Best practices for the dissemination and implementation of neuromuscular training injury prevention warm-ups in youth team sport: a systematic review.

OBJECTIVE: To evaluate best practices for neuromuscular training (NMT) injury prevention warm-up programme dissemination and implementation (D&I) in youth team sports, including characteristics, contextual predictors and D&I strategy effectiveness. DESIGN: Systematic review. DATA SOURCES: Seven databases were searched. ELIGIBILITY: The literature search followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. INCLUSION CRITERIA: participation in a team sport, ≥70% youth participants (<19 years), D&I outcomes with/without NMT-related D&I strategies. The risk of bias was assessed using the Downs & Black checklist. RESULTS: Of 8334 identified papers, 68 were included. Sport participants included boys, girls and coaches. Top sports were soccer, basketball and rugby. Study designs included randomised controlled trials (RCTs) (29.4%), cross-sectional (23.5%) and quasi-experimental studies (13.2%). The median Downs & Black score was 14/33. Injury prevention effectiveness (vs efficacy) was rarely (8.3%) prioritised across the RCTs evaluating NMT programmes. Two RCTs (2.9%) used Type 2/3 hybrid approaches to investigate D&I strategies. 19 studies (31.6%) used D&I frameworks/models. Top barriers were time restrictions, lack of buy-in/support and limited benefit awareness. Top facilitators were comprehensive workshops and resource accessibility. Common D&I strategies included Workshops with supplementary Resources (WR; n=24) and Workshops with Resources plus in-season Personnel support (WRP; n=14). WR (70%) and WRP (64%) were similar in potential D&I effect. WR and WRP had similar injury reduction (36-72%) with higher adherence showing greater effectiveness. CONCLUSIONS: Workshops including supplementary resources supported the success of NMT programme implementation, however, few studies examined effectiveness. High-quality D&I studies are needed to optimise the translation of NMT programmes into routine practice in youth sport.

A National Survey on the Relationship of Youth Sport Specialization Behaviors to Self-Reported Anxiety and Depression in Youth Softball Players.

BACKGROUND: There are little to no data on whether any associations exist between sport specialization and mental health in youth softball athletes. HYPOTHESIS: Highly specialized youth softball athletes will have worse self-reported depression and anxiety symptom scores compared with low and moderate specialized athletes. STUDY DESIGN: Cross-sectional survey. LEVEL OF EVIDENCE: Level 4. METHODS: An online cross-sectional survey was distributed in the fall of 2021 to a national sample of female youth softball athletes between the ages of 12 and 18 years. Sport specialization status was determined using a 3-point specialization scale that classifies either low, moderate, or high. The patient health questionnaire-9 (PHQ-9) and the 7-item general anxiety disorder scale (GAD-7) were used to assess self-reported symptoms of depression and anxiety. Comparison also included sports participation and specialization behaviors between specialization groups. RESULTS: A total of 1283 subjects (mean age, 15.1 ± 1.7 years) fully completed the survey. After adjusting for covariates, lower scores were reported on both the PHQ-9 and GAD-7 by highly specialized athletes compared with moderate or low specialization athletes (PHQ-9, high = 8.6 ± 0.4; moderate = 11.2 ± 0.3; low = 10.9 ± 0.5; P < 0.01; GAD-7, high = 6.5 ± 0.4; moderate = 8.6 ± 0.3; low = 8.4 ± 0.4, P < 0.01). Conversely, higher scores were reported on both scales for athletes who received private softball coaching compared with those who did not (PHQ-9, 11.5 ± 0.3 vs 9.0 ± 0.3; P < 0.01; GAD-7, 8.8 ± 0.3 vs 6.9 ± 0.3, P < 0.01). Finally, athletes who reported an arm overuse injury in the previous year reported higher PHQ-9 scores (10.8 ± 0.3 vs 9.8 ± 0.3; P < 0.01). CONCLUSION: While sport specialization, as measured by the validated 3-point scale, was not associated with increased anxiety and depression symptom scores, other aspects of specialization behavior such as private coaching or overuse injury history were associated with worse scores on these scales, indicating potential concern for anxiety and depression. However, although the differences we observed were statistically significant, they did not exceed the minimal clinically important difference values that have been established for the PHQ-9 (5 points) or GAD-7 (4 points). CLINICAL RELEVANCE: This project is a first step toward understanding the sport specialization behaviors and their influence on the mental health of youth softball athletes. Focusing on investigating specialization behaviors further may reveal to be a better indicator of risk of developing anxiety and depression symptoms compared with utilizing the 3-point specialization scale.

Coaches of youth field sports as delivery agents of injury prevention programmes: how are we training the trainers? A scoping review.

OBJECTIVE: To systematically map the coach education (CE) component of injury prevention programmes (IPPs) for youth field sports by identifying and synthesising the design, content and facilitation strategies used to address competency drivers and behaviour change. DESIGN: Scoping review. DATA SOURCES: PubMed, PsycInfo, EMBASE, CINAHL, SportDiscus and Google Scholar electronic databases were searched using keywords related to IPPs and youth field sports. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies of IPPs in youth field sports, that provided 'train-the-trainer' education to coaches as designated delivery agents. RESULTS: 20 studies from two field sports (soccer/football; n=17, Rugby Union; n=3) fulfilled the eligibility criteria. Eleven CE interventions occurred in the preseason and 18 occurred at one time-point (single day). Five studies cited use of a behavioural change theory or model in the design of their CE, most frequently the Health Action Process Approach model (n=5); and use of behavioural change techniques varied. Twelve of twenty studies (60%) reported some form of ongoing support to coaches following the CE primary intervention concurrent with IPP implementation. CONCLUSION: CE that occurs on 1 day (one time-point) is most popular for preparing coaches as delivery agents of IPPs in youth field sports. While recognising pragmatic barriers, more expansive in-service training, support and feedback may enhance the effective implementation of IPPs. TRIAL REGISTRATION NUMBER: https://doi.org/10.17605/OSF.IO/FMHGD.

Injury Profile in Youth Female Athletes: A Systematic Review and Meta-Analysis.

BACKGROUND: An increasing number of epidemiological studies assessing the incidence, prevalence and severity of injury in youth female sport are available. However, no study has sought to synthesise the current evidence base across all youth female sport. As such, a systematic review and meta-analysis of injury in this cohort is necessary to understand the diversity of injury and its associated burden between sports in addition to identifying the density of research available. OBJECTIVE: To conduct a systematic review and meta-analysis of epidemiological data of injuries in youth female athletes with particular attention to injury incidence, mean days lost and injury burden. METHODS: Searches were performed in PubMed, EBSCO (SPORTDiscus with Full Text MEDLINE, APA PsycINFO, CINAHL, Academic Search Complete) and Cochrane databases. Studies were considered if they reported time-loss injury incidence or prevalence in youth female (≤ 19 years old) athletes. Study quality and risk of bias were assessed using STROBE-SIIS extension, Newcastle-Ottawa Scale, and funnel plots, respectively. Injury incidence and burden rate data were modelled using a mixed-effect Poisson regression model. Days lost data were modelled using a generalised linear mixed model. RESULTS: Thirty-two studies were included. The overall incidence rate, mean days lost per injury, and burden rate were 4.4 injuries per 1000 h (95% CI 3.3-5.9), 10 days (95% CI 6-15), and 46 days per 1000 h (95% CI 23-92), respectively. Forty percent of athletes sustained at least one time-loss injury. Competitive level was a significant moderator of match and training injury incidence, with elite youth athletes presenting greater pooled injury incidence estimates than non-elite athletes (p = 0.0315 and p = 0.0047, respectively). The influence of moderators on days lost and injury burden could not be determined due to an insufficient number of studies for analysis. CONCLUSION: Despite a broad inclusion criterion, there is limited injury surveillance research available across youth female sport. Outside of soccer, little research density is evidenced with single studies available in popular team sports such as Australian football and rugby union. Insufficient study numbers reporting mean days lost and injury burden data were available for analysis, and pooled days lost data could only be estimated for soccer. This highlights a need for future research to report days lost data alongside injury number and exposure so burden can be calculated and the full risk of injury to youth female athletes can be identified.

Youth Sport Specialization and Risk of Injury: A General Review.

OBJECTIVE: The purpose of this literature review was to analyze, understand, and disclose prior empirical findings about the injury risks associated with youth sport specialization. DATA SOURCES: Articles were included in this review if they examined the association between youth sport specialization status and injury. Nine articles from 5 journals met these criteria. All articles summarized the findings of cross-sectional (N = 5) or cohort studies (N = 4). MAIN RESULTS: Each article included in this review indicated that specialized youth athletes are more susceptible to injury. Only 5 studies assessed the injury risks linked to specialization independent of sport training volume. These studies produced contradictory results. CONCLUSIONS: Although specialized youth athletes are more prone to injury, future research is needed to determine the independent and inherent injury risk associated with specialization. Nevertheless, youth athletes should refrain from specialization until at least adolescence.

Youth sport specialization associated with poorer lower extremity function & pain as young adults.

OBJECTIVE: Examine the link between youth sports specialization and long-term lower extremity joint health after sports by comparing lower extremity function, pain, and history of sport-related injuries between young adults that were highly, moderately, and low specialized in youth sports. METHODS: We used a cross-sectional design, and all data was collected using an electronic survey. Our sample included N = 356 young adults who participated in a primary sport during youth and high school sports but were no longer participating in that sport as a young adult. Participants were stratified into high (n = 111), moderate (n = 119), and low (n = 126) specialization groups using a 3-criteria sport specialization questionnaire based on youth sports participation prior to high school. We compared participants current Lower Extremity Functional Scale (LEFS) score (0-80), the proportion of participants with clinically important deficits in LEFS score (≤71/80), current lower extremity (foot/ankle, knee, hip) pain scores (0-10), and history of lower extremity (foot/ankle, knee, hip) injuries between the high, moderate, and low specialization groups. RESULTS: The high specialization group reported significantly lower overall LEFS scores, and a greater proportion (40%) reported clinically important deficits in LEFS scores compared to the low specialization group (20%). The high specialization group also reported greater foot/ankle and knee pain and a greater proportion of sport-related knee injuries than the low specialization group (49% vs 25%). CONCLUSIONS: Our findings suggest that even after discontinuing sports, young adults who were highly specialized in youth sports before high school reported clinically important deficits in lower extremity function, greater foot/ankle and knee pain, and a greater history of knee injuries than young adults who were not specialized in youth sports, suggesting a possible link between youth sports specialization and long-term lower extremity health after sports.

Training volume recommendations and psychosocial outcomes in adolescent athletes.

OBJECTIVES: Researchers have recommended that youth athletes limit their practice volume to the number of hours/week that they are old in years. We examined sport perceptions, burnout, anxiety, and depressive symptoms among youth athletes who did and did not report playing more hours/week of organized sports than their age. METHODS: Uninjured athletes aged 13-18 years old completed questionnaires documenting demographics, sport participation volume, health and injury history, depressive symptoms, anxiety, burnout, and sport perceptions during a pre-participation physical examination. We grouped participants as those who reported more hours/week in organized sports than their age (exceeds age/volume recommendation) vs. those who reported equal/less hours/week in organized sports than their age (meets age/volume recommendation). RESULTS: Of 161 participants, 21% (n = 33) were in the 'exceeds age/volume recommendation' group (age = 15.2 ± 1.3 years; 55% female; 18.7 ± 4.0 hours/week) and 79% (n = 128) were in the 'meets age/volume recommendation' group (age = 15.6 ± 1.2 years; 50% female; 10.2 ± 3.4 hours/week). A higher proportion of the 'exceeds age/volume recommendation' group agreed with the statement 'youth in my sport play too many games before college' than the 'meets age/volume recommendation' group (33% vs. 16%; p = 0.03). After adjusting for the effect of age, sport specialization level, and weight, exceeding age/volume recommendations was associated with the perception that youth in sports play too many games before college (aOR = 3.24; 95% CI = 1.26, 8.29; p = 0.01), while burnout (aOR = 0.99; 95% CI = 0.94, 1.06; p = 0.93), anxiety (aOR = 0.97; 95% CI = 0.84, 1.11; p = 0.65), and depressive symptoms (aOR = 0.90; 95% CI = 0.74, 1.10; p = 0.30) were not significantly related. CONCLUSION: Athletes who spend more hours in sport than their age appear to perceive their competition load during youth sports to be excessive. Coaches and providers should monitor athlete's training hours and perceptions of competition load to offer support and potentially prevent burnout development.

Does a history of youth sport-related knee injury still impact accelerometer-measured levels of physical activity after 3-12 years?

OBJECTIVES: To examine accelerometer-measured physical activity (PA) in individuals with a knee injury history and controls and the association of moderate to vigorous PA (MVPA) with self-reported and performance measures of knee function. DESIGN: Historical cohort. PARTICIPANTS: Participants with a 3-12 year history of youth sport-related knee injury and matched controls. MAIN OUTCOME MEASURES: MVPA (Actigraph GT3x-BT), Knee Injury and Osteoarthritis Outcome Score (KOOS), Triple Single-Leg Hop, Y-Balance and isometric knee strength was measured. Regression analyses examined differences in PA and the association between MVPA and knee function, adjusted for injury history, sex and time since injury. RESULTS: Participants (42 injured, 43 controls) had a median age of 23.4 (range 16-29) years. The previously injured group spent less daily adjusted minutes in MVPA [-13.5 (95% CI -25.6, -1.4)] than controls, and females had 10.8 min (95% CI -20.2, -1.4) less MVPA than males. Higher MVPA was associated with better KOOS sport and recreation [ß = 0.05, 95% CI (0.01, 0.09)] adjusted for injury history. No other associations were observed. CONCLUSION: Previously injured youth participated in less MVPA compared to controls 3-12 years later. Lower MVPA is associated with poorer self-reported sport and recreation knee function which may have long-term negative health consequences.

Financial and medical burdens of youth sports specialization: survey of pediatric sports patients.

BACKGROUND: The trend towards youth sports specialization has led to increased costs from higher injury rate and from private club fees. The aim of this study was to represent the financial and medical burdens of sports specialization with single sport participation or club sports involvement. METHODS: An 18-item survey on sports participation and musculoskeletal injury was administered to parents of patients visiting the clinic of a pediatric sports medicine orthopaedic surgeon over a three-month period. Comparisons were made between groups to identify differences in medical and financial burdens. Logistic regressions were performed to evaluate Odds Ratios for binary outcomes. RESULTS: Club athletes were significantly younger than non-club athletes (12.9±3.1 years versus 14.9±2.8 years, P=0.0002) with club athletes starting sports at average of 7.2±3.1 years. Club sports participation (adjusted OR 5.88, 95% CI: 1.10, 31.4) and female sex (adjusted OR 3.47, 95% CI: 1.12, 10.74) were significant predictors of spending >$1000 USD on sports annually. Multisport participation (OR 5.72, 95% CI: 1.21, 26.96) and spending >$1000 on sports annually (OR 17.21, 95% CI: 1.49, 199.25) were significant predictors of presenting to clinic for a sports-related injury. Single sport athletes had a higher number of medical appointments for sports injuries (18.6±23.0 versus 9.3±10.0 for multisport, P=0.0042). CONCLUSIONS: Youth sports specialization is of substantial financial and medical burden to families. This data can help identify areas of intervention to mitigate injury risk and reduce financial barriers to youth sports participation.

Primary Periphyseal Stress Injuries in Young Athletes: A Systematic Review.

BACKGROUND: Overuse injuries are common in sporting children and adolescents. These injuries are a particular concern when they involve the epiphyseal-physeal-metaphyseal (EPM) complex given their potential to disturb skeletal growth. Specifically, the limits of mechanical tolerance of the EPM complex to repetitive stress may be exceeded by the intense and continuous training characteristic of many youth sports today. OBJECTIVE: This article describes the present status of knowledge on the occurrence and outcome of primary periphyseal stress injuries (PPSIs) affecting the EPM complex in the extremities of children and adolescents involved in youth sports. METHODS: A comprehensive review of the sports medicine literature was conducted to determine the nature and extent of PPSIs affecting the EPM complex of the extremities among youth sports participants and the potential for consequent skeletal growth disturbance and resultant limb deformity associated with these injuries. RESULTS: Our initial search uncovered 128 original published scientific articles reporting relevant data on PPSIs. There were 101 case reports/series, 19 cross-sectional, 1 case-control, and 7 cohort studies with relevant data. The case reports/series studies reported 448 patients with PPSIs involving the extremities. Children and adolescents representing a variety of high impact repetitive youth sports activities-including baseball, badminton, climbing, cricket, dance, gymnastics, rugby, soccer, swimming, tennis, and volleyball-may sustain PPSIs involving the shoulder, elbow, hand and wrist, knee, and ankle and foot. Although incidence data from prospective cohort studies are lacking, data arising from cross-sectional studies suggest that PPSIs may be common in select groups of youth athletes-including the shoulder in baseball players (0-36.6%), wrist in gymnasts (10-83%) and platform divers (52.6%), and fingers in rock climbers (5-58%). Notably, not all stress-related skeletal changes detected on imaging were symptomatic in these studies. When diagnosed and treated with an appropriate period of rest and rehabilitation, most patients studied were able to return to their sport activities. However, our data also show that 57/448 PPSIs (12.7%) produced growth disturbance, and that 28/448 patients (6.2%) underwent surgery for their injuries. Absence of treatment, delayed presentation and diagnosis, and non-compliance with a rest regimen were common in cases that produced growth disturbance. CONCLUSIONS: PPSIs may affect the extremities of children and adolescents engaged in a variety of youth sports, especially at advanced levels of training and competition. Most skeletally immature patients with PPSIs respond well to timely treatment; however, in extreme cases, PPSIs can progress to produce skeletal growth disruption which may necessitate surgical intervention. Clearly, establishing the early diagnosis of PPSIs and providing timely treatment of these injuries are needed to ensure the skeletal health of youth sports participants. Rigorous prospective longitudinal epidemiological and imaging studies designed to provide incidence rates of PPSIs and to determine the effect of PPSIs on long-term skeletal health are also necessary.

The National Interscholastic Cycling Association Mountain Biking Injury Surveillance System: 40,000 Student-Athlete-Years of Data.

ABSTRACT: A web-based injury surveillance system was implemented through a collaboration between University of Utah researchers and the National Interscholastic Cycling Association (NICA) to better understand injury characteristics in mountain biking. Data were collected from NICA leagues during the 2018 and 2019 seasons. Injuries were tracked in 41,327 student-athlete-years, identifying 1750 unique injuries during 1155 injury events. Rider-dependent and rider-independent variables were analyzed. The most commonly reported injuries were concussion (23.6%), injuries to the wrist/hand (22.3%), and shoulder (15.6%). Half of all injury events occurred on downhills. Men and women reported similar yet significantly different injury rates (2.69% and 3.21%, respectively; P = 0.009). Women sustained more lower-limb injuries (37.8% vs 28.3%; P = 0.003). Nearly 50% of crashes resulted in an emergency room visit. Youth mountain bike racing is a rapidly growing sport. Acute traumatic injuries are common. Injury surveillance system data are now being used to inform injury prevention strategies and direct future research.

The Epidemiology, Risk Factors, and Nonsurgical Treatment of Injuries Related to Endurance Running.

ABSTRACT: Running is a popular form of exercise that is easily accessible to various populations; endurance running, defined as distances beyond 5 km, continues to grow within the sport. Endurance running-related injuries are common in the lower extremities and are primarily overuse related. A multitude of risk factors for injury exist, including extrinsic factors, such as running distance and frequency, and intrinsic factors, such as biomechanics and nutrition status. Training and rehabilitation techniques vary with a general focus on strengthening and gradual increase in activity, but evidence is mixed, and it is difficult to generalize programs across different running populations. Management of specific running groups, including youth runners, is an area in which additional research is needed. New treatments, such as orthobiologics and wearable technology, have promising potential to optimize performance and recovery and minimize injury. However, they need to be further evaluated with high-quality studies.

Subconcussive Head Impacts and Neurocognitive Function Over 3 Seasons of Youth Football.

OBJECTIVE: To determine the association between repetitive subconcussive head impacts and neurobehavioral outcomes in youth tackle football players. METHODS: Using helmet-based sensors, we measured head impacts for 3 consecutive seasons of play in 29 male players age 9-11. Cumulative impact g's were calculated. Players completed a battery of outcome measures before and after each season, including neuropsychological testing, vestibular-ocular sensitivity, and self- and parent-reported measures of symptoms and attention-deficit hyperactivity disorder (ADHD). RESULTS: Average cumulative impact over 3 seasons was 13 900g. High-intensity hits predicted worse change for self-reported social adjustment (P = .001). Cumulative impact did not predict change in any of the outcome measures. History of ADHD, anxiety, and depression predicted worse change for self-reported symptoms and social adjustment, independent of head impacts. When players were stratified into 3 groups based on cumulative impact across all 3 seasons, differences in outcome measures existed prior to the start of the first season. These differences did not further increase over the course of the 3 seasons. CONCLUSION: Over 3 consecutive seasons of youth tackle football, we found no association between cumulative head impacts and neurobehavioral outcomes. Larger sample sizes and longer follow-up times would further assist in characterizing this relationship.

Prevalence and Consequences of Sport Specialization Among Little League Baseball Players.

BACKGROUND: Baseball is one of the most popular boy's youth sports, and there has been a rise in the rates of certain overuse injuries among players. Specialization has been identified as a risk factor for overuse injury in high school athlete populations, but there is little understanding of the prevalence or consequences of sport specialization in Little League baseball players. HYPOTHESIS: Sport specialization will be highly prevalent among Little League baseball players and specialization will be associated with worse throwing arm health. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 246 Little League baseball players (male; N = 241; age, 9.5 ± 1.6 years) between 7 and 12 years old completed an anonymous, online questionnaire with their parent's assistance. The questionnaire consisted of participant demographics and baseball participation information, including sport specialization status and the Youth Throwing Score (YTS), a valid and reliable patient-reported outcome measure for youth baseball players. RESULTS: Only 29 (11.8%) players met the criteria for high specialization. Approximately one-third of all players (n = 77; 31.3%) reported participating in baseball year-round or receiving private coaching outside of their league (n = 81; 32.9%). Highly specialized athletes demonstrated worse scores on the YTS on average compared with low-specialization athletes (mean [SE]: 56.9 [1.6] vs 61.1 [1.2]; P = 0.01). Similarly, pitching in the previous year (P < 0.01) or traveling overnight regularly for showcases (P = 0.01) were associated with a worse score on the YTS. CONCLUSION: While the prevalence of high sport specialization was low among Little League baseball players, other behaviors associated with specialization such as year-round play and the receiving of private coaching were more common. Highly specialized Little League players demonstrated worse throwing arm health compared with low-specialization players. CLINICAL RELEVANCE: Little League players and their parents may represent a potential target audience for dissemination campaigns regarding sport specialization.

Defining a Research Agenda for Youth Sport Specialization in the United States: The AMSSM Youth Early Sport Specialization Summit.

ABSTRACT: Sport specialization is becoming increasingly common among youth and adolescent athletes in the United States and many have raised concern about this trend. Although research on sport specialization has grown significantly, numerous pressing questions remain pertaining to short- and long-term effects of specialization on the health and well-being of youth, including the increased risk of overuse injury and burnout. Many current elite athletes did not specialize at an early age. Methodological and study design limitations impact the quality of current literature, and researchers need to prioritize pressing research questions to promote safe and healthy youth sport participation. The American Medical Society for Sports Medicine hosted a Youth Early Sport Specialization Summit in April 2019 with the goal of synthesizing and reviewing current scientific knowledge and developing a research agenda to guide future research in the field based on the identified gaps in knowledge. This statement provides a broad summary of the existing literature, gaps and limitations in current evidence, and identifies key research priorities to help guide researchers conducting research on youth sport specialization. Our goals are to help improve the quality and relevance of research on youth sport specialization and to ultimately assure that opportunities for healthy and safe sport participation continue for all youth.

Injuries in youth football and the relationship to player maturation: An analysis of time-loss injuries during four seasons in an English elite male football academy.

A better insight into injuries in elite-youth football may inform prevention strategies. The purpose of this prospective cohort study was to investigate the frequency, incidence, and pattern of time-loss injuries in an elite male football academy, exploring injuries in relation to age and maturation status. Across four consecutive playing seasons, playing exposure and injuries to all academy players (U'9 to U'21) were recorded by club medical staff. Maturation status at the time of injury was also calculated for players competing in U'13 to U'16 aged squads. Time-loss injury occurrence and maturation status at time of injury were the main outcome measures. A total of 603 time-loss injuries were recorded, from 190 different players. Playing exposure was 229 317 hours resulting in an overall injury rate of 2.4 p/1000 h, ranging from 0.7 p/1000 h (U'11) to 4.8 p/1000 h (U'21). Most injuries were traumatic in mechanism (73%). The most common injury location was the thigh (23%), and the most common injury type was muscle injury (29%) combining to provide the most common injury diagnosis; thigh muscle injury (17%). In U'13-U'16 players, a higher number of injuries to early-maturing players were observed in U'13-U'14 players, while more injuries to U'15-U'16 players occurred when classed as "on-time" in maturity status. Maturation status did not statistically relate to injury pattern; however, knee bone (not-fracture) injuries peaked in U'13 players while hip/groin muscle injuries peaked in U'15 players.

Association between lower extremity muscle strength and acute ankle injury in youth team-sports athletes.

OBJECTIVES: To investigate lower extremity muscle strength as risk factor for an acute ankle injury in youth athletes. DESIGN: Cohort study. SETTING: Basketball and floorball clubs. PARTICIPANTS: 188 youth (≤21) male and 174 female athletes. MAIN OUTCOME MEASURES: 1RM leg press, maximal concentric isokinetic quadriceps and hamstrings as well as maximal isometric hip abductor strength were measured and athletes were followed for an acute ankle injury up to three years. Cox regression models were used in statistical analyses. RESULTS: In males, greater 1RM leg press and maximal quadriceps strength increased the risk of any type of acute ankle injury (Hazard ratio [HR] for 1 SD increase, 1.63 [95% CI, 1.12-2.39] and 1.43 [95% CI, 1.01-2.01], respectively). In females, greater 1RM leg press and difference between legs in hip abduction strength increased the risk of acute non-contact ankle injury (HR for 1 SD increase, 1.44 [95% CI, 1.03-2.02] and 1.44 [95% CI, 1.03-2.00], respectively). However, ROC curve analyses showed AUC:s of 0.57-0.64 indicating "fail" to "poor" combined sensitivity and specifity of these tests. CONCLUSION: Greater strength in both sexes along with asymmetry in hip abductor strength in females increased the risk of acute ankle injury.

Employing Standardised Methods to Compare Injury Risk Across Seven Youth Team Sports.

Injury surveillance systems seek to describe injury risk for a given sport, in order to inform preventative strategies. This often leads to comparisons between studies, although these inferences may be inappropriate, considering the range of methods adopted. This study aimed to describe the injury epidemiology of seven youth sports, enabling valid comparisons of injury risk. Consistent methods were employed across seven sports [male American football, basketball, soccer, rugby league, rugby union; female soccer and rugby union] at a high school in England. A 24-hour time-loss injury definition was adopted. Descriptive statistics and injury incidence (/1000 match-hours) are reported. In total, 322 injuries were sustained by 240 athletes (mean age=17.7±1.0) in 10 273 player-match hours. American football had a significantly greater injury incidence (86/1000 h; 95% CI 61-120) than all sports except female rugby union (54/1000 h; 95% CI 37-76). Concussion was the most common injury (incidence range 0.0-26.7/1000 h), while 59% of injuries occurred via player contact. This study employed standardized data collection methods, allowing valid and reliable comparisons of injury risk between youth sports. This is the first known study to provide epidemiological data for female rugby union, male basketball and American football in an English youth population, enabling the development of preventative strategies.

Quantitative Multimodal Assessment of Concussion Recovery in Youth Athletes.

OBJECTIVE: To evaluate recovery trajectories among youth athletes with a concussion and healthy controls across different domains using a quantitative and multifaceted protocol. STUDY DESIGN: Prospective repeated measures. PARTICIPANTS: Youth athletes diagnosed with a concussion between the ages of 8 and 18 years were evaluated (1) within 10 days after injury, (2) approximately 3 weeks after injury, and (3) after return-to-play clearance. Control participants completed the same protocol. SETTING: Sport concussion clinic. INTERVENTIONS: N/A. MAIN OUTCOME MEASURES: Participants underwent a multifaceted protocol that assessed symptoms (postconcussion symptom scale [PCSS]), dual-task gait, event-related potentials (ERPs), and eye tracking. RESULTS: Sixty-seven athletes participated: 36 after concussion (age = 14.0 ± 2.6 years; 44% female) and 31 controls (age = 14.6 ± 2.2 years; 39% female). Concussion symptoms were higher for the concussion group compared with controls at the first (PCSS = 31.7 ± 18.8 vs 1.9 ± 2.9; P < 0.001) and second time points (PCSS = 10.8 ± 11.2 vs 1.8 ± 3.6; P = 0.001) but resolved by the final assessment (PCSS = 1.7 ± 3.6 vs 2.0 ± 3.8; P = 0.46). The concussion group walked slower during dual-task gait than controls at all 3 tests including after return-to-play clearance (0.83 ± 0.19 vs 0.95 ± 0.15 m/s; P = 0.049). There were no between-group differences for ERP connectivity or eye tracking. Those with concussions had a decrease in ERP connectivity recovery over the 3 time points, whereas control participants' scores increased (concussion Δ = -8.7 ± 28.0; control Δ = 13.9 ± 32.2; χ2 = 14.1, P = 0.001). CONCLUSIONS: Concussion is associated with altered dual-task gait speeds after resolution of concussion symptoms, but ERP and eye tracking measures did not demonstrate between-group differences across time. Some objective approaches to concussion monitoring may support with identifying deficits after concussion, but further work is required to delineate the role of gait, electrophysiological, and eye tracking methods for clinical decision-making.