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Objectives: To investigate if the 11+ injury prevention programme decreases the risk of hamstring injury and improves recovery time and determine whether compliance with the 11+ affects hamstring injury risk., Methods: This study is a secondary analysis from a prospective cluster randomised controlled trial that included 65 National Collegiate Athletic Association (NCAA) division I and II men's soccer teams over the fall 2012 season. Thirty-one teams were randomised to the intervention group that were using the 11+ as their warm-up and 35 teams to the control group that continued to use their traditional warm-up. Each certified athletic trainer (ATC) collected data on demographics, hamstring injury (HSI), mechanism of injury, position, playing surface, time lost due to injury and compliance to the 11+ programme., Results: The 11+ decreased the risk of HSI by 63% compared with the control group (RR=0.37, 95% CI 0.21 to 0.63). Difference in return to play after HSI between the control (9.4±11.2 days) and intervention groups (10.2±11.3 days) was not significant (p=0.8). High compliance (>2 or more doses on average per week) reduced the risk of HSI by 78% (RR=0.22, 95% CI 0.06 to 0.87) compared with low compliance (<1 dose on average per week), and moderate compliance (1 to <2 doses on average per week) decreased the risk of HSI by 67% (RR=0.33, 95% CI 0.11 to 0.97) compared with low compliance. There was no significant difference between high and moderate compliance., Conclusion: The 11+ decreased the risk of HSI by 63% but did not improve recovery time. High to moderate compliance is essential and makes the programme more effective at reducing HSI., Competing Interests: Competing interests: The authors have not indicated any direct competing interests in conjunction with this manuscript. HS-G is a research consultant for Major League Soccer (MLS), National Football League (NFL) and the Aspetar Scientific Board. KT and MB both have editorial board positions with the British Journal of Sports Medicine., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The Fédération Internationale de Football Association (FIFA) 11+ Kids is an exercise-based injury prevention program developed by an international group of experts to prevent injuries among child soccer players., Hypothesis: It was hypothesized that the FIFA 11+ Kids program would be more effective than performing a typical warm-up regimen in reducing overall injuries among soccer players aged 7 to 13 years., Study Design: A clustered randomized controlled trial., Level of Evidence: Level 1., Methods: A total of 94 boys' soccer teams, including 780 players, were randomly allocated into an experimental or control group. Complete datasets were collected from 45 teams (377 players) and 43 teams (363 players) in the experimental and control groups, respectively. The experimental group underwent the FIFA 11+ Kids program as a warm-up during training sessions and matches at least twice a week, and the control group continued performing their usual warm-ups. Participants were prospectively followed during 1 season (6 months). The primary outcomes included the incidence of overall and recurrent injuries and their mechanism and severity. The secondary outcome was the rate of compliance with the intervention program., Results: A total of 43 injuries were reported in the experimental group in 50,120 hours of exposure (0.85 injuries/1000 exposure hours). A total of 86 injuries were reported in the control group in 42,616 hours of exposure (2.01 injuries/1000 exposure hours). The injury risk ratio was 0.43 (0.29-0.61), suggesting that the experimental group experienced 57% fewer injuries than those in the control group., Conclusion: The FIFA 11+ Kids program reduced overall injury rates in children playing soccer more than the usual warm-ups., Clinical Relevance: The results of this study provide evidence for children's coaches to consider including the FIFA 11+ Kids program in their warm-up regimen. Such a program may prevent injury risk and decrease absenteeism and injury-related financial burdens.

Background: The side effects of the FIFA 11+ program on performance have not been generally reviewed. The objective of this study was to synthesize the literature on the effects of the 11+ on players' performance., Methods: Five online databases (PubMed, Scopus, ScienceDirect, Springer, and Google Scholar) were searched (from April 2006 to March 2022) using predefined keywords and sub-keywords. The potential references were primarily recorded through Endnote and imported to Covidence. Out of the 123 references screened by 2 blinded researchers through the software, 59 full texts were assessed for eligibility, 33 of which were ultimately included. The quality of the studies and the risk of bias were then assessed. Study ID, title, place, aim, design, start/end dates, population description, study criteria, statistical analysis, and outcomes were extracted., Results: Studies were conducted on male and female players aged 10-32 years old. The quality of the studies was moderate to high, and except for unclear bias for blinding outcome assessment, the risk of bias for all domains was low. Long-term application of the 11+ improved most biomechanical measures and physiological responses except for lower extremity stability, ankle evertors time latency, ankle dorsiflexion, and proprioception. Conversely, the 11+ showed acute negative effects on physical performance compared to dynamic warm-ups and non-significant effects on technical abilities., Conclusion: Mid-to-long-term implementation of the 11+ improved the majority of biomechanical and a couple of physical measures but showed no effects on technical skills. Precaution must be observed for using the 11+ before competitions, as it could acutely decrease physical/technical performance. Given the contradictory nature of the literature, further studies should evaluate the short-to-mid-term effects of the 11+. Further studies are required to address ankle responses to the 11+ intervention., Competing Interests: Competing interests The authors declare that they have no competing interests., (Copyright © 2022. Production and hosting by Elsevier B.V.)

Objective: The Fédération International de Football Association (FIFA) 11+ Referees Injury Prevention Program (FIFA 11+ Referees Program) is a structured warm-up program specially designed to prevent injuries in soccer referees. However, its effectiveness has yet to be fully documented in the literature. Therefore, the purpose of this study was to investigate the effectiveness of the FIFA 11+ Referees Program in reducing injury rates among soccer referees., Methods: A randomized controlled trial was conducted. Two hundred male amateur soccer referees (mean ± SD age, 31.6 ± 4.1 years) participated in this study. Participants were randomly allocated to the experimental and control groups. The experimental group performed the FIFA 11+ Referees Program as a warm-up during training sessions at least twice a week, and the control group performed their usual warm-ups. The participants were followed up for one season. The outcome measures were the incidence of overall injury, initial injury, recurrent injury, injury mechanism, and injury severity (primary), and the rate of adherence to the intervention program (secondary)., Results: A total of 24 injuries were reported among 100 referees in the control group in 16 606 h of exposure (1.45 injuries/1000 exposure h), and a total of nine injuries were reported across 100 referees within the experimental group in 17 834 exposure h (0.50 injuries/1000 exposure h). The Injury Risk Ratio (IRR) was 0.35 (95% CI 0.26-0.45)., Conclusion: The results indicated that the FIFA 11+ Referees Program effectively reduced injuries in the experimental group by 65% compared to the control group., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Soccer is one of the most popular sports worldwide. Goalkeepers are more likely to injure their upper limbs, particularly their shoulders, than outfield players. To reduce upper extremity injuries, the FIFA 11+ Shoulder Injury Prevention Program (FIFA 11+S) was developed., Purpose: The purpose of this study was to assess the effectiveness of the FIFA 11+S program in reducing the incidence of upper extremity injuries among amateur soccer goalkeepers., Study Design: Randomized controlled trial; Level of evidence, 1., Methods: A total of 726 goalkeepers, who were blinded to study intent, were randomly assigned to the experimental group (n = 360) or control group (n = 366). The experimental group was instructed to perform the FIFA 11+S program before all training sessions for 1 season (6 months). The control group was instructed to continue performing their usual routine warm-up program before training sessions for 1 season. Primary outcomes included the incidence of upper extremity injury and incidence of mechanism, type, and severity of injury measured using injury risk ratios (IRR); compliance with the experimental and control interventions was also recorded., Results: A total of 50 injuries (0.62 injuries per 1000 exposure-hours) were reported in the experimental group, and 122 injuries (1.94 injuries/1000 hours) were reported in the control group. The FIFA 11+S program reduced the total number of upper extremity injuries by 68% (IRR = 0.32 [95% CI, 0.27-0.34]) compared with the usual warm-up. The FIFA 11+S program reduced the incidence of contact injury (IRR = 0.30 [95% CI, 0.25-0.31]), noncontact injury (IRR = 0.40 [95% CI, 0.35-0.43]), initial injury (IRR = 0.34 [95% CI, 0.29-0.36]), recurrent injury (IRR = 0.20 [95% CI, 0.17-0.21]), and overuse injury (IRR = 0.40 [95% CI, 0.35-0.43]). Participants in the experimental group demonstrated a significant decrease in injuries of minor (IRR = 0.32 [95% CI, 0.27-0.34]) and moderate severity (IRR = 0.33 [95% CI, 0.29-0.35]) compared with the control group. We noted no difference in compliance between the experimental and control groups (80% vs 73%, respectively; P = .92)., Conclusion: The FIFA 11+S program resulted in 50% fewer upper extremity injuries among soccer goalkeepers, compared with a regular warm-up., Registration: ACTRN12618001080213 (Australian New Zealand Clinical Trials Registry).

Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising, a 'food first' philosophy (ie, food over supplements), is fundamental to ensure effective player support. This requires relevant scientific evidence to be applied according to the constraints of what is practical and feasible in the football setting. The science underpinning sports nutrition is evolving fast, and practitioners must be alert to new developments. In response to these developments, the Union of European Football Associations (UEFA) has gathered experts in applied sports nutrition research as well as practitioners working with elite football clubs and national associations/federations to issue an expert statement on a range of topics relevant to elite football nutrition: (1) match day nutrition, (2) training day nutrition, (3) body composition, (4) stressful environments and travel, (5) cultural diversity and dietary considerations, (6) dietary supplements, (7) rehabilitation, (8) referees and (9) junior high-level players. The expert group provide a narrative synthesis of the scientific background relating to these topics based on their knowledge and experience of the scientific research literature, as well as practical experience of applying knowledge within an elite sports setting. Our intention is to provide readers with content to help drive their own practical recommendations. In addition, to provide guidance to applied researchers where to focus future efforts., Competing Interests: Competing interests: JC has received payment for sports nutrition consultancy work with Arsenal Football Club, England Football Association and France Football Federation. Through his consultancy he also receives payment for nutrition services with individuals and corporate organisations. He is author of a book (The Energy Plan) for which he receives payment from Penguin Random House. He has written articles for BBC Good Food for which he has received payment. He co-authored an article in 2014 and presented at European College of Sports Sciences in 2019 for The Gatorade Sports Science Institute, for which he received honoraria. He has received travel and accommodation expenses to speak at conferences over the past 5 years including; UEFA Medical Symposium, Isokinetic Football Medicine Strategies, Swedish Sports Medicine Congress and International Sport & Exercise Nutrition Conference. He is a council member and past president of The Royal Society of Medicine’s Food & Health Forum. He received from UEFA the cost of flight and accommodation to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript.” He did not receive any other form of financial support directly related to this manuscript. RM holds an honorary (unpaid) professorship at the School of Medicine, St Andrews University, Scotland. He holds visiting (unpaid) professorships at Stirling University and at the Chinese University of Hong Kong. He is co-author of two books published by Oxford University Press (Biochemistry of Exercise and Training; The Biochemical Basis of Sports Performance) for which he receives royalties. He is Program Director on the IOC Diploma programs in Sports Medicine, Sports Nutrition and Sports Physical Therapies, for which he receives honoraria and additionally contributes lectures to those programs, for which he has received honoraria. He was a member of the Expert Scientific Committee of the IOC Medical and Scientific Commission. This position was unpaid, but travel to meetings and accommodation were provided. He contributed a scientific review to a meeting of the Gatorade Sports Science Institute in Texas in March 2019: travel and accommodation were paid and an honorarium was received for participation in the meeting and for preparation of a summary paper for publication in the SSI Sports Science Exchange. He participated in an ACSM online podcast in 2019 for which an honorarium was received. He participated in a sports medicine education meeting organised by the Medical Committee of the German Football Federation in Frankfurt in January 2020: travel expenses and an honorarium were paid. He has participated in numerous other international sports nutrition symposia between 2015 and the present for which travel and accommodation were provided. He received from UEFA the cost of flight and accommodation to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript.” He did not receive any other form of financial support directly related to this manuscript. MG is co-author of two books published by Oxford University Press (Biochemistry of Exercise and Training; The Biochemical Basis of Sports Performance) for which he receives royalties. He is also co-author of 3 other books; one published by Human Kinetics (Sport Nutrition), one published by Routledge (Exercise Immunology) and the other by Meyer & Meyer Sport (Eat, Move, Sleep, Repeat; Beating Type 2 Diabetes) all of which he receives royalties for. He has contributed to several recorded lectures for which he received honoraniums for; 2020 to the IOC Diploma program Sports Nutrition, 2020 to the Nutrition Society Training Academy, 2020 to the My Sport Science Academy. He was a member of the IOC Expert Scientific Group on training load and illness/injury in 2015. This position was unpaid, but travel to a meeting and accommodation were provided. Other international symposia were attended as speaker where honorarium was paid plus travel and accommodation; Japan, 2016, London 2015, Barcelona 2015, Vienna, 2015. Mike also contributed a scientific review on nutrition, exercise and immune function for a sport nutrition company, NutritionX, in 2020 for which an honorarium was received. He has received complimentary tickets for Leicester City FC football matches for occasional nutrition consultancy advice but no honoraria were received. He has spoken at a number of other conferences, symposia and other events within the last five years: travel and accommodation were provided for most of these, but no record has been kept. He did not receive any form of financial support directly related to this manuscript. JB has presented at the Arsenal Sports & Exercise Medicine conference in London, UK, where travel and accommodation were paid by Arsenal FC. He has co-authored two chapters in the book, ‘The Science and Application of High-intensity interval training (HIIT) with no honorarium nor any royalties received. He did not receive any form of financial support directly related to this manuscript. AJ holds a visiting professorship at the Loughborough University, UK and is director of mysportscience. He is also co-founder and CEO of CORE Nutrition planning. He is author of a book sport nutrition by Human Kinetics for which he receives royalties. He is board member of the IOC Diploma programs in Sports Medicine. Asker worked as a consultant for the Dutch Olympic Committee NOC*NSF, Red Bull Leipzig, FC Barcelona, PSV Eindhoven, Athletic Club de Bilbao, US Soccer, Red Bull Athlete Performance Center, Jumbo Visma Pro cycling, Universidad d’Europea de Madrid, University of Barcelona, CAR, VIC University, Hiddit, SinSeb, Enervit, Volanthen, Friesland Campina, Nutrition Society, Clif, Snelle Jelle, Jumbo Supermarkten, PepsiCo, Unit Nutrition, BF Eventos, Mexican sports nutrition federation and the Turkish sports nutrition federation. Travel expenses and an honorarium were paid. He has participated in numerous other international sports nutrition symposia between 2015 and the present for which travel and accommodation were provided. He did not receive any form of financial support directly related to this manuscript. JM has received research grants from UEFA, Science in Sport, Lucozade Ribena Suntory, GlaxoSmithKline, Liverpool Football Club, Everton Football Club, British Horseracing Authority, Racing Welfare Foundation, Port Adelaide FC, English Institute of Sport and MuscleSound. He has received paid consultancy for Liverpool Football Club, Team Sky, Healthspan Elite, FA Premier League, Irish Football Association, The Football Association, Rangers FC and Science in Sport. He is the current Director of Performance Solutions for Science in Sport. He is the co-author of the textbook Biochemistry for Sport and Exercise Metabolism and receives annula royalties form Wiley. He has received travel and accommodation costs to speak at over 50 conferences in the last 5 years. He did not receive any form of financial support directly related to this manuscript. SP reports personal fees from Enhanced Recovery (donated to charity), equity from Exerkine (donated to charity), grants from Canadian Institutes of Health Research, grants from National Science and Engineering Council, personal fees (Travel and Honorarium, 2018) from US National Dairy Council, personal fees from US Dairy Export Council (Traval and Honorarium, 2019), personal fees from Leprino Foods (2017), personal fees from Agropur (2018), grants from Alliance for Potato Research and Education, grants from US National Dairy Council, outside the submitted work; In addition, Dr. Phillips has a patent 3052324 (Canadian) issued to Exerkine, a patent 16/182891 (US) pending to Exerkine, and a patent 2018157258 (Worldwide) pending to Exerkine. He did not receive any form of financial support directly related to this manuscript. LA received honoraria as an occasional consultant and reimbursement for travel expenses from the Drinking Water Research Foundation, Alexandria, VA, USA and from Danone Nutricia Research, France. He previously received research grant funding from both organizations. He formerly served as the elected President of the American College of Sports Medicine (unpaid), 2015-2016. He received honoraria and reimbursement of travel expenses from five universities and the Texas Regional Chapter of the American College of Sports Medicine during a speaking tour in 2018. He presently serves as a member of the Medical & Science Advisory Board, Korey Stringer Institute, University of Connecticut, USA (unpaid). Professor Armstrong received no financial support for participating in this manuscript. LB is an author or editor of textbooks on sports nutrition for which she receives royalties. She is a Program Director and contributor to the IOC Diploma programs in Sports Nutrition for which she receives honoraria. Prior to June 2020 she was Head of Sports Nutrition and Chief of Nutrition Strategy at the Australian Institute of Sport, where her representation at numerous international sports nutrition symposia and workshops was generally undertaken within her job description and any travel reimbursements and honoria were provided to the AIS. Presentations during the period of 2015-2020 in which the activity and its support were undertaken as private consultancy include: 2015 Berlin Marathon powerbar conference; 2019 ACSM meeting and pre-conference GSSI workshop (supported by the International Association of Athletics Federation and Gatorade); 2019 Northern Ireland Workshop on Sports Nutrition (supported by Dairy Council Northern Ireland) and the 2016 SCAN conference and 2019 FNCE conference (supported by the Academy of Nutrition and Dietetics). She has received a research grant from the Alliance of Potato Research and Education. She did not receive any form of financial support directly related to this manuscript. GC has previously received payment for nutrition consultancy at Everton, Nottingham Forest and West Bromwich Albion and Aston Villa Football clubs, Munster Rugby, England Rugby The Lawn Tennis Association The Football Association, The English Institute of Sport and The Saudi Arabian Olympic Association and The European Tour Golf. He currently advises HealthSpan Elite and NutritionX for which he receives an honorarium and in the past has advised GetBuzzing bars. GC has spoken on several occasions for GSSI and produced articles for their exchange series for which he received an honorarium. He has spoken at a number of other conferences, symposia and other events within the last five years: travel and accommodation were provided for most of these, but no record has been kept. GC currently or has previous received research grants from the MRC, BSSRC, GSK, Sirtris, Research into Ageing, Aliment Nutrition, Naturecan, HH Sheikh Mansour Bin Zayad Al Nahyan Global Arabian Horse Flat Racing Festival, The Racing Foundation, The British Horse Racing Association, The Rugby Football Union, The Lawn Tennis Association, Newport Gwent Dragons, Gloucester Rugby, Everton FC, Aston Villa FC. GC has delivered guest lectures for the IOC diploma in Sport Nutrition and The Football Science Institute for which he received an honorarium. GC has previously performed consultancy work for Callaway Golf and Quooker Taps. He did not receive any form of financial support directly related to this manuscript. RD receives is Joint Head of Research & Development at Football Federation Australia and is paid for this role. He has received travel and accommodation funding to speak / present at several international congress, including; the Football Science Institute, Football Federation Australia, Tennis Australia, Brazil National Football Federation, UFSC Brazil, Canadian Institute of Sport, Bristol City FC and UdS Germany. He is not affiliated or received any travel, accommodation, funding from any nutrition company in the last 10 years. He did not receive any form of financial support directly related to this manuscript. EL-M is author of a book published by Human Kinetics (Plant-Based Sports Nutrition: Expert Fueling Strategies for Training, Recovery, and Performance) for which she receives royalties. She was a member of the Dietary Supplements and the High-Performance Athlete Expert Scientific Committee of the IOC Medical and Scientific Commission in 2017; this committee assignment was unpaid, but travel to the group meeting and accommodation were provided. She contributed scientific presentations to a meeting of the Gatorade Sports Science Institute in Florida in Oct 2017 and Gatorade at NFL Combine in Feb 2020: travel and accommodation were paid and an honorarium was received for participations at both meetings and for preparation of a summary paper for publication in the SSI Sports Science Exchange in 2018. She presented at a Danone Essential Dairy and Plant-Based Proteins Board Meeting in New York in July in 2019 for which travel, accommodations and an honorarium were paid. She has participated in numerous other national nutrition and medical conferences between 2015 and the present for which travel and accommodation and typically an honorarium were received. She did not receive any form of financial support directly related to this manuscript. JL has received payment for sport nutrition consultancy work with French Football Federation, Liverpool Football Club, Lille Football Club, Paris-Dakar association. He has received travel/accommodation funding and honorariums to speak / present at several national/international conferences between 2015 to present) including: Research day of the Dairy Council UK; European College of Sport and Exercise Physicians, Paris, France; International conference of Sports Physiotherapy, Kuala Lumpur, Malaysia; French Football Federation congress for S&C coaches, Paris; congress of the Mexican Nutrition Society, Guadalajara; and congress of the Swiss Nutrition society, Nottwil. He has contributed to several recorded lectures for which he received honorariums for the IOPN Diploma, London, UK. He co-supervised a PhD project funded by a nutrition company (Lactalis, Laval, France). He did not receive any form of financial support directly related to this manuscript. DM has no conflicts to disclose. He did not receive any form of financial support directly related to this manuscript. FM is the main editor of a book published by CRC Press, Taylor & Francis Group (Fluid Balance, Hydration and Athletic Performance) for which she receives royalties. She hold a visiting professor position at the Human Movement Graduate Program from 2018 to 2020 (unpaid) at the Federal University of Rio Grande do Sul. She did not receive any form of financial support directly related to this manuscript. IR is an employee of the Gatorade Sports Science Institute (GSSI), a division of PepsiCo, Incorporated. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Incorporated. Ian leads the FC Barcelona, innovation hub certificate in sports nutrition, he is co-author on the FC Barcelona Sports Nutrition guide for Football and co-organises the FCB conference in Sports nutrition, all as part of his role with GSSI. Ian co-authored a chapter on nutrition in the book “Elite Soccer Players” with no honorarium nor any royalties received. He not receive any form of financial support directly related to this manuscript. JSB holds a professorship at the Norwegian School of Sports Science in Oslo Norway. She receives research grants from The Norwegian Woman's Public Health Association, the Norwegian Extra Foundation for Health and Rehabilitation, The Norwegian Association of Youth Mental Health, and the Dam Foundation and TINE SA. She has contributed with lectures for the IOC Diploma programs in Sports Medicine and Sports Nutrition and receives honoraria for about one lecture per year. She was a member of the Expert Scientific Committee of the IOC Medical and Scientific Commission. She has also been a member in IOC working group (position papers). These positions were unpaid, but travel to meetings and accommodation were provided. She is also an International trustee (ACSM) and Vice president in Nordic Eating Disorder Society. These positions are unpaid, but travel to meetings and accommodation are provided. BW Received honorarium for consultancy with Nutricia. BW is the editor of one book (carnitine metabolism and human nutrition) published by CRC press for which he receives royalties. He has made lecture contributions to the International Society for Sports and Exercise Conference (ISENC), Nutrition Society, European Society for Parenteral and Enteral Nutrition (ESPEN) and Physiological Society which were unpaid for which he received expenses. He has received travel and expenses for an organised symposium (by Ketchum PR, US) at American Society for Nutrition (ASN) and the Reducetarian Conference. He has received payments from various UK universities for external examining with the last 5 years. He did not receive any form of financial support directly related to this manuscript. BB is co-author of two books, one published by McGrawHill (Nutrición Deportiva) for which she receives royalties and another one published by Organización Panamericana de la Salud (La Receta de los Campeones) for which she received royalties in the past. She is Program Director on the FMND-Nutrinfo Curse in Sports Nutrition, for which she receives honoraria and additionally contributes with one lectures to these program, for which she has received honoraria. She has participated in numerous international sports nutrition symposia between 2011 and the present for which travel and accommodation were paid by The Mexican Football Federation. She advises The Coca Cola Company for issues related to their Sport Beverage Powerade since 2012 for which she receives honoraria. She did not receive any form of financial support directly related to this manuscript. GD is head of performance for CF Real Madrid. He holds visiting (unpaid) professorships at Liverpool John Moores University He previously worked for the French Football Federation, Lille FC and the universities of Artois and Lille. He is co-author of a book on training methodology and performance (2007, three chapters (monitoring fatigue and recovery, Thieme eds, 2017; Targeted Systems of the Body for Training in Football Science, Human Kinetics, 2016; Boosting Aerobic Performance in High-Performance training for Sports, Human Kinetics, 2016), for which he received royalties. He has lectured for Aspetar twice (2013, 2016) recovery and nutrition courses for which he has received travel expenses, accommodation and an honorarium. He has spoken at 33 international conferences on sports science and football for which he has received travel expenses and accommodation, no honorariums have been received. He did not receive any form of financial support directly related to this manuscript. MAL: Toña is Professor of the Human Nutrition and Dietetics degree at the University of Barcelona and Nutritional Advisor of FCB. She is involved in clinical consultation and advice to competitive athletes and she did not receive any form of financial support directly related to this manuscript. PR is currently employed by the Dutch Olympic Team. He was formerly employed by AFC Ajax Amsterdam. He is owner of PR Sportvoedingsadvies. Through his consultancy he also receives payment for nutrition services with individuals and corporate organisations. He co-authored an article for The Gatorade Sports Science Institute, for which he received honoraria. He received honoraria as an invited speaker for the Barça Sport Nutrition Conference and FrieslandCampina Institute congress “sport en voeding”. He did not receive any form of financial support directly related to this manuscript. MB has received travel and accommodation funding (from the organizers and/or the Schulthess Clinic) to speak/present at several international congress between 2015 to present, including: the Isokinetic Football Medicine Strategies Conferences (2015-2019, London & Barcelona), Team Concept Conference 2016 (Las Vegas), the IOC World Conference 2017, the World Conference of Sports Physical Therapy (Belfast 2017, Vancouver 2019), the Salzburg Sports PT Congress 2019, the ACL Consensus Meeting (Pittsburgh 2019), the International Conference on Football Refereeing (Lisbon 2019), the International Society of Hip Arthroscopy Physiotherapy Meeting (Madrid 2019). As a member of F-MARC (2002- 2016) he received compensation from FIFA for his work during this time, but no other compensations or grants have been received. Between 2015 and 2019 he has authored/co-authored nine book chapters (football medicine, sports medicine) with no honorarium nor any royalties received. He did not receive any form of financial support directly related to this manuscript. CC: Since 2007 I have been invited in international conference/seminar by FIFA and UEFA for lectures on refereeing receiving no honorary but having paid travels, accommodation and daily expenses. I did not receive any form of payment for the contribution to this manuscript. CC has not received any honorarium from any company in the last 5 years. She is employed by the Football Association and has a private medical practice. She is member of the UEFA medical committee and have paid expenses (travel & accommodation) for UEFA medical committee meetings. She received from UEFA the cost of flight and accommodation to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript.” She did not receive any other form of financial support directly related to this manuscript. MD: The travel to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript was paid by UEFA. No other conflicts to declare. He did not receive any other form of financial support directly related to this manuscript. HG has received honorarium and reimbursement of travel and accommodation expenses for expert statements in doping cases in connection with nutritional supplements for several federations and anti-doping organisations, including UEFA and FIFA and several National Anti-Doping Agencies. He has received daily fees and reimbursement of travel and accommodation expenses for his participation in WADA expert groups for the athlete biological passport. He has received honorarium and reimbursement of travel and accommodation expenses for lectures about doping risks of nutritional supplements in congresses of several medical societies. He has received reimbursement of travel and accommodation expenses for his participation at the IOC consensus conference about nutritional supplements. The travel to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript was paid by UEFA. No other conflicts to declare. He did not receive any other form of financial support directly related to this manuscript. TM has never received any royalties or fees from nutritional companies or other relevant sources. For none of his publications has he ever received any financial compensation except for one article about the management of infectious diseases in the Aspetar Sports Medicine Journal. He received from UEFA the cost of flight and accommodation to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript.” He did not receive any other form of financial support directly related to this manuscript. NP: The travel to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript was paid by UEFA. No other conflicts to declare. She did not receive any other form of financial support directly related to this manuscript. MV: The travel to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript was paid by UEFA. No other conflicts to declare. He did not receive any other form of financial support directly related to this manuscript. AM has received a grant from FIFA to investigate health and performance of footballers during the transition from club to national teams. He has received travel and accommodation funding to speak / present at several international congress between 2015 to present), including; the Isokinetic Football Medicine Strategies Conference (London and Barcelona), KNVB national federation, Danish SportsKongress, Denmark, Sportsfisio congress, Switzerland, The Barça Innovation Hub, Barcelona, Spain. Oslo Sports Trauma Research Group, Oslo, Norway. Mapei Research Centre, Bergamo, Italy. Brazil National Football Federation, Rio, Brazil, French Football Federation, Paris, France. He is not affiliated or received any travel, accommodation, funding from any nutrition company. He also received consultancy fee from the French Football Federation for injury prevention recommendations for the 2018 FIFA World Cup. He received from UEFA the cost of flight and accommodation to attend an Expert Group Meeting with the UEFA Medical Committee in Brussels, Belgium, to discuss preparation of this manuscript.” He did not receive any other form of financial support directly related to this manuscript., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: Competing interests: See COI document linked to the main paper (too large to copy paste in here).

Background: To assess the effects of the injury prevention programme '11+ Kids' on reducing severe injuries in 7 to 13 year old football (soccer) players., Methods: Football clubs (under-9, under-11 and under-13 age groups) from the Czech Republic, Germany, the Netherlands and Switzerland were cluster-randomised (clubs) into an intervention (INT) and a control group (CON). INT replaced their usual warm-up by '11+ Kids' two times a week. CON followed their regular training regime. Match and training exposure and injury characteristics were recorded and injury incidence rates (IRs) and 95% CIs calculated. For the present analysis, only severe injuries (absence from training/match ≥28 days) were considered. Hazard ratios (HR) were calculated using extended Cox models., Results: The overall IR of severe injuries per 1000 football hours was 0.33 (95% CI 0.25 to 0.43) in CON and 0.15 (95% CI 0.10 to 0.23) in INT. There was a reduction of severe overall (HR 0.42, 95% CI 0.24 to 0.72), match (0.41, 0.17 to 0.95) and training injuries (0.42, 0.21 to 0.86) in INT. The injury types that were prevented the most were: other bone injuries 66%, fractures 49% and sprains and ligament injuries 37%. Severe injuries located at the knee (82%), hip/groin (81%), the foot/toe (80%) and the ankle (65%) were reduced tremendously., Conclusions: '11+ Kids' has a large preventive effect on severe injuries by investing only 15 to 20 min per training session. The present results should motivate coaches to implement effective injury prevention programmes such as the '11+ Kids' in children's football., Trial Registration Number: NCT02222025., Competing Interests: Competing interests: RR, KadF, MB, JC, EV, AJ and OF were responsible for the conception of ‘11+ Kids’. MB, AJ and JD were involved in the conception of ‘The 11’ and ‘The 11+’., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Castagna, C, Bizzini, M, Araújo Póvoas, SC, Schenk, K, Büsser, G, and D'Ottavio, S. Aerobic fitness in top-class soccer referees. J Strength Cond Res 33(11): 3098-3104, 2019-The aim of this study was to examine the aerobic fitness status of top-class male soccer officials using a cross-sectional design and known population group constructs. Fifty-two field referees (FRs, age 38.4 ± 3.3 years; height 181 ± 5.6 cm; body mass 76.8 ± 6.8 kg; body mass index [BMI] 23.4 ± 1.7 kg·m; body fat 20.4 ± 3.6%; and international refereeing experience 5 ± 3.5 years) and 104 assistant referees (ARs, age 37.8 ± 4.1 years; height 176.9 ± 7.5 cm; body mass 72.1 ± 7.4 kg; BMI 23 ± 1.6 kg·m; body fat 19.2 ± 3.6%; and international refereeing experience 7 ± 3.8 years) from 53 National Football Associations worldwide, and candidates of the preliminary open-list developed by the FIFA Refereeing Department for the 2014 World Cup Final Tournament, were tested for aerobic fitness in laboratory conditions with a progressive speed treadmill test to exhaustion. Large (+8.54%, d = 0.8) and small (+3.1%, d = 0.3) differences in absolute (L·min) and relative (ml·kg·min) VO2max were found between FR and AR, respectively. Trivial differences (d = 0.07) were shown in running economy (RE) (6 minutes at 8 km·h) between AR and FR. Using the scaling notation (b = 0.64), medium and significant differences were found between match officials for VO2max and RE (FR > AR; d = 0.6 and 0.67, respectively). Using receiver operating characteristic curve statistics, cutoff values of 3.93 L·min and 50.6 ml·kg·min were detected in absolute and relative VO2max for the FR and the AR (FR > AR), respectively. The FR showed superior aerobic fitness compared with AR. Training prescription should consider intensities at anaerobic threshold speed (14 km·h, 91% heart rate max) when aerobic fitness development is the aim in elite officials.

Background and Aim: Understanding the barriers to programme use is important to facilitate implementation of injury prevention programmes in real-word settings. This study investigated the barriers to coaches of adolescent female soccer teams, in Victoria, Australia, implementing the evidence-based FIFA 11+ injury prevention programme., Methods: Concept mapping with data collected from 19 soccer coaches and administrators., Results: Brainstorming generated 65 statements as barriers to 11+ implementation. After the statements were synthesised and edited, participants sorted 59 statements into groups (mean, 6.2 groups; range, 3-10 groups). Multidimensional scaling and hierarchical cluster analysis identified a six-cluster solution: Lack of 11+ knowledge among coaches (15 statements), Lack of player enjoyment and engagement (14), Lack of link to football-related goals (11), Lack of facilities and resources (8), Lack of leadership (6) and Lack of time at training (5). Statements in the 'Lack of 11+ knowledge among coaches' cluster received the highest mean importance (3.67 out of 5) and feasibility for the Football Federation to address (3.20) rating. Statements in the 'Lack of facilities and resources' cluster received the lowest mean importance rating (2.23), while statements in the 'Lack of time at training' cluster received the lowest mean feasibility rating (2.19)., Conclusions: A multistrategy, ecological approach to implementing the 11+-with specific attention paid to improving coach knowledge about the 11+ and how to implement it, linking the 11+ to the primary goal of soccer training, and organisational leadership-is required to improve the uptake of the 11+ among the targeted coaches., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2019. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Castagna, C, Bizzini, M, D'Ottavio, S, and Araújo Póvoas, SC. Sex differences in aerobic fitness in top-class soccer referees. J Strength Cond Res 32(11): 3216-3221, 2018-The aim of this study was to assess the aerobic-fitness differences between male and female top-class soccer field referees (FRs). This with the purpose to provide cutoff values useful for training prescription in female FRs. Forty female top-class FRs (age 34.18 ± 3.50 years and 5 ± 3.9 years international refereeing experience) and 52 male FRs (age 38.4 ± 3.3 years and 5 ± 3.5 years international refereeing experience) candidates in the preliminary open list developed by the FIFA Refereeing Department for the 2014 and 2015 World Cup Tournaments, participated in the study. The FRs were tested for aerobic fitness under laboratory conditions with a progressive speed treadmill test until exhaustion. Female FRs showed to possess, on average, lower (large effect) levels of aerobic fitness and performance compared with their male counterparts. The female FRs' V[Combining Dot Above]O2max (48.1 ± 4.4 ml·kg·min) was 7% (large effect) lower than the male FRs (51.9 ml·kg·min). Peak treadmill speed was 11% lower (large effect) in female FRs (16.27 ± 0.94 vs. 14.64 ± 0.96 km·h). The receiver operating characteristic curve analysis enabled cutoff values (47.8 ml·kg·min for V[Combining Dot Above]O2max) that may be used as preliminary cues to guide physiological selection and training prescription in female FRs aiming to officiate male-soccer matches. Only 2.5% of the female FRs showed V[Combining Dot Above]O2max higher than the mean values of male FRs when using the scaled notation (0.68). Female FRs aiming to officiate male competitions should consider training intensities at anaerobic threshold speed (13 km·h, 95% heart rate max) when developing aerobic fitness. Given the very large sex differences in aerobic performance, strength/power training should be proposed to perspective female top-class FRs.

Competing Interests: Competing interests: None declared.

Purpose: The 11+ injury prevention program has been shown to decrease injury rate. However, few studies have investigated compliance and if it is correlated to time loss. The purpose of this study was to (1) analyze how differences in compliance may impact injury rate and (2) if compliance may impact time loss due to injury., Methods: This study was a Level 1 prospective cluster randomized controlled trial conducted in NCAA men's football (soccer) teams that examined the efficacy of the 11+ injury prevention program. The two outcome variables examined were number of injuries and number of days missed from competition. Twenty-seven teams (n = 675 players) used the 11+ program. Compliance, injuries and time loss were recorded. There were three compliance categories, low (LC, 1-19 doses/season), moderate (MC, 20-39 doses/season), and high (HC, > 40 doses/season)., Results: There was a significant difference among the groups for injuries, p = 0.04, p η 2  = 0.23. The LC group [mean (M) = 13.25, 95% confidence interval (CI) 9.82-16.68, injury rate (IR) = 10.35 ± 2.21] had a significantly higher injury rate than the HC group (M = 8.33, 95%CI 6.05-10.62, IR = 10.35 ± 2.21), p = 0.02. The MC group (M = 11.21, 95%CI 9.38-13.05, IR = 8.55 ± 2.46) was not significantly different than the LC group, p = 0.29, but was significantly greater than the HC group, p = 0.05. When examined as a continuous variable, compliance was significantly negatively related to injury rate (p = 0.004). It was also significantly negatively related to number of days missed (p = 0.012)., Conclusions: When compliance was high, there was a significant reduction in injury and time loss. This evidence reinforces the importance of consistent injury prevention program utilization. Clinically, these findings have important implications when discussing the importance of consistent utilization of an injury prevention protocol in sport., Level of Evidence: Level 1-Randomized controlled trial (RCT).

Objectives: To describe the Return to competition after Achilles Tendon rupture (ATR) in an elite soccer player., Design: Case report., Setting: Return to sport (RTS) of a professional soccer player who suffered an ATR during a match. The RTS phase started 15 weeks after surgery and specific on-field activities were gradually introduced. Criteria used to monitor the transition through the different phases were strength and endurance of the calf muscle and ability to sustain specific on-field training loads (TL) monitored with Global Positioning System and heart-rate system. TLs were weekly compared to pre-injury values to evaluate recovery and to prescribe future sessions., Participant: A 39-year-old (height 178 cm, weight 75 kg) elite soccer defender player, playing in Italian Serie-A league., Results: Days of absence were lower compared to a cohort presented in UEFA study (119 versus 161 ± 65 days, respectively). External-TL and Internal-TL were organized to gradually increase during RTS and resulted in higher values prior to return to competition compared to pre-injury values. Concentric plantar flexion peak torque increased till 9th months after surgery., Conclusions: Monitoring of the field activities allowed comparison with pre-injury values and provided a useful and functional criteria to pass return to team activity and competition., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Purpose: To examine the effect of recall timing on training-session rating of perceived exertion (sRPE) in a population of athletes well familiarized with the method and procedures during a 5-d training microcycle., Methods: Fifty-one top-class field referees (FRs) (age 38.4 ± 3.3 y, height 181 ± 5.6 cm, body mass 76.8 ± 6.8 kg, body-mass index 23.4 ± 1.7 kg/m 2 , body fat 20.4% ± 3.6%, international refereeing experience 5 ± 3.5 y) from 43 national football associations worldwide, preselected by the FIFA refereeing department for officiating during the FIFA World Cup 2014 Brazil, volunteered for this study. The FRs were randomly allocated into 3 assessment groups (n = 17 each), defined according to the timing of the sRPE, ie, immediately at the end of or 30 min or 7 h after the training sessions' end. The CR10 Borg scale was used to rate the training sessions (n = 5). All FRs again rated each training session of the 5-d training microcycle on the next morning (~20 h after) for confirmation (absolute and relative reliability)., Results: No significant timing effect was found between or within groups. Relative reliability ranged from large to very large with trivial within- and between-groups differences., Conclusions: This study showed no effect of recall timing on postexercise RPE when well-familiarized athletes are submitted to training during a weekly microcycle. Posttraining RPE was reported to be a reliable subjective measure; however, specific timing is advisable to reduce difference in RPE values.

Background: The FIFA 11+ injury prevention program has been shown to decrease the risk of soccer injuries in men and women. The program has also been shown to decrease time loss resulting from injury. However, previous studies have not specifically investigated how the program might impact the rate of anterior cruciate ligament (ACL) injury in male soccer players., Questions/purposes: The purpose of this study was to examine if the FIFA 11+ injury prevention program can (1) reduce the overall number of ACL injuries in men who play competitive college soccer and whether any potential reduction in rate of ACL injuries differed based on (2) game versus practice setting; (3) player position; (4) level of play (Division I or II); or (5) field type., Methods: This study was a prospective cluster randomized controlled trial, which was conducted in 61 Division I and Division II National Collegiate Athletic Association men's soccer teams over the course of one competitive soccer season. The FIFA 11+ is a 15- to 20-minute on-the-field dynamic warm-up program used before training and games and was utilized as the intervention throughout the entire competitive season. Sixty-five teams were randomized: 34 to the control group (850 players) and 31 to the intervention group (675 players). Four intervention teams did not complete the study and did not submit their data, noting insufficient time to complete the program, reducing the number for per-protocol analysis to 61. Compliance to the FIFA 11+ program, athletic exposures, specific injuries, ACL injuries, and time loss resulting from injury were collected and recorded using a secure Internet-based system. At the end of the season, the data in the injury surveillance system were crosshatched with each individual institution's internal database. At that time, the certified athletic trainer signed off on the injury collection data to confirm their accuracy and completeness., Results: A lower proportion of athletes in the intervention group experienced knee injuries (25% [34 of 136]) compared with the control group (75% [102 of 136]; relative risk [RR], 0.42; 95% confidence interval [CI], 0.29-0.61; p < 0.001). When the data were stratified for ACL injury, fewer ACL injuries were reported in the intervention group (16% [three of 19]) compared with the control group (84% [16 of 19]), accounting for a 4.25-fold reduction in the likelihood of incurring ACL injury (RR, 0.236; 95% CI, 0.193-0.93; number needed to treat = 70; p < 0.001). With the numbers available, there was no difference between the ACL injury rate within the FIFA 11+ group and the control group with respect to game and practice sessions (games-intervention: 1.055% [three of 15] versus control: 1.80% [12 of 15]; RR, 0.31; 95% CI, 0.09-1.11; p = 0.073 and practices-intervention: 0% [zero of four] versus control: 0.60% [four of four]; RR, 0.14; 95% CI, 0.01-2.59; p = 0.186). With the data that were available, there were no differences in incidence rate (IR) or injury by player position for forwards (IR control = 0.339 versus IR intervention = 0), midfielders (IR control = 0.54 versus IR intervention = 0.227), defenders (IR control = 0.339 versus IR intervention = 0.085), and goalkeepers (IR control = 0.0 versus IR intervention = 0.0) (p = 0.327). There were no differences in the number of ACL injuries for the Division I intervention group (0.70% [two of nine]) compared with the control group (1.05% [seven of nine]; RR, 0.30; CI, 0.06-1.45; p = 0.136). However, there were fewer ACL injuries incurred in the Division II intervention group (0.35% [one of 10]) compared with the control group (1.35% [nine of 10]; RR, 0.12; CI, 0.02-0.93; p = 0.042). There was no difference between the number of ACL injuries in the control group versus in the intervention group that occurred on grass versus turf (Wald chi square [1] = 0.473, b = 0.147, SE = 0.21, p = 0.492). However, there were more ACL injuries that occurred on artificial turf identified in the control group (1.35% [nine of 10]) versus the intervention group (0.35% [one of 10]; RR, 0.14; 95% CI, 0.02-1.10; p = 0.049)., Conclusions: This program, if implemented correctly, has the potential to decrease the rate of ACL injury in competitive soccer players. In addition, this may also enhance the development and dissemination of injury prevention protocols and may mitigate risk to athletes who utilize the program consistently. Further studies are necessary to analyze the cost-effectiveness of the program implementation and to analyze the efficacy of the FIFA 11+ in the female collegiate soccer cohort., Level of Evidence: Level I, therapeutic study.

The Functional Movement Screen™ (FMS™) is aimed at assessing fundamental movements and is often used to identify players' injury risk. The purpose of this study was to determine whether the FMS™ can be used to predict injuries in veteran footballers (aged > 32 years). Eighteen veteran football teams (n = 238) were recruited and prospectively followed for 9 months. The players (44 ± 7 years; 178 ± 7 cm, 84 ± 11 kg) performed the FMS™ at the start of the study period. Players' exposure hours and injuries were recorded. The difference of FMS™ overall score between injured and uninjured players was not significant (11.7 ± 2.9 vs 12.2 ± 2.8 points; Mann-Whitney U-test P = 0.17). Players scoring <10 (score < 1 standard deviation [SD]) below the mean) had a significantly higher injury incidence (z-statistics P < 0.05) compared to an intermediate reference group (mean ± 1 SD; scores of 10-14). No lower injury incidence for players with scores of >14 (score > 1 SD above the mean) was found. Further analyses of potential risk factors suggest higher age, lower body mass and a longer football career to be risk factors for injuries. The findings of this study suggest that the suitability of the FMS™ for injury prediction in veteran footballers is limited.

Background: The Fédération Internationale de Football Association (FIFA) 11+ program has been shown to be an effective injury prevention program in the female soccer cohort, but there is a paucity of research to demonstrate its efficacy in the male population., Hypothesis: To examine the efficacy of the FIFA 11+ program in men's collegiate United States National Collegiate Athletic Association (NCAA) Division I and Division II soccer., Study Design: Randomized controlled trial; Level of evidence, 1., Methods: Before the commencement of the fall 2012 season, every NCAA Division I and Division II men's collegiate soccer team (N = 396) was solicited to participate in this research study. Human ethics review board approval was obtained through Quorum Review IRB. Sixty-five teams were randomized: 34 to the control group (CG; 850 players) and 31 to the intervention group (IG; 675 players). Four teams in the IG did not complete the study, reducing the number for analysis to 61. The FIFA 11+ injury prevention program served as the intervention and was utilized weekly. Athlete-exposures (AEs), compliance, and injury data were recorded using a secure Internet-based system., Results: In the CG, 665 injuries (mean ± SD, 19.56 ± 11.01) were reported for 34 teams, which corresponded to an incidence rate (IR) of 15.04 injuries per 1000 AEs. In the IG, 285 injuries (mean ± SD, 10.56 ± 3.64) were reported for 27 teams, which corresponded to an IR of 8.09 injuries per 1000 AEs. Total days missed because of injury were significantly higher for the CG (mean ± SD, 13.20 ± 26.6 days) than for the IG (mean ± SD, 10.08 ± 14.68 days) (P = .007). There was no difference for time loss due to injury based on field type (P = .341)., Conclusion: The FIFA 11+ significantly reduced injury rates by 46.1% and decreased time loss to injury by 28.6% in the competitive male collegiate soccer player (rate ratio, 0.54 [95% CI, 0.49-0.59]; P < .0001) (number needed to treat = 2.64)., (© 2015 The Author(s).)

Purpose: The available scientific research regarding injury prevention practices in international football is sparse. The purpose of this study was to quantify current practice with regard to (1) injury prevention of top-level footballers competing in an international tournament, and (2) determine the main challenges and issues faced by practitioners in these national teams., Methods: A survey was administered to physicians of the 32 competing national teams at the FIFA 2014 World Cup. The survey included 4 sections regarding perceptions and practices concerning non-contact injuries: (1) risk factors, (2) screening tests and monitoring tools, (3) preventative strategies and (4) reflection on their experience at the World Cup., Results: Following responses from all teams (100%), the present study revealed the most important intrinsic (previous injury, accumulated fatigue, agonist:antagonist muscle imbalance) and extrinsic (reduced recovery time, training load prior to and during World Cup, congested fixtures) risk factors during the FIFA 2014 World Cup. The 5 most commonly used tests for risk factors were: flexibility, fitness, joint mobility, balance and strength; monitoring tools commonly used were: medical screen, minutes/matches played, subjective and objective wellness, heart rate and biochemical markers. The 5 most important preventative exercises were: flexibility, core, combined contractions, balance and eccentric., Conclusions: The present study showed that many of the National football (soccer) teams' injury prevention perceptions and practices follow a coherent approach. There remains, however, a lack of consistent research findings to support some of these perceptions and practices., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

In 2009, FIFA promoted and disseminated the FIFA 11+ injury prevention programme worldwide. Developed and studied by the FIFA Medical Assessment and Research Centre (F-MARC), the programme was based on a randomised controlled study and one countrywide campaign in amateur football that significantly reduced injuries and healthcare costs. Since the FIFA 11+ launch, key publications have confirmed the preventive effects of the programme and have evaluated its performance effects in female as well as male amateur football players. Furthermore, implementation strategies of this prevention programme have also been studied. The goal of this narrative review was to summarise the available scientific evidence about the FIFA 11+ programme. While FIFA continues to disseminate and implement FIFA 11+ among its Member Associations, adaptations of the injury prevention programme for children and referees have been developed and are currently being evaluated., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

The warm-up programme "FIFA 11+" has been shown to reduce football injuries in different populations, but so far veteran players have not been investigated. Due to differences in age, skill level and gender, a simple transfer of these results to veteran football is not recommended. The purpose of this study was to investigate the preventive effects of the "FIFA 11+" in veteran football players. Twenty veteran football teams were recruited for a prospective 9-month (1 season) cluster-randomised trial. The intervention group (INT, n = 146; 45 ± 8 years) performed the "FIFA 11+" at the beginning of each training session, while the control group (CON, n = 119; 43 ± 6 years) followed its regular training routine. Player exposure hours and injuries were recorded according to an international consensus statement. No significant difference was found between INT and CON in overall injury incidence (incidence rate ratio [IRR]: 0.91 [0.64-1.48]; P = 0.89). Only severe injuries reached statistical significance with higher incidence in CON (IRR: 0.46 [0.21-0.97], P = 0.04). Regular conduction (i.e. once a week) of the "FIFA 11+" did not prevent injuries in veteran footballers under real training and competition circumstances. The lack of preventive effects is likely due to the too low overall frequency of training sessions.

Despite significant advances in the diagnostics and treatment of knee injuries over the last decade, several challenges related to the subject "return to sport" remain largely unknown. For example, how should "return to sport" be defined precisely? What is the optimal timing and progression to enable a return to sport? Which criteria should be used during this process? What type of training is indicated? Which measurements can support the decision-making process? How do we optimally prepare athletes for competition without risking re-injury? This paper critically addresses these questions, and proposes a return to play model to prepare football players to compete after major knee surgery (anterior cruciate ligament reconstruction, cartilage repair). The goal is to re-integrate the player gradually into the game, taking into account his individual characteristics. Several evidence-based and empirical criteria are needed to plan and monitor the efficient return to competitive football. Injury-prevention education should be part of this process to maximise the chance of a durable career and decrease the risk of re-injury. However, because of the paucity of research on "return to sport", further research is more than warranted.

In the last decade, injury prevention has received a lot of attention in sports medicine, and recently international sports-governing bodies, such as the International Olympic Committee, declared the protection of the athletes' health as one of their major objectives. In 1994, the Fédération Internationale de Football Association (FIFA) established its Medical Assessment and Research Centre (F-MARC) with the aim 'to prevent football injuries and to promote football as a health-enhancing leisure activity, improving social behaviour'. Since then, FIFA has developed and evaluated its injury-prevention programmes 'The 11' and 'FIFA 11+' have demonstrated in several scientific studies how simple exercise-based programmes can decrease the incidence of injuries in amateur football players. This paper summarises 18 years of scientific and on-field work in injury prevention by an international sports federation (FIFA), from formulating the aim to make its sport safer to the worldwide dissemination of its injury-prevention programme in amateur football.

Background: A protective effect on injury risk in youth sports through neuromuscular warm-up training routines has consistently been demonstrated. However, there is a paucity of information regarding the quantity and quality of coach-led injury prevention programmes and its impact on the physical performance of players., Objective: The aim of this cluster-randomised controlled trial was to assess whether different delivery methods of an injury prevention programme (FIFA 11+) to coaches could improve player performance, and to examine the effect of player adherence on performance and injury risk., Method: During the 2011 football season (May-August), coaches of 31 tiers 1-3 level teams were introduced to the 11+ through either an unsupervised website or a coach-focused workshop with and without additional on-field supervisions. Playing exposure, adherence to the 11+, and injuries were recorded for female 13-year-old to 18-year-old players. Performance testing included the Star Excursion Balance Test (SEBT), single-leg balance, triple hop and jumping-over-a-bar tests., Results: Complete preseason and postseason performance tests were available for 226 players (66.5%). Compared to the unsupervised group, single-leg balance (OR=2.8; 95% CI 1.1 to 4.6) and the anterior direction of the SEBT improved significantly in the onfield supervised group of players (OR=4.7; 95% CI 2.2 to 7.1), while 2-leg jumping performance decreased (OR=-5.1; 95% CI -9.9 to -0.2). However, significant improvements in 5 of 6 reach distances in the SEBT were found, favouring players who highly adhered to the 11+. Also, injury risk was lower for those players (injury rate ratio, IRR=0.28, 95% CI 0.10 to 0.79)., Conclusions: Different delivery methods of the FIFA 11+ to coaches influenced players' physical performance minimally. However, high player adherence to the 11+ resulted in significant improvements in functional balance and reduced injury risk.

Background: Injury prevention programme delivery on adherence and injury risk, specifically involving regular supervisions with coaches and players on programme execution on field, has not been examined., Aim: The objective of this cluster-randomised study was to evaluate different delivery methods of an effective injury prevention programme (FIFA 11+) on adherence and injury risk among female youth football teams., Method: During the 4-month 2011 football season, coaches and 13-year-old to 18-year-old players from 31 tier 1-3 level teams were introduced to the 11+ through either an unsupervised website ('control') or a coach-focused workshop with ('comprehensive') and without ('regular') additional supervisions by a physiotherapist. Team and player adherence to the 11+, playing exposure, history and injuries were recorded., Results: Teams in the comprehensive and regular intervention groups demonstrated adherence to the 11+ programme of 85.6% and 81.3% completion of total possible sessions, compared to 73.5% for teams in the control group. These differences were not statistically significant, after adjustment for cluster by team, age, level and injury history. Compared to players with low adherence, players with high adherence to the 11+ had a 57% lower injury risk (IRR 0.43, 95% CI 0.19 to 1.00). However, adjusting for covariates, this between-group difference was not statistically significant (IRR=0.44, 95% CI 0.18 to 1.06)., Conclusion: Following a coach workshop, coach-led delivery of the FIFA 11+ was equally successful with or without the additional field involvement of a physiotherapist. Proper education of coaches during an extensive preseason workshop was more effective in terms of team adherence than an unsupervised delivery of the 11+ programme to the team., Trial Registration: ISRCTN67835569.

Background: Precompetition screening was implemented for male referees during the 2010 Fédération Internationale de Football Association (FIFA) Word Cup. In contrast, female football referees have been neglected in this respect although they experience similar physical work loads compared to male referees., Methods: The standardised football-specific pre-competition medical assessment (PCMA) was performed in 51 referees and assistant referees selected for the 2011 FIFA Women's World Cup., Results: Family history for sudden cardiac death (SCD) was positive in four referees (7.8%), but cardiac examinations did not reveal any pathological findings. Training-unrelated ECG changes were identified in three referees (5.9%), all without correlates in echocardiography or clinical examination. Most common echocardiography findings (66.6%, n=34) were asymptomatic tricuspid and mitral regurgitations., Conclusions: During the present screening, no elite female referee was identified being at risk for SCD, and no referee had to be excluded from participating in the 2011 FIFA Women's World Cup.

The aim of this study was to examine the training effects of an injury prevention programme on neuromuscular control, strength and performance in male amateur football players. Eighty-one players were allocated to the "FIFA 11+" (n = 42) or a control group (CON, n = 39). The "FIFA 11+" group performed the programme 3 times a week for 9 weeks; the control group completed the usual warm-up. Primary outcomes were: time-to-stabilisation test and eccentric/concentric flexors strength. Secondary outcomes were: eccentric/concentric extensors strength, star excursion balance test, core-stability test, vertical jump, sprint, and agility. After controlling for covariates, significant between-group differences after the intervention (in favour of the "FIFA 11+" players) were found for time-to-stabilisation (-2.8%, 90% confidence interval [CI] -4.4 to -1.2%) and core-stability (-8.9%, -14.6 to -3.1%). Differences were also found for eccentric (3.8%, 1.4 to 6.2%) and concentric flexors strength (3.2%, 0.6 to 5.9%) at 60° · s(-1) but this difference was only possibly meaningful (62.4%) from a practical point of view. No substantial and/or significant differences were found for the other outcomes. Performing "FIFA 11+" for 9 weeks can improve neuromuscular control. Possible worthwhile differences were found for flexors strength but there were no substantial effects in the other performance measures.

The aim of the study was to examine the post-exercise effects of the "FIFA 11+" on various physical performance and physiological variables, to understand whether this programme is an appropriate warm-up for football players. Results were compared with the literature using a meta-analytical approach. Twenty amateur male football players [mean age 25.5 (s ± 5.1) years, body mass 75(8) kg, height 181(6) cm] participated in the study. They were tested twice before (control period) and once after the "FIFA 11+" for: 20-m sprints, agility, vertical jump, stiffness, isometric maximal voluntary contraction (MVC), rate of force development (RFD), and star excursion balance test. Oxygen uptake, lactate and core temperature were also measured. Pre-post warm-up differences were found for all the performance variables (from 1.0 to 6.2%; 0.015 < P < 0.001) with the exclusion of MVC (-13%; P = 0.426) and RFD (-10%; P = 0.205). After the warm-up there was an increase (0.004

Soccer referees are required to keep up with play at all times to ensure optimal positioning in making key decisions. While the physiological aspects of soccer refereeing have been extensively reviewed, other key areas of preparation and performance have yet to be considered in detail. We present a contemporary examination of methodological considerations for the interpretation of referees' match activities, the validation of fitness testing and training protocols, match and training injury profiles, and the understanding and development of perceptual-cognitive expertise. A referee covers approximately 11 km during a match, with ∼900 m of high-speed running and, consequently, the demands of match play represent a significant physical challenge. The analyses of within-match activity profiles have attempted to assess the possible occurrence of referee fatigue, with equivocal findings. However, researchers have demonstrated that referees' physical performances are interrelated with those of the players during the same match. Therefore, the evaluation of referees' match activity profiles should be made in the context of the players' performances. High match-to-match variability in key variables, namely, high-speed running and sprinting, along with age-related reductions in match running are other factors that require due consideration when interpreting physical performances. Fitness testing is used by national and international referee governing bodies as part of their match selection criteria. Therefore, the tests need to reflect the physical task of refereeing, yet for the recent fitness tests introduced by the Fédération Internationale de Football Association--a 20 × 150 m high-intensity and 6 × 40 m repeated-sprint test - only the repeated-sprint test possesses the appropriate construct validity for assessment of match-related running capacity. Also, the performance standards of the tests have not been validated. Consequently, the scientific rationale behind the tests and their associated standards is not clear. Soccer referees dedicate a large proportion of their overall training to the development of physical capacity and researchers have demonstrated that high-intensity (>85% maximal heart rate) training protocols are effective for improving fitness and match running performance. These high training loads combined with increasing age could, in part, explain an incidence of non-contact match injuries (18 injuries per 1000 match hours) similar to players, with lower leg muscle strains being the most common type of non-contact injuries in referees. The implementation of injury prevention programmes along with the careful monitoring of training and match loads may help minimize referee's injury incidence. The perceptual-cognitive demands of soccer refereeing are significant, yet there remains limited research examining the perceptual and cognitive processes informing referees' decisions. As such, a three-step approach for the study of expertise in soccer referees is proposed. First, objective and reliable markers of decision making should be established, with due consideration to the development of naturalistic test situations while maintaining experimental control. Second, process-tracing measures can be used to identify the perceptual and cognitive mechanisms involved in accurate decision making. Finally, research is required to help understand the acquisition of superior decision making and whether such expertise can be developed via training programmes.

Successful return to play remains a challenge for a soccer player after anterior cruciate ligament reconstruction. In addition to a successful surgical intervention, a soccer-specific functional rehabilitation program is essential to achieve this goal. Soccer-like elements should be incorporated in the early stages of rehabilitation to provide neuromuscular training specific to the needs of the player. Gym-based and, later, field-based drills are gradually intensified and progressed until the player demonstrates the ability to return to team practice. In addition to the recovery of basic attributes such as mobility, flexibility, strength, and agility, the surgically repaired knee must also regain soccer-specific neuromuscular control and conditioning for an effective return to sports. The individual coaching of the player by the sports physiotherapist and compliance with the training program by the player are key factors in the rehabilitation process. To minimize reinjury risk and to maximize the player's career, concepts of soccer-specific injury prevention programs should be incorporated into the training routine during and after the rehabilitation of players post-ACL reconstruction.

Background: Several proposals for preparticipation screening to detect risk factors for sudden cardiac death in sports have been published, but referees have been neglected in this respect., Methods: A standardised precompetition medical assessment (comprising a general physical, orthopaedic and cardiac examination and blood analysis) was performed in all 90 referees and assistant referees selected for the 2010 Fédération Internationale de Football Association World Cup., Results: More than a third of the referees showed at least one pathological finding in cardiac examinations; however, all follow-up examinations proved to be normal. The relatively high prevalence of pathological findings in the blood analysis and the orthopaedic examination can be attributed to the average age of the referees and none of them was performance limiting., Conclusions: Considering their risk of occult ischaemic heart disease, a precompetition medical assessment including an exercise ECG is recommended in elite male football referees.

The aim of this study was to examine the applicability of a test for change of direction ability (10-8-8-10 test, involving line and sideward sprinting, 36 m) in elite-level soccer assistant referees (ARs). One hundred AR of the first-second and third Italian Championships (ARA-B and ARC, n = 50, respectively) performed the 10-8-8-10 on 3 separate occasions. Twenty AR authorities scored test relevance (1-5 scale, from trivial to very large) for logical validity using a questionnaire. Construct validity was examined comparing ARA-B and ARC for the 10-8-8-10 performance. Short-term reliability was assessed testing a random selection of ARs (n = 64) over 3 separate occasions every other day. Performance in the 10-8-8-10 test was assumed as total coverage time using telemetric photocells. Results showed that the 10-8-8-10 test was perceived as possessing from large (n = 4/20) to very-large (n = 16/20) relevance to AR physical match performance. No significant performance difference was found between competitive levels (p = 0.57). Area under the curve (= 0.49; p = 0.87) showed no significant sensitivity of 10-8-8-10 in detecting competitive-level difference. The intraclass correlation coefficient (n = 64) and typical error of measurement (test 2 vs. 3) values were 0.90 (p < 0.0001) and 0.18 seconds, respectively. This study showed that the 10-8-8-10 test possesses logical validity, good reliability, and it is independent of the competitive level. As such, this original investigation represents the first step in the identification and assessment of a valid and reliable AR change of direction test. Given the strength of our findings, governing bodies should look to integrate the 10-8-8-10 test into the fitness test protocols devised for ARs, with scores ≥ 9.67 being considered as a starting point for the empirical validation of minimum selection criteria for elite-level ARs.

Background: In Switzerland, the national accident insurance company registered a total of 42 262 soccer injuries, resulting in costs of approximately 145 million Swiss francs (~US$130 million) in 2003. Research on injury prevention has shown that exercise-based programs can reduce the incidence of soccer injuries., Purpose: This study was conducted to assess the implementation and effects of a countrywide campaign to reduce the incidence of soccer injuries in Swiss amateur players., Study Design: Cohort study; Level of evidence, 3., Methods: All coaches of the Schweizerischer Fussballverband (SFV) received information material and were instructed to implement the injury prevention program "The 11" in their training of amateur players. After the instruction, the coaches were asked to rate the quality and the feasibility of "The 11." Before the start of the intervention and 4 years later, a representative sample of about 1000 Swiss soccer coaches were interviewed about the frequency and characteristics of injuries in their teams. Teams that did or did not practice "The 11" were compared with respect to the incidence of soccer injuries., Results: A total of 5549 coaches for amateur players were instructed to perform "The 11" in the training with their teams. The ratings of the teaching session and the prevention program were overall very positive. In 2008, 80% of all SFV coaches knew the prevention campaign "The 11" and 57% performed the program or most parts of it. Teams performing "The 11" had an 11.5% lower incidence of match injuries and a 25.3% lower incidence of training injuries than other teams; noncontact injuries in particular were prevented by the program., Conclusion: "The 11" was successfully implemented in a countrywide campaign and proved effective in reducing soccer injuries in amateur players. An effect of the prevention program was also observed in the population-based insurance data and health-care costs.

Objective: To analyze the extent and characteristics of injuries and musculoskeletal complaints in elite football referees and to analyze differences between match and assistant referees., Design: Retrospective cohort study., Setting: Training camp organized by the Swiss Referees Association., Participants: All 71 referees of the 2 top divisions of the Swiss Football League (2005-2006 season)., Interventions: The referees (66 males and 5 females) completed a questionnaire on their personal characteristics, referee qualifications, time spent in training and matches, career history of injuries, and musculoskeletal complaints caused by training or refereeing and were subsequently interviewed about the location, type, circumstances, and consequences of reported injuries., Main Outcome Measures: Incidence of injuries, frequency of musculoskeletal complaints, type of injuries, and complaints., Results: A total of 41 injuries during the career were reported by 31 of 71 referees (44%). Injuries were incurred more frequently in training than during matches, and all injuries reported resulted in at least 2 weeks of absence from sport. About a quarter of the referees reported an injury, and almost 90% of the referees reported musculoskeletal complaints caused by refereeing during the preceding 12 months. In male referees, hamstring strains and ankle sprains were the most common injuries, and the hamstrings, knee, Achilles tendon, and calf were the most prevalent locations of musculoskeletal complaints. No significant difference in the incidence of injury or in the frequency of complaints was observed between match and assistant referees., Conclusions: Future studies should be designed prospectively and should include a larger group of female referees. Regarding the incidence of injuries and frequency of musculoskeletal complaints related to refereeing, prevention programs for football referees should be developed, evaluated, and implemented.

Objective: To examine the effect of a comprehensive warm-up programme designed to reduce the risk of injuries in female youth football., Design: Cluster randomised controlled trial with clubs as the unit of randomisation., Setting: 125 football clubs from the south, east, and middle of Norway (65 clusters in the intervention group; 60 in the control group) followed for one league season (eight months)., Participants: 1892 female players aged 13-17 (1055 players in the intervention group; 837 players in the control group)., Intervention: A comprehensive warm-up programme to improve strength, awareness, and neuromuscular control during static and dynamic movements., Main Outcome Measure: Injuries to the lower extremity (foot, ankle, lower leg, knee, thigh, groin, and hip)., Results: During one season, 264 players had relevant injuries: 121 players in the intervention group and 143 in the control group (rate ratio 0.71, 95% confidence interval 0.49 to 1.03). In the intervention group there was a significantly lower risk of injuries overall (0.68, 0.48 to 0.98), overuse injuries (0.47, 0.26 to 0.85), and severe injuries (0.55, 0.36 to 0.83)., Conclusion: Though the primary outcome of reduction in lower extremity injury did not reach significance, the risk of severe injuries, overuse injuries, and injuries overall was reduced. This indicates that a structured warm-up programme can prevent injuries in young female football players., Trial Registration: ISRCTN10306290.

To examine the effects of aerobic interval training on the decline in short-passing ability caused by a short bout of high-intensity intermittent activities. For this randomized controlled trial, 26 junior soccer players (mean age, 17.8 +/- 0.6 years; mean height, 178 +/- 5 cm; mean body mass, 74.5 +/- 6.9 kg) were recruited. After baseline measurements, subjects were randomly allocated to 1 of 2 groups: the control group (CG) or the aerobic interval training group (ITG). The ITG completed 4 weeks of high-intensity aerobic training, consisting of 4 bouts of running for 4 min at 90%-95% of maximal heart rate, with 3 min of active recovery between sets, in addition to normal training. Maximum oxygen uptake, Yo-Yo Intermittent Recovery Test level 1 (YYIRT), and short-passing ability (measured using the Loughborough Soccer Passing Test (LSPT)) were measured before and after a 5 min high-intensity simulation (HIS), reproducing the most intense phase of a match. The ITG (n = 11), but not the CG (n = 10), showed a significant 12% and 4% increase in YYIRT and maximal oxygen consumption after training, respectively, and reduced the worsening in LSPT penalty time after the HIS (p < 0.05). The relative exercise intensity during HIS decreased in the ITG only (p < 0.01). Our results demonstrated that junior soccer players may benefit from aerobic training to attenuate the decline in short-passing ability caused by a short bout of intermittent activities completed at the same pretraining workload.

The 11+ is a structured warm-up program designed to prevent injuries in soccer players, but has proven efficacy in many populations, settings and sports. It consists of 15 exercises that target the most common injury sites, such as the knee, ankle, and groin. However, the implementation and adherence of the 11+ remain suboptimal, and recent compelling data indicates underlying mechanisms of injury risk related to neural control of movement may not be adequately targeted. Updates to the 11+ considering practical implications of neurocognitive and ecological motor learning may be warranted for coaches and practitioners. We review the evidence on how an updated 11+ may influence the cognitive and perceptual processes involved in motor control and learning, such as attention, anticipation, decision making, and feedback. How the 11+ can be adapted to the ecological constraints and affordances of the football (soccer) environment is also discussed, including the task, the individual, and the context. By considering these factors, the 11+ can be more effective, engaging, and enjoyable for the players, and thus improve its adoption and compliance. The 11+ has the capability to not only a physical warm-up, but also a neurocognitive and ecological preparation for the game. Therefore, the purpose of this manuscript is to describe the conceptual design of a new ecological neurocognitively enriched 11+, that builds on the strong foundation of the original intervention with considerations for the newly discovered potential neural control of movement risk factors. [ABSTRACT FROM AUTHOR]

Background The 11+ injury prevention program (IPP) has been shown to decrease injury rates. However, few studies have investigated compliance and its overall relationship to team performance. Hypothesis/Purpose To examine if level of compliance while implementing the 11+ would impact team performance outcomes (wins, losses and ties). The authors hypothesized that higher team compliance to the IPP would be consistent with improved overall team performance (more wins and fewer losses). Study Design Prospective, cluster randomized controlled trial Methods This study was conducted in NCAA men's soccer teams for one season and examined the efficacy of the 11+ IPP. The outcome variables examined were levels of compliance and team performance record: wins, losses, and ties. Twenty-seven teams (n=675 players) served as the intervention group (IG) and used the 11+ program while 34 teams (n=850 players) served as the control group (CG). Compliance and team performance were recorded. There were three compliance categories that were defined prospectively, low (LC, < 1 dose/week), moderate (MC, >1 and <2 doses/week), and high (HC, >2 doses/week). Descriptive and inferential tests were used to compare the CG, the IG, and compliance to team performance. Three independent t-tests were used to analyze outcome to group (IG vs. CG). A one way-MANOVA test was used to analyze compliance to win/loss/tie record, followed up by one-way ANOVA tests to analyze how compliance impacted wins, losses and ties, independently. Partial η2 measures were calculated to determine the effect size of level of compliance on outcome. A Tukey post-hoc analysis was used to analyze specific differences between levels of compliance and specific outcome measures. Results There were significantly more wins (IG: 10.67±2.63 versus CG: 8.15±3.83, CI, 7.95 -- 9.69, p = 0.005) and fewer losses (IG: 5.56±1.97 versus CG: 8.12±3.59, CI, 5.66 to 7.43, p = 0.002) recorded for the teams using the 11+ program. There was a statistically significant difference between levels of compliance (high, moderate or low) on the dependent variables (wins, losses, and ties), F(3, 22) = 3.780, p =0.004; Wilks' Λ = .435; partial η2 = .340. Conclusion The 11+ has the capacity to improve overall team performance in male collegiate soccer teams. The higher the compliance, the more favorable the team performance. This research may be a vital addition when attempting to persuade coaching staffs to adopt an IPP into their training regimen. [ABSTRACT FROM AUTHOR]

The article outlines clinical practice guidelines for exercise-based knee and anterior cruciate ligament injury prevention. It suggests effective exercise-based knee injury prevention programs for athletes under specific subgroups, including HarmoKnee for soccer players and Sportsmetrics for women athletes. It list abbreviations related to knee and anterior cruciate ligament injury and prevention.

The recent COVID-19 pandemic resulted in a total lockdown of the major football leagues, aiming to prevent the threat of an uncontrolled spread of infections, and forcing the players and match officials to home-based physical training. Differently from players, no health and physical fitness maintenance guidelines were published for match officials. Before the return to structured conditioning and officiating, match officials must perform a medical assessment, as well as systematic COVID-19 testing and detailed pulmonary function evaluation. The hygienic-sanitary prevention strategies for virus transmission must be strictly followed. In the remaining part of the present season, alterations of the game rules, namely halves of 30-40 min and no allowance for lost time, aiming to reduce the match officials physiological load may result as a safer option. Nonetheless, match officials' cognitive and physical demands, will probably be exacerbated by the increased number of substitutions per game, proposed to reduce players' match load. The proposed match scenario further stresses the importance of well-developed aerobic and anaerobic fitness in elite level match officials. Therefore, the aim of this paper was to guide a safe and successful return to play for match officials. [ABSTRACT FROM AUTHOR]

Coaches are essential to participant safety, particularly by implementing injury prevention programs. The evidence-based injury prevention programs developed by sports scientists will not prevent injuries in real-world sports settings if they are not properly implemented. This study investigated the knowledge and use of the highly efficacious 11+ injury prevention program among coaches of adolescent, female football teams, in Victoria, Australia. A cross-sectional online survey based on the RE-AIM framework identified that nearly half (42%) of the 64 respondents (response rate = 36%) were not aware of the 11+, and only one-third (31%) reported using it. Three-quarters (74%) of the 19 respondents who reported on the 11+ components they used, did not use the entire program. Nearly half (44%) of the 18 respondents who reported the frequency with which they used the 11+, used it less than the recommended twice a week. Barriers to implementing the 11+ included: limited awareness of the 11+; lack of knowledge about how to implement it; not having time to implement it; and believing that the 11+ does not incorporate appropriate progression. This study suggests that it is unlikely that the 11+ prevents a significant number of injuries in real-world football settings due to the lack of awareness and use among coaches. Football-governing bodies should use evidence-based strategies to raise awareness of the 11+, build coach competency to implement it, and address time-related implementation barriers that coaches experience. Coaches should keep up-to-date with injury prevention research evidence and prioritize injury prevention at training, including allocating time to implement injury prevention programs properly. [ABSTRACT FROM AUTHOR]