Marx-Berger Daniela
Children’s Hospital of Eastern Switzerland, St. Gallen
A few months ago, a high school graduate contacted me with a request for an interview for her “Matura thesis”. The topic of her thesis was the (possible) ban on headers in children and adolescents in soccer. Shortly afterwards, the same question came up at the general assembly of the Society for Paediatric Sports Medicine (GPS): why are headers banned in youth soccer in England/US, but not in Germany and Switzerland? Reason enough to take a closer look at this topic and try to find evidence-based answers to this question.
Soccer is the world’s most popular sport with more than 265 million players, of which 22 million are youth players [1]. Headers are deliberately used to influence the game. Headers are a fundamental part of the sport of soccer. It is also unique in sport to use a header to influence the game. However, there is a recurring question in the literature as to whether headers have an impact on brain function and brain structures [2-6]. In the US, headers were banned for children up to 11 years of age following a lawsuit by parents of children playing soccer. Fear of concussions in the still developping brains of children was the motivation of the parents – alarmed by cases of brain diseases in athletes, apparently caused by concussions during sport. There is a danger of equating concussions and heading, and also of transferring findings from other sports with a high risk of head injuries (e.g. American football, rugby, ice hockey) to soccer. However, the soccer leagues of England, Scotland and Ireland have also decided in 2020 that there will be no headers- training under 11 years of age and only limited training from 12-16 years of age. In competitions, however, headers are not banned because only few headers are played in matches in this age group.
In 2016, Nina Feddermann-Demont and Alexander Tarnutzer conducted a meta-analysis on the topic of “Effects of headers on brain functions and structures” [7]. In a literature search, 118 articles related to this topic were identified, published between 1.1.2020 and 17.11.2015, of which 39 (33%) met the inclusion criteria (exclusively original papers). Their conclusions were, that at that time it had not been clearly proven that playing headers has neither acute effects nor long-term effects on brain functions or structures. The results of the studies were sometimes very contradictory. Common problems of the studies were low case numbers, insufficient methodology to establish causality, recall bias (questionnaires retrospectively on the number of headers and concussions) and inadequate definitions. An important challenge in conducting long-term effects studies is, that there is a very long latency between headers and disease onset. Prospective studies would require a large sample to identify few cases. An example of the contradictory results can be seen in the following two studies: Koerte et al. [6] found reduced thickness of the cerebral cortex on MRI in 15 former professional soccer players in 2016. In contrast, Oliveira et al. found in 375 adult amateur soccer players, that neither headers nor concussions had led to reduced cortex thickness or brain volume on MRI [8].
In addition to the question of long-term consequences, headers are also a possible cause of acute head injury. In childhood, however, the main mechanism for a head injury has been defined as contact with a surface (pitch or hall floor), the goal post or hall wall, or contact with another player [9]. Intentional headers are rarely the cause of a concussion; fighting for a ball in the air and the possible head-to-head or elbow-to-head mechanism is much more common. This lack of distinction often makes epidemiological interpretation of studies difficult. Nevertheless, there are studies that have found that in 25-30% of concussions in soccer, the header was the triggering factor and in 62-78% it was an accidental head-to-head contact [10].
Kontos et al. also conducted a meta-analysis (28 included studies) on the effects of headers in soccer on neurocognitive functions [11]. Their conclusion was, that there is no empirical evidence for potential negative effects of headers in soccer, especially in relation to neurocognitive functions or concussion symptoms. They concluded that, based on the available data, a ban of headers is currently premature. More studies are needed, with better data to distinguish headers from concussions. They also suggest, studying whether the rule changes in the US (banning headers for children/youth) lead to fewer header-associated concussions.
A congress was held in New York in 2017 on the topic of “Head injuries in soccer: from science to the field”. The consensus article by Putukian et al. [12] summarises the results of this congress:
1. Head injuries in soccer and concussions in particular are a relevant topic.
2. The majority of concussions in soccer happen in the air during a fight, not during a deliberate header.
3. There is limited biomechanical data on the forces involved in headers, but the forces appear to be less than in sports such as American football or ice hockey.
4. Recognition of concussion by all involved (coaches, referees, athletes, medical staff) is immensely important.
5. Detection/diagnosis/therapy should be carried out according to current guidelines.
6. At this stage, the majority of available data in both adolescents and adults show no evidence of a negative long-term outcome of neurocognitive functions from headers. There are no data for children/adolescents. The only data that exist relate to headaches.
7. There are no prospective data showing that possible neurodegenerative changes, e.g. chronic traumatic encephalopathy (CTE), are triggered by playing soccer.
8. Injury prevention is an important field for future research. Soft head protectors can possibly reduce the impact of forces in “stiff impact” (head-to-head, head-to-post). However, they seem to be less helpful in head-to-head play. Much of this data comes from the laboratory and has not yet been tested on the field.
9. Rule changes and compliance are essential in injury prevention. This includes, for example, the punishment of the “high elbow” with a red card. It also includes newer rules such as sufficient time for the medical evaluation of a player with a head injury, the possibility of substituting without this substitution counting in relation to the maximum number of substitutions possible.
10. In summary, it must be said that intentional heading very rarely triggers a concussion.
11. Athletes, parents, coaches, referees, administrators and health workers should unite and emphasise the importance of fair play to make soccer a safe sport at all levels.
The question of whether strengthening neck muscles has a protective effect against head injuries is also a popular topic of discussion. However, the data are controversial. One can train the neck muscles and would also assume that this leads to a reduction in acceleration during an “impact”, but the increased strength alone does not yet lead to improved head stabilisation during headers. A randomised clinical trial on the topic of strengthening neck muscles and the subsequent occurrence of concussions does not yet exist [12].
The UEFA has issued the UEFA Heading Guidelines for youth players [14] as a recommendation on this subject. They are intended as a recommendation on how heading should be handled during training and matches in youth soccer. UEFA encourages national associations to implement these guidelines as a minimum and to develop their own guidelines, taking into account national circumstances. UEFA’s recommendations for coaches are:
1. Ball size: Use appropriate size and weight of balls according to the age category (see “FIFA Youth Football Specification Recommendations”).
2. Ball pressure: For training and competition use the lowest pressure allowed by the Laws of the Game. Foam balls are an alternative for the first training exercises.
3. Number of headers: Reduce header training as much as possible, taking into account the header requirements in the match. This is especially important for younger players. The goal of reducing the number of headers can be achieved through various rule changes: Reducing the size of the pitch, fewer players, reducing the height of the goal. Coaches should be advised that it is important to gradually increase header training in the different age groups.
4. Strengthening the neck muscles: Recent scientific data suggests that strengthening the neck muscles may be beneficial in header training by leading to a reduction in the application of force to the head. Techniques on how to achieve strength training of neck muscles should be considered in coach education and included in heading guidelines.
5. Awareness of recognising symptoms of possible concussion: if symptoms such as dizziness, headache, unsteadiness of gait, etc. are expressed by players following header training, they should take a complete break for one week with medical follow-up. It should be noted that girls are more susceptible to concussion and possibly header exposure compared to boys.
Critical comments should be made here, however, e.g. point 5: If neurological symptoms occur, it is imperative that a rapid medical consultation takes place and if the diagnosis of concussion is made, an appropriate return-to-school and return-to-sport protocol is issued instead of the blank recommendation of a complete week of rest, which no longer corresponds to the current return-to-sport guidelines [15].
In summary, additional scientific work is needed to understand what happens, for example, when fighting for the ball in the air, what acute and chronic effects headers have (or don’t have) or what motor and visual skills are important to learn a clean heading technique. For now we do not have clear evidence that justifies a ban on headers at the moment, but it is not wrong, under the existing data, to rather take the path of greatest possible safety.
Corresponding author
Daniela Marx-Berger
Ostschweizer Kinderspital St. Gallen
Nephrologie/Sportmedizin
Leitende Ärztin
Claudiusstrasse 6, 9006 St. Gallen
Tel.: +41 (0)71 243 7111
daniela.marx-berger@kispisg.ch
References
1. http://www.fifa.com
2. Matser EJ, Kessels AG, Lezak MD, Jordan BD, Troost J. Neuropsychological impairment in amateur soccer players. JAMA. 1999 Sep 8;282(10):971-3. doi: 10.1001/jama.282.10.971. PMID: 10485683.
3. Matser JT, Kessels AG, Jordan BD, Lezak MD, Troost J. Chronic traumatic brain injury in professional soccer players. Neurology. 1998 Sep;51(3):791-6. doi: 10.1212/wnl.51.3.791. PMID: 9748028.
4. Matser JT, Kessels AG, Lezak MD, Troost J. A dose-response relation of headers and concussions with cognitive impairment in professional soccer players. J Clin Exp Neuropsychol. 2001 Dec;23(6):770-4. doi: 10.1076/jcen.23.6.770.1029. PMID: 11910543.
5. Koerte IK, Mayinger M, Muehlmann M, Kaufmann D, Lin AP, Steffinger D, Fisch B, Rauchmann BS, Immler S, Karch S, Heinen FR, Ertl-Wagner B, Reiser M, Stern RA, Zafonte R, Shenton ME. Cortical thinning in former professional soccer players. Brain Imaging Behav. 2016 Sep;10(3):792-8.
6. Lipton ML, Kim N, Zimmerman ME, Kim M, Stewart WF, Branch CA, Lipton RB. Soccer heading is associated with white matter microstructural and cognitive abnormalities. Radiology. 2013 Sep; 268(3):850-7. doi: 10.1148/radiol.13130545. Epub 2013 Jun 11.
7. Feddermann-Demon, N. und Tarnutzer A.A., Effekte des Kopfballspiels auf Hirnfunktionen und – strukturen; https://www.srf.ch/sendungen/content/download/10125322/file/DFB Wissenschaftskongress 20Nov2015 NFAT-final.pdf
8. Oliveira TG, Ifrah C, Fleysher R, Stockman M, Lipton ML. Soccer heading and concussion are not associated with reduced brain volume or cortical thickness. PLoS One. 2020 Aug 10;15(8):e0235609. doi: 10.1371/journal.pone.0235609. PMID: 32776940; PMCID: PMC7416951.
9. Giannotti M, Al-Sahab B, McFaull S, Tamim H. Epidemiology of acute head injuries in Canadian children and youth soccer players. Injury. 2010 Sep;41(9):907-12. doi: 10.1016/j.injury.2009.09.040. Epub 2009 Oct 29. PMID: 19878944.
10. Comstock RD, Currie DW, Pierpoint LA. An evidence-based discussion of heading the ball and concussion in high school soccer. In Ethics IsSLa,ed. Santa Clara University, 2015.
11. Kontos AP, Braithwaite R, Chrisman SPD, McAllister-Deitrick J, Symington L, Reeves VL, Collins MW. Systematic review and meta-analysis of the effects of football heading. Br J sports Med 2017; 51:1118-1124.
12. Putukian M, Echemendia RJ, Chiampas G, Dvorak J, Mandelbaum B, Lemak LJ, Kirkendall D. Head Injury in Soccer: From Science to the Field; summary of the head injury summit held in April 2017 in New York City, New York. Br J Sports Med. 2019 Nov;53(21):1332. doi: 10.1136/bjsports-2018-100232. Epub 2019 Feb 13. PMID: 30760457.
13. Collins CL, Fletcher EN, Fields SK, Kluchurosky L, Rohrkemper MK, Comstock RD, Cantu RC. Neck strength: a protective factor reducing risk for concussion in high school sports. J Prim Prev. 2014 Oct;35(5):309-19. doi: 10.1007/s10935-014-0355-2. PMID: 24930131.
14. UEFA Heading Guidelines for Youth players; http://www.uefa.com/
15. McCrory P, Meeuwisse W, Dvorak J, et al. Consensus statement on concussion in sport – the 5th international conference on concussion in sport held in Berlin, October 2016 British Journal of Sports Medicine 2017; 51:838-847.
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