British Journal of Sports Medicine

Published by BMJ Publishing Group
Online ISSN: 1473-0480
Print ISSN: 0306-3674
Publications
Mucosal immune concentrations (IgA and IgA1) measured in saliva at baseline and after each of the experimental treatments 
Changes in whole-blood cytokine concentrations between L fermentum and placebo treatments 
To evaluate the ability of a probiotic Lactobacillus fermentum VRI-003 (PCC) to enhance the mucosal immune system of elite athletes. A double-blind, placebo-controlled, crossover trial was conducted over a 4-month period of winter training. PARTICIPANTS; 20 healthy elite male distance runners. PCC was given at a daily dose of 1.26 x 10(10) as a freeze-dried powder in gelatin capsules. Placebo capsules contained an inert excipient. Treadmill performance (monthly), mucosal and systemic immunity (monthly), training (daily) and illness (daily) were assessed. Serum cytokine levels, salivary IgA levels and incidence, duration and severity of respiratory tract infections were measured. Subjects reported less than half the number of days of respiratory symptoms during PCC treatment (30 days) compared with placebo (72 days, p<0.001). Illness severity was also lower for episodes occurring during the PCC treatment (p = 0.06). There were no significant differences in the mean change in salivary IgA and IgA1 levels, or in interleukin (IL)4 and IL12 levels, between treatments. However, PCC treatment elicited a twofold (p = 0.07) greater change in whole-blood culture interferon gamma (IFNgamma) compared with placebo. No substantial changes in running performance measures were seen over the study period. Prophylactic administration of PCC was associated with a substantial reduction in the number of days and severity of respiratory illness in a cohort of highly trained distance runners. Maintenance of IFNgamma levels may be one mechanism underpinning the positive clinical outcomes.
 
Regular exercise is promoted for its over- all health benefits. Pregnancy is recog- nised as a unique time for behaviour modification and is no longer considered a condition for confinement. It is cur- rently recognised that habits adopted during pregnancy could affect a woman's health for the rest of her life.For the first time the recommendation suggests a possible role for exercise in the preven- tion and management of gestational diabetes. The recommendations also promote exercise for sedentary women and those with medical or obstetric complications, but only after medical evaluation and Sports Medicine (CDC-ACSM) have rec- ommended the accumulation of 30 min- utes or more of moderate intensity physical activity on most, and preferably all,days of the week. 4 Moderate intensity physical activity is defined as activity with an energy requirement of 3-5 metabolic equivalents (METS). For most healthy adults, this is equivalent to brisk walking at 3-4 mph. The CDC-ACSM statement also recognises that more intense exercise performed in 20-60 minute sessions on three to five days a week will result in higher levels of physi- cal fitness. Despite the fact that pregnancy is associated with profound anatomical and physiological changes, there are few instances that should preclude otherwise healthy,pregnant women from following the same recommendations.
 
Extensive effort has been put into awareness and prevention programs to decrease the overall rate of injury and the difference between sexes. The objective of this review is to document the rate of ACL injury in 14 collegiate sports over an eight year period and compare it to an earlier 16 year review. Descriptive Epidemiology. Universities in the U.S. NCAA athletes. There was no intervention. The primary outcome chosen apriori is injury. The majority of ACL injuries to women occurred by a non-contact mechanism of injury while the majority of ACL injuries to men occurred by a contact mechanism. The highest rates of ACL injury for men were found in American football (0.17 per 1000 A-E and wrestling (0.16 per 1000 A-E). The highest rates of ACL injury for women were found in basketball and lacrosse (0.23 per 1000 A-E). Within the 8 year study period men's and women's ice hockey showed the greatest increase over time with an average annual rate of change of 105% and 136% respectively. Mens' baseball and women's lacrosse showed the greatest decrease in average annual rate of change (16.9% and 17% respectively).When comparing the current 8 years of data to previously reported 16 years of data baseball and women's basketball, showed no change, men's basketball, lacrosse, and wrestling along with field hockey showed an increase and American football, men's and women's ice hockey and soccer, women's lacrosse, softball, and volleyball showed a decrease in overall injury rate. Despite focused scientific efforts and prevention programs ACL injuries remain a significant injury in collegiate sports. Women continue to sustain ACL injuries at higher rates than men in the comparable sports of soccer, basketball, and lacrosse.
 
In my peregrinations from the ACSM meeting in St Louis to England, Norway, and Canada recently, I found myself desperately searching the airport bookshops for something distracting to while away the hours of travel and came across an absolute cracker of a sports medicine book. No, I don't mean yet another soccer book, although I do note that the quality of the books has improved out of sight in recent years. It makes a pleasant change given that many sports books are written for fans that follow the text with their fingers! No, this book is about muscles. It is called Prime mover: a natural …
 
Data on the sporting disciplines of the athletes 
Electrocardiograph changes in an elite soccer player from a British Premier League club showing sinus bradycardia, sinus arrhythmia, and Sokolow voltage criterion for left ventricular hypertrophy typical of that seen in most of the athletes in this study. In addition, there is right axis deviation and tall T waves. 4 by 2.5s + 1 rhythm ld 10.0 mm/mV 25.0 mm/s 
Electrocardiographic results 
To evaluate the spectrum of electrocardiographic (ECG) changes in 1000 junior (18 or under) elite athletes. A total of 1000 (73% male) junior elite athletes (mean (SD) age 15.7 (1.4) years (range 14-18); mean (SD) body surface area 1.73 (0.17) m2 (range 1.09-2.25)) and 300 non-athletic controls matched for gender, age, and body surface area had a 12 lead ECG examination. Athletes had a significantly higher prevalence of sinus bradycardia (80% v 19%; p<0.0001) and sinus arrhythmia (52% v 9%; p<0.0001) than non-athletes. The PR interval, QRS, and QT duration were more prolonged in athletes than non-athletes (153 (20) v 140 (18) milliseconds (p<0.0001), 92 (12) v 89 (7) milliseconds (p<0.0001), and 391 (27) v 379 (29) milliseconds (p = 0.002) respectively). The Sokolow voltage criterion for left ventricular hypertrophy (LVH) and the Romhilt-Estes points score for LVH was more common in athletes (45% v 23% (p<0.0001) and 10% v 0% (p<0.0001) respectively), as were criteria for left and right atrial enlargement (14% v 1.2% and 16% v 2% respectively). None of the athletes with voltage criteria for LVH had left axis deviation, ST segment depression, deep T wave inversion, or pathological Q waves. ST segment elevation was more common in athletes than non-athletes (43% v 24%; p<0.0001). Minor T wave inversion (less than -0.2 mV) in V2 and V3 was present in 4% of athletes and non-athletes. Minor T wave inversion elsewhere was absent in non-athletes and present in 0.4% of athletes. ECG changes in junior elite athletes are not dissimilar to those in senior athletes. Isolated Sokolow voltage criterion for LVH is common; however, associated abnormalities that indicate pathological hypertrophy are absent. Minor T wave inversions in leads other than V2 and V3 may be present in athletes and non-athletes less than 16 but should be an indication for further investigation in older athletes.
 
Background The knowledge on the relation between running patterns and Running Related Injuries (RRIs) is sparse. Studies have tried to document a relationship. However, no firm conclusions can be made. Still it is necessary to identify which running exposures increase the risk of injuries and which exposures might be considered safe. Objective The purpose of this study is to investigate the link between the running volume and the development of RRIs. Design Observational prospective follow up study. Setting Clinical setting on novice and recreational athletes. Participants Healthy individuals (N=1000) who have not been running the past 1 year is included. All participants receive a global positioning system (GPS) watch (Garmin FR 110) and a pair of neutral running shoes (Adidas Glide 2). They are instructed to start running as much as they want, two times a week as a minimum. They must wear their GPS watch at each training session and upload data to an internet based database. All participants are followed for 1 year. Assessment of risk factors Running volume measured as absolute number of kilometres and the graduation in kilometres pr. week over a period of 3 weeks. Main outcome measurement RRI is defined as any musculoskeletal complaint of the lower extremity or back causing a restriction of running for at least 1 week. Results Time to RRI is compared between groups with different absolute running volumes. In a similar way time to injury is compared between individuals with different weekly training graduations. Conclusion This study may be the first study to adequately measure running patterns reliably in a large sample. The exposure is quantified by GPS, which is not affected by subject recall and is therefore a clear methodological improvement compared to previous studies. If absolute volume or running graduation over time seems to lead to injury, the study findings and methodology create a solid foundation for future randomised controlled trials in this field.
 
Adaptive rowing (AR) at the Paralympic level is accessible for rowers with physical disability. AR was included for the first time in the Beijing 2008 Paralympic Games. Racing distance for all AR events is currently 1000 m, which impedes public recognition of this sport and leads to many organisational challenges during the inclusive World Rowing Championships. The aim of this report was to discuss the feasibility of increasing AR race distance to 2000 m from a sports injury and athletic health perspective. As limited data on injury and illness risks exist in AR, knowledge and experiences had to be taken from other Paralympic sports. The anticipated duration of 2000 m AR competitions is either comparable or considerably lower than that of the other Paralympic disciplines with similar characteristics. AR has inherent injury and health risks especially within thorax, shoulders and low back region, but they are not expected to be significantly modified by increased racing times. Specific considerations need to be taken into account for athletes with a spinal cord injury, like in other sport disciplines. There are no distinctive contra-indications for AR events of 2000 m based on the current literature review and a 10-year experience in this sport. Long-term follow-ups are needed to understand fully the injury and health risk associated with AR and to develop appropriate prevention strategies.
 
The blood glucose response of a male ultramarathon runner was monitored throughout a 1005-km race. Before the race the runner had a fasting blood glucose concentration of 5.1 mM. At no stage during the race were his mean blood glucose levels less than 5.8 mM. This was partially attributed to the eating patterns of the athlete, the times at which blood samples were taken, the glycaemic index of food ingested and hyperglycaemia. While there was no evidence of glucosuria, ketones were present in the urine on one day of the event. There were other signs suggesting that at various stages of the event the runner had a metabolic acidosis. Possible reasons for this are discussed.
 
Serum concentrations of the biochemical markers of brain damage S-100B (A) and neurone specific enolase (NSE) (B) before and after a competitive game of soccer. Symbols corresponding to each player are connected with a line.  
It is a matter of debate whether or not ordinary heading of the ball in soccer causes injury to brain tissue. To analyse concentrations of the biochemical markers of brain tissue damage S-100B and neurone specific enolase (NSE) in serum of female elite soccer players in association with a competitive game. Venous blood samples were obtained from 44 female soccer players before and after a competitive game for analysis. The number of headers and trauma events (falls, collisions, etc) was assessed from videotape recordings for each player. Concentrations of both brain damage markers were increased after the game (S-100B, 0.18 (0.11) v 0.11 (0.05) microg/l (p = 0.000); NSE, 10.14 (1.74) v 9.05 (1.59) microg/l (p = 0.001)). There was a significant correlation between changes in S-100B concentrations and both the number of headers (r = 0.430, p = 0.004) and the number of other trauma events (r = 0.517, p < 0.001). The concentrations of both S-100B and NSE were increased by game associated activities and events. The increases in S-100B concentration were significantly related to the number of headers and other trauma events, which indicates that both these factors may have contributed to these increases.
 
Genes associated with soft-tissue injuries 
Acute and chronic (overuse) musculoskeletal soft tissues injuries are common as a result of sports and occupational related physical activities. These injuries have no single cause -- instead, they result from a complex interaction of intrinsic and extrinsic factors which include genetic factors. Specific genetic elements have been identified for certain soft tissue injuries and I will summarise those in this editorial. I also explore the possible clinical implications of including genetic risk factors in multifactorial models developed to understand the molecular mechanisms of musculoskeletal soft tissue injuries.
 
Mean (SD) of demographic characteristics of all the respondents and of the respondents within each gender. 
Median (IQR) or % of characteristics of the training routine among all the respondents and among the respondents within each gender. 
Background We know that high-performance sports place high stress in the musculoskeletal system, often resulting in injury, pain, or other complaints. It is not unusual for athletes to decide to participate in important competitions, despite an ongoing disability or injury. However, we are unaware of any study that has presented any clear information about this issue in recreational runners. Objective The aims of this study were to calculate the prevalence of presence of musculoskeletal pain in amateur runners immediately before a race and to identify possible factors that could be associated with presence of musculoskeletal pain in this population. Design This is a cross-sectional survey study. Setting These runners were recreational athletes that participated in different races in São Paulo (Brazil), the distance of these races ranged from 5.000/10.000 meters. Participants A convenience sample of 1049 runners, 24.1% women (n=253) and 75.9% men (n=796). Assessment of risk factors This questionnaire contained information on presence of musculoskeletal pain, demographic characteristics, weight, body mass index, running experience, running mileage/week, number of training sessions/week, predominant training surface and coaching utilisation. We used logistic regression analysis to indentify associations between possible factors and presence of musculoskeletal pain (p<0.05). The data were collected 1-2 h prior to the races. Main outcome measurements Presence of musculoskeletal pain. Results The prevalence of presence of musculoskeletal pain was 20% and 26.9% for men and women respectively. Running experience (OR=2.97, 95% CI 1.59 to 5.56) and weekly running distance (OR=1.88, 95% CI 1.02 to 3.48) were associated with presence of musculoskeletal pain in men prior to the race. Conclusion The prevalence of presence of musculoskeletal pain in amateur runners prior to the race was high. We have observed higher experience in running (ie, more than 10 years) and high training volumes (ie, more than 50 Km/week) were associated with presence of musculoskeletal pain.
 
To analyse the characteristics of fatal incidents in fixed object sport parachuting (building, antenna, span, earth (BASE) jumping) and create a basis for prevention. Descriptive epidemiological study. Data on reported fatal injury events (n = 106) worldwide in 1981-2006 retrieved from the BASE fatality list. Assessment of risk factors: Human, equipment and environmental factors. Main outcome measurements: Identification of typical fatal incident and injury mechanisms for each of the four fixed object types of BASE jumping (building, antenna, span, earth). Human factors included parachutist free fall instability (loss of body control before parachute deployment), free fall acrobatics and deployment failure by the parachutist. Equipment factors included pilot chute malfunction and parachute malfunction. In cliff jumping (BASE object type E), parachute opening towards the object jumped was the most frequent equipment factor. Environmental factors included poor visibility, strong or turbulent winds, cold and water. The overall annual fatality risk for all object types during the year 2002 was estimated at about one fatality per 60 participants. Participants in BASE jumping should target risk factors with training and technical interventions. The mechanisms described in this study should be used by rescue units to improve the management of incidents.
 
Population characteristics 
Athletes with a new cardiac diagnosis: clinical characteristics 
history, physical examination and ECG in the study population and test required for each abnormality 
The usefulness and modalities of cardiovascular screening in young athletes remain controversial, particularly concerning the role of 12-lead ECG. One of the reasons refers to the presumed false-positive ECGs requiring additional examinations and higher costs. Our study aimed to assess the total costs and yield of a preparticipation cardiovascular examination with ECG in young athletes in Switzerland. Athletes aged 14-35 years were examined according to the 2005 European Society of Cardiology (ESC) protocol. ECGs were interpreted based on the 2010 ESC-adapted recommendations. The costs of the overall screening programme until diagnosis were calculated according to Swiss medical rates. A total of 1070 athletes were examined (75% men, 19.7±6.3 years) over a 15-month period. Among them, 67 (6.3%) required further examinations: 14 (1.3%) due to medical history, 15 (1.4%) due to physical examination and 42 (3.9%) because of abnormal ECG findings. A previously unknown cardiac abnormality was established in 11 athletes (1.0%). In four athletes (0.4%), the abnormality may potentially lead to sudden cardiac death and all of them were identified by ECG alone. The cost was 157 464 Swiss francs (CHF) for the overall programme, CHF147 per athlete and CHF14 315 per finding. Cardiovascular preparticipation examination in young athletes using modern and athlete-specific criteria for interpreting ECG is feasible in Switzerland at reasonable cost. ECG alone is used to detect all potentially lethal cardiac diseases. The results of our study support the inclusion of ECG in routine preparticipation screening.
 
To evaluate the osmotic and non-osmotic regulation of arginine vasopressin (AVP) during endurance cycling. Design: Observational study. Setting 109 km cycle race. 33 Cyclists. None. Plasma sodium concentration ([Na(+)]), plasma volume (PV) and plasma arginine vasopressin (AVP) concentration ([AVP](p)). A fourfold increase in [AVP](p) occurred despite a 2-mmol l(-1) decrease in plasma [Na(+)] combined with only modest (5%) PV contraction. A significant inverse correlation was noted between [AVP](p) Delta and urine osmolality Delta (r = -0.41, p<0.05), whereas non-significant inverse correlations were noted between [AVP](p) and both plasma [Na(+)] Delta and % PV Delta. Four cyclists finished the race with asymptomatic hyponatraemia. The only significant difference between the entire cohort with this subset of athletes was postrace plasma [Na(+)] (137.7 vs 133.5 mmol l(-1), p<0.001) and plasma [Na(+)] Delta (-1.9 vs -5.1 mmol l(-1), p<0.05). The mean prerace [AVP](p) of these four cyclists was just below the minimum detectable limit (0.3 pg ml(-1)) and increased marginally (0.4 pg ml(-1)) despite the decline in plasma [Na(+)]. The osmotic regulation of [AVP](p) during competitive cycling was overshadowed by non-osmotic AVP secretion. The modest decrease in PV was not the primary non-osmotic stimulus to AVP. Partial suppression of AVP occurred in four (12%) cyclists who developed hyponatraemia during 5 h of riding. Therefore, these results confirm that non-osmotic AVP secretion and exercise-associated hyponatraemia does, in fact, occur in cyclists participating in a 109 km cycle race. However, the stimuli to AVP is likely different between cycling and running.
 
To report a case of exertional hyponatraemic encephalopathy that occurred despite a modest rate of fluid intake during a 109 km cycling race. Men and women cyclists were weighed before and after the race. All subjects were interviewed and their water bottles measured to quantify fluid ingestion. A blood sample was drawn after the race for the measurement of serum Na(+) concentration. From the full set of data (n = 196), one athlete was found to have hyponatraemic encephalopathy (serum [Na(+)] 129 mmol/l). She was studied subsequently in the laboratory for measurement of sweat [Na(+)] and sweat rate. Despite a modest rate of fluid intake (735 ml/h) and minimal predicted sweat Na(+) losses, this female athlete developed hyponatraemic encephalopathy. The rate of fluid intake is well below the rate currently prescribed as optimum. Drinking to thirst and not to a set hourly rate would appear to be the more appropriate behaviour.
 
On Sunday 11 June 2006, 8000 people undertook a “fun run” in Hyde Park, the BUPA Capital 10K. During the course of the afternoon, St Mary’s Hospital emergency department received four, and another local hospital received three, collapsed adult runners. All collapsed at 7–10 km, were confused, and showed signs of severe heat stroke (with core temperatures of 40–41°C). Three patients required intubation, and three required sedation and high dependency unit care. One patient was admitted to the intensive care unit for 72 hours. Happily all survived, but there are some important lessons to be learnt for future similar events. No official temperatures were recorded at …
 
Sixty male distance athletes were divided into three equal groups according to their personal best time for the 10km run. The runners were measured anthropometrically and each runner completed a detailed questionnaire on his athletic status, training programme and performance. The runners in this study had similar anthropometric and training profiles to other distance runners of a similar standard. The most able runners were shorter and lighter than those in the other two groups and significantly smaller skinfold values (P less than 0.05). There were no significant differences between the groups for either bone widths or circumferences but the elite and good runners had significantly higher ponderal indices (P less than 0.05) than the average runners, indicating that they are more linear. Elite and good runners were also less endomorphic but more ectomorphic than the average runners. The elite runners trained more often, ran more miles per week and had been running longer (P less than 0.05) than good or average runners. A multiple regression and discriminant function analysis indicated that linearity, total skinfold, the type and frequency of training and the number of years running were the best predictors of running performance and success at the 10km distance.
 
Hyperglycaemia accelerates collagen cross-linking in tendons, which may manifest as an increased thickness or as an altered response to load. Type 1 diabetes mellitus (T1DM) is a unique population exhibiting hyperglycaemia independent of obesity and low physical activity. Ultrasound tissue characterisation (UTC) quantifies the structural integrity of a tendon based on the alignment of collagen, represented as echo-types (I-IV). To measure achilles tendon response to a 10km run among individuals with T1DM and controls. In this case-control study, UTC scans were taken at day 0, 2, 4 after a 10 km run. Analysis of UTC scans was performed in a blinded fashion. Social running club for people with T1DM. Individuals with T1DM (n=7) were diagnosed 13±12 years ago. Control participants (n=10) had no diagnosis or family history of T1DM. Participants all regularly ran ≥5 km in a recreational capacity with an average weekly distance of 18±3 km. VISA-A scores were 94±11 (T1DM) and 94±10 (control). The independent variable was diagnosis of T1DM (yes/no). HbA1c and blood glucose were also measured. Tendon response to a 10km run measured with UTC was defined as the key outcome variable before data collection. Baseline structure was the same in control and T1DM groups for all UTC four echo-types (I-IV) and for anteroposterior thickness (P>.05). Furthermore, no significant differences were observed within each group in response to the run. A novel finding that Achilles tendon baseline structure and response to a 10 km run over 4-days is the same in controls and T1DM. This suggests that T1DM individuals who are regularly physically active do not undergo the same structural changes to their Achilles tendon as previously demonstrated in the general diabetic population.
 
Background The 11 and The 11+ are accepted effective injury-prevention training programs for junior football players. However, their impact on physical fitness is unclear. Objective To elucidate the effectiveness of The 11 and The 11+A in injury prevention and physical fitness improvement. Design A prospective and pre-post intervention study. Setting The first division of a Japanese collegiate football league. Participants This study included 182 collegiate male football players, who were divided into three groups: The 11 (n=62), The 11+A (n=60) and Control (n=59). 77 players were evaluated for physical fitness. Interventions The 11 program, originally developed by FIFA, and The 11+A, by one of the authors, were conducted once or twice a week for 6 months. The 11+A focuses on plyometric training and differs slightly from The 11+. Main outcome measures Injury incidence rates during football (game and training), game and training were reported as the number of injuries per 1000 player-hours (PH). Using several field tests (sprint, pro-agility, bounding and balance), each subject's physical fitness level was evaluated prior to and 6 months after training. Results The incidence rates during football, game and training were 3.62, 19.18 and 2.58 injuries/PH in the Control group, 2.27, 11.92 and 1.53 injuries/PH in The 11 group and 2.24, 10.75 and 1.75 injuries/PH in The 11+A group, respectively. The injury incidence rate during football was significantly lower in both the training groups than in the Control group (p<0.05). Pro-agility time was significantly decreased in both training groups than in the Control groups (p<0.05). Balance ability improved significantly only in the 11 group (p<0.05). Conclusion The 11 and The 11+A were effective in injury prevention and physical fitness improvement.
 
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-player exposure during training sessions and matches were recorded. Injury rate was defined as the number of injuries/1000 h. A total of 1080 ankle injuries were recorded (13% of all injuries) with lateral ligament ankle sprain being the most common injury subtype (51% of all ankle injuries). The rates of ankle injury and ankle sprain were 1/1000 h and 0.7/1000 h, respectively. The ankle sprain rate declined slightly over time during the 11-year study period (on average 3.1%/season) with a statistically significant seasonal trend (p=0.041). Foul play according to the referee was involved in 40% of the match-related ankle sprains. Syndesmotic sprains and ankle impingement were uncommon causes of time loss (3% each of all ankle injuries). Lateral ligament ankle sprain constituted half of all ankle injuries in male professional football, whereas ankle impingement syndromes were uncommon. The ankle sprain rate decreased slightly over time, but many ankle sprains were associated with foul play. Our data extend the body of literature that provides football policy makers with a foundation to review existing rules and their enforcement.
 
Injury knowledge and beliefs influence uptake of injury prevention programs. The effect of exposure to prevention programs on knowledge and beliefs is not well understood. To explore the effect of exposure to the FIFA 11+ program on the injury knowledge and beliefs of female youth soccer coaches and players. A sub-cohort analysis from a cluster-randomized controlled trial. Youth soccer league venues in Alberta, Canada. 31 female teams [coaches n=29, players (ages 13-18) n=258]. Teams recorded FIFA 11+ adherence during the season. Coaches and players completed pre-season and post-season questionnaires to assess changes in injury knowledge and prevention beliefs after FIFA 11+ exposure. At baseline, 62.8% (95% CI: 48.4-77.3) of coaches and 75.8% (95% CI: 71.5-80.1) of players considered "inadequate warm-up" a risk factor for injury. There was no effect of 11+ adherence on this belief (odds ratio=1.0; 95% CI: 0.9-1.1), although more players (78.7%; 95% CI: 73.77-83.7) than coaches (51.7%; 95% CI: 33.55-69.9) considered "inadequate warm-up" a risk factor at post-season. At baseline, 13.8% (95% CI: 1.3-26.4) of coaches believed a warm-up could prevent muscle injuries, but none believed it could prevent knee and ankle injuries. For players, 9.7% (95% CI: 6.1-13.3), 4.7% (95% CI: 2.1-7.3), and 4.7% (95% CI: 2.1-7.3) believed a warm-up would prevent muscle, knee, and ankle injuies, respectively. There was no effect of adherence on post-season beliefs that a warm-up could prevent an injury, for coaches or players. Exposure to the FIFA 11+ appears insufficient for changing injury risk or prevention beliefs over a single season. This could have implications for program delivery strategies and may influence sustained program use.
 
Medial collateral ligament injuries of the knee in professional football
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). Team medical staffs recorded player exposure and time loss injuries. MCL injuries were classified into four severity categories. Injury rate was defined as the number of injuries per 1000 player-hours. Results 346 MCL injuries occurred during 1 057 201 h (rate 0.33/1000 h). The match injury rate was nine times higher than the training injury rate (1.31 vs 0.14/1000 h, rate ratio 9.3, 95% CI 7.5 to 11.6, p<0.001). There was a significant average annual decrease of approximately 7% (p=0.023). The average lay-off was 23 days, and there was no difference in median lay-off between index injuries and reinjuries (18 vs 13, p=0.20). Almost 70% of all MCL injuries were contact-related, and there was no difference in median lay-off between contact and non-contact injuries (16 vs 16, p=0.74). Conclusions This largest series of MCL injuries in professional football suggests that the time loss from football for MCL injury is 23 days. Also, the MCL injury rate decreased significantly during the 11-year study period.
 
Descriptive statistics of ballet dancers (n = 64) 
To examine in a cross sectional study the influence of femoral torsion (FT) and passive hip external rotation (PER) on turnout (TO). Starting age, years of classical ballet training, and current and past dance training intensity were assessed to determine their influence on FT, PER, and TO in pre-professional female dancers. Sixty four dancers (mean (SD) age 18.16 (1.80) years) were recruited from four different dance training programmes. They completed a dance history questionnaire. FT was measured using a clinical method. PER was measured with the subjects prone, and TO was measured with the subjects standing. Mean TO was 136 degrees, mean unilateral PER was 49.4 degrees, and mean FT was 18.4 degrees. A positive correlation was observed between PER combined (PERC) and TO (r = 0.443, p < 0.001). A negative association was found between FT combined (FTC) and PERC (r = -0.402, p = 0.001). No association was found between starting age or years of classical ballet training and FTC, PERC, or TO. Dancers who trained for six hours a week or more during the 11-14 year age range had less FT than those who trained less (mean difference 6 degrees, 95% confidence interval 1.4 to 10.3). Students currently training for longer had higher levels of TO (p < 0.001) but comparable PERC and FTC. FT is significantly associated with PERC. Dancers who trained for six hours a week or more at 11-14 years of age had significantly less FT. FTC had a significant influence on PERC, but no influence on the execution of TO.
 
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.
 
Operational definitions used in the study
Seasonal variation in match injury rates among male professional football players.  
Seasonal variation in severe injury rates among male professional football players.  
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 medical staff recorded individual player exposure and time loss injuries. A total of 8029 time loss injuries were recorded. The match unavailability due to injury was 14% and constant over the study period. On average, a player sustained two injuries per season, resulting in approximately 50 injuries per team and season. The ligament injury rate decreased during the study period (R(2)=0.608, b=-0.040, 95% CI -0.065 to -0.016, p=0.005), whereas the rate of muscle injury (R(2)=0.228, b=-0.013, 95% CI -0.032 to 0.005, p=0.138) and severe injury (R(2)=0.141, b=0.015, 95% CI -0.013 to 0.043, p=0.255) did not change over the study period. In addition, no changes in injury rates over the 11-year period were found for either training (R(2)=0.000, b=0.000, 95% CI -0.035 to 0.034, p=0.988) or match play (R(2)=0.282, b=-0.015, 95% CI -0.032 to 0.003, p=0.093). The injury rate has decreased for ligament injuries over the last 11 years, but overall training, match injury rates and the rates of muscle injury and severe injury remain high.
 
Male sex, total training volume (number of hours per week) and match exposure (number of sets played per week) are risk factors for jumper's knee among young elite volleyball players. However, it is not known whether jump frequency differs among players on the same squad. To examine interindividual and sex differences in jump frequency during training and matches in young elite volleyball players. Observational study. Norwegian elite volleyball boarding school training programme. Student-athletes (26 boys and 18 girls, 16-18 years). Individual jump counts were recorded based on visual analysis of video recordings obtained from 1 week of volleyball training (9 training sessions for boys and 10 for girls, 14.1 h and 17.8 h of training, respectively) and 10 matches (5.9 h for boys (16 sets) and 7.7 h for girls (21 sets). A total of 11 943 jumps were recorded, 4138 during matches and 7805 during training. As training attendance and jump frequency varied substantially between players, the total exposure in training ranged from 50 to 666 jumps/week among boys and from 11 to 251 jumps/week among girls. On average, this corresponded to 35.7 jumps/h for boys and 13.7 jumps/h for girls (Student t test, p=0.002). Total jump exposure during matches ranged between 1 and 339 jumps among boys and between 0 and 379 jumps among girls, corresponding to an average jump frequency of 62.2 jumps/h for boys and 41.9 jumps/h for girls (Student t test, p<0.039). The interindividual differences in jump frequency were substantially greater than any differences observed among player functions. Jump frequency has substantial interindividual and sex differences during training and matches in young elite volleyball players. Total jump volume may represent a more important risk factor for jumper's knee than total training volume, warranting further research attention.
 
Operational definitions used in the study
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 11 seasons between 2001 and 2012. The team medical staff recorded individual player exposure and time-loss injuries. Results A total of 203 (2.5% of all injuries) Achilles tendon disorders were registered. A majority (96%) of the disorders were tendinopathies, and nine were partial or total ruptures. A higher injury rate was found during the preseason compared with the competitive season, 0.25 vs 0.18/1000 h (rate ratio (RR) 1.4, 95% CI 1.1 to 2.0; p=0.027). The mean lay-off time for Achilles tendinopathies was 23±37 (median=10, Q1=4 and Q3=24) days, while a rupture of the Achilles tendon, on average, caused 161±65 (median=169, Q1=110 and Q3=189) days of absence. Players with Achilles tendon disorders were significantly older than the rest of the cohort, with a mean age of 27.2±4 years vs 25.6±4.6 years (p<0.001). 27% of all Achilles tendinopathies were reinjuries. A higher reinjury risk was found after short recovery periods (31%) compared with longer recovery periods (13%) (RR 2.4, 95% CI 2.1 to 2.8; p<0.001). Conclusions Achilles tendon disorders account for 3.8% of the total lay-off time and are more common in older players. Recurrence is common after Achilles tendinopathies and the reinjury risk is higher after short recovery periods.
 
To provide information from practice based evidence on the structure of teaching the protocol of "11+" to potential instructors for coaches/handlers of teams as part of an on-goin implementation study. Prequel to an implementation study of the "11+" included sytematic recruitment of interested persons, taking them through a course of training in the Protocol using a self-developed syllabus for two-hours per session over a course of 16 sessions. The individuals recruited were in 2011 and 2012 designated as group A and B respectively. Considerations: 1) The majority of the group of interested people trained can be classified as relatively active but not athletic, 2) Applying principles of exercise training which should be carried out progressively from low intensity to transition accordingly, 3) Time frame allocated at the training venue THE GRANGE SCHOOL IKEJA, LAGOS where the team had access pitch/classroom for a period of two hours for free on Saturdays. Group A completed thier training over a course of 16 weeks which helped in developing a teaching syllabus in 2012. The specified number of sessions was adequate to transfer knowledge effectively from Group A to Group B and equip participants effectively to prepare to teach potential target audience without being lost in translation. It created an opportunity for GROUP A to develop their teaching, technical ability and time management over the course of the sessions. It also created a template adoptable for implementation structure when training coaches/handlers/teams. It is pertinent to have implementation strategies clearly outlined and structured to facilitate better outcomes of learning which may differ from place to place considering a host of factors contributing to affecting the implementation plan. The 16 sessions proposed is deemed adequate but can be completed in a shorter timeline if there is access to facilities for training and funding to facilitate program. The need for research outcome implemetation to target population.
 
Currently, in all regions of the world apart from Africa, more deaths are linked to non-communicable diseases (NCDs) than communicable diseases (WHO, 2010). Being overweight is a major contributory risk factor for NCDs such as high blood pressure, coronary heart disease and type II diabetes. Of the six WHO-designated regions, the Region of the Americas has the highest prevalence (>60%) of overweight adults (aged 20+ years). Mexico is no exception—the proportion of Mexican adults who are overweight or obese has increased from 61.8% in 2000 to 69.7% in 2006 to 71.2% in 2012.1 The prevalence of overweight and obese adolescents is, however, of even greater concern; for example, the prevalence of overweight and obesity among girls (12-19 years old) has grown rapidly in less than 30 years; in this period, the prevalence has more than tripled, rising from 11.1% in 1988 to 28.3% in 1999 to 33.4% in 2006, and is now standing at 35.8% in 2012.2 This situation sent strong alarm bells to the Government and Ministry of Health in Mexico … [Full text of this article]
 
Life-threatening medical emergencies are an infrequent but regular occurrence on the football field. Proper prevention strategies, emergency medical planning and timely access to emergency equipment are required to prevent catastrophic outcomes. In a continuing commitment to player safety during football, this paper presents the FIFA Medical Emergency Bag and FIFA 11 Steps to prevent sudden cardiac death. These recommendations are intended to create a global standard for emergency preparedness and the medical response to serious or catastrophic on-field injuries in football.
 
The countries in the dark colour are the ones whose coaches attended a ‘FIFA 11+’ instructor course (2008–2012).
Eleven steps to implement ‘FIFA 11+’.
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.
 
To assess precautions needed to avoid dangerous hypothermia in endurance sports swims in water below 11 degrees C, using rectal temperature, anthropometric measurements, and voluntary swim times during a six day marathon relay swim. The time in the water and the decrease in rectal temperature were measured during the longest of three to five relay swims by each of eight experienced swimmers in 9.4-11.0 degrees C water. Height, weight, and four skinfold thicknesses were measured. Swimmers with less subcutaneous fat terminated their swims after significantly less time in the water than those with thicker skinfold thickness, even though their rectal temperatures were not significantly lower. The lowest rectal temperature recorded was 34.3 degrees C. Subjective sensation in these experienced swimmers gave reliable guidance on safe durations for swims, and all voluntarily left the water with rectal temperatures that present no threat to people able to rewarm in safe surroundings. Endurance swims in highly competitive conditions or water below 9 degrees C may require continuous temperature monitoring for safety.
 
An 11-year-old high-level competitive female gymnast presented with back pain. Approximately 10 months earlier, she experienced acute pain in the (thoracic-lumbar) mid-spine during a training camp, on the uneven bar. She reported no acute trauma. The pain was located at the paravertebral right side and was provoked by rotation movements to the right. Night-time pain existed. She went to a physiotherapist, who at physical examination found a movement with typical local fixation in the spine (paradox movement). There were no neurological symptoms. The pain was mainly felt when her posture changed from anterior flexion to extension of the spine and with rotation to the right. At this first presentation of symptoms, she trained 20 h a week. Although physiotherapy, manual therapy and a period of rest slightly improved the situation, a setback occurred after another intensive training camp, now with continuous pain, increasing during jumping (like dismounts from the gymnastics apparatus) and running. On examination, there was a painful right straight leg raise without neurological symptoms. There was painful limited range of motion during extension of the spine; anterior flexion was only slightly painful. The pain was again located on the right side (paravertebral) and on palpation of the vertebra in the proximal lumbar spine. The patient was first referred for conventional radiography (figure 1) and 1 month later for MRI of the lumbar spine (figures 2 and 3).
 
To implement and assess Fédération Internationale de Football Association Medical Assessment and Research Centre's '11 for Health' football-based health education programme for children. Prospective, 2-cohort study. In-school groups (Mauritius); out-of-school groups (Zimbabwe). Mauritius: 389 children, aged 12-15 years; Zimbabwe: 395 children, aged 10-14 years. Eleven 90-min sessions, each divided into two 45-min halves of Play Football (focusing on one football skill) and Play Fair (focusing on one health issue). 30-item questionnaire implemented pre and postintervention to assess children's health knowledge; six-item questionnaire implemented postintervention to assess children's views about the '11 for Health' programme. Mean pre and postintervention health knowledge scores were greater in Mauritius (pre: 69.3%; post: 87.1%) than Zimbabwe (pre: 57.8%; post: 76.2%) but the mean gain in health knowledge was greater in Zimbabwe (18.4%) than Mauritius (17.8%). There were few significant differences in the outcomes for boys and girls in both countries. The '11 for Health' programme was received positively by the children in both countries and there were no significant differences in the views of boys and girls in either country. The study demonstrated that it was possible to achieve significant increases in children's knowledge for all health messages by implementing the '11 for Health' programme in a school-based setting in collaboration with a national Football Association and in an out-of-school setting in collaboration with a non-government organisation. Based on these positive results, the authors recommend that the programme be widely implemented in Africa in co-operation with government and non-government organisations.
 
Subjects characteristics
Pre and post intervention result for EXP and CON group
Futsal is a high risk sport, especially in youth level. But none has studied the application of FIFA 11+, the football injury prevention program among youth futsal players in Indonesia. To determine the effectiveness of FIFA 11+ in improving physical fitness components affecting injury risks among youth futsal players. This experimental study was recruiting two groups of youth futsal players by doing purposive/judgmental random sampling to the senior high school futsal teams in Yogyakarta, Indonesia. High school futsal league. The subjects were high school students participating in the school futsal team. From the total of 28 subjects (15 subjects in the experiment group and 13 in control group), 8 subjects were dropping out, leaving 9 subjects in the experiment group and 11 in the control group for the final analysis. The experiment (EXP) group underwent FIFA 11+ training twice per week for four weeks while the control (CON) group underwent routine futsal training. Both groups performed physical fitness tests before and after the intervention. Changes in performance (pre- vs. post-intervention) for each group were analyzed using dependent t-test (P<.05). Change in performance of each group were compared using independent t-test (P<.05). Core strength (evaluated using plank test), leg power (vertical jump test) and agility (Illinois agility test). The core strength (P=.007) and agility (P=.01) of the EXP group increased significantly, while no change were observed in the CON group. The increase of agility in EXP group was found to be significantly different compared to the one in CON group (P=.039). FIFA 11+ can improve certain physical fitness components that contribute in preventing injury. Thus it is recommended to add FIFA 11+ to the routine futsal training as an injury prevention program Table 1Pre-post intervention result. .
 
and final measurements of range of motion together with diVerences for dancers and controls, given as mean (SD) 
To evaluate in a 12 month longitudinal study changes in hip and ankle range of motion and hip muscle strength in young female novice ballet dancers. Fifty three of the original 77 (69%) female dancers aged 8-11 years and 40 of the original 49 (82%) controls returned for follow up measurements one year later. Supine right active hip external (ER) and internal (IR) rotation were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. Range of right weight bearing ankle dorsiflexion and calf muscle length were measured in a standing lunge position using an inclinometer. A manual muscle tester was used to assess right hip flexor, IR, ER, abductor and adductor strength. The mean (SD) 12 month change in hip ER did not differ between dancers (11.7 (11.3)degrees) and controls (8.1 (17.6)degrees). Dancers gained 12.5 (13.5)degrees hip IR which was significantly greater than controls (0.5 (13.9)degrees). Greater IR change was associated with improved IR strength (r = 0.34, p<0.001). Dancers increased total turnout (12.0 (16.7)degrees) significantly more than controls (2.2 (20.0)degrees). There was no significant change in ankle dorsiflexion range in either group. Dancers and controls increased in all measures of hip muscle strength (p<0.001) and dancers achieved significantly greater gains in three out of five muscle groups (all, p<0.05). Total hip range of motion increased in both ballet students and controls at this young age. However, ankle dorsiflexion did not, which is probably due to this movement being blocked by bony apposition, rather than soft tissue stretch. This has implications for ballet teachers, as it has long been accepted that this movement could be improved with training. Dancers had greater increases in hip strength after 12 months compared with controls in muscles specific for ballet, suggesting that hip strength can be trained at this young age. Whether these gains are permanent requires further study.
 
The FIFA 11+ warm-up program can significantly reduce injury risk in youth soccer, but community uptake of the program has been suboptimal. A health behaviour theory, the Health Action Process Approach (HAPA) model, may identify predictors of program uptake that can inform targeted promotion strategies. To determine whether HAPA constructs (risk perceptions, outcome expectancies, self-efficacy, action and coping plans, facilitators and barriers) predict uptake intention and adherence to the FIFA 11+ in elite female youth soccer. Sub-analysis of data from a cluster randomized controlled trial. Elite (Tier 1 and 2) female soccer teams (ages 12-16) competing in Calgary, Canada. 12 teams (coaches n=12, players n=200) who were randomly recruited prior to the 2013 season as wave 1 of the larger trial. Participants completed a baseline questionnaire assessing risk perceptions, outcome expectancies and self-efficacy associated with the FIFA 11+, and barriers/facilitators to program use. Intention to follow the FIFA 11+ (from the HAPA questionnaire) and prospectively reported adherence during the season. Preliminary analyses demonstrate that for coaches, risk perceptions, outcome expectancies, and task self-efficacy accounted for 92.7% of uptake intention variance [F(3,3)=12.71, P=.0327, R(2)=0.9271]. The most commonly identified facilitator was access to FIFA 11+ materials (videos, manuals). The largest barrier was not having enough time to complete the program. For players, the HAPA model accounted for only 41.4% of intention variance [F(7, 154)=15.53, P<.001, R(2)=0.4139]. Identified facilitators included having adequate time, personal effort, and enjoying the program. Barriers included poor team leadership, uncooperative teammates, and lack of time. Relationships between HAPA constructs and adherence will also be presented. The HAPA model appears to strongly predict coach, but not player, intentions to uptake the FIFA 11+. The development of role-targeted promotion strategies may improve program uptake.
 
Baseline characteristics by study group 
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.
 
Standard Doppler inflow and tissue Doppler measurements at baseline and after 2 months of endurance training 
Superior global cardiac performance (ie stroke volume) is classically reported after training in children. Current knowledge of the impact of exercise training on myocardial relaxation, a major component of left ventricular (LV) filling and subsequently stroke volume, is, however, limited in the paediatric population. This study aimed to investigate the effect of aerobic training on LV wall motion velocities by tissue Doppler imaging (TDI) in healthy children. 25 children (11 girls, 14 boys) were enrolled in a 2 month high-intensity aerobic training programme and 25 (12 girls and 13 boys) served as controls. The children (9-11 years old) performed a graded maximal exercise test on a treadmill to evaluate maximal oxygen uptake. Standard Doppler echocardiography and TDI measurements were performed at baseline and end of the study. Tissue Doppler systolic, early and late myocardial velocities were obtained at the mitral annulus in the septal, lateral, inferior and posterior walls. Maximal oxygen uptake increased by 6.5% (before: 51.6 (SD 4.2), after: 55.0 (4.5) ml/min/kg p<0.001) after training. A modest but significant increase in left ventricular end-diastolic diameter was also noticed (before: 46.1 (3.4), after: 48.3 (4.3) mm.BSA(-1/2), p<0.001), whereas left ventricular wall thickness and mass were unchanged. Neither transmitral inflow velocities nor early and late wall motion (Em: before = 18.4 (2.7), after = 18.0 (2.3) cm/s, Am: before = 6.8 (1.2), after = 6.7 (1.3) cm/s) were affected by training. Shortening fraction and regional systolic function (Sm: before = 10.1 (1.6), after = 10.2 (1.4) cm/s) by TDI were also unchanged. High-intensity aerobic sessions repeated over a 2 month period failed to improve regional diastolic function assessed by TDI in healthy young children.
 
Physical activity has been associated with improved survival, but it is unclear whether this increase in longevity is accompanied by preserved mental and physical functioning, also known as healthy ageing. We designed this study to determine whether physical activity is associated with healthy ageing in later life. We recruited a community-representative sample of 12 201 men aged 65-83 years and followed them for 10-13 years. We assessed physical activity at the beginning and the end of the follow-up period. Participants who reported 150 min or more of vigorous physical activity per week were considered physically active. We monitored survival during the follow-up period and, at study exit, assessed the mood, cognition and functional status of survivors. Healthy ageing was defined as being alive at the end of follow-up and having a Patient Health Questionnaire score <10, Telephone Interview for Cognitive Status score >27, and no major difficulty in any instrumental or basic activity of daily living. Cox regression and general linear models were used to estimate HR of death and risk ratio (RR) of healthy ageing. Analyses were adjusted for age, education, marital status, smoking, body mass index and history of hypertension, diabetes, coronary heart disease and stroke. Two thousand and fifty-eight (16.9%) participants were physically active at study entry. Active men had lower HR of death over 10-13 years than physically inactive men (HR=0.74, 95% CI=0.68 to 0.81). Among survivors, completion of the follow-up assessment was higher in the physically active than inactive group (risk ratio, RR=1.18, 95% CI=1.08 to 1.30). Physically active men had greater chance of fulfilling criteria for healthy ageing than inactive men (RR=1.35, 95% CI=1.19 to 1.53). Men who were physically active at the baseline and follow-up assessments had the highest chance of healthy ageing compared with inactive men (RR=1.59, 95% CI=1.36 to 1.86). Sustained physical activity is associated with improved survival and healthy ageing in older men. Vigorous physical activity seems to promote healthy ageing and should be encouraged when safe and feasible.
 
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.
 
Player availability, injuries and team performance 
Association between team season injury rates and performance in professional football 
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 for 11 seasons (2001-2012), including 155 team-seasons. Individual training and match exposure and time-loss injuries were registered. To analyse the effect of injury rates on performance, a Generalised Estimating Equation was used to fit a linear regression on team-level data. Each team's season injury rate and performance were evaluated using its own preceding season data for comparison in the analyses. Results: 7792 injuries were reported during 1 026 104 exposure hours. The total injury incidence was 7.7 injuries/1000 h, injury burden 130 injury days lost/1000 h and player match availability 86%. Lower injury burden (p=0.011) and higher match availability (p=0.031) were associated with higher final league ranking. Similarly, lower injury incidence (p=0.035), lower injury burden (p<0.001) and higher match availability (p<0.001) were associated with increased points per league match. Finally, lower injury burden (p=0.043) and higher match availability (p=0.048) were associated with an increase in the Union of European Football Association (UEFA) Season Club Coefficient, reflecting success in the UEFA Champions League or Europa League. Conclusions: Injuries had a significant influence on performance in the league play and in European cups in male professional football. The findings stress the importance of injury prevention to increase a team's chances of success.
 
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 according to recovery days before each match (≤3 vs >3 days, and ≤4 vs ≥6 days). Injury rates and team performance were compared between groups. Match load in match sequences containing five consecutive matches was determined by the number of days separating the first match and the last training session during that match sequence. Linear regression was used to study associations between match load and injury rates and team performance. Team performance showed no association with match load, or recovery days prior to matches, except for Europa League matches that indicated more matches lost with short recovery (≤3 days) (p=0.048). Total injury rates and muscle injury rates were increased in league matches with ≤4 days compared with ≥6 days' recovery (RR 1.09, 95% CI 1.00 to 1.18, and RR 1.32, 95% CI 1.15 to 1.51, respectively), specifically hamstring and quadriceps injuries. High match load was associated with increase in muscle injury rate in matches in the same match sequence (p=0.012), and increase in ligament injury rate in training in the subsequent match sequence (p=0.003). Fixture congestion was associated with increased muscle injury rates but had no, or very limited, influence on team performance.
 
Medial collateral ligament injuries of the knee in professional football
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 were recorded. Highest leagues in Europe. 1 743 male professional players. Seasonal trend, expressed as the average annual percentage of change, was analysed using linear regression with log-transformed injury rates as the dependent variable. A 2-year moving average approach, by summarising two consecutive seasons, was also used to smooth out large seasonal variations. Injury circumstances such as player contact and foul play was also studied. Injury rate was defined as the number of injuries per 1000 player hours. 346 MCL injuries occurred during the study period, being the most common knee injury constituting 4% of all injuries. The MCL injury rate was 0.33 per 1000 hours, and a time trend analysis indicated a significant average annual decrease of approximately seven per-cent over the study period (P=.023). Almost 70% of all MCL injuries were contact-related, and no difference in lay-off times between contact (median=16, Q1=8, Q3=29) and non-contact (median=16, Q1=7, Q3=30) injuries was detected (P=.741). A higher percentage of foul play injuries were found in MCL contact injuries compared with other contact injuries during match play (24% vs. 18%, P=.015). MCL injury is still the most frequent knee injury in professional football, but the rate has decreased significantly during the 11-year study period. MCL injuries are commonly caused by contact situations and foul play.
 
Those who are old enough to have been working in the world of sports science/medicine in 1992 will remember a watershed moment: the publication of a paper by Roger Harris and co-workers(1) on the capacity of the muscle to increase its phosphocreatine concentration following supplementation with a creatine product. With the genie out of the bottle, we bore witness to an explosion of interest in this unique ergogenic aid a product of apparently genuine value to biochemists, sports scientists, athletes, coaches, clinicians and the supplement industry. This review will outline why the production and sales of creatine have increased exponentially over the past two decades, and will summarise which of the claims made about creatine supplements are evidence based.
 
The strength profile of the hamstrings is reported to be important to prevent strain and anterior cruciate ligament (ACL) injuries. There is little information about the functional state of muscles around the knee in young soccer players. To determine the differences in the characteristics of knee extensors and flexors in 11-16-year old, male soccer players. Randomized cross-sectional study. Laboratory, youth sports. 60 randomly selected young male soccer players (11-16 years) - without lower extremity injury history - were assigned into 6 age groups: under 11, 12, 13, 14, 15 and U16 (10 players/group). The peak torque of isometric hamstring (ICH) and quadriceps (ICQ) (70° of knee flexion), eccentric hamstring (ECH) and concentric quadriceps (CCQ) (60°/s, 10-90° knee flexion range of movement) for both lower extremities were measured on an isokinetic dynamometer (Multicont II). Hecc/Qcc and rate of torque development (RTD) H/Q ratio were calculated 50 ms after the onset of the contraction (RTD H/Q50). ICH and ICQ significantly differed (P<.05) between U11 and U14 for both legs. There were no significant differences in ICH and in ECH between U13-U16 in the dominant leg, similarly between U14-U16 in the non-dominant leg (P>.05). Hecc/Qcc was significantly higher in the U11 group than in the U16 group (P<.05) in the dominant leg. There were no differences in RTD H/Q50 across age groups for both legs (P>.05). As eccentric and isometric hamstring peak torques did not differ between U14-U16, hamstring-emphasized strength training is advisable. RTD H/Q50 may have clinical relevance, as most ACL injuries occur 17-50 ms after initial contact. It did not differ between age groups, so the effects of intervention programs should be tested aiming to increase the RTD of the hamstrings.
 
Top-cited authors
Jiri Dvorak
  • Schulthess Klinik, Zürich
Jan Ekstrand
  • Linköping University
Lars Engebretsen
  • University of Oslo
Martin Hägglund
  • Linköping University
Markus Waldén
  • Region Skåne