Head Injuries in Professional Football (Soccer)

Introduction: Head injuries in sports may have been an underestimated health risk for many years. However, they potentially bear the risk of serious long-term sequelae with a potential impact on the athletes’ activities of daily living, sports, or career. Although the incidence of head injuries in professional football (soccer) is relatively low in comparison to so-called high-risk sports such as American football, rugby, boxing, or ice hockey, absolute numbers are substantial because of the high popularity of this sport and the large number of players. In 2006, a first step towards head injury prevention in football was made by altering a rule: henceforth intentional elbow to head contacts had to be punished by a red card. This action determined one of the three aims of this thesis: i) to present incidence rates of head injuries including their time trends and injury mechanisms; ii) to identify circumstances of head injury incidents, the behavior of referees, and their decisions; and iii) to investigate the effect of the rule change on the reduction of head injuries in professional male football. Methods: i) To investigate the time trends of head injuries, an analysis of head injuries in the 1st German Bundesliga was generated comprising the 11 consecutive seasons (2006/07 to 2016/17) following the rule change. The head injury database was based on continuously published data from the German football magazine “kicker Sportmagazin®” and other media sources. Injury mechanisms were analysed from video recordings. Injury incidence rates (IR) and 95% confidence intervals (95% CI) were calculated. Time trends were analysed via linear regression. ii) To identify circumstances of head injury incidents, the video analyses of all head injuries from 13 consecutive seasons (2000/01 to 2012/13) were screened. iii) To provide a description of injury mechanisms of head injuries and the effect of the rule change, the database of all head injuries comprising seasons 2000/01 to 2012/13 were screened and the equal number of seasons before and after the rule change were compared. Head injury mechanisms were analysed from video recordings. IRs and 95% CI as well as incidence rate ratios (IRR) to assess differences in injury rates six seasons before and six seasons after the rule change were calculated. Results: i) During the 11 consecutive seasons, 238 head injuries occurred during matches (IR 1.77 per 1000 match hours). There were no significant seasonal changes (expressed as annual average year-to-year change) in IRs over the 11-year period for total head injuries, facial and head fractures, head and face lacerations and abrasions, and head contusions. The average year-toyear increase for concussion was 6.4%. There were no seasonal changes in head injury mechanisms over the study period. ii) Most head injury incidents involved two players. Those players who suffered a subsequent head injury predominantly jumped (60%), headed the ball (36%), and ran forwards (20%), whereas the non-injured players mainly jumped (64%), headed the ball (27%), and raised the elbow to the head (23%). Free ball situations (two players challenging/dueling for the ball) caused the largest proportion of the head injuries (81%). iii) 356 head injuries were recorded (IR 2.22 per 1000 match hours) in 13 consecutive seasons. Contact with another player resulted in the greatest proportion of head injuries, especially head to head (34%) and elbow to head (17%) contacts. After the rule change the total number of head injuries was reduced by 29%. The subcategories head and face lacerations and abrasions declined by 42%, concussions by 29%, head contusions by 18% and facial and head fractures by 16%. Discussion/Conclusion: The first study in this thesis revealed that the subcategory concussion increased slightly over the (2006/07 to 2016/17) seasons, which could be the result of increasing match dynamics and/or a raised awareness for this injury type among team physicians and players. Total head injuries and the other subcategories remained reasonably stable over 11 consecutive seasons. The second study showed that heading duels are particularly associated with head injuries and could be target of future prevention strategies. The third study provided evidence that the incidence rates for total number of head injuries and their respective subcategories were lower in the six seasons after the rule change compared to the equal number of seasons before. Therefore, rule changes in football appear to be effective in reducing the occurrence of head injuries. To summarize, the increasing number of concussions requires action. Ongoing monitoring and surveying of head injuries allows practitioners to keep track of head injuries. For future research, the development of preventative measures to avoid potential (serious) health consequences of head injuries is warranted

Head Impact Situations in Professional Football (Soccer)

To assess head impact incidents (HIIs) and to distinguish diagnosed head injuries from other incidents, a video observation analysis of match HIIs was conducted in the German Bundesliga (2017/18 season). Video recordings of each match were screened to identify the respective events. Head injury data were identified by a prospective injury registry. HII and head injury incidence rates (IR) were calculated with 95 % CIs. The total number of HIIs was 1362 corresponding to an IR of 134.9/1000 match hours (95% CI 127.9–142.2). In 123 HII (IR 12.2, 95% CI 10.2–14.5) the contact was classified as severe. Head contact with the opponent was the most frequent cause (85%). The most frequent mechanism was in 44% (combined) the arm and elbow-to-head, followed by head-to-head and hand-to-head contacts (each 13%). In 58%, the HIIs occurred during header duels. Twenty-nine head injuries were recorded (IR 2.9, 95% CI 2.0–4.1). Concussions/traumatic brain injuries accounted for 48%, head/facial fractures 24%, head/facial contusions 21%, and lacerations/abrasions 7%. The number of HIIs not classified as concussions/more severe trauma was high. Identification of HIIs and head injury severity should be improved during on-field assessment as many head injuries might go unrecognised based on the large number of HIIs

Epidemiology of Football Injuries of the German Bundesliga: A Media-Based, Prospective Analysis over 7 Consecutive Seasons

Background: This study describes the implementation of a standardised, prospective injury database covering the entire 1st male German football league (“Bundesliga”) based on publicly available media data. For the first time, various media sources were used simultaneously as the external validity of media-generated data was low in the past compared to data obtained by way of the “gold standard”, i.e. by the teams’ medical staffs. Methods: The study covers 7 consecutive seasons (2014/15–2020/21). The primary data source was the online version of the sport-specific journal “kicker Sportmagazin™” complemented by further publicly available media data. Injury data collection followed the Fuller consensus statement on football injury studies. Results: During the 7 seasons, 6653 injuries occurred, thereof 3821 in training and 2832 in matches. The injury incidence rates (IRs) per 1000 football hours were 5.5 [95% CI 5.3–5.6], 25.9 [25.0–26.9] per 1000 match, and 3.4 [3.3–3.6] per 1000 training hours. Twenty-four per cent of the injuries (n = 1569, IR 1.3 [1.2–1.4]) affected the thigh, 15% (n = 1023, IR 0.8 [0.8–0.9]) the knee, and 13% (n = 856, IR 0.7 [0.7–0.8]) the ankle. Muscle/tendon injuries contributed 49% (n = 3288, IR 2.7 [2.6–2.8]), joint/ligament injuries 17% (n = 1152, IR 0.9 [0.9–1.0]), and contusions 13% (n = 855, IR 0.7 [0.7–0.8]). Compared to studies using injury reports from the clubs’ medical staff, media data revealed similar proportional distributions of the injuries, but the IRs tended towards the lower end. Obtaining specific locations or diagnosis especially with regard to minor injuries is difficult. Conclusions: Media data are convenient for investigating the quantity of injuries of an entire league, for identifying injuries for further subanalysis, and for analysing complex injuries. Future studies will focus on the identification of inter- and intraseasonal trends, players' individual injury histories, and risk factors for subsequent injuries. Furthermore, these data will be used in a complex system approach for developing a clinical decision support system, e.g. for return to play decisions

Ribonucleoprotein-dependent localization of the yeast class V myosin Myo4p

Class V myosins are motor proteins with functions in vesicle transport, organelle segregation, and RNA localization. Although they have been extensively studied, only little is known about the regulation of their spatial distribution. Here we demonstrate that a GFP fusion protein of the budding yeast class V myosin Myo4p accumulates at the bud cortex and is a component of highly dynamic cortical particles. Bud-specific enrichment depends on Myo4p's association with its cargo, a ribonucleoprotein complex containing the RNA-binding protein She2p. Cortical accumulation of Myo4p at the bud tip can be explained by a transient retention mechanism that requires SHE2 and, apparently, localized mRNAs bound to She2p. A mutant She2 protein that is unable to recognize its cognate target mRNA, ASH1, fails to localize Myo4p. Mutant She2p accumulates inside the nucleus, indicating that She2p shuttles between the nucleus and cytoplasm and is exported in an RNA-dependent manner. Consistently, inhibition of nuclear mRNA export results in nuclear accumulation of She2p and cytoplasmic Myo4p mislocalization. Loss of She2p can be complemented by direct targeting of a heterologous lacZ mRNA to a complex of Myo4p and its associated adaptor She3p, suggesting that She2p's function in Myo4p targeting is to link an mRNA to the motor complex

The UEFA Heading Study: Heading incidence in children's and youth' football (soccer) in eight European countries

To assess the real‐life magnitude of the heading incidence in children's and youth’ football in eight European countries with different “football cultures,” a cross‐sectional observational design, in which one match per team in 480 different teams from eight European countries (2017/18‐2018/19), was recorded by video. One training session was recorded in 312 teams. Clubs with Under‐10, Under‐12 (female/male/mixed), and Under‐16 female and male teams were eligible to participate. Heading frequencies and types were analyzed. Results are presented as headers per match/training and per team. Incidence rates (IR) per 1000 match/training hours were calculated. Under‐10 teams carried out the lowest average number of headers per match (8.8), followed by Under‐16 female (17.7), Under‐12 (18.4), and Under‐16 male (35.5). Total number of headers per match and team varied between countries. 80% of the total number of headers were single intentional headers, 12% heading duels, 3% unintentional headers by getting hit, and 5% others (trends apparent in all age groups). Three head injuries occurred during match play corresponding to an IR of 0.70 (95% CI, 0.23‐2.16). The lowest number of headers per training and team was found in Under‐10 (21.3), followed by Under‐16 females (34.1), Under‐12 (35.8), and Under‐16 males (45.0). In conclusion, this large‐scale study presents novel data about the number and type of headers in youth’ football throughout Europe. A more precise understanding of the heading incidence, specifically in young players, is mandatory for the debate of restrictions on heading in youth football

The UEFA Heading Study:Heading incidence in children's and youth' football (soccer) in eight European countries

To assess the real-life magnitude of the heading incidence in children's and youth' football in eight European countries with different "football cultures" a cross-sectional observational design, in which one match per team in 480 different teams from eight European countries (2017/18-2018/19) was recorded by video. One training session was recorded in 312 teams. Clubs with Under-10, Under-12 (female/male/mixed) and Under-16 female and male teams were eligible to participate. Heading frequencies and types were analysed. Results are presented as headers per match/training and per team. Incidence rates (IR) per 1000 match/training hours were calculated. Under-10 teams carried out the lowest average number of headers per match (8.8), followed by Under-16 female (17.7), Under-12 (18.4), and Under-16 male (35.5). Total number of headers per match and team varied between countries. 80% of the total number of headers were single intentional headers, 12% heading duels, 3% unintentional headers by getting hit and 5% others (trends apparent in all age groups). Three head injuries occurred during match play corresponding to an IR of 0.70 (95% CI, 0.23-2.16). The lowest number of headers per training and team was found in Under-10 (21.3), followed by Under-16 females (34.1), Under-12 (35.8), and Under-16 males (45.0). In conclusion, this large-scale study presents novel data about the number and type of headers in youth' football throughout Europe. A more precise understanding of the heading incidence, specifically in young players, is mandatory for the debate of restrictions on heading in youth football

Evaluating effects of a multi-generation pollution on Caenorhabditis elegans' population

The assessment of toxic effects at biologically and ecologically relevant scales is an important challenge in ecosystem protection. Indeed, in most time, stressors impact populations over longterm. The selection pressure exerted by a pollutant is known to amplify the phenomenon of natural selection and could lead to evolutionary changes across generations. It is therefore important to study the evolutionary response of a population submitted to a long term stress. Regarding this background, we assessed the evolution of two populations (control and exposed to 1.1 mM of the heavy radiotoxic metal, uranium) of the ubiquitous nematode Caenorhabditis elegans submitted to a long-term exposure to uranium. The experimentation was conducted over 16 generations and life history traits (growth, reproduction and survival) as well as dose-response evolution were assessed. These parameters were followed daily on individuals extracted from the populations and exposed to a range of concentration (from 0 to 1.2 mM U). Our experiment showed an increase of adverse effects as a function of uranium concentration. Indeed the NOEC for reproduction and growth traits were respectively of 0.5 mM U and 0.9 mM U. Moreover, reproduction and growth were respectively reduced by over 60% and 20% for individual exposed at 1.1 mM U. This reduction remained constant throughout the generations. We also pointed out the appearance of genetics differentiations on reproduction traits throughout the generations. This differentiation, observed from generation 3, showed us that the total egg-laying of the uranium population was significantly decreased compared with the control population. In contrast, no differentiations were highlighted on growth traits. Our results confirm the importance of studying environmental risks related to pollutant through multi-generational studies in order to capture effects that may appear after several generation of exposition

Consequences of a multi-generation exposure to uranium on Caenorhabditis elegans life parameters and sensitivity.

International audienceThe assessment of toxic effects at biologically and ecologically relevant scales is an important challenge in ecosystem protection. Indeed, stressors may impact populations at much longer term than the usual timescale of toxicity tests. It is therefore important to study the evolutionary response of a population under chronic stress. We performed a 16-generation study to assess the evolution of two populations of the ubiquitous nematode Caenorhabditis elegans in control conditions or exposed to 1.1 mM of uranium. Several generations were selected to assess growth, reproduction, survival, and dose-responses relationships, through exposure to a range of concentrations (from 0 to 1.2 mM U) with all endpoints measured daily. Our experiment showed an adaptation of individuals to experimental conditions (increase of maximal length and decrease of fecundity) for both populations. We also observed an increase of adverse effects (reduction of growth and fertility) as a function of uranium concentration. We pointed out the emergence of population differentiation for reproduction traits. In contrast, no differentiation was observed on growth traits. Our results confirm the importance of assessing environmental risk related to pollutant through multi-generational studies