Showing papers in "British Journal of Sports Medicine in 2016"

The training—injury prevention paradox: should athletes be training smarter and harder?

Abstract: Background There is dogma that higher training load causes higher injury rates. However, there is also evidence that training has a protective effect against injury. For example, team sport athletes who performed more than 18 weeks of training before sustaining their initial injuries were at reduced risk of sustaining a subsequent injury, while high chronic workloads have been shown to decrease the risk of injury. Second, across a wide range of sports, well-developed physical qualities are associated with a reduced risk of injury. Clearly, for athletes to develop the physical capacities required to provide a protective effect against injury, they must be prepared to train hard. Finally, there is also evidence that under-training may increase injury risk. Collectively, these results emphasise that reductions in workloads may not always be the best approach to protect against injury. Main thesis This paper describes the ‘Training-Injury Prevention Paradox’ model; a phenomenon whereby athletes accustomed to high training loads have fewer injuries than athletes training at lower workloads. The Model is based on evidence that non-contact injuries are not caused by training per se , but more likely by an inappropriate training programme. Excessive and rapid increases in training loads are likely responsible for a large proportion of non-contact, soft-tissue injuries. If training load is an important determinant of injury, it must be accurately measured up to twice daily and over periods of weeks and months (a season). This paper outlines ways of monitoring training load (‘internal’ and ‘external’ loads) and suggests capturing both recent (‘acute’) training loads and more medium-term (‘chronic’) training loads to best capture the player's training burden. I describe the critical variable—acute:chronic workload ratio—as a best practice predictor of training-related injuries. This provides the foundation for interventions to reduce players risk, and thus, time-loss injuries. Summary The appropriately graded prescription of high training loads should improve players’ fitness, which in turn may protect against injury, ultimately leading to (1) greater physical outputs and resilience in competition, and (2) a greater proportion of the squad available for selection each week.

How much is too much? (Part 2) International Olympic Committee consensus statement on load in sport and risk of illness

Abstract: Athletes participating in elite sports are exposed to high training loads and increasingly saturated competition calendars. Emerging evidence indicates that poor load management is a major risk factor for injury. The International Olympic Committee convened an expert group to review the scientific evidence for the relationship of load (defined broadly to include rapid changes in training and competition load, competition calendar congestion, psychological load and travel) and health outcomes in sport. We summarise the results linking load to risk of injury in athletes, and provide athletes, coaches and support staff with practical guidelines to manage load in sport. This consensus statement includes guidelines for (1) prescription of training and competition load, as well as for (2) monitoring of training, competition and psychological load, athlete well-being and injury. In the process, we identified research priorities.

Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study

Abstract: Background Knee reinjury after ACL reconstruction is common and increases the risk of osteoarthritis. There is sparse evidence to guide return to sport (RTS) decisions in this population. Objectives To assess the relationship between knee reinjury after ACL reconstruction and (1) return to level I sports, (2) timing of RTS and (3) knee function prior to return. Methods 106 patients who participated in pivoting sports participated in this prospective 2-year cohort study. Sports participation and knee reinjury were recorded monthly. Knee function was assessed with the Knee Outcome Survey—Activities of Daily Living Scale, global rating scale of function, and quadriceps strength and hop test symmetry. Pass RTS criteria were defined as scores >90 on all tests, failure as failing any. Results Patients who returned to level I sports had a 4.32 (p=0.048) times higher reinjury rate than those who did not. The reinjury rate was significantly reduced by 51% for each month RTS was delayed until 9 months after surgery, after which no further risk reduction was observed. 38.2% of those who failed RTS criteria suffered reinjuries versus 5.6% of those who passed (HR 0.16, p=0.075). More symmetrical quadriceps strength prior to return significantly reduced the knee reinjury rate. Conclusions Returning to level I sports after ACL reconstruction leads to a more than 4-fold increase in reinjury rates over 2 years. RTS 9 months or later after surgery and more symmetrical quadriceps strength prior to return substantially reduce the reinjury rate.

The Warwick Agreement on femoroacetabular impingement syndrome (FAI syndrome): an international consensus statement

Abstract: The 2016 Warwick Agreement on femoroacetabular impingement (FAI) syndrome was convened to build an international, multidisciplinary consensus on the diagnosis and management of patients with FAI syndrome. 22 panel members and 1 patient from 9 countries and 5 different specialties participated in a 1-day consensus meeting on 29 June 2016. Prior to the meeting, 6 questions were agreed on, and recent relevant systematic reviews and seminal literature were circulated. Panel members gave presentations on the topics of the agreed questions at Sports Hip 2016 , an open meeting held in the UK on 27–29 June. Presentations were followed by open discussion. At the 1-day consensus meeting, panel members developed statements in response to each question through open discussion; members then scored their level of agreement with each response on a scale of 0–10. Substantial agreement (range 9.5–10) was reached for each of the 6 consensus questions, and the associated terminology was agreed on. The term ‘femoroacetabular impingement syndrome’ was introduced to reflect the central role of patients' symptoms in the disorder. To reach a diagnosis, patients should have appropriate symptoms, positive clinical signs and imaging findings. Suitable treatments are conservative care, rehabilitation, and arthroscopic or open surgery. Current understanding of prognosis and topics for future research were discussed. The 2016 Warwick Agreement on FAI syndrome is an international multidisciplinary agreement on the diagnosis, treatment principles and key terminology relating to FAI syndrome. The Warwick Agreement on femoroacetabular impingement syndrome has been endorsed by the following 25 clinical societies: American Medical Society for Sports Medicine (AMSSM), Association of Chartered Physiotherapists in Sports and Exercise Medicine (ACPSEM), Australasian College of Sports and Exercise Physicians (ACSEP), Austian Sports Physiotherapists, British Association of Sports and Exercise Medicine (BASEM), British Association of Sport Rehabilitators and Trainers (BASRaT), Canadian Academy of Sport and Exercise Medicine (CASEM), Danish Society of Sports Physical Therapy (DSSF), European College of Sports and Exercise Physicians (ECOSEP), European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA), Finnish Sports Physiotherapist Association (SUFT), German-Austrian-Swiss Society for Orthopaedic Traumatologic Sports Medicine (GOTS), International Federation of Sports Physical Therapy (IFSPT), International Society for Hip Arthroscopy (ISHA), Groupo di Interesse Specialistico dell’A.I.F.I., Norwegian Association of Sports Medicine and Physical Activity (NIMF), Norwegian Sports Physiotherapy Association (FFI), Society of Sports Therapists (SST), South African Sports Medicine Association (SASMA), Sports Medicine Australia (SMA), Sports Doctors Australia (SDrA), Sports Physiotherapy New Zealand (SPNZ), Swedish Society of Exercise and Sports Medicine (SFAIM), Swiss Society of Sports Medicine (SGMS/SGSM), Swiss Sports Physiotherapy Association (SSPA).

Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review.

Abstract: Background Monitoring athlete well-being is essential to guide training and to detect any progression towards negative health outcomes and associated poor performance. Objective (performance, physiological, biochemical) and subjective measures are all options for athlete monitoring. Objective We systematically reviewed objective and subjective measures of athlete well-being. Objective measures, including those taken at rest (eg, blood markers, heart rate) and during exercise (eg, oxygen consumption, heart rate response), were compared against subjective measures (eg, mood, perceived stress). All measures were also evaluated for their response to acute and chronic training load. Methods The databases Academic search complete, MEDLINE, PsycINFO, SPORTDiscus and PubMed were searched in May 2014. Fifty-six original studies reported concurrent subjective and objective measures of athlete well-being. The quality and strength of findings of each study were evaluated to determine overall levels of evidence. Results Subjective and objective measures of athlete well-being generally did not correlate. Subjective measures reflected acute and chronic training loads with superior sensitivity and consistency than objective measures. Subjective well-being was typically impaired with an acute increase in training load, and also with chronic training, while an acute decrease in training load improved subjective well-being. Summary This review provides further support for practitioners to use subjective measures to monitor changes in athlete well-being in response to training. Subjective measures may stand alone, or be incorporated into a mixed methods approach to athlete monitoring, as is current practice in many sport settings.

Likelihood of ACL graft rupture: not meeting six clinical discharge criteria before return to sport is associated with a four times greater risk of rupture

Abstract: Background The decision as to whether or not an athlete is ready to return to sport (RTS) after ACL reconstruction is difficult as the commonly used RTS criteria have not been validated. Purpose To evaluate whether a set of objective discharge criteria, including muscle strength and functional tests, are associated with risk of ACL graft rupture after RTS. Materials and methods 158 male professional athletes who underwent an ACL reconstruction and returned to their previous professional level of sport were included. Before players returned to sport they underwent a battery of discharge tests (isokinetic strength testing at 60°, 180° and 300°/s, a running t test, single hop, triple hop and triple crossover hop tests). Athletes were monitored for ACL re-ruptures once they returned to sport (median follow-up 646 days, range 1–2060). Results Of the 158 athletes, 26 (16.5%) sustained an ACL graft rupture an average of 105 days after RTS. Two factors were associated with increased risk of ACL graft rupture: (1) not meeting all six of the discharge criteria before returning to team training (HR 4.1, 95% CI 1.9 to 9.2, p≤0.001); and (2) decreased hamstring to quadriceps ratio of the involved leg at 60°/s (HR 10.6 per 10% difference, 95% CI 10.2 to 11, p=0.005). Conclusions Athletes who did not meet the discharge criteria before returning to professional sport had a four times greater risk of sustaining an ACL graft rupture compared with those who met all six RTS criteria. In addition, hamstring to quadriceps strength ratio deficits were associated with an increased risk of an ACL graft rupture.

2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern

Abstract: Deciding when to return to sport after injury is complex and multifactorial-an exercise in risk management. Return to sport decisions are made every day by clinicians, athletes and coaches, ideally in a collaborative way. The purpose of this consensus statement was to present and synthesise current evidence to make recommendations for return to sport decision-making, clinical practice and future research directions related to returning athletes to sport. A half day meeting was held in Bern, Switzerland, after the First World Congress in Sports Physical Therapy. 17 expert clinicians participated. 4 main sections were initially agreed upon, then participants elected to join 1 of the 4 groups-each group focused on 1 section of the consensus statement. Participants in each group discussed and summarised the key issues for their section before the 17-member group met again for discussion to reach consensus on the content of the 4 sections. Return to sport is not a decision taken in isolation at the end of the recovery and rehabilitation process. Instead, return to sport should be viewed as a continuum, paralleled with recovery and rehabilitation. Biopsychosocial models may help the clinician make sense of individual factors that may influence the athlete's return to sport, and the Strategic Assessment of Risk and Risk Tolerance framework may help decision-makers synthesise information to make an optimal return to sport decision. Research evidence to support return to sport decisions in clinical practice is scarce. Future research should focus on a standardised approach to defining, measuring and reporting return to sport outcomes, and identifying valuable prognostic factors for returning to sport.

Hamstring injuries have increased by 4% annually in men's professional football, since 2001: a 13-year longitudinal analysis of the UEFA Elite Club injury study

Abstract: 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 2014. Team medical staff recorded individual player exposure and time-loss injuries. Injuries per 1000 h were compared as a rate ratio (RR) with 95% CI. Injury burden was the number of lay off days per 1000 h. Seasonal trend for injury was analysed using linear regression. Results A total of 1614 hamstring injuries were recorded; 22% of players sustained at least one hamstring injury during a season. The overall hamstring injury rate over the 13-year period was 1.20 injuries per 1000 h; the match injury rate (4.77) being 9 times higher than the training injury rate (0.51; RR 9.4; 95% CI 8.5 to 10.4). The time-trend analysis showed an annual average 2.3% year on year increase in the total hamstring injury rate over the 13-year period (R 2 =0.431, b=0.023, 95% CI 0.006 to 0.041, p=0.015). This increase over time was most pronounced for training injuries—these increased by 4.0% per year (R 2 =0.450, b=0.040, 95% CI 0.011 to 0.070, p=0.012). The average hamstring injury burden was 19.7 days per 1000 h (annual average increase 4.1%) (R 2 =0.437, b=0.041, 95% CI 0.010 to 0.072, p=0.014). Conclusions Training-related hamstring injury rates have increased substantially since 2001 but match-related injury rates have remained stable. The challenge is for clubs to reduce training-related hamstring injury rates without impairing match performance.

Complex systems approach for sports injuries: moving from risk factor identification to injury pattern recognition—narrative review and new concept

Abstract: Injury prediction is one of the most challenging issues in sports and a key component for injury prevention. Sports injuries aetiology investigations have assumed a reductionist view in which a phenomenon has been simplified into units and analysed as the sum of its basic parts and causality has been seen in a linear and unidirectional way. This reductionist approach relies on correlation and regression analyses and, despite the vast effort to predict sports injuries, it has been limited in its ability to successfully identify predictive factors. The majority of human health conditions are complex. In this sense, the multifactorial complex nature of sports injuries arises not from the linear interaction between isolated and predictive factors, but from the complex interaction among a web of determinants. Thus, the aim of this conceptual paper was to propose a complex system model for sports injuries and to demonstrate how the implementation of complex system thinking may allow us to better address the complex nature of the sports injuries aetiology. According to this model, we should identify features that are hallmarks of complex systems, such as the pattern of relationships (interactions) among determinants, the regularities (profiles) that simultaneously characterise and constrain the phenomenon and the emerging pattern that arises from the complex web of determinants. In sports practice, this emerging pattern may be related to injury occurrence or adaptation. This novel view of preventive intervention relies on the identification of regularities or risk profile, moving from risk factors to risk pattern recognition.

Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus

Abstract: Aim The Royal Dutch Society for Physical Therapy (KNGF) instructed a multidisciplinary group of Dutch anterior cruciate ligament (ACL) experts to develop an evidence statement for rehabilitation after ACL reconstruction. Design Clinical practice guideline underpinned by systematic review and expert consensus. Data sources A multidisciplinary working group and steering group systematically reviewed the literature and wrote the guideline. MEDLINE and the Cochrane Library were searched for meta-analyses, systematic reviews, randomised controlled trials and prospective cohort studies published between January 1990 and June 2015. Eligibility criteria for selecting studies Included literature must have addressed 1 of 9 predetermined clinical topics: (1) preoperative predictors for postoperative outcome, (2) effectiveness of physical therapy, (3) open and closed kinetic chain quadriceps exercises, (4) strength and neuromuscular training, (5) electrostimulation and electromyographic feedback, (6) cryotherapy, (7) measurements of functional performance, (8) return to play and (9) risk for reinjury. Summary Ninety studies were included as the basis for the evidence statement. Rehabilitation after ACL injury should include a prehabilitation phase and 3 criterion-based postoperative phases: (1) impairment-based, (2) sport-specific training and (3) return to play. A battery of strength and hop tests, quality of movement and psychological tests should be used to guide progression from one rehabilitation stage to the next. Postoperative rehabilitation should continue for 9–12 months. To assess readiness to return to play and the risk for reinjury, a test battery, including strength tests, hop tests and measurement of movement quality, should be used.

Consensus on Exercise Reporting Template (CERT): Explanation and Elaboration Statement.

Abstract: Exercise is effective for prevention and management of acute and chronic health conditions. However, trial descriptions of exercise interventions are often suboptimal, leaving readers unclear about the content of effective programmes. To address this, the 16-item internationally endorsed Consensus on Exercise Reporting Template (CERT) was developed. The aim is to present the final template and provide an Explanation and Elaboration Statement to operationalise the CERT. Development of the CERT was based on the EQUATOR Network methodological framework for developing reporting guidelines. We used a modified Delphi technique to gain consensus of international exercise experts and conducted 3 sequential rounds of anonymous online questionnaires and a Delphi workshop. The 16-item CERT is the minimum data set considered necessary to report exercise interventions. The contents may be included in online supplementary material, published as a protocol or located on websites and other electronic repositories. The Explanation and Elaboration Statement is intended to enhance the use, understanding and dissemination of the CERT and presents the meaning and rationale for each item, together with examples of good reporting. The CERT is designed specifically for the reporting of exercise programmes across all evaluative study designs for exercise research. The CERT can be used by authors to structure intervention reports, by reviewers and editors to assess completeness of exercise descriptions and by readers to facilitate the use of the published information. The CERT has the potential to increase clinical uptake of effective exercise programmes, enable research replication, reduce research waste and improve patient outcomes.

Why screening tests to predict injury do not work—and probably never will…: a critical review

Abstract: This paper addresses if and how a periodic health examination to screen for risk factors for injury can be used to mitigate injury risk. The key question asked is whether it is possible to use screening tests to identify who is at risk for a sports injury-in order to address the deficit through a targeted intervention programme. The paper demonstrates that to validate a screening test to predict and prevent sports injuries, at least 3 steps are needed. First, a strong relationship needs to be demonstrated in prospective studies between a marker from a screening test and injury risk (step 1). Second, the test properties need to be examined in relevant populations, using appropriate statistical tools (step 2). Unfortunately, there is currently no example of a screening test for sports injuries with adequate test properties. Given the nature of potential screening tests (where test performance is usually measured on a continuous scale from low to high), substantial overlap is to be expected between players with high and low risk of injury. Therefore, although there are a number of tests demonstrating a statistically significant association with injury risk, and therefore help the understanding of causative factors, such tests are unlikely to be able to predict injury with sufficient accuracy. The final step needed is to document that an intervention programme targeting athletes identified as being at high risk through a screening programme is more beneficial than the same intervention programme given to all athletes (step 3). To date, there is no intervention study providing support for screening for injury risk.

The acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk in elite rugby league players

Abstract: Aim Investigate whether acute workload (1 week total distance) and chronic workload (4-week average acute workload) predict injury in elite rugby league players. Methods Data were collected from 53 elite players over two rugby league seasons. The 'acute:chronic workload ratio' was calculated by dividing acute workload by chronic workload. A value of greater than 1 represented an acute workload greater than chronic workload. All workload data were classified into discrete ranges by z-scores. Results Compared with all other ratios, a very-high acute:chronic workload ratio (2.11) demonstrated the greatest risk of injury in the current week (16.7% injury risk) and subsequent week (11.8% injury risk). High chronic workload (>16 095 m) combined with a veryhigh 2-week average acute:chronic workload ratio (1.54) was associated with the greatest risk of injury (28.6% injury risk). High chronic workload combined with a moderate workload ratio (1.02-1.18) had a smaller risk of injury than low chronic workload combined with several workload ratios (relative risk range from 0.3 to 0.7×/1.4 to 4.4; likelihood range=88-94%, likely). Considering acute and chronic workloads in isolation (ie, not as ratios) did not consistently predict injury risk. Conclusions Higher workloads can have either positive or negative influences on injury risk in elite rugby league players. Specifically, compared with players who have a low chronic workload, players with a high chronic workload are more resistant to injury with moderate-low through moderate-high (0.85-1.35) acute:chronic workload ratios and less resistant to injury when subjected to 'spikes' in acute workload, that is, very-high acute:chronic workload ratios 1.5.

Evidence review for the 2016 International Ankle Consortium consensus statement on the prevalence, impact and long-term consequences of lateral ankle sprains.

Abstract: Lateral ankle sprains (LASs) are the most prevalent musculoskeletal injury in physically active populations. They also have a high prevalence in the general population and pose a substantial healthcare burden. The recurrence rates of LASs are high, leading to a large percentage of patients with LAS developing chronic ankle instability. This chronicity is associated with decreased physical activity levels and quality of life and associates with increasing rates of post-traumatic ankle osteoarthritis, all of which generate financial costs that are larger than many have realised. The literature review that follows expands this paradigm and introduces emerging areas that should be prioritised for continued research, supporting a companion position statement paper that proposes recommendations for using this summary of information, and needs for specific future research.

2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: Terminology, definitions, clinical examination, natural history, patellofemoral osteoarthritis and patient-reported outcome measures

Abstract: Patellofemoral pain (PFP) typically presents as diffuse anterior knee pain, usually with activities such as squatting, running, stair ascent and descent. It is common in active individuals across the lifespan,1–4 and is a frequent cause for presentation at physiotherapy, general practice, orthopaedic and sports medicine clinics in particular.5 ,6 Its impact is profound, often reducing the ability of those with PFP to perform sporting, physical activity and work-related activities pain-free. Increasing evidence suggests that it is a recalcitrant condition, persisting for many years.7–9 In an attempt to share recent innovations, build on the first three successful biennial retreats and define the ‘state of the art’ for this common, impactful condition; the 4th International Patellofemoral Pain Research Retreat was convened. The 4th International Patellofemoral Research Retreat was held in Manchester, UK, over 3 days (September 2–4th, 2015). After undergoing peer-review for scientific merit and relevance to the retreat, 67 abstracts were accepted for the retreat (50 podium presentations, and 17 short presentations). The podium and short presentations were grouped into five categories; (1) PFP, (2) factors that influence PFP (3) the trunk and lower extremity (4) interventions and (5) systematic analyses. Three keynote speakers were chosen for their scientific contribution in the area of PFP. Professor Andrew Amis spoke on the biomechanics of the patellofemoral joint. Professor David Felson spoke on patellofemoral arthritis,10 and Dr Michael Ratleff's keynote theme was PFP in the adolescent patient.11 As part of the retreat, we held structured, whole-group discussions in order to develop consensus relating to the work presented at the meeting as well as evidence gathered from the literature. ### Consensus development process In our past three International Patellofemoral Research Retreats, we developed a consensus statement addressing different presentation categories.12–14 In Manchester in 2015, we revised the format. For the exercise and …

Short biceps femoris fascicles and eccentric knee flexor weakness increase the risk of hamstring injury in elite football (soccer): a prospective cohort study

Abstract: Background/Aim - To investigate the role of eccentric knee flexor strength, between-limb imbalance and biceps femoris long head (BFlh) fascicle length on the risk of a future hamstring strain injury (HSI). Methods - Elite soccer players (n=152) from eight different teams participated. Eccentric knee flexor strength during the Nordic hamstring exercise and BFlh fascicle length were assessed at the beginning of pre-season. The occurrences of a HSI following this were recorded by the team medical staff. Relative risk (RR) was determined for univariate data, and logistic regression was employed for multivariate data. Results - Twenty-seven new HSIs were reported. Eccentric knee flexor strength below 337N (RR = 4.4; 95% CI = 1.1 to 17.5) and BFlh fascicles shorter than 10.56cm (RR = 4.1; 95% CI=1.9 to 8.7) significantly increased the risk of a subsequent HSI. Multivariate logistic regression revealed significant effects when combinations of age, previous history of HSI, eccentric knee flexor strength and BFlh fascicle length were explored. From these analyses the likelihood of a future HSI in older athletes or those with a previous HSI history was reduced if high levels of eccentric knee flexor strength and longer BFlh fascicles were present. Conclusions - The presence of short BFlh fascicles and low levels of eccentric strength in elite soccer players increase the risk of a future HSI. The greater risk of a future HSI in older players or those with a previous HSI is reduced when they possess longer BFlh fascicles and high levels of eccentric strength.

Has the athlete trained enough to return to play safely? The acute:chronic workload ratio permits clinicians to quantify a player's risk of subsequent injury

Abstract: The return to sport from injury is a difficult multifactorial decision, and risk of reinjury is an important component. Most protocols for ascertaining the return to play status involve assessment of the healing status of the original injury and functional tests which have little proven predictive ability. Little attention has been paid to ascertaining whether an athlete has completed sufficient training to be prepared for competition. Recently, we have completed a series of studies in cricket, rugby league and Australian rules football that have shown that when an athlete's training and playing load for a given week (acute load) spikes above what they have been doing on average over the past 4 weeks (chronic load), they are more likely to be injured. This spike in the acute:chronic workload ratio may be from an unusual week or an ebbing of the athlete's training load over a period of time as in recuperation from injury. Our findings demonstrate a strong predictive (R(2)=0.53) polynomial relationship between acute:chronic workload ratio and injury likelihood. In the elite team setting, it is possible to quantify the loads we are expecting athletes to endure when returning to sport, so assessment of the acute:chronic workload ratio should be included in the return to play decision-making process.

The incidence of concussion in youth sports: a systematic review and meta-analysis

Abstract: Objective To conduct a comprehensive systematic review and meta-analysis of studies assessing the incidence of concussion in youth athletes. Specifically, we estimate the overall risk of concussion in youth sports and compare sport-specific estimates of concussion risk. Design Systemic review and meta-analysis. Data sources A search of Medline, Embase (1980 through September 2014), and SportDiscus (1985 through September 2014) supplemented by manual searches of bibliographies and conference proceedings. Inclusion criteria We included studies if they met the inclusion criteria of study design (prospective cohort study), relevant sports identified from the literature (eg, American football, rugby, hockey, lacrosse, soccer/football, basketball, baseball, softball, wrestling, field hockey, track, taekwondo, volleyball and cheerleading), population (males and females ≤18 years old), and outcome (concussion). Results Of the 698 studies reviewed for eligibility, 23 articles were accepted for systematic review and 13 of which were included in a meta-analysis. Random effects models were used to pool overall and sport-specific concussion incidence rates per 1000 athlete exposures (AEs). The overall risk of concussion was estimated at 0.23 (95% CI 0.19 to 0.28). The three sports with the highest incidence rates were rugby, hockey and American football at 4.18, 1.20 and 0.53, respectively. Lowest incidence rates per 1000 AEs occurred in volleyball, baseball and cheerleading at 0.03, 0.06 and 0.07, respectively. Quality of the included studies varied, with the majority of studies not reporting age and gender-specific incidence rates or an operational definition for concussion. Conclusions There are striking differences in the rates of incident youth concussion across 12 sports. This systematic review and meta-analysis can serve as the current sport-specific baseline risk of concussion among youth athletes.

Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research?

Abstract: The pathogenesis of tendinopathy and the primary biological change in the tendon that precipitates pathology have generated several pathoaetiological models in the literature. The continuum model of tendon pathology, proposed in 2009, synthesised clinical and laboratory-based research to guide treatment choices for the clinical presentations of tendinopathy. While the continuum has been cited extensively in the literature, its clinical utility has yet to be fully elucidated. The continuum model proposed a model for staging tendinopathy based on the changes and distribution of disorganisation within the tendon. However, classifying tendinopathy based on structure in what is primarily a pain condition has been challenged. The interplay between structure, pain and function is not yet fully understood, which has partly contributed to the complex clinical picture of tendinopathy. Here we revisit and assess the merit of the continuum model in the context of new evidence. We (1) summarise new evidence in tendinopathy research in the context of the continuum, (2) discuss tendon pain and the relevance of a model based on structure and (3) describe relevant clinical elements (pain, function and structure) to begin to build a better understanding of the condition. Our goal is that the continuum model may help guide targeted treatments and improved patient outcomes.

International Olympic Committee consensus statement: harassment and abuse (non-accidental violence) in sport.

Abstract: Despite the well-recognised benefits of sport, there are also negative influences on athlete health, well-being and integrity caused by non-accidental violence through harassment and abuse. All athletes have a right to engage in 'safe sport', defined as an athletic environment that is respectful, equitable and free from all forms of non-accidental violence to athletes. Yet, these issues represent a blind spot for many sport organisations through fear of reputational damage, ignorance, silence or collusion. This consensus statement extends the 2007 IOC Consensus Statement on Sexual Harassment and Abuse in Sport, presenting additional evidence of several other types of harassment and abuse-psychological, physical and neglect. All ages and types of athletes are susceptible to these problems but science confirms that elite, disabled, child and lesbian/gay/bisexual/trans-sexual (LGBT) athletes are at highest risk, that psychological abuse is at the core of all other forms and that athletes can also be perpetrators. Harassment and abuse arise from prejudices expressed through power differences. Perpetrators use a range of interpersonal mechanisms including contact, non-contact/verbal, cyber-based, negligence, bullying and hazing. Attention is paid to the particular risks facing child athletes, athletes with a disability and LGBT athletes. Impacts on the individual athlete and the organisation are discussed. Sport stakeholders are encouraged to consider the wider social parameters of these issues, including cultures of secrecy and deference that too often facilitate abuse, rather than focusing simply on psychopathological causes. The promotion of safe sport is an urgent task and part of the broader international imperative for good governance in sport. A systematic multiagency approach to prevention is most effective, involving athletes, entourage members, sport managers, medical and therapeutic practitioners, educators and criminal justice agencies. Structural and cultural remedies, as well as practical recommendations, are suggested for sport organisations, athletes, sports medicine and allied disciplines, sport scientists and researchers. The successful prevention and eradication of abuse and harassment against athletes rests on the effectiveness of leadership by the major international and national sport organisations.

2016 update on eating disorders in athletes: A comprehensive narrative review with a focus on clinical assessment and management

Abstract: Eating disorders, such as anorexia nervosa and bulimia nervosa, can have devastating effects on both the health and performance of athletes. Compared to non-athletes, both female and male athletes are at higher risk of developing an eating disorder. This is especially true for athletes participating in sports where low body weight or leanness confers a competitive advantage. Screening for disordered eating behaviours, eating disorders and for related health consequences should be a standard component of preparticipation examinations, and team physicians should be knowledgeable of the updated diagnostic criteria for eating disorders in the Diagnostic and Statistical Manual-V. Athletes with eating disorders should undergo thorough evaluation and treatment by an experienced multidisciplinary team. Team physicians play a critical role in decision-making on clearance for participation and return to play. Using evidence-based guidelines for clearance and return to play encourages transparency and accountability between the sports medicine care team and the athlete. Efforts to prevent eating disorders should be aimed at athletes, coaches, parents and athletic administrators, and focused on expanding knowledge of healthy nutrition in support of sport performance and health.

ACL injuries in men's professional football: a 15-year prospective study on time trends and return-to-play rates reveals only 65% of players still play at the top level 3 years after ACL rupture

Abstract: 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 on the subsequent playing career in male professional football players. Methods 78 clubs were followed between 2001 and 2015. Time trend in ACL injury rate was analysed using linear regression. ACL-injured players were monitored until RTP and tracked for 3 years after RTP. Results We recorded 157 ACL injuries, 140 total and 17 partial ruptures, with a non-significant average annual increase in the ACL injury rate by 6% (R(2)=0.13, b=0.059, 95% CI -0.04 to 0.15, p=0.20). The match ACL injury rate was 20-fold higher than the training injury rate (0.340 vs 0.017 per 1000 h). 138 players (98.6%) with a total rupture underwent ACL reconstruction; all 134 players with RTP data (4 players still under rehabilitation) were able to return to training, but 9 of them (6.7%) suffered complications before their first match appearance (5 reruptures and 4 other knee surgeries). The median layoff after ACL reconstruction was 6.6 months to training and 7.4 months to match play. We report 3-year follow-up data for 106 players in total; 91 players (85.8%) were still playing football and 60 of 93 players (65%) with ACL reconstruction for a total rupture played at the same level. Conclusions The ACL injury rate has not declined during the 2000s and the rerupture rate before return to match play was 4%. The RTP rate within a year after ACL reconstruction was very high, but only two-thirds competed at the highest level 3 years later.

Prevalence of clinically elevated depressive symptoms in college athletes and differences by gender and sport

Abstract: Background There are approximately 400 000 National Collegiate Athletic Association (NCAA) student athletes and 5–7 million high school student athletes competing each year. According to the US Department of Health and Human Services, the depression prevalence rate for young adults, which ranges from 10% to 85% across studies, is higher than that of other age groups. Given the relatively high prevalence of depression in individuals of collegiate age in the general population, the prevalence of depression among athletes in this age group warrants further study. This multiyear study examined the prevalence of depressive symptoms in college athletes, as well as demographic factors related to increased or decreased rates of depressive symptoms by gender and sport. Objective To describe the prevalence of depression symptoms among NCAA division I student athletes at a single institution over 3 consecutive years. Method Participants (n=465) completed a battery of measures during their yearly spring sports medicine physical across 3 consecutive years. The battery included the Center for Epidemiological Studies Depression Scale (CES-D) and a demographic questionnaire, administered during the course of routine sports medicine physical examinations. Differences in depressive symptoms prevalence and relative risk ratios were calculated by gender and sport. Results The prevalence rate for a clinically relevant level of depressive symptoms, as measured on the CES-D (CES-D ≥16), was 23.7%. A moderate to severe level of depressive symptoms was reported by 6.3%. There was a significant gender difference in prevalence of depressive symptoms, χ 2 (1)=7.459, p=0.006, with female athletes exhibiting 1.844 times the risk of male athletes for endorsing clinically relevant symptoms. Conclusions The CES-D identified clinically relevant levels of depressive symptoms in nearly one-quarter of college student athletes in this large cross-sectional sample. Female college athletes reported significantly more depressive symptoms than males. Findings suggest that depression prevalence among college athletes is comparable to that found in the general college population. In light of these findings, sports medicine personnel may wish to implement depression screening and assessment of depressive symptoms across sports to identify at-risk athletes. Risk factors related to depression in college athletes warrant additional study.

Aerobic exercise ameliorates cognitive function in older adults with mild cognitive impairment: a systematic review and meta-analysis of randomised controlled trials

Abstract: Objective To evaluate the effect of aerobic exercise on cognitive function in people with mild cognitive impairment (MCI). Design Systematic review and meta-analysis of aerobic exercise intervention for cognitive function in older adults with MCI. Data sources PubMed, EMBASE, SinoMed, China National Knowledge Infrastructure (CNKI), Wanfang and Chinese Science and Technology Periodical (VIP) databases from their inception to 31 January 2015, the Cochrane Central Register of Controlled Trials (Cochrane Library, 2015, Issue 3) and the reference lists of all retrieved articles. Eligibility criteria Randomised controlled trials, older adults with MCI, aerobic exercises compared with no specific exercise intervention for global cognitive ability and any specific domains of cognition. Data synthesis Meta-analysis was conducted with RevMan V.5.3 software using the fixed-effect model for the available data without significant heterogeneity, or the random-effect model was used if appropriate. Results 11 studies were identified involving 1497 participants. Meta-analysis showed that aerobic exercise significantly improved global cognitive ability (Mini-Mental State Examination (MMSE) scores: MD=0.98, 95% CI 0.5 to 1.45, p Conclusions Aerobic exercise led to an improvement in global cognitive ability and had a positive effect with a small effect size on memory in people with MCI. However, owing to the limitations of the included studies, these findings should be interpreted cautiously.

Dose-response association of screen time-based sedentary behaviour in children and adolescents and depression: a meta-analysis of observational studies.

Abstract: Background Depression represents a growing public health burden. Understanding how screen time (ST) in juveniles may be associated with risk of depression is critical for the development of prevention and intervention strategies. Findings from studies addressing this question thus far have been inconsistent. Therefore, we conducted a comprehensive systematic review and meta-analysis of data related to this question. Methods The meta-analysis was conducted in accordance with the PRISMA guideline. We searched the electronic databases of PubMed, Web of Science and EBSCO systematically (up to 6 May 2015). OR was adopted as the pooled measurement of association between ST and depression risk. Dose–response was estimated by a generalised least squares trend estimation. Results Twelve cross-sectional studies and four longitudinal studies (including 1 cohort study) involving a total of 127 714 participants were included. Overall, higher ST in preadolescent children and adolescents was significantly associated with a higher risk of depression (OR=1.12; 95% CI 1.03 to 1.22). Screen type, age, population and reference category acted as significant moderators. Compared with the reference group who had no ST, there was a non-linear dose–response association of ST with a decreasing risk of depression at ST<2 h/day, with the lowest risk being observed for 1 h/day (OR=0.88; 95% CI 0.84 to 0.93). Conclusions Our meta-analysis suggests that ST in children and adolescents is associated with depression risk in a non-linear dose–response manner.

Effects and dose–response relationships of resistance training on physical performance in youth athletes: a systematic review and meta-analysis

Abstract: Objectives To quantify age, sex, sport and training type-specific effects of resistance training on physical performance, and to characterise dose–response relationships of resistance training parameters that could maximise gains in physical performance in youth athletes. Design Systematic review and meta-analysis of intervention studies. Data sources Studies were identified by systematic literature search in the databases PubMed and Web of Science (1985–2015). Weighted mean standardised mean differences (SMD wm ) were calculated using random-effects models. Eligibility criteria for selecting studies Only studies with an active control group were included if these investigated the effects of resistance training in youth athletes (6–18 years) and tested at least one physical performance measure. Results 43 studies met the inclusion criteria. Our analyses revealed moderate effects of resistance training on muscle strength and vertical jump performance (SMD wm 0.8–1.09), and small effects on linear sprint, agility and sport-specific performance (SMD wm 0.58–0.75). Effects were moderated by sex and resistance training type. Independently computed dose–response relationships for resistance training parameters revealed that a training period of >23 weeks, 5 sets/exercise, 6–8 repetitions/set, a training intensity of 80–89% of 1 repetition maximum (RM), and 3–4 min rest between sets were most effective to improve muscle strength (SMD wm 2.09–3.40). Summary/conclusions Resistance training is an effective method to enhance muscle strength and jump performance in youth athletes, moderated by sex and resistance training type. Dose–response relationships for key training parameters indicate that youth coaches should primarily implement resistance training programmes with fewer repetitions and higher intensities to improve physical performance measures of youth athletes.

Cardiorespiratory fitness cut points to avoid cardiovascular disease risk in children and adolescents; what level of fitness should raise a red flag? A systematic review and meta-analysis.

Abstract: Background Poor cardiorespiratory fitness is associated with cardiovascular disease risk factors. Aim To perform a systematic review and meta-analysis of the relationship between poor cardiorespiratory fitness and cardiovascular disease risk in children and adolescents. Methods Systematic literature search (1980 to 11 April 2015) for studies that determined a cardiorespiratory fitness cut point that predicted cardiovascular disease risk in children and adolescents. Results We identified 7 studies that included 9280 children and adolescents (49% girls) aged 8–19 years from 14 countries. Cardiovascular disease risk was already present in boys (6–39%) and girls (6–86%). Boys with low fitness ( Summary Fitness levels below 42 and 35 mL/kg/min for boys and girls, respectively, should raise a red flag. These translate to 6 and 3 stages on the shuttle run test for a boy and a girl, both aged 15 years, respectively. These cut points identify children and adolescents who may benefit from primary and secondary cardiovascular prevention programming.

Greater vertical impact loading in female runners with medically diagnosed injuries: a prospective investigation

Abstract: Background Running has been critical to human survival. Therefore, the high rate of injuries experienced by modern day runners is puzzling. Landing on the heel, as most modern day shod runners do, results in a distinct vertical impact force that has been shown to be associated with running-related injuries. However, these injury studies were retrospective in nature and do not establish cause and effect. Objective To determine whether runners with high impacts are at greater risk for developing medically diagnosed injuries. Methods 249 female runners underwent a gait analysis to measure vertical instantaneous loading rate, vertical average loading rate (VALR), vertical impact peak (VIP) and peak vertical force. Participants then recorded their mileage and any running-related injuries monthly in a web-based, database programme. Variables were first compared between the entire injured (INJ; n=144) and uninjured (n=105) groups. However, the focus of this study was on those injured runners seeking medical attention (n=103) and those who had never injured (n=21). Results There were no differences between the entire group of injured and uninjured groups. However, all impact-related variables were higher in those with medically diagnosed injuries compared with those who had never been injured. (effect size (ES) 0.4–0.59). When VALR was >66.0 body weight (BW)/s, the odds of being DX_INJ were 2.72 (95% CI 1.0 to 7.4). Impact loading was associated with bony and soft-tissue injuries. Conclusions Vertical average loading rate was lower in female runners classified as ‘never injured’ compared with those who had been injured and sought medical attention.

2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions (exercise, taping, bracing, foot orthoses and combined interventions)

Abstract: Patellofemoral pain affects physically active and sedentary individuals, accounting for 11–17% of knee pain presentations to general practice1 ,2 and 25–40% of all knee problems seen in a sports injury clinic.3 ,4 Patellofemoral pain is characterised by anterior knee pain associated with activities such as squatting, rising from sitting and stair ambulation. While traditionally viewed as self-limiting, increasing research data suggest that patellofemoral pain is often recalcitrant and can persist for many years,5–8 and may cause a decline in sports participation.8 ,9 Despite its high prevalence among active individuals9–12 and frequent presentations for treatment, there are few published guidelines to help clinicians choose the appropriate evidence-based treatment for patellofemoral pain. The most recent and relevant paper from Barton and colleagues13 combined systematic review findings with qualitative interviews from expert clinicians to provide a clinically relevant synthesis, covering the literature up to September 2013. At the International Patellofemoral Pain Research Retreat in Manchester 2015, we held a consensus meeting to update the current evidence base and produce consensus-based recommendations regarding treatment for patellofemoral pain. All retreat registrants were active researchers in patellofemoral pain and presented their research findings. Many of the world leading researchers (eg, 8 out of the top 10 researchers with the highest number of publications, when the term ‘patellofemoral pain’ was searched in Scopus, February 2016) were in attendance and contributed to the consensus meeting. The consensus meeting during the retreat resulted in recommendations, based on evidence published between January 2010 and June 2015. These recommendations should be combined with information gathered from individual patients, regarding their preferences, experiences, presentation and values, along with the values, expertise and skills of individual practitioners to create a patient-centred treatment approach. ### Literature review CJB searched EMBASE, MEDLINE, CINAHL and Current Contents for systematic reviews …

The psychological response to injury in student athletes: a narrative review with a focus on mental health

Abstract: Background Injury is a major stressor for athletes and one that can pose significant challenges. Student athletes must handle rigorous academic as well as athletic demands that require time as well as significant physical requirements. Trying to perform and succeed in the classroom and on the playing field has become more difficult as the demands and expectations have increased. If an athlete is injured, these stressors increase. Main thesis Stress is an important antecedent to injuries and can play a role in the response to, rehabilitation and return to play after injury. The psychological response to injury can trigger and/or unmask mental health issues including depression and suicidal ideation, anxiety, disordered eating, and substance use/abuse. There are barriers to mental health treatment in athletes. They often consider seeking help as a sign of weakness, feeling that they should be able to ‘push through’ psychological obstacles as they do physical ones. Athletes may not have developed healthy coping behaviours making response to injury especially challenging. Purpose I discuss the current state of knowledge regarding the psychological response to injury and delineate resources necessary to direct the injured athlete to a mental health care provider if appropriate.