Latest research in football - week 44 - 2022

As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases. 


Following studies were retrieved for this week:

#1 Day type and start time may influence sleep in adolescent professional football players

Reference: Int J Sports Med. 2022 Nov 8. doi: 10.1055/a-1974-5441. Online ahead of print.

Authors: Luke Edinborough, Stewart Bruce-Low, Jessica Hill, Jonny Woodhouse, Mark Jarvis, Charles Pedlar

Summary: This study assessed if scheduling (start time and day type) and workload variables influenced sleep markers (activity monitor) in professional academy footballers (n=11; 17.3±0.7yrs) over a 10-week in-season period. Separate linear mixed regressions were used to describe the effect of start time on the previous nights sleep, and the effect of day type (matchday, matchday+1) and workload on subsequent sleep. Workload variables were modelled by day (day), 7-day (acute), and 28-day (chronic) periods. Sleep duration following matchday+1 (400mins; 95%CI:368-432) was significantly reduced compared to all other day types(p<0.001). Sleep onset time following matchday (00:35; CI:00:04-01:12) and wake time on matchday+1 (09:00; CI:08:37-09:23) were also significantly later compared to all other day types (p<0.001). Sleep duration (19.1mins; CI:9.4-28.79), wake time (18mins; CI:9.3-26.6), and time in bed (16.8mins; CI:2.0-31.5) were significantly increased per hour delay in start time. When no activity was scheduled sleep duration (37mins; CI:18.1-55.9), sleep onset (42.1mins; CI:28.8-56.2), and wake times (86mins; CI:72-100) were significantly extended, relative to a 09:00 start time. Day, acute, and chronic workloads were associated with sleep onset and wake times only. Scheduled start times were associated with changes in sleep duration, therefore, delaying start times may increase sleep in this population.



#2 Do sports-related concussions induce subsequent injuries in elite male football players?

Reference: Int J Sports Med. 2022 Nov 8. doi: 10.1055/a-1974-3965. Online ahead of print.

Authors: Florian Beaudouin, Tobias Tröß, Abed Hadji, Ida Bo Steendahl, Tim Meyer, Karen Aus der Fünten

Summary: To assess the players' risk of a subsequent injury after sustaining concussive injuries and their return-to-competition in German professional men's football. A prospective injury database in the 1st Bundesliga was created encompassing 7 seasons (2014/15-2020/21). Cox proportional hazard model analyzed whether a concussive injury increased the risk of a subsequent injury in the first year after the index injury. 6,651 injuries were reported (n=182 concussive injuries). The incidence rate was 0.15 (95% CI 0.13-0.17) per 1000 football hours. A concussive injury was associated with only a slightly numerical higher risk of 7% (HR=1.07, 95% CI 0.78-1.47) in the subsequent year after the injury compared to a randomly selected non-concussive injury, but the effect was not significant. The risk was higher after 6-12 months post-SRC reaching 70% (HR=1.70, 95% CI 1.15-2.52). For 0-3 months (HR=0.76, 95% CI 0.48-1.20) and 3-6 months (HR=0.97, 95% CI 0.62-1.50) the injury risk was lower. The present data do not confirm previously published investigations about an increased injury risk after SRC. Contrasting effects of lower hazard ratios were found early after SRC, followed by an increase after 6-12 months. Further research should look into compliance rates with regards to return-to-competition protocols.



#3 Prevalence of sport specialisation and association with injury history in youth football

Reference: Phys Ther Sport. 2022 Oct 29;58:160-166. doi: 10.1016/j.ptsp.2022.10.013. Online ahead of print.

Authors: Anja Zoellner, Chris Whatman, Kelly Sheerin, Paul Read

Summary: The aims of this study were to determine the prevalence of sport specialisation in youth football, and to investigate the associations of sport specialisation and volume of sport participation with injury history. New Zealand youth football teams were used for analysis. Therer were 414 youth football players aged 10-15 years. The level of specialisation, average weekly sport participation and free-play volume were recorded. 12-month injury history was captured and grouped by injury type. Associations between level of specialisation and demographic variables were analysed using chi square tests. Logistic regression was used to investigate associations between injury history, level of specialisation, and volume of participation. Participants were classified as high (43%), moderate (38%), or low (19%) specialised (n = 399 complete). High specialisation was more likely in boys, older participants, and those from large schools. Highly specialised participants were more likely to report a history of gradual onset injury than those who were low specialised (n = 340 with complete injury data). Odds of reporting a gradual onset injury also increased with greater weekly and annual sport participation volume. There is a high prevalence of sport specialisation in youth football, and it is associated with increased incidence of gradual onset injury.



#4 Selected Immunoendocrine Measures for Monitoring Responses to Training and Match Load in Professional Association Football: A Review of the Evidence

Reference: Int J Sports Physiol Perform. 2022 Nov 7;1-10. doi: 10.1123/ijspp.2022-0226. Online ahead of print.

Authors: Matthew Springham, Robert U Newton, Anthony J Strudwick, Mark Waldron

Summary: Biomarkers relating to player "stress balance," immunological (ie, immunoglobulin-A), and hormonal (ie, testosterone and cortisol [T:C]) status are now commonly used in football. This article is our critical review of the scientific literature relating to the response of these measures to player load and their relationships with player health. The commonly reported relationship between immunoglobulin-A and training or match load highlights its sensitivity to changes in psychophysiological stress and the increased risk of compromised mucosal immunity. This is supported by its close relationship with symptoms of upper respiratory tract infection and its association with perceived fatigue in football players. Testosterone and cortisol concentrations and the testosterone-cortisol ratio are sensitive to changes in player load, but the direction of their response is often inconsistent and is likely influenced by player training status and non-sport-related stressors. Some evidence indicates that sustained periods of high training volume can increase resting testosterone and that sustained periods of low and high training intensity can increase resting cortisol, compromising the testosterone-cortisol ratio. These findings are noteworthy, as recent findings indicate interrelationships between testosterone, cortisol, and testosterone:cortisol and perceived measures of fatigue, sleep quality, and muscle soreness in football players. Variability in individual responses suggests the need for a multivariate and individualized approach to player monitoring. Overall, we consider that there is sufficient evidence to support the use of salivary immunoglobulin-A, testosterone, cortisol, and testosterone:cortisol measures as part of a multivariate, individualized player monitoring system in professional football.



#5 Physical demands in Spanish male and female elite football referees during the competition: a prospective observational study

Reference: Sci Med Footb. 2022 Nov 7. doi: 10.1080/24733938.2022.2145015. Online ahead of print.

Authors: Maria Luisa Martin-Sanchez, José M Oliva-Lozano, Jorge Garcia-Unanue, Jose Luis Felipe, Víctor Moreno-Pérez, Leonor Gallardo, Javier Sánchez-Sánchez

Summary: The aim of this study was to analyze the physical demands of elite male and female field referees in match play and compare the physical demands between male and female football referees in the competition. Match data were collected from 36 elite football referees (19 males and 17 females) during a total of 409 football matches. Electronic performance and tracking systems based on global positioning systems (GPS) were used in this research. Male referees experienced significantly greater physical demands (p<0.05) in men league than female referees in women league for total distance, explosive distance, high-intensity breaking distance, total of sprints, sprinting distance, high-speed running distance, high-speed running actions, maximal speed, total of accelerations and decelerations, maximal acceleration and deceleration, acceleration/deceleration. Therefore, strength and conditioning coaches should consider these gender differences in match demands to maximize the fitness-fatigue response of the referees since this may lead to a better performance during the decision making process in the competition.



#6 Injury characteristics in Norwegian male professional football: A comparison between a regular season and a season in the pandemic

Reference: Front Sports Act Living. 2022 Oct 21;4:915581. doi: 10.3389/fspor.2022.915581. eCollection 2022.

Authors: Torstein Dalen-Lorentsen, Thor Einar Andersen, Christian Thorbjørnsen, Michael Brown, David Tovi, Anders Braastad, Tom Gerald Lindinger, Christian Williams, Eirik Moen, Benjamin Clarsen, John Bjørneboe

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Summary: The Coronavirus Disease-19 (COVID-19) pandemic forced the Norwegian male premier league football season to reschedule, reducing the fixture calendar substantially. Previous research has shown that a congested match schedule can affect injury rates in professional football. Therefore, we aimed to investigate whether the Norwegian premier league teams suffered more injuries in the more match congested 2020 season than in the regular 2019-season. We invited all teams having participated in both seasons to export their injury data. Only teams that used the same medical staff to register injuries in both seasons were included, and to maximize data comparability between seasons, we applied a time-loss injury definition only. Seven of 13 teams agreed to participate and exported their injury data. Both seasons had 30 game weeks, but the 2020 season was 57 days shorter than the 2019 season. The match injury incidence did not differ significantly [incidence rate ratio 0.76 (0.48-1.20; p = 0.24) in the 2020 season compared to the 2019 season. Furthermore, we found no differences in the number of injuries, days lost to injury, matches missed to injury, or injury severity. We could not detect any differences between the two seasons, suggesting the congested match calendar combined with the safety measures in the 2020 season can be a safe alternative in future seasons.



#7 Neuromuscular control of the lower extremities can be better enhanced by applying ankle taping and kinesiological taping rather than elastic bandaging: a randomized control study in amateur soccer players

Reference: J Phys Ther Sci. 2022 Nov;34(11):741-744. doi: 10.1589/jpts.34.741. Epub 2022 Nov 1.

Authors: Panagiotis Dendrinos, Athina Fassoi, Maria Tsekoura, Pavlos Angelopoulos, Konstantinos Mylonas, Dimitris Mandalidis, Georgios Krekoukias, Elias Tsepis, Konstantinos Fousekis

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Summary: This study evaluated the effects of ankle elastic bandaging, taping, and kinesiology taping on the neuromuscular control of the lower extremities before and after their application and after exercise in soccer athletes. Fifty-five amateur soccer players were randomly divided into four research sub-groups either receiving bandaging (n=15), taping (n=15), and kinesiology taping (n=15) on their ankle or serving as controls (n=10). The dynamic stability of the non-dominant limb was assessed through the star excursion balance test (SEBT) in three research conditions: a) before sports taping application, b) after the application, and c) after a 15 min laboratory simulation of soccer activities. Taping and kinesiology taping improved the dynamic stabilization of the lower limb more statistically significantly than bandaging. The addition of exercise significantly improved the SEBT results in the taping and kinesiology taping more than the bandaging and control groups. Exercise activates the proprioceptive mechanisms of the lower limb and improves its neuromuscular control. This functional improvement of the lower limb appears to be enhanced after ankle taping and kinesiology taping compared with elastic bandaging and controls.



#8 An Unusual Case of Arm Pain in a Young Soccer Player: Herpes Zoster in the Pediatric Athlete

Reference: Curr Sports Med Rep. 2022 Nov 1;21(11):386-390. doi: 10.1249/JSR.0000000000001005.

Authors: James MacDonald, Joy Mosser-Goldfarb, Cristina Tomatis Souverbielle, Steven Cuff

Summary: Herpes zoster (HZ), shingles, is caused by the varicella-zoster virus (VZV). HZ develops as a reactivation of latent VZV and is characterized by a painful, vesicular rash typically manifesting in a dermatomal distribution on the arms, trunk or face. HZ occurs in individuals who had primary VZV disease (chickenpox) as a child or in those who have received live, attenuated VZV vaccine. HZ is common in the elderly and the immunocompromised, with age being the single greatest risk factor. The incidence of HZ in children is 74/100,000 person years for the unvaccinated and 38/100,000 person years for the vaccinated. We discuss the case of a 12-year-old soccer player with HZ who presented with right arm pain after a putative traumatic event. Diagnosis was made after two emergency department visits where the condition was not identified. HZ should be considered in the clinician's differential even in immunocompetent, vaccinated children.



#9 Intensity demands and peak performance of elite soccer referees during match play

Reference: J Sci Med Sport. 2022 Oct 14;S1440-2440(22)00440-6.  doi: 10.1016/j.jsams.2022.10.006. 

Authors: Farzad Yousefian, Abdullah Zafar, Pedro Peres, João Brito, Bruno Travassos, Pedro Figueiredo

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Summary: This study examined the peak physical and physiological (heart rate) performance intensities andassociated decrements in elite soccer referees during match play. Physical performancevariables and heart rate were analyzed during 457 matches across two seasons. Differences between halves, and the rate ofdecline in peak performance intensities across moving average durations of 1-10 minutes were assessed using linear mixed models and power-law analysis, respectively. Large significant differences were observed between halves for mean total distance, mean velocity, mean heart rate, and percentage of maximal heart rate (p ≤ 0.05; r = 0.51-0.64). Peak intensities (p ≤ 0.05; r = 0.15-0.17) and the rate of decline (p < 0.001; r = 0.17-0.37) were significantly higher in the 2nd half compared to the 1st half, for relative total distance, relative high-intensity running and mean velocity. The rate of decline was significantly greater in the 2nd half than the 1st half for relative distance covered by high-intensity acceleration (>2 m/s-2/min), deceleration (<-2 m/s-2/min), and relative mean heart rate (p < 0.001; r = 0.28-0.61). Elite soccer referees might have experienced transient fatigue during match play, as relative high-intensity running immediately following the most intense 5-minute period significantly declined by 61.2% ( p< 0.001; r = 0.94), and was 16.2% lower than the mean 5-minute period (p < 0.001; r = 0.34). Increased physical and physiological demands during match play, with associated declines in the second half and transient signs of fatigue throughout the match, supports the inclusion of high-intensity interval and endurance training programs to prepare soccer referees for the intensity demands and peak performance outcomes of match play.



#10 Normalising the conversation: A qualitative analysis of player and stakeholder perceptions of menstrual health support within elite female soccer

Reference: Sci Med Footb. 2022 Nov 7. doi: 10.1080/24733938.2022.2145349. Online ahead of print.

Authors: Samuel J McHaffie, Carl Langan-Evans, James C Morehen, Juliette A Strauss, José L Areta, Christopher Rosimus, Martin Evans, Kirsty J Elliott-Sale, Colum J Cronin, James P Morton

Summary: This qualitative study explores player and stakeholder perceptions of menstrual health support in elite female soccer. Semi-structured interviews were conducted with 47 participants including players (n = 12), parents (n = 9), coaches (n = 9), sport scientists (n = 7), nutritionists (n = 5) and medical staff (n = 5). Via thematic analysis, data demonstrate that elite female soccer players experience a range of physical and psychological symptoms primarily at the onset of and during menses (as also perceived by stakeholders), with most participants perceiving these symptoms to impact performance. Nonetheless, menstrual health support is perceived as minimal and although players have their menstrual status tracked, they report little understanding as to why or how this information is used. This confusion was also present among stakeholders, often as a result of uncertainty about the evidence supporting the need for menstrual health support. The perceived lack of support may also be reflective of a culture where conversations about the menstrual cycle are not normalised. Overall, this may result in failure to identify and treat menstrual irregularities despite non-coaching staff members perceiving them to be common amongst players. These data support the need for individualised support based on the lived experiences of individual players and support staff. Furthermore, our research identifies the need for organisational, stakeholder, and player centred education programmes (led by experts in female athlete health) that create an environment where players receive personalised menstrual health support.



#11 Cerebral and cognitive modifications in retired professional soccer players: TC-FOOT protocol, a transverse analytical study

Reference: BMJ Open. 2022 Nov 9;12(11):e060459. doi: 10.1136/bmjopen-2021-060459.

Authors: Sabrina Kepka, François Lersy, Julien Godet, Frederic Blanc, Mathias Bilger, Anne Botzung, Catherine Kleitz, Jeanne Merignac, Emmanuel Ohrant, Franck Garnier, François Pietra, Vincent Noblet, Caroline Deck, Remy Willinger, Stéphane Kremer

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Summary: Soccer is the most popular sport in the world. This contact sport carries the risk of exposure to repeated head impacts in the form of subconcussions, defined as minimal brain injuries following head impact, with no symptom of concussion. While it has been suggested that exposure to repetitive subconcussive events can result in long-term neurophysiological modifications, and the later development of chronic traumatic encephalopathy, the consequences of these repeated impacts remain controversial and largely unexplored in the context of soccer players. This is a prospective, single-centre, exposure/non-exposure, transverse study assessing the MRI and neuropsychological abnormalities in professional retired soccer players exposed to subconcussive impacts, compared with high-level athletes not exposed to head impacts. The primary outcome corresponds to the results of MRI by advanced MRI techniques (diffusion tensor, cerebral perfusion, functional MRI, cerebral volumetry and cortical thickness, spectroscopy, susceptibility imaging). Secondary outcomes are the results of the neuropsychological tests: number of errors and time to complete tests. We hypothesise that repeated subconcussive impacts could lead to morphological lesions and impact on soccer players' cognitive skills in the long term. Ethics approval has been obtained and the study was approved by the Comité de Protection des Personnes (CPP) No 2021-A01169-32. Study findings will be disseminated by publication in a high-impact international journal. Results will be presented at national and international imaging meetings.



#12 Negative Impact of the UEFA European Soccer Championship on Central Hemodynamics and Arterial Stiffness: A Multicenter Study

Reference: Life (Basel). 2022 Oct 25;12(11):1696. doi: 10.3390/life12111696.

Authors: Klaas F Franzen, Kai Mortensen, Christian Ott, Katrin Herber, Marlene Busse, Charlotte Söling, Daniel Schneppe, Saskia Lässig, Marcus Dörr, Roland Tilz, Daniel Drömann, Heribert Schunkert, Michael Reppel

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Summary: Watching sporting events may trigger cardiovascular events by elevating emotional stress levels. The underlying reasons and specific populations at risk are not well defined.  We conducted a multicenter prospective trial at three German sites during the UEFA Soccer EC 2012 and 2021 comprising 52 healthy participants (noCVD) and 18 patients hospitalized with cardiovascular disease (CVD). Subjects were studied during matches of the German national team (GP) as well as corresponding matches without German participation (noGP). Peripheral and central blood pressure (BP) and parameters of arterial stiffness were measured (Mobil-O-Graph™, I.E.M., Stolberg, Germany) before, during, and after the matches. In terms of CVD, peripheral as well as central BP and heart rate increased significantly during GP as well as noGP matches and remained elevated beyond the end of the matches. Likewise, arterial stiffness parameters and vascular resistance were higher during the matches and remained elevated after the matches. No consistent significant differences were found between GP and noGP matches. This is the first study on real-life changes in hemodynamics during sport-associated emotional stress, with comparison between noCVD and CVD. We found that alterations were profound in CVD and remained elevated even after the matches.



#13 Plantar Fasciitis in Soccer Players-A Systemic Review

Reference: Int J Environ Res Public Health. 2022 Nov 3;19(21):14426. doi: 10.3390/ijerph192114426.

Authors: David C Noriega, Ángel Cristo, Alejandro León, Belén García-Medrano, Alberto Caballero-García, Alfredo Córdova-Martinez

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Summary: Soccer is one of the most popular sports in the world. Players often suffer a variety of injuries, the most common being injuries to muscles and tendons. It is striking that with soccer, being the most practiced sport, and considering that most injuries occur in the lower extremities, plantar fasciitis (PF) is not one of the most frequent injuries (at least in terms of clinical data collected). The purpose of this review was to provide a comprehensive update of the topic "plantar fasciitis" focusing on soccer players. The review was conducted in accordance with the PRISMA (Preferred Reportiog ltems for Systmiatic reviews and Meta-Analyses) statement. PubMed, Cochrane Library and Scopus were researched. PICO (Patient, Population or Problem; Intervention; Comparison; and Outcome) components were identified. The keywords used were "plantar fasciitis", "plantar fasciitis and sport", "plantar fasciitis risk factors", "plantar fasciitis soccer" and "plantar fasciitis football players". With respect to the objective proposed for the research, we found eight specific articles focused on soccer. Of these, five were general reviews discussing the different methods of treatment of this pathology, and we have only found three studies that focused on PF in soccer, with two of them referring to a clinical case whereby the report and discussion only dealt with the specific treatment followed by the soccer player. After reviewing the manuscripts included in this work, we were surprised that there is no data in which the Silfverskiöld test was performed, as this test explores the passive mobility of the ankle and the degree of dorsiflexion in the supine position. We concluded that soccer players suffer pain in the sole of the foot compatible with plantar fasciitis; however, as indicated by Suzue et al., it is often not diagnosed because the athlete does not consider performing the clinical examinations necessary for its diagnosis. The shortage of reported publications in soccer may mask other PF-associated injuries.



#14 Effects of a 9-weeks arch support intervention on foot morphology in young soccer players: a crossover study

Reference: BMC Sports Sci Med Rehabil. 2022 Nov 14;14(1):193. doi: 10.1186/s13102-022-00590-3.

Authors: Kohei Hikawa, Toshiharu Tsutsui, Takehiro Ueyama, Jin Yang, Yukina Hara, Suguru Torii

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Summary: A flat foot is a common cause of chronic sports injuries and therefore many opportunities for arch support interventions exist. However, young athletes change their foot morphology due to developmental influences even without intervention. Therefore, developmental influences need to be considered when examining the effects of arch support, but there have not been sufficient longitudinal studies to date. This study aimed to determine the effect of the arch support intervention by performing a 9-weeks arch support intervention on the foot morphology and cross-sectional area of the foot muscles in flat-footed young athletes. Thirty-one elementary school boys (Age 11.4 ± 0.5 years, Height 145.2 ± 7.4 cm, Weight 38.8 ± 8.3 kg, BMI 18.2 ± 2.2 kg/m2) with a decreased medial longitudinal arch in the foot posture index were selected as participants from a local soccer club and randomly divided into two groups. In one group, in the intervention period, an existing arch supporter was used to provide arch support, while in the other group, no special intervention was provided in the observation period. To account for developmental effects, the intervention study was conducted as an 18-weeks crossover study in which the intervention and observational phases were switched at 9 weeks after the intervention. Foot morphology was assessed using a three-dimensional foot measuring machine, and the cross-sectional area (CSA) of the internal and external muscles of the foot was assessed using an ultrasound imaging device. We examined the effect of the intervention by comparing the amount of change in the measurement results between the intervention and observation periods using corresponding t-tests and Wilcoxon signed-rank sum test, analysis of covariance methods. After adapting the exclusion criteria, 14 patients (28 feet) were included in the final analysis. The CSA of the abductor hallucis muscle (ABH) increased 9.7% during the intervention period and 3.0% during the observation period (p = 0.01). The CSA of the flexor digitorum longus muscle (FDL) increased 7.7% during the intervention period and 4.2% during the observation period (p = 0.02). A 9-weeks arch supporter intervention may promote the development of the ABH and FDL CSA in young flat-footed soccer players.



#15 Utilizing Soccer for Delivery of HIV and Substance Use Prevention for Young South African Men: 6-Month Outcomes of a Cluster Randomized Controlled Trial

Reference: AIDS Behav. 2022 Nov 15. doi: 10.1007/s10461-022-03819-x. Online ahead of print.

Authors: Stephan Rabie, Mark Tomlinson, Ellen Almirol, Jackie Stewart, Zwelibanzi Skiti, Robert E Weiss, Lodewyk Vogel, Mary Jane Rotheram-Borus

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Summary: Young men in South Africa face the intersecting epidemics of HIV, substance use and endemic poverty. We tested the effectiveness of a behavioral intervention using soccer training to reduce the cluster of risks associated with HIV and substance use. This cluster randomized controlled trial was conducted with men aged 18-29 years old in 27 neighborhoods in the townships of Cape Town, South Africa. Neighborhoods were randomized to receive for 6 months either: (1) Soccer League (SL; n = 18 neighborhoods, n = 778 men) who attended soccer three times weekly (72 sessions; 94% uptake, 45.5% weekly attendance rate), combined with an HIV/substance use, cognitive-behavioral intervention; or (2) a Control Condition (CC; n = 9; 415 men) who received educational materials and referrals at 3 month intervals. The primary outcome was the number of significant changes in a cluster of outcomes including HIV-related risks, substance abuse, employment/income, mental health, violence, and community engagement. There was only one significant difference on the rapid diagnostic tests for mandrax at 6 months, an insufficient number of changes to indicate a successful intervention. A group-based behavioral intervention was ineffective in addressing multiple risk behaviors among at-risk young men, similar to the findings of several recent soccer-related interventions. Early adulthood may be too late to alter well-established patterns of risk behaviors.Clinical Trial Registration This trial was prospectively registered on 24 November 2014 with NCT02358226.



#16 A randomised controlled trial of 1- versus 2-day per week formats of Nordic hamstring training on explosive athletic tasks in prepubertal soccer players

Reference: J Sports Sci. 2022 Nov 16;1-9. doi: 10.1080/02640414.2022.2145737. Online ahead of print.

Authors: Mahmoudi Abdelkader, Raouf Hammami, Ben Drury, Nicholas Clark, Gavin Sandercock, Ina Shaw, Brandon S Shaw, Sabri Gaied Chortane, Jason Moran

Summary: This randomised controlled trial examined the effect of volume-equated programmes of Nordic hamstring exercise (NHE) training, executed at frequencies of 1- or 2-days per week, on explosive athletic tasks (30 m sprint, 15 m manoeuvrability and standing long jump [SLJ]) in male youth soccer players (mean age: 10.3 ± 0.5 years). Players were divided into an experimental group (n = 31) which was further subdivided into 1-day (n = 16) and 2-days (n = 15) per week training conditions, and a control group (n = 14). There were significant group-by-time interactions for 30-m sprint (p < 0.001, d = 0.6), SLJ (p = 0.001, d = 1.27) and 15 m manoeuvrability (p < 0.001, d = 0.61). The experimental group demonstrated small to moderate effect sizes in 30-m sprint (d = 0.42, p = 0.077), SLJ (d = 0.97, p < 0.001) and 15 m manoeuvrability (d = 0.61, p < 0.001). The control group showed small significant performance decrements or no change in these variables. There were no significant differences between the 1-day and 2-day training groups. In two of the three tests (30 m sprint, SLJ) the 2-day group demonstrated larger effect sizes. The NHE enhances explosive athletic task performance in prepubertal youth soccer players and there may be only small advantages to spreading training over two days instead of one.



#17 Growth, maturation and injuries in high-level youth football (soccer): A mini review

Reference: Front Sports Act Living . 2022 Nov 1;4:975900. doi: 10.3389/fspor.2022.975900. eCollection 2022.

Author: Eirik Halvorsen Wik

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Summary: Understanding the challenges football (soccer) players face during adolescence is fundamental to avoid disruptions in their development due to injury. This mini review will describe basic concepts of somatic growth and biological maturity, examine data from 53 prospective epidemiological studies on high-level youth football players and discuss how age, growth and maturity may affect the injury patterns observed. Based on the existing evidence, at least every third player sustains an injury during a football season. The thigh (median for studies of boys: 25%, median for girls: 21%), ankle (b: 18%, g: 30%), knee (b: 17%, g: 18%) and hip/groin (b: 14%, g: 10%) are the body parts injured most often, while muscle strains (b: 31%, g: 25%), sprains (b: 20%, g: 27%) and contusions (b: 17%, g: 16%) are the most common injury types. Injury trends are, however, not consistent throughout adolescence, and players' age, maturity status and position relative to peak height velocity (PHV) have shown to influence the number, type and location of injuries sustained. Despite a high volume of observational injury studies published on high-level youth players, girls (7 studies) and settings outside of Europe (included in 23% of studies) are underrepresented and should receive extra attention in the future. Based on the available epidemiological data, tailored injury reduction programmes can be considered in youth football, alongside application of general training principles such as progression, variation and individualization which may be especially important during vulnerable phases such as the adolescent growth spurt.


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