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

Recovery kinetics of knee flexor and extensor strength after a football match

© 2015 The Authors. Published by PLOS. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1371/journal.pone.0128072We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a football match. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KFecc/KEcon) and conventional (KFcon/KEcon) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (P<0.05) at 12h (both limbs) and 36h (dominant limb only), b) eccentric and concentric peak torque of knee extensors and flexors declined (P<0.05) in both limbs for 36h at 60°/s and for 60h at 180°/s with eccentric peak torque of knee flexors demonstrating a greater (P<0.05) reduction than concentric peak torque, c) strength deterioration was greater (P<0.05) at 180°/s and in dominant limb, d) the functional ratio was more sensitive to match-induced fatigue demonstrating a more prolonged decline. Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes' football-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical conditioning level.Published versio

Indirect evaluation and training of lower limb proprioception ability of elite young soccer

Soccer is one of the most popular team sports, however, at the same time appeared an increased frequency of lower limb musculoskeletal injuries. The purpose of the present study was to investigate the effect of a balance training program on proprioception ability of young soccer players (16,11+1,19), performed under different fatigue conditions. More specific the purposes of this study were: a) to investigate the effect of a balance training program on healthy young soccer players proprioception ability, b) to investigate which is the most effective time for balance intervention program performance, before or after the soccer training, c) to examine the maintenance of the proprioception ability improvements after the completion of the intervention balance training program, and d) to set a unite of proprioception ability tests and to control their effectiveness on different balance ability form assessments. The sample of this study comprised of 41 young soccer players, who divided into three groups, two experimental (N=26), and one control (N=15). The two experimental group followed the same intervention balance program, 3 time per week, with 20 minutes duration for 3 months. The two experimental group performed that balance program at different moment. The first group (N=13) performed it before the soccer training (group “before”) and the other (N=13), after the soccer training (group “after”). The control group (N=15) didn’t participate in any balance training program. Before the beginning of the training program a unite of tests performed. Evaluated isokinetic the extensors and flexors muscular performance-peak torque, in two angular velocities (60 and 180°/sec) at the three groups. The balance ability evaluated with a unite of tests performed on a balance system and on balance boards. That tests performed: 1) at the initial measures, a) before the soccer training, by the three groups, b) after the soccer training, by the two experimental groups, 2) at the intermediate measures (after 45 days), a) before the soccer training, by the two experimental groups, 3) at the final measures (after 90 days) a) before the soccer training, by the three groups, b) after the soccer training, by the two experimental groups, 4) at the maintenance measures (45 days after the completion of the intervention program) a) before the soccer training, by the two experimental groups. Anova and Anova Repeated Measures were used in order to determine possible statistical significant differences among the four measurements, among the experimental groups and control, and among the dominant and no dominant lower limb. The analysis of the results shown significant statistical differences among the measurements for the experimental groups, contrary to the control group that showed no similar variation from measurement to measurement. Specifically, improvements showed at the tests performed on the balance system and evaluated a) the deviations from the horizontal plane, and b) the time completion of the target agility test, and at the tests performed on balance boards and evaluated the time balance maintenance. Also, the two experimental groups improved the same their balance ability. Finally, didn’t find differences between the dominant and the nondominant lower limb in all the balance and muscular performance tests. Considering the total results of the present study, proposed the performance of balance exercises by healthy athletes in order to improve their proprioception ability. The performance of balance exercises could take place before or after the sport specific training.Το αγώνισμα του ποδοσφαίρου είναι ένα από τα πιο δημοφιλή ομαδικά αθλήματα, παρουσιάζοντας όμως ταυτόχρονα και μια αυξημένη συχνότητα εμφάνισης μυοσκελετικών τραυματισμών στα κάτω άκρα. Σκοπός της παρούσας μελέτης ήταν να εξετάσει την επίδραση που έχει η εφαρμογή ενός προγράμματος ισορροπίας για την έμμεση εξάσκηση της ιδιοδεκτικής ικανότητας σε νεαρούς ποδοσφαιριστές (16,11±1,19), κάτω από διαφορετικές συνθήκες κόπωσης. Πιο αναλυτικά, στόχοι της έρευνας αυτής ήταν: α) να διερευνηθεί η επίδραση ενός προγράμματος ισορροπίας στη βελτίωση της ιδιοδεκτικής ικανότητας υγιών νεαρών ποδοσφαιριστών, β) να διαπιστωθεί ποια είναι η πιο αποτελεσματική χρονική στιγμή εφαρμογής του παρεμβατικού προγράμματος ισορροπίας, πριν ή μετά την προπόνηση του ποδοσφαίρου, συγκεκριμένα να εξεταστεί εάν η κόπωση που προέρχεται από την προπόνηση του ποδοσφαίρου διαφοροποιεί τα οφέλη από την εξάσκηση της ικανότητας της ισορροπίας, γ) να αξιολογηθεί η ικανότητα της ισορροπίας 45 ημέρες μετά από την ολοκλήρωση του παρεμβατικού προγράμματος άσκησης της ισορροπίας (διατήρηση των πιθανών βελτιώσεων της ιδιοδεκτικότητας) και δ) να συγκροτηθεί μια δέσμη από τεστ ισορροπίας για την έμμεση αξιολόγηση της ιδιοδεκτικής ικανότητας, και να ελεγχθεί η αποτελεσματικότητά της στην αξιολόγηση των διαφορετικών πτυχών της ικανότητας της ισορροπίας. Το δείγμα της έρευνας αποτέλεσαν 41 νεαροί ποδοσφαιριστές, οι οποίοι χωρίστηκαν σε τρεις ομάδες. Δύο πειραματικές (Ν=26), ομάδα "πριν" (Ν=13), ομάδα "μετά" (Ν=13) και μια ομάδα ελέγχου (Ν=15). Οι δυο πειραματικές ομάδες είχαν την ίδια συχνότητα εξάσκησης, 3 φορές την εβδομάδα και ακολούθησαν το ίδιο παρεμβατικό πρόγραμμα, ημερήσιας διάρκεια 20 λεπτών και για χρονικό διάστημα 3 μηνών. Η διαφοροποίηση των δυο πειραματικών ομάδων ήταν στην χρονική στιγμή εφαρμογής του προγράμματος εξάσκησης της ισορροπίας. Η μια ομάδα το εκτέλεσε πριν την προπόνηση του ποδοσφαίρου (ομάδα “πριν”) και η άλλη μετά την προπόνηση του ποδοσφαίρου (ομάδα “μετά”). Η ομάδα “ελέγχου” δεν συμμετείχε σε κανένα πρόγραμμα εξάσκησης της ισορροπίας. Πριν την έναρξη της πειραματικής διαδικασίας πραγματοποιήθηκε μια σειρά αξιολογήσεων. Αξιολογήθηκε η μυϊκή απόδοση-μέγιστη ροπή των εκτεινόντων και καμπτήρων μυών του γόνατος, ισοκινητικά σε δύο γωνιακές ταχύτητες (60 και 180μοίρες/δευτ.) και στις τρεις ομάδες. Η ικανότητα της ισορροπίας αξιολογήθηκε με μια δέσμη από τεστ που έγιναν σε σύστημα ισορροπίας και σε σανίδες ισορροπίας. Στο σύστημα ισορροπία αξιολογήθηκε α) η ικανότητα στήριξης του ατόμου σε ασταθή πλατφόρμα και καταγράφηκε η απόκλιση της πλατφόρμας στήριξης σε μοίρες από το οριζόντιο επίπεδο και β) η ικανότητα εκτέλεσης συγκεκριμένης δυναμικής δεξιότητας (επίτευξη στόχων) όπου καταγράφηκε ο χρόνος ολοκλήρωσής τους. Στις σανίδες ισορροπίας καταγράφηκε ο χρόνος διατήρησης της ισορροπίας. Τα τεστ αυτά εκτελέστηκαν στις: 1) Αρχικές αξιολογήσεις, και συγκεκριμένα α) πριν την προπόνηση του ποδοσφαίρου και από τις τρεις ομάδες, και β) μετά την προπόνηση του ποδοσφαίρου μόνο από τις δυο πειραματικές ομάδες, 2) Ενδιάμεσες αξιολογήσεις (μετά από 45 ημέρες εξάσκησης της ισορροπίας) α) πριν την προπόνηση του ποδοσφαίρου, από τις δυο πειραματικές ομάδες, 3) Τελικές αξιολογήσεις (μετά από 90 ημέρες εξάσκησης της ισορροπίας) α) πριν την προπόνηση του ποδοσφαίρου και από τις τρεις ομάδες, β) μετά την προπόνηση του ποδοσφαίρου μόνο από τις δυο πειραματικές ομάδες, 4) αξιολογήσεις Διατήρησης (45 ημέρες μετά το τέλος του προγράμματος εξάσκησης της ισορροπίας) α) πριν την προπόνηση του ποδοσφαίρου από τις δυο πειραματικές ομάδες. Για την ανάλυση των δεδομένων, χρησιμοποιήθηκε η ανάλυση διακύμανσης (Anova) και η ανάλυση διακύμανσης επαναλαμβανόμενων μετρήσεων (Anova Repeated Measures), για να διαπιστωθούν πιθανές στατιστικά σημαντικές διαφορές μεταξύ των μετρήσεων, μεταξύ των πειραματικών ομάδων και της ομάδας ελέγχου. Η ανάλυση των αποτελεσμάτων έδειξε στατιστικά σημαντικές διαφορές μεταξύ των μετρήσεων για τις πειραματικές ομάδες, σε αντίθεση με την ομάδα ελέγχου, που δεν παρουσίασε ανάλογη διαφοροποίηση από μέτρηση σε μέτρηση. Συγκεκριμένα βελτιώσεις παρουσιάστηκαν τόσο στα τεστ που εκτελέστηκαν στο σύστημα ισορροπίας και αξιολόγησαν α) τις αποκλίσεις της πλατφόρμας στήριξης σε μοίρες από το οριζόντιο επίπεδο και β) το χρόνο ολοκλήρωσης της δεξιότητας των στόχων όσο και στα τεστ που εκτελέστηκαν στις σανίδες ισορροπίας και αξιολόγησαν το χρόνο διατήρησης της ισορροπίας. Επιπλέον δεν παρουσιάστηκε διαφορά στην βελτίωση μεταξύ των δυο πειραματικών ομάδων που εκτέλεσαν το πρόγραμμα ισορροπίας διαφορετική χρονική στιγμή. Επίσης δεν παρουσιάστηκε διαφορά τόσο στην μυϊκή απόδοση όσο και στην ικανότητα της ισορροπίας μεταξύ του κυρίαρχου και του μη κυρίαρχου κάτω άκρου. Λαμβάνοντας υπόψη τα συγκεντρωτικά αποτελέσματα της παρούσας έρευνας, προτείνεται η εκτέλεση ασκήσεων ισορροπίας από υγιείς αθλητές για την έμμεση εξάσκηση της ιδιοδεκτικής ικανότητας. Η εξάσκηση μπορεί να γίνεται πριν ή μετά την επιβάρυνση που δέχονται κατά την συμμετοχή τους στην προπόνηση του αθλήματος

Effects of a soccer training session fatigue on balance ability

The purpose of the present study was to investigate the effects of a soccer training session on the balance ability of the young soccer players. Participants were twenty-six young soccer players. Standard testing balance boards and Biodex Stability System were used to assess balance ability before (pre-training) and immediately after (post-training) the completion of a soccer training session. Also, Isokinetic knee joint moment measurements (60°/sec and 180°/sec) were carried out pre- and post-soccer training. The results revealed that no differences (p>0.05) were found in balance ability and knee joint moment production between pre- and post-soccer training. Result is in contrast to the notion of a link between fatigue induced by a soccer training session or game and injury caused by impaired balance

The effects of soccer training and timing of balance training on balance ability

The purpose of the present study was to investigate the effects of a soccer training session on the balance ability of the players and assess whether the effectiveness of a balance program is affected by its performance before or after the regular soccer training. Thirty-nine soccer players were randomly divided into three subject groups (n=13 each), one control group (C group), one training group that followed a balance program (12 weeks, 3 times per week, 20 min per session) before the regular soccer training (TxB group), and one training group that performed the same balance program after the soccer training (TxA group). Standard testing balance boards and the Biodex Stability System were used to assess balance ability in the C, TxB, and TxA groups at baseline (T0) and after completing the balance program (T12). The same tests and additional isokinetic knee joint moment measurements were carried out in the TxB and TxA groups pre- and post-soccer training. Two main results were obtained: (1) No differences (p>0.05) were found in balance ability and knee joint moment production between pre- and post-soccer training. (2) The balance program increased (p<0.01) the balance ability in the TxB and TxA groups, and the improvement in the TxA group was greater (p<0.05) than that in the TxB group post-soccer training. Result (1) is in contrast to the notion of a link between fatigue induced by a soccer training session or game and injury caused by impaired balance, and result (2) has implications for athletic training and rehabilitation

Balance training programs for soccer injuries prevention

The purpose of the study was to compare 2 different balance training programs, based on distinct exercise frequencies, with the aim of improving proprioceptive ability. Thirty eight professional soccer players, were randomly assigned into 3 groups: the A group, exercised with a frequency of 6 times per week, for 3 weeks, the B group exercised with a frequency of 3 times per week, for 6 weeks and the C group (control) did not follow a highly specific balance training, but only a standard soccer training. All participants were evaluated with the use of an electronic stability system (indices-deviations) and of a wooden balance board (time on balance) before (pre test) and after the training period (post test). Analyses of variance (ANOVAs), with repeated measures on the last factor, were conducted to determine effect of training programs and measures (pre-test, post-test) on balance test indices (SI, API, and MLI) and time on balance board. The results showed that both training groups improved their balance ability similarly (p<0.05) despite the different frequency of the balance training program. The authors proposed that balance training program can be applied in soccer players on a daily basis or at least 3 times per week, according to the demands of the training period