Jan Ekstrand

• MD, PhD
• Professor (Full) at Linköping University

Communication influences players’ performance and health and is influenced by the leadership style of coaches, internal team communication and the integration of the medical team in the professional men’s football setting. However, the communication process between medical teams and other stakeholders in professional football has not been described...

Objectives External risk factors connected to club, team and coaching are believed to be important in the causation of hamstring injuries, but little is known about the preventive measures used. The objective was to analyse the association between preventive factors and hamstring muscle injury burden. Methods 14 teams participated in the Union of...

Purpose The objective was to describe the location, examination procedures, diagnoses, and treatment for gradual-onset Achilles tendon pain in male professional football (soccer) players. Patients and Methods Forty-seven teams were followed prospectively for at least one season from 2013/14 to 2017/18. Time-loss injuries were recorded by the teams...

Introduction Players in women’s elite football teams appear to have a lower risk for sustaining injuries compared to players in men’s elite teams, especially during matches. Between-study comparisons are, however, difficult to interpret because of different designs/definitions. The objective of this study was to investigate potential differences in...

Objective Injuries in women’s football (soccer) have scarcely been investigated, and no study has been conducted in the highest competitive level involving club teams from different countries. Our aim was to investigate the time-loss injury epidemiology and characteristics among women’s elite football players over four seasons. Methods 596 players...

Objective To evaluate whether a change of head coach or other head staff before or during a season is correlated to hamstring injury (HI) burden in male elite-level football (soccer) in Europe. Methods The survey was conducted using a questionnaire reporting any staff change within the team. Data about the head staff changes and hamstring injury b...

Objectives The primary objective was to study the reach, effectiveness, adoption, implementation and maintenance of the Nordic Hamstring Exercise (NHE) programme in women’s elite teams in Europe in the 2020–21 season. The secondary objective was to compare hamstring injury rates between teams that used the NHE programme regularly in team training a...

Purpose: To describe the perceived importance of suggested hamstring injury risk factors according to chief medical officers (CMOs) of European women's professional football clubs. A secondary objective was to compare if these perceptions differed between teams with a lower-than-average and higher-than-average hamstring injury burden. Methods: T...

Objectives To describe the perceived importance of suggested hamstring injury risk factors according to chief medical officers (CMOs) of European male professional football clubs. A secondary objective was to compare if these perceptions differed between teams with a lower-than-average hamstring injury burden and teams with a higher than average ha...

Objectives To: (1) describe hamstring injury incidence and burden in male professional football players over 21 seasons (2001/02 to 2021/22); (2) analyse the time-trends of hamstring muscle injuries over the most recent eight seasons (2014/15 to 2021/22); and (3) describe hamstring injury location, mechanism and recurrence rate. Methods 3909 playe...

Background Studies on football and the coronavirus disease 2019 (COVID-19) have mainly focused on the lockdown consequences for player fitness, the resumption of football training, and how to safely restart the league play, but injury data are scarce. Objective To describe the injury incidence and injury burden in men’s professional football teams...

Objectives The primary objective was to study the adoption of the NHE programme in European football teams in the 2020/21 season and to compare it to the previous study. A second objective was to compare hamstring injury rates between teams that used the NHE programme in the team training and teams that used the NHE only for players with previous o...

Purpose To study the epidemiology and return to play characteristics of anterior and posterior ankle impingement syndromes (AAIS and PAIS) over 18 consecutive seasons in male professional soccer players. Methods Between the 2001–2002 and 2018–2019 seasons, 120 European soccer teams were followed prospectively for various seasons. Time loss injurie...

Objective To describe the injury epidemiology in professional football in South America and compare it with European professional football. Methods Data about football exposures and injury occurrences were registered in Six teams participating in Copa Libertadores in 2016. These teams’ exposure and injury data were compared with teams participatin...

Background Studies on subsequent anterior cruciate ligament (ACL) ruptures and career length in male professional football players after ACL reconstruction (ACLR) are scarce. Aim To investigate the second ACL injury rate, potential predictors of second ACL injury and the career length after ACLR. Study design Prospective cohort study. Setting Me...

Background: The UEFA Elite Club Injury Study is the largest and longest running injury surveillance programme in football. Objective: To analyse the 18-season time trends in injury rates among male professional football players. Methods: 3302 players comprising 49 teams (19 countries) were followed from 2000-2001 through 2018-2019. Team medica...

Background The literature on upper extremity injuries in professional soccer players is scarce, and further insight into the onset and cause of these injuries as well as potential differences between goalkeepers and outfield players is important. Purpose To investigate the epidemiology of hand, wrist, and forearm injuries in male professional socc...

Kvinnor har en väldokumenterad ökad risk att drabbas av främre korsbandsskada i fotboll jämfört med män. Under säsongen 2012 drabbades hela 18 spelare i Damallsvenskans 12 lag av främre korsbandsskada och under första halvåret 2013 drabbades ytterligare tio spelare, så-ledes 28 främre korsbandsskador på 18 månader. Efterföljande år har det glädjand...

Background There is limited epidemiological information on injury rates and injury mechanisms for lateral collateral ligament (LCL) and posterior cruciate ligament (PCL) injuries in male professional soccer. In addition, time trends and lay-off times for these injuries have not yet been determined. Aim To determine injury rates and circumstances o...

Background Preseason training develops players’ physical capacities and prepares them for the demands of the competitive season. In rugby, Australian football, and American football, preseason training may protect elite players against in-season injury. However, no study has evaluated this relationship at the team level in elite soccer. Purpose/Hy...

Objectives To evaluate time to return to play following surgical stabilisation of isolated unstable syndesmosis injuries in a cohort of professional male football players. Methods All professional football players undergoing surgery for isolated unstable syndesmosis injury (West Point grade ≥IIB) at a specialised Orthopaedic and Sports Medicine Ho...

Background It has been hypothesised that injury risk after return to play following an injury absence is influenced by the amount of training completed before return to competition. Aim To analyse if the number of completed training sessions between return to play and the first subsequent match appearance was associated with the odds of injury in...

Purpose: Medial collateral ligament (MCL) injury is the single most common traumatic knee injury in football. The purpose of this study was to study the epidemiology and mechanisms of MCL injury in men's professional football and to evaluate the diagnostic and treatment methods used. Methods: Fifty-one teams were followed prospectively between o...

Background Hip and groin injuries are common in men’s professional football, but the time-trend of these injuries is not known. Aim To investigate hip and groin injury rates, especially time-trends, in men’s professional football over 15 consecutive seasons. Study design Prospective cohort study. Setting Men’s professional football. Methods 47...

The high injury rate among men’s professional football players is well-known. Therefore, the Union of European Football Associations (UEFA) launched an injury study already in 2001. This study, the UEFA Elite Club Injury Study (ECIS), currently includes data from a total of 51 clubs from 18 European countries with more than 14,000 registered injuri...

Background Internal workload (ie, from training and matches) is considered one of the most important injury risk factors for elite European football teams, however there is little published evidence to support this belief. Objective We examined the association and predictive power of internal workload and non-contact injuries. Methods Five elite...

Women’s football is today a big global sport played in all continents. Current literature implies that female football players have a similar overall injury rate compared with male players, but they are more susceptible to sustain concussions, anterior cruciate ligament (ACL) injuries, and stress fractures. This chapter will review the injury chara...

More than half of all registered football players in the world are under 18 years of age. Despite this, the scientific literature on injuries in youth football is scarce compared to senior football, especially in players younger than 12 years. The literature suggests that injuries to the upper extremities are relatively more frequent in players you...

Aim To explore whether high level endurance training in early age has an influence on the arterial wall properties in young women. Methods Forty-seven athletes (ATH) and 52 controls (CTR), all 17 to 25 years of age, were further divided into runners (RUN), whole-body endurance athletes (WBA), sedentary controls (SC) and normally active controls (A...

Since the start in 2001, the UEFA Elite Club Injury Study (UEFA-ECIS) has collected player exposure and injury data from nearly 50 top-level football clubs from 17 different countries. In total, 13,000 injuries during 1.8 million hours have been registered between 2001 and 2016, making it the biggest database of its kind in professional football. A...

Aim To determine the epidemiology of isolated syndesmotic injuries in professional football players. Methods Data from 15 consecutive seasons of European professional football between 2001 and 2016 contributed to the dataset of this study. Match play and training data from a total of 3677 players from 61 teams across 17 countries have been include...

Background The association between match congestion and injury rates in professional football has yielded conflicting results. Aim To analyse associations between match congestion on an individual player level and injury rates during professional football matches. Methods Data from a prospective cohort study of professional football with 133 170...

Background Do coaches’ leadership styles affect injury rates and the availability of players in professional football? Certain types of leadership behaviour may cause stress and have a negative impact on players’ health and well-being. Aim To investigate the transformational leadership styles of head coaches in elite men’s football and to evaluate...

Objectives: Player unavailability negatively affects team performance in elite football. However, whether player unavailability and its concomitant performance decrement is mediated by any changes in teams' match physical outputs is unknown. We examined whether the number of players injured (i.e. unavailable for match selection) was associated wit...

Background There are conflicting results concerning associations between match congestion and injury rates in professional football. Objective To analyze associations between short term match congestion and injury rates in professional football and to study the influence of long term match congestion on such associations. Design Prospective cohor...

Background Studies have shown that previous injury, not necessarily anatomically related, is an important injury risk factor. However, it is not known whether a player runs an increased risk of anterior cruciate ligament (ACL) injury after returning to play from other injury types. Purpose To analyze whether professional soccer players are more su...

Football (soccer) is one of the most popular sports in the world with high-reported injury rates; many injuries are potentially career ending. Stress fractures represent the inability of a normal or weakened bone to withstand repeated stresses and are reported to account for 0.5% of all football-related injuries. The pathophysiology of stress facto...

OVERUSE INJURY IS A ‘TRAINING LOAD ERROR’ Inappropriately high training loads cause overuse injuries.1 However, it has recently been proposed that overuse injuries should be considered in terms of both ‘overloading’ and ‘underloading’.2 The rationale is that increased injury risk is associated with ‘spikes’ in workload (ie, overloading) and low chr...

Background There are limited data on the nature, type and incidence of illness in football. Previous studies indicate that gastrointestinal and respiratory tract illnesses are most common. Aim To describe the incidence and burden of illness in male professional football. Methods Over the 4-year study period, 2011-2014, 73 professional football team...

Svensk Idrottsforskning 2014;2:6-9.

Marta Fotbollsmagasin 2013;1:20-24.

Svensk Idrottsmedicin 2005:(3):38-40.

Dansk Sportsmedicin 2002: 2(6): 11-12.

Aim: The present study evaluated whether the MRI parameters of hamstring injuries in male professional football players correlate with time to return to play (RTP). Methods: 46 elite European football teams were followed prospectively for hamstring injuries between 2007 and 2014. Club medical staff recorded individual player exposure and time-lo...

Background There are limited data on the nature, type and incidence of illness in football. Previous studies indicate that gastrointestinal and respiratory tract illnesses are most common. Aim To describe the incidence and burden of illness in male professional football. Methods Over the 4-year study period, 2011–2014, 73 professional football team...

Background Studies investigating the development of ACL injuries over time in football are scarce and more data on what happens before and after return to play (RTP) are needed. Aim To investigate (1) time trends in ACL injury rates, (2) complication rates before return to match play following ACL reconstruction, and (3) the influence of ACL injury...

Background Previous injury is a well-documented risk factor for football injury. The time trends and patterns of recurrent injuries at different playing levels are not clear. Aim To compare recurrent injury proportions, incidences and patterns between different football playing levels, and to study time trends in recurrent injury incidence. Methods...

Background Determining fracture risk and rehabilitation periods after specific fractures in professional football is essential for team planning. Aim To identify fracture epidemiology and absences after different types of fractures in male professional football players. Methods 2439 players from 41 professional male teams in 10 countries were follo...

Purpose (1) To quantify current practice at the most elite level of professional club football in Europe with regard to injury prevention strategy; (2) to describe player adherence and coach compliance to the overall injury prevention programme. Methods A structured online survey was administered to the Head medical officers of 34 elite European te...

Background There are limited data on hamstring injury rates over time in football. Aim To analyse time trends in hamstring injury rates in male professional footballers over 13 consecutive seasons and to distinguish the relative contribution of training and match injuries. Methods 36 clubs from 12 European countries were followed between 2001 and 2...

Methodological considerations of football injury epidemiology have only scarcely been described. The aim of this study was to evaluate the inter-rater agreement in injury capture rate and injury categorization for data registered in two different prospective injury surveillance audits studying the same two Norwegian male professional football clubs...

To explore the associations of severe musculoskeletal injuries (joint and muscles) and surgeries with symptoms of common mental disorders (distress, anxiety/depression, sleeping disturbance, adverse alcohol behaviour , smoking, adverse nutrition behaviour) among male European professional footballers. Cross-sectional analyses were conducted on elec...

To investigate frequent surface shifts and match play on an unaccustomed surface as potential risk factors for injury in Scandinavian male professional football. Prospective cohort study. Thirty two top-division clubs (16 Swedish, 16 Norwegian) were followed during seasons 2010 and 2011. The influence from (1) number of surface shifts (between arti...

Heterogeneous taxonomy of groin injuries in athletes adds confusion to this complicated area. The 'Doha agreement meeting on terminology and definitions in groin pain in athletes' was convened to attempt to resolve this problem. Our aim was to agree on a standard terminology, along with accompanying definitions. A one-day agreement meeting was held...

The Nordic hamstring (NH) exercise programme was introduced in 2001 and has been shown to reduce the risk of acute hamstring injuries in football by at least 50%. Despite this, the rate of hamstring injuries has not decreased over the past decade in male elite football. To examine the implementation of the NH exercise programme at the highest level...

Groin injuries are troublesome in men's and women's football. To review the literature on the epidemiology of groin injury in senior football and compare injury occurrence between sexes. Studies were identified through a search of PubMed, EMBASE, CINAHL and Web of Science, in the reference lists of the selected articles and the authors' bibliograph...

Data regarding direct athletic muscle injuries (caused by a direct blunt or sharp external force) compared to indirect ones (without the influence of a direct external trauma) are missing in the current literature-this distinction has clinical implications. To compare incidence, duration of absence and characteristics of indirect and direct anterio...

Background Little is known about the short-term and long-term sequelae of concussion, and about when athletes who have sustained such injuries can safely return to play. Purpose To examine whether sports-related concussion increases the risk of subsequent injury in elite male football players. Study design Prospective cohort study. Methods Injuries...

Abstract This prospective cohort study described return-to-play (RTP) data for different types of muscle injuries in male elite-level football players in Europe. Eighty-nine European professional teams were followed between 2001 and 2013. Team medical staff recorded individual player exposure and time-loss injuries. A total of 17,371 injuries occur...

Medial collateral ligament (MCL) injury of the knee is scarcely investigated in football. To investigate the rate and circumstances of MCL injuries and their development over the past decade. Prospective cohort study, in which 27 professional football teams were followed between 2001/02 and 2011/12. Individual player exposure and time loss injuries...

Background The influence of fixture congestion on injury rates and team performance has only been scarcely investigated. Objective To study associations between match load, recovery days, injury rates and team match performances in professional football. Design Prospective cohort study. Setting European professional football. Participants 27 teams,...

Background Studies generally report similar acute injury rates when playing football on artificial turf (AT) compared with natural grass (NG), but the association between playing surface and overuse injury rates is rarely reported. Objective To compare (i) acute injury rates in professional football played on AT and NG at the individual player leve...

Although athletic muscle injuries are very frequent, a consistent and comprehensive classification system as well as a clear terminology were so far missing. In order to facilitate effective communication among medical practitioners and to support the development of systematic treatment strategies, we developed practical and systematic definitions...

Australian Football League (AFL) teams in northern (warmer) areas generally have higher rates of injury than those in southern (cooler) areas. Conversely, in soccer (football) in Europe, teams in northern (cooler) areas have higher rates of injury than those in southern (warmer) areas, with an exception being knee anterior cruciate ligament (ACL) i...

The influence of fixture congestion on injury rates and team performance has only been scarcely investigated. To study associations between recovery time and match load and injury rates and team performance in professional football. Exposure and time loss injuries were registered prospectively from 27 teams over 11 seasons. Matches were grouped acc...

The risk of injury in professional football has been estimated at about 1000 times greater than for typical industrial occupations generally regarded as high risk.1 Hence, prevention of injury in football should be of the utmost importance, and conducting injury surveillance studies is the fundamental first step in the process of prevention.2 The...

Limited information is available on the variation in injury rates over multiple seasons of professional football. To analyse time-trends in injury characteristics of male professional football players over 11 consecutive seasons. A total of 1743 players comprising 27 teams from 10 countries were followed prospectively between 2001 and 2012. Team me...

This issue of the BJSM contains 10 injury surveillance articles concentrated on the world's largest and most popular sport, football. As presented by Bizzini et al , football is played by almost 300 million people—or around 4% of the world's population.1 From a medical perspective, football contains many positive motivational and social factors t...

Ankle injury is common in football, but the circumstances surrounding them are not well characterised. To investigate the rates, especially time-trends, and circumstances of ankle injuries in male professional football. 27 European clubs with 1743 players were followed prospectively between 2001/2002 and 2011/2012. Time loss injuries and individual...

Background There is limited information about Achilles tendon disorders in professional football. Aims To investigate the incidence, injury circumstances, lay-off times and reinjury rates of Achilles tendon disorders in male professional football. Methods A total of 27 clubs from 10 countries and 1743 players have been followed prospectively during...

Background Previously, no difference in acute injury rate has been found when playing football on artificial turf (AT) compared with natural grass (NG). Aim To compare acute injury rates in professional football played on AT and NG at the individual player level; and to compare, at club level, acute and overuse injury rates between clubs that have...

Background Owing to the complexity and heterogeneity of muscle injuries, a generally accepted classification system is still lacking. Aims To prospectively implement and validate a novel muscle injury classification and to evaluate its predictive value for return to professional football. Methods The recently described Munich muscle injury classifi...

Background: The influence of injuries on team performance in football has only been scarcely investigated. Aim: To study the association between injury rates and team performance in the domestic league play, and in European cups, in male professional football. Methods: 24 football teams from nine European countries were followed prospectively...

Background: Player activities in soccer matches are influenced by the match result and match venue. It is not known whether injury rates are influenced by these factors. Purpose: To investigate whether there are associations between injury rates and the match result, venue, and type of competition in male soccer. Study design: Cohort study; Le...

Background Medial collateral ligament (MCL) injury is the most common knee ligament injury in professional football. Aim To investigate the rate and circumstances of MCL injuries and development over the past decade. Methods Prospective cohort study, in which 27 professional European teams were followed over 11 seasons (2001/2002 to 2011/2012). Tea...

Background: No study has investigated whether newcomers to professional soccer have a different injury rate than established players. Purpose: The primary objective was to investigate whether being a newcomer to professional soccer influences injury rates. The secondary objective was to evaluate whether playing position and player age influence...

Background There is little information about Metatarsal Five (MT-5) fractures for specific sports. Objective To study the occurrence, the imaging characteristics, the lay-off times and healing problems of MT-5 fractures among male footballers. Methods Sixty-four European elite teams were monitored from 2001 to 2012. x-Rays were collected and classi...

Objective: To investigate the rate of and risk factors for head and neck injury in male soccer. Design: Prospective cohort study. Setting: Professional soccer. Participants: Twenty-six European teams between 2001/2002 and 2009/2010. Assessment of risk factors: Simple and multiple risk factor analyses were evaluated using Cox regression for...

Objective: To present some results from the on-going survey on male professional football players in Europe, the UEFA Champions League (UCL) injury study. Methods: A total of 27 clubs from ten countries and 1500 players have been followed prospectively during eleven seasons between 2001 and 2012. The design harmonizes with the FIFA-UEFA consensus s...

Background: Muscle injury is the most common injury type in professional soccer players. Despite this, risk factors for common lower extremity injuries remain elusive. Purpose: To evaluate the effects of various player- and match-related risk factors on the occurrence of lower extremity muscle injury in male professional soccer. Study design:...

Objective To provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies. Methods Thirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to comple...

Purpose To investigate the epidemiology of upper extremity injuries in male elite football players and to describe their characteristics, incidence and lay-off times. Methods Between 2001 and 2011, 57 male European elite football teams (2,914 players and 6,215 player seasons) were followed prospectively. Time-loss injuries and exposure to training...

Background Football turf is increasingly used in European soccer competition. Little is known on the rotational torque that players experience on these fields. High rotational torques between the shoe outsole and the sports surface has been correlated with torsional injuries of the lower limb and knee. Purpose To evaluate the effect of six paramete...

A prospective study of thigh muscle injuries in European male professional football teams was carried out during the years 2001–2008. The objective was to evaluate the risk and circumstances of thigh muscle injuries in a homogenous material of male professional football players. The participants were first team squads of 21 teams selected by UEFA a...

Purpose: Identification of the most relevant diagnostic and prognostic factors of physical examination and imaging of hamstring injuries in (elite) athletes. Methods: A literature search was conducted in MEDLINE and EMBASE for articles between 1950 and April 2011. A survey was distributed among the members of the European Society of Sports Traum...

Hamstring injury is the single most common injury in professional football. MRI is commonly used to confirm the diagnosis and provide a prognosis of lay-off time. To evaluate the use of MRI as a prognostic tool for lay-off after hamstring injuries in professional football players and to study the association between MRI findings and injury circumst...

The objective of this study was to investigate regional differences in injury incidence in men's professional football in Europe. A nine-season prospective cohort study was carried out between 2001-2002 and 2009-2010 involving 1357 players in 25 teams from nine countries. Teams were categorized into different regions according to the Köppen-Geiger...

Patellar tendinopathy is common among athletes in jumping sports and in sports with prolonged repetitive stress of the knee extensor apparatus. The epidemiology in soccer is not well described. This study was undertaken to investigate and describe the epidemiology of patellar tendinopathy in elite male soccer players and evaluate potential risk fac...

Football (soccer), the most popular sport worldwide, is associated with a high injury risk, and the knee joint is often affected. Several studies have found female players to be more susceptible to knee injury, anterior cruciate ligament (ACL) injury in particular, compared to their male counterparts. There is, however, some controversy regarding t...

Background Patellar tendon injuries are common in jumping sports. The epidemiology in soccer is not well described. Objective To study the epidemiology of patellar tendon injury in elite male soccer players and evaluate potential risk factors. Design Prospective cohort study. Setting Men's professional soccer. Participants 51 European elite soc...

Background The influence of different weather conditions on injury risk has only been scarcely investigated. Objective The objective was to study the influence of climate type on injury epidemiology in men's professional football in Europe. Design Prospective cohort study. Setting Men's professional football from nine European football associati...

Muscle injuries constitute a large percentage of all injuries in football. To investigate the incidence and nature of muscle injuries in male professional footballers. Cohort study; Level of evidence, 2. Fifty-one football teams, comprising 2299 players, were followed prospectively during the years 2001 to 2009. Team medical staff recorded individu...