injuries and concussions that soccer players actually experience, followed by some information on the positions that are most prone to concussions and why, and end in a summary of what all of this means for you and your family.  I should point out that this post does not go in to depth about the science of concussions, or the long-term damage that they can cause.  This post is focused on answering your questions on the prevalence of concussions, and what you should know to avoid them.  

This post has been written in a question/answer format, with the first question I asked myself being:

As a frame of reference, how many injuries (concussions and otherwise) are suffered by high school athletes?

The incidence (or rate) of injuries for high school athletes is between 1 and 3 injuries per 1,000 athletic events [9,17]. An athletic event is not exactly what you think it is and it’s an abstract number for sure.  So let me provide some context, and I’ll provide that context in the realm of soccer because that’s the focus of this post.  

For the average high-level soccer player who participates in five athletic events (practices and/or games) each week during an 11-month year and is on a 18-person team, an injury rate of 1-3 injuries per 1,000 athletic events would equate to the ENTIRE team experiencing five to eleven injuries during the year.  So the average high school team would be forecast to experience 5 to 11 injuries per season.  Keep in mind that’s all injuries (which would include concussions, sprained ankles, broken bones, etc) for all of the players combined.  For teams who have shorter seasons, smaller rosters or fewer practices/games, the numbers would be smaller.

  

Now let’s whittle that down.  How many concussions do high school athletes suffer?

The number of concussions experienced by the average high school athlete is reported to be approximately 2 to 4 per 10,000 athletic events [4,11]. 

In context: using the average team described above, that would equate to an incidence of approximately one or two concussions per year for the entire team. 

 

How many concussions do high school soccer players suffer?

The incidence of concussions in high school soccer is approximately the same as that of other high school sports, namely 2 to 4 per every 10,000 athletic events [8,11,19]. 

In context: for a player on the team described above, the entire team would be forecast to have one to two concussions per year (or 11-month season). 

It should be noted that female soccer high school players have a higher incidence of concussions than male soccer players [8, 11, 19].   That being said, a team of female soccer players similar to the one described above would be expected to experience two or fewer concussions per 11-month season. 

 

Do soccer players suffer more concussions than other athletes in high school?

The incidence of concussions for male soccer players is approximately the same as that of other male athletes in high school.  However, the incidence of concussions for female soccer players is higher than that of other girls’ sports in general.   All of the numbers are summarized graphically in Figure 1 below.  That being said, we should remember that the average high school soccer team would be forecast to have 1 to 2 concussions per year.

   
  
 
  
    
  
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      Figure 1   : Concussion rates among high school athletes of different sports [19]

Figure 1: Concussion rates among high school athletes of different sports [19]

Do college soccer players experience more concussions than high school players?

The incidences of concussions in college soccer are slightly higher than those in high school [3, 11,15], averaging 4 to 5 concussions per 10,000 athletic events. 

In context: for a player on a college team similar to that described above, the entire team would be forecast to have 2 concussions per 11-month season.  Similarly, Boden et al. found that the incidence of concussion in college soccer was 0.96 concussions per team per season [3].  Which is approximately the same as that of high school soccer players. 

  

My soccer player is in elementary school or middle school.  How prevalent are concussions in players of those ages?

Witol et al. have found that “the injury rate for the 14–17-year-old group was twice as high as that for the younger players” [29].   Conversely, other studies have reported higher incidences of concussions for female middle school soccer players [23]. Which is right? I’m not sure, and the lack of published studies focused on youth players makes it difficult to answer that question definitively.  But I would estimate that the incidence is in the same ballpark of those discussed above.  

 

How serious are the concussions when they do happen?

When researches analyzed the types of concussions sustained by college soccer players by concussion grade, 72% were grade 1 (also known as mild concussions), 28% grade 2 (or moderate concussions), and none were grade 3 (or severe)  [3].  

 

How do head injuries occur in soccer?

Most concussions are caused by the following (in decreasing order of incidence):

  • Player/player collisions (such as contact with another player)
  • Player/equipment collisions (such as collisions with goalposts)
  • Player/Playing surface contact (such as striking the ground)
  • A single hard blow from the ball

Repeated heading of the ball has also been associated loosely with head trauma or what some call "micro concussions", but data do not exist supporting that relationship [1]. 

   
  
 
  
    
  
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      Figure 2   : Causes of soccer-related concussions in high school and college athletes [3,19]

Figure 2: Causes of soccer-related concussions in high school and college athletes [3,19]

If most of the concussions are caused by collisions, how many of the concussions are actually due to a head colliding with a ball?

18% of concussions have been found to result from the act of heading [1].  However, that doesn’t mean that the culprit was actually a ball colliding with a head.   In fact, none of the references reviewed documented a concussion resulting from head-to-ball contact during the intentional heading of the ball [1,3,14,16].   

That being said, concussions have been caused by a collision of the ball with the temporal area of the head (the side of the head above the ear) [8, 16].   Why? Because the head whips around in a rotational movement when the ball contacts the side of head.  Kirkendall et al. stated “in soccer, head injury from ball contact is mostly due to rotational impacts from accidental contact of the ball to the head. Head-ball contacts on the side of the head of an unprepared player can obviously lead to rotational impacts. Preparation of the head cannot be understated: strike an unprepared player on the forehead, and linear forces (pushing the head posteriorly) can be coupled with transverse rotation (as in a whiplash injury)” [16].

So when a concussion is caused by contact between a head and the ball, the ball was not being headed properly but had either accidentally collided with the head and caused the head to whip around, or had been headed improperly. 

  

Are there areas of the field where injuries occur more frequently?

Kirkendall et al. found that “the penalty area (where players compete for a cross-corner kick) and the collision of an onrushing forward and goalkeeper are the most likely circumstances for a head injury” [16].  “Near the midfield line, where players compete for airballs (eg, punts, goal kicks), is another troublesome place on the field.”  It was also reported that goalpost collisions are possible but not common.   So the penalty area, the midfield line, and the areas around goalposts are the most likely places in which concussions occur. 

 

Are certain player positions more prone to concussions?

Research has shown that  “those players directly involved in attack or defense are those most likely to be injured” [30]. Those players include the center back, the center forward, full-backs and the goalkeeper, who combined accounted for 86% of the medical treatments needed [30]. 

 

What’s important when correctly heading the ball?

“Correct heading involves use of the frontal bone to contact the ball, the neck muscles to restrict head motion, and the muscles of the lower body to position the torso in line with the head and neck to increase the resistant mass and decrease acceleration of the head” [1].

Why is this technique so important? Because “studies have shown that concussion is induced with difficulty when the head is held in a fixed position but more easily when the head is allowed to move freely” [1].   Which is why concussions are caused by balls accidentally hitting the head and causing it to whip around, and not when the ball is being intentionally headed by a player. 

 

Would the presence of an athletic trainer or physician onsite decrease the severity of concussion symptoms?

No.  Research has shown that “there were no significant associations between having a medical professional on site at the time of injury and duration of symptoms or timing of return to play” [21].

 

What about those reports linking repeated heading to brain trauma in older soccer players?

All of us have probably heard about those studies and read those magazine articles.  “Older soccer players reported to have neurological deficits”.  I’ve studied some of those publications and the results were scary but not conclusive (in my humble opinion).  In fact, the researchers themselves concluded that the results did not provide “unambiguous evidence that ball-to-head contacts are responsible for impaired functioning” [29].  Why? Because in the few neurological measurements where differences were seen, those differences were either insignificant, significant but not large, or the measurements obtained was different but still within the normal range.  Does that mean that repeated heading is completely safe? No.  But studies are inconclusive at this point. 

 

What do the experts recommend to mitigate any potential harm of heading?

Researchers and experts had several recommendations for mitigating the harm of heading in soccer. Those suggestions include:

EDUCATION.  “Education should be enhanced to increase awareness of the potential for injury from heading a soccer ball” [1]. Researchers have suggested “with better data comes an improved understanding of the types of actions and activities that typically result in concussions”.  So a better understanding of how concussions take place (namely player/player contact or player/equipment contact) and which areas of the field are most important (such as the penalty area and the midfield line) is invaluable to preventing future concussions.  

TRAINING.  “Correct heading technique must be emphasized and promoted” [1]. This should be accompanied by emphasizing the importance of avoiding unnecessary player/player  or player/equipment contact whenever possible. 

RULES.  “Rules that protect players should be enforced by referees and supported by coaches, parents, and fans” [1]. These include rules to protect the goalie and to deter reckless player/player contact.   

TREATMENT.  “Physicians should continue to appreciate the potential for brain injury from heading” [1].  This includes understanding the symptoms of concussions and making sure that players are not allowed to return to play too quickly after a concussion.  For example, researchers recommend  athletes take "approximately 1 week after becoming asymptomatic to return to the normal level of sports activity” [19]. 

 

So what should we conclude about heading and concussions?

Based on the research reviewed, my conclusion is that concussions are scary but infrequent, and are generally caused by impact with other players or objects, not by the act of intentionally heading the ball.  That being said, head-to-ball contact can cause a concussion when the ball collides with the side of the head or forces the head to whip around quickly during accidental contact. 

So what should we do?  Well, we should educate ourselves (and perhaps other soccer moms and dad) and realize that the act of heading the ball in itself maybe shouldn't be of highest concern.  But the collisions that can occur while trying to head the ball should be.  And although these collisions may be unavoidable, we can be more knowledgeable about them.  Especially for soccer players playing in the positions that are most prone to concussions. 

We should also make sure that we’re aware of the symptoms of a concussion (loss of consciousness, headache, dizziness, nausea, amnesia, etc.) and make sure that any players suspected of having a concussion are seen by a medical professional and withheld from activity until those symptoms have abated for a sustained period of time.  

But perhaps most importantly, we should contextualize the importance of concussions and understand how frequently they occur, which is actually infrequently.  Concussions are scary, especially for parents watching their child play a sport where concussions can happen.  But hopefully some of your questions have been answered and you now know with confidence how best to educate your player about the incidence of concussions.   

 

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