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Purpose: Symptom scores commonly measured following concussion were compared between male and female adolescents with (Hx+) and without (Hx−) a history of concussion, pre and post physical exertion testing. Methods: Eighty (males [n = 60; Hx+ = 19], female [n = 20; Hx+ = 5]) high school students (ages 15–17 y) completed the Buffalo Concussion Treadmill Test once and the modified shuttle run test twice. Symptom scores were collected using the 22-point Symptom Evaluation Scale on the Sport Concussion Assessment Tool (version 5) immediately pre and post physical exertion testing. Results: The symptoms most reported during preexertional testing were fatigue/low energy, feeling slowed down, and nervous/anxious, whereas feeling slowed down, fatigue/low energy, “pressure in head” (males only), and headache (females only) were most frequently reported during postexertion testing. Conclusion: An understanding of the common exertion-related symptoms at baseline in a laboratory or field-based setting in adolescents may be advantageous for clinicians as they manage individual recovery postconcussion. This is particularly important during an adolescent’s recovery and return to play when exertional testing may be implemented, especially since symptoms were reported pre and post exertional testing in both males and females regardless of concussion history.

Purpose: This study assessed physical activity (PA) and body composition of ambulatory children and adolescents with cerebral palsy (CP) and their typically developing peers. Methods: Participants included youth with CP (ages 8–18 y and Gross Motor Function Classification System [GMFCS] levels I–III) and their typically developing peers. Outcomes included PA (actigraphy) and fat/lean mass index (FMI/LMI; dual-energy X-ray absorptiometry). Statistical analyses included linear mixed effects models with Bonferroni adjustment. Fixed effects were study group (CP and typically developing); random effects were participant clusters (sex and age). Exploratory analyses included association of body composition and PA, GMFCS level, and CP involvement (unilateral and bilateral). Results: Seventy-eight participants (CP: n = 40, girls: n = 29; GMFCS I: n = 20; GMFCS II: n = 14; GMFCS III: n = 6) met inclusion criteria. Individuals with CP had lower moderate to vigorous PA (MVPA; β = −12.5; 98.3% confidence interval, −22.6 to −2.5 min; P = .004) and lower LMI (β = −1.1; 97.5% confidence interval, −2.1 to −0.0 kg/m2; P = .020). Exploratory analyses indicated increased LMI with greater MVPA (P = .001), reduced MVPA for GMFCS II (P = .005) and III (P = .001), increased sedentary time for GMFCS III (P = .006), and greater fat mass index with unilateral motor impairment (P = .026). Conclusions: The findings contribute to the knowledge base of increasing MVPA and LMI deficits with the greater functional impact of CP. Associations of increasing LMI with greater MVPA support efforts targeting enhanced PA participation to promote independent mobility.

Ringette and female ice hockey are high participation sports in Canada. Despite policies disallowing body checking, both sports have high injury and concussion rates. This study aimed to compare physical contact (PC), head contact (HC), and suspected injury and concussion incidence rates (IRs) in female varsity ringette and ice hockey.Cross-sectional.Canadian ice arenas.Eighteen Canadian female university ringette and ice hockey tournament/playoff games in the 2018-2019/2019-2020 seasons.Game video-recordings were analyzed using Dartfish video-analysis software to compare both sports.Univariate Poisson regression analyses (adjusted for cluster by team, offset by game-minutes) were used to estimate PC, HC, and suspected injury IRs and incidence rate ratios (IRRs) to compare rates across sports. Proportions of body checks (level 4-5 trunk PC) and direct HC (HC1) penalized were reported.Analyses of 36 team-games (n = 18 ringette, n = 18 hockey) revealed a 19% lower rate of PCs in ringette than ice hockey {IRR = 0.81 [95% confidence interval (CI), 0.73-0.90]}, but a 98% higher rate of body checking [IRR = 1.98 (95% CI, 1.27-3.09)] compared to ice hockey. Ringette had a 40% higher rate of all HC1s [IRR = 1.40 (95% CI, 1.00-1.96)] and a 3-fold higher rate of suspected injury [IRR = 3.11 (95% CI, 1.13-8.60)] than ice hockey. The proportion of penalized body checks and HC1s were low across sports.Body checking and HC1 rates were significantly higher in ringette compared to ice hockey, despite rules disallowing both, and very few were penalized. These findings will inform future injury prevention research in ringette and female ice hockey.

The objective of this study was to identify and report the incidence and mechanisms of suspected injury and concussion in women's rugby union.A cross-sectional video analysis study.Using video analysis of non-professional, single-angle footage, cases of suspected injury and concussion were identified and reported, based on content validation and consensus by eight rugby-specific researchers, therapists, and sport medicine physicians.There were 225 suspected injuries recorded in 48 games [Suspected injury rate (IR) = 117.5/1000 h (95 % CI;102.6-133.9) or 4.7 suspected injuries per match]. The on-field medical attention IR was 95.0/1000 h (95 % CI;81.7-109.9: 3.8 per game). Suspected concussions accounted for 26 % of injuries (30.8/1000 h: 95 % CI;23.5-39.7: 1.2 per game). The attacking team sustained 64 % of suspected injuries. Permanent removal from play was observed for 29 % of suspected injuries. The most common suspected injury locations were head/neck (28.4 %) and lower extremity (27.6 %). The tackle accounted for 67.1 % of all suspected injuries, with a propensity of 11.2/1000 tackle events (95 % CI;9.5-13.2) or 3.1 tackle-related injuries/game. Of tackle-related injuries, 63.6 % were to the ball carrier while 52.2 % of tackle-related concussions were to the ball carrier.This study adds to the growing body of literature examining women's rugby. The rate of suspected injury is high compared with other studies. It is acknowledged that these are suspected injuries not supported by prospective injury surveillance. The high proportion of suspected injuries that are tackle-related warrants specific attention to identify tackle characteristics associated with injury and concussion.

Background. Youth around the globe place their shoulders at risk for injury when participating in sports. Shoulder injuries may vary in severity, produce the potential for time-loss from sport, and result in functional disability. We sought to explore sport-related shoulder injuries in youth by identifying injury rates, risk factors, injury mechanisms, and injury prevention strategies. Methods. All relevant full-text articles were identified by searching MEDLINE, EMBASE, CINAHL, Sport Discus, and the Cochrane Controlled Trials Registry. No date restrictions were used. All full-text studies reporting original research describing sport-related shoulder injury among female and/or male youth from 5 to 18 years old were included. Results. Of 3,889 studies screened, 97 described shoulder injury in youth sports. Shoulder injuries were identified in 24 unique sports. The median seasonal prevalence of shoulder injury was 10.9% (range 1.2–28.2%). The most common injury mechanisms identified were contacted with another player, contact with the playing environment, and falling to the ground. Risk factors for shoulder injury identified were side-to-side strength imbalances, weak external rotator muscles, and scapular dyskinesia. One study evaluated a successful training strategy to prevent shoulder injuries, but two other interventions demonstrated no effect. Conclusions. Sport-related shoulder injuries are prevalent among youth athletes. Injury risk factors identified included modifiable intrinsic factors such as strength, range of motion, and training load. The most common injury mechanism was direct contact with either another person or an object in the playing environment. Innovative shoulder-specific strategies are needed to reduce shoulder injuries in this population. Trial Registration: PROSPERO ID: CRD42020189142.

The risk of concussion is high in Canadian youth ice hockey. Aiming to reduce this burden, in 2011, Hockey Canada implemented a national "zero tolerance for head contact (HC)" policy mandating the penalization of any player HC. In 2018 to 2020, Hockey Canada further amended this HC policy including stricter enforcement of severe HCs. This study aimed to compare HC rates, head impact location, and HC enforcement prepolicy, postpolicy, and after policy amendments in elite U15 Canadian youth ice hockey.This is a prospective cohort study.A collection of events with the video camera located at the highest point near center ice in public ice hockey arenas in Calgary, Alberta.A convenience sample of 10 AA U15 games prepolicy (2008-2009), 8 games postpolicy (2013-2014), and 10 games after policy amendments (2020-2021).An analysis of 3 cohort years regarding the HC-policy implementation and amendments.Using Dartfish video-analysis software, all player contacts and HCs [direct (HC1), indirect (eg, boards, ice) (HC2)] were tagged using validated criteria. Univariate Poisson regression clustering by team-game offset by game length (minutes) was used to estimate incidence rates (IR) and incidence rate ratios (IRR) between cohorts.With additional rule modifications, a 30% reduction in HC1s emerged (IRR 2013-2020 = 0.70, 95% CI, 0.51-0.95). Since the HC-policy implementation, HC1s decreased by 24% (IRR 2008-2020 = 0.76, 95% CI, 0.58-0.99). The proportion of HC1s penalized was similar across cohorts (P 2008-2009 = 14.4%; P 2013-2014 = 15.5%; P 2020-2021 = 16.2%).The HC-policy amendments have led to decreased HC1 rates. However, referee enforcement can further boost the HC-policy effectiveness. These findings can help future referee training and potential rule modifications to increase player safety nationally.

Neuromuscular training (NMT) warm-up programs effectively prevent injuries in youth, but monitoring exercise fidelity is challenging. The purpose of this study was to compare the exercise fidelity as measured via an inertial measurement unit (IMU) with direct observations of selected exercises. Youth basketball and soccer players performed single leg jumps, squat jumps, Nordic hamstring curls, and/or single leg balance exercises as part of an NMT warm-up. An IMU was placed on the lower back of each participant and the warm-up was video recorded. A physiotherapist evaluated the volume aspect of exercise fidelity (i.e., performing the prescribed number of repetitions) using the video recordings and a checklist. Algorithms were developed to count the number of repetitions from the IMU signal. The repetitions from the algorithms were compared with the physiotherapist’s evaluation, and accuracy, precision, and recall were calculated for each exercise. A total of 91 (39 female, 52 male) athletes performed at least one of the four warm-up exercises. There was an accuracy, precision, and recall of greater than 88% for all exercises. The single leg jump algorithm classified all sets correctly. IMUs may be used to quantify exercise volume for exercises that involve both impact during landing and changes in orientation during rotations.

Although high rates of injury occur in youth ice hockey, disagreements exist about the risks and benefits of permitting bodychecking. We sought to evaluate associations between experience with bodychecking and rates of injury and concussion among ice hockey players aged 15-17 years.We obtained data from a prospective cohort study of ice hockey players aged 15-17 years in Alberta who played in leagues that permitted bodychecking. We collected data over 3 seasons of play (2015/16-2017/18). We compared players based on experience with bodychecking (≤ 2 v. ≥ 3 yr), estimated using local and national bodychecking policy and region of play. We used validated methodology of ice hockey injury surveillance to identify all injuries related to ice hockey games and defined concussions according to the Consensus Statement on Concussion in Sport.We included 941 players who contributed to 1168 player-seasons, with 205 players participating in more than 1 season. Compared with players with 2 years or less of bodychecking experience, those with 3 or more years of experience had higher rates of all injury (adjusted incidence rate ratio [IRR] 2.55, 95% confidence interval [CI] 1.57-4.14), injury with more than 7 days of time loss (adjusted IRR 2.65, 95% CI 1.50-4.68) and concussion (adjusted IRR 2.69, 95% CI 1.34-5.42).Among ice hockey players aged 15-17 years who participated in leagues permitting bodychecking, more experience with bodychecking did not protect against injury. This provides further support for removing bodychecking from youth ice hockey.

Sport-related concussion (SRC) is a major concern among athletes and clinicians around the world. Research into fluid biomarkers of SRC has made significant progress in understanding the complex underlying pathophysiology of concussion. However, little headway has been made toward clinically validating any biomarkers to improve the clinical management of SRC. A major obstacle toward clinical translation of any fluid biomarker is the heterogeneity of SRC overlapping with multiple physiological systems involved in pathology and recovery. Neuroinflammation post-SRC is one such system that may confound fluid biomarker data on many fronts. Neuroinflammatory processes consist of cell mediators, both within the central nervous system and the periphery, that play vital roles in regulating the response to brain injury. Further, neuroinflammation is influenced by many biopsychosocial variables present in most athletic populations. In this commentary, we propose that future fluid biomarker research should take a systems biology approach in the context of the neuroinflammatory response to SRC. We highlight how biological variables, such as age, sex, immune challenges, and hypothalamic-pituitary-adrenal (HPA)-axis responses to stress, may alter neuroinflammation. Further, we underscore the importance of accounting for health and lifestyle variables, such as diet, exercise, sleep, and pre-morbid medical factors, when measuring inflammatory markers of SRC. To successfully move toward clinical translation, fluid biomarker research should take a more holistic approach in study design and data interpretation, collecting information on hidden variables that may be influencing the neuroinflammatory response to SRC.

The systematic review evaluated the evidence related to how physical activity affects recovery following a sport-related concussion (SRC) in adolescents. Databases indexed were PUBMED, MEDLINE, and SPORTDiscus. Inclusion criteria included 1) original research article, 2) ≥66% have an SRC diagnosed by a clinician, 3) human research, and 4) evaluated the effect of an SRC on physical activity in adolescents only (

Background: At 2 to 3 years after anterior cruciate ligament reconstruction (ACLR), the relationship between known modifiable osteoarthritis (OA) risk factors and recurrent knee injury is unknown. This study aimed to determine the odds of new or recurrent traumatic knee injury in a cohort of young female athletes with ACLR 2 to 3 years postsurgery compared with healthy control participants. Secondary objectives were to explore the relationships of moderate and vigorous physical activity (MVPA) and body mass index (BMI) with knee injury, and to document self-reported MVPA satisfaction and beliefs about OA. Study Design: Prospective cohort. Level of Evidence: Level 2. Methods: A total of 51 female athletes with unilateral ACLR 1 to 2 years previously and 51 age and sport-matched control participants underwent assessment of MVPA (GT3X accelerometers) and BMI. One year later, participants self-reported knee injuries. Bivariable conditional logistic regression explored the association between knee injury, MVPA, and BMI in each group (injury/control). Results: At 1-year follow-up (n = 101), 19.6% of the injured cohort and 6.0% of control participants sustained a new or recurrent knee injury. The odds of knee injury for the injury group increased 7-fold over controls [odds ratio (OR) = 7.00 (95% CI = 0.86, 56.90)], although this was not statistically significant. The OR for MVPA was 0.98 (95% CI = 0.93, 1.03) and BMI was OR = 1.24 (95% CI = 0.85, 1.82). Half (56.0%) of injury participants and 66% of controls were satisfied with their MVPA; 81.6% of injury participants believed they had increased knee OA risk compared with someone who had never had a knee injury. Conclusion: In the 2 to 3 years after ACLR, 1 in 5 young female athletes had a new or recurrent knee injury. Based on the point estimate, injured participants were more likely to suffer a traumatic knee injury than matched control participants. MVPA and BMI were not associated with increased odds of knee injury. Clinical Relevance: Clinicians should be encouraged to have in-depth conversations with female athletes with previous ACLR regarding enjoyable and sustainable MVPA participation to promote long-term joint health.

To examine injury (including concussion) rates, location, type, mechanisms, and risk factors in sledge hockey players.Cross-sectional survey.Sledge hockey players, worldwide, across all levels of play.Sledge hockey players (ages ≥14 years) who played in the 2019 to 2020 season were recruited through email, social media, and word of mouth communication.Participant characteristics (eg, age, sex, disability) were examined as potential injury risk factors.Injury rates (IR) and incidence rate ratios (IRR) examining potential risk factors were reported based on univariate Poisson regression analyses. Injury proportions by type, location, and mechanism were described.Ninety-two players initiated the survey, and 77 (83.7%) provided some injury information. Forty-seven injuries included 16 concussions in 9 of 77 players (11.7%) and 31 non-concussion injuries in 20 of 77 players (26.0%) were reported. The overall IR was 13.2 injuries/1000 athlete-exposures [95% confidence interval (CI); 9.6-17.6]. The game IR (28.4 injuries/1000 game-exposures, 95% CI; 18.6-41.7) was higher than practice IR (4.4 injuries/1000 practice-exposures, 95% CI; 2.2-7.9) (IRR = 6.5, 95% CI; 3.1-14.5). The most common injury locations were the head (34.0%), wrist/hand (14.8%), and shoulder (10.6%). The most common significant injury types were concussion (36.2%) and bone fracture (8.5%). Body checking was the primary mechanism for injuries caused by contact with another player (42.1%) Age, sex, disability, and level of play were not found as injury risk factors.Concussions and upper extremity injuries were the most common sledge hockey injuries reported, with body checking being the most common mechanism. This research will inform development of prevention strategies in sledge hockey.

Background Rugby Union is a collision team sport played globally. Despite this, significant concerns have been raised regarding the sport’s safety, particularly in youth players. Given this, a review of injury rates, risk factors and prevention strategies is required across different youth age groups as well as in males and females. Objective The objective of this systematic review (SR) and meta-analysis was to investigate injury and concussion rates, risk factors and primary prevention strategies in youth rugby. Methods To be included, studies were required to report either rates, risk factors or prevention strategies in youth rugby and to have a randomised controlled trial, quasi-experimental, cohort, case control, or ecological study design. Exclusion criteria included non-peer-reviewed grey literature, conference abstracts, case studies, previous systematic reviews and studies not written in English. Nine databases were searched. The full search strategy and list of sources are available and pre-registered on PROSPERO (Ref: CRD42020208343). Each study was assessed for risk of bias using the Downs and Black quality assessment tool. Meta-analyses were conducted using a DerSimonian Laird random effect model for each age group and sex. Results Sixty-nine studies were included in this SR. The match injury rates (using a 24-h time-loss definition) were 40.2/1000 match hours (95% CI 13.9–66.5) in males and 69.0/1000 match hours (95% CI 46.8–91.2) in females. Concussion rates were 6.2/1000 player-hours (95% CI 5.0–7.4) for males and 33.9/1000 player-hours (95% CI: 24.1–43.7) for females. The most common injury site was lower extremity (males) and the head/neck (females). The most common injury type was ligament sprain (males) and concussion (females). The tackle was the most common event associated with injury in matches (55% male, 71% females). Median time loss was 21 days for males and 17 days for females. Twenty-three risk factors were reported. The risk factors with the strongest evidence were higher levels of play and increasing age. Primary injury prevention strategies were the focus of only eight studies and included law changes (n = 2), equipment (n = 4), education (n = 1) and training (n = 1). The prevention strategy with the most promising evidence was neuromuscular training. The primary limitations included a broad range of injury definitions (n = 9) and rate denominators (n = 11) used, as well as a limited number of studies which could be included in the meta-analysis for females (n = 2). Conclusion A focus on high-quality risk factor and primary prevention evaluation should be considered in future studies. Targeting primary prevention and stakeholder education remain key strategies in the prevention, recognition and management of injuries and concussions in youth rugby.

Osteoarthritis management aims to reduce pain and improve function. Many factors affect whether patients follow recommended strategies. Locus of control refers to individual beliefs around who and what influences health. Locus of control is related to the treatment strategies patients prefer. Currently, no studies explore locus of control in non-surgical management of osteoarthritis.To explore patients' beliefs about the influences on their osteoarthritis symptoms and disease progression.Semi-structured interviews were conducted with individuals experiencing self-reported hip and/or knee osteoarthritis who had at least one joint that had not undergone replacement surgery. We used a qualitative description approach and the Braun and Clarke method for thematic analysis. Participants' locus of control classifications-internal, chance, doctors, or other people-were based on the Multidimensional Health Locus of Control (MHLC) Scales Form C score.Locus of control was discussed in relation to aetiology, progression, and symptoms. Participants' opinions varied on whether their osteoarthritis progression could be influenced. 46% of participants attributed control to other people. Most participants believed that a previous injury had caused their osteoarthritis and that both themselves and others had some influence over their osteoarthritis symptoms, regardless of their locus of control classification.This research highlights the need for education about: the aetiology of osteoarthritis, the link between management and progression, and patient management of osteoarthritis. Further research is required to discern why expected patterns were not observed between participants' beliefs and locus of control classifications.

To evaluate the effectiveness of a neuromuscular training warm-up prevention program, Surveillance in High school and community sport to Reduce (SHRed) Injuries Basketball, for reducing all-complaint ankle and knee injuries in youth basketball players.Quasi-experimental study.High school/club basketball teams (male and female players aged 11-18 years) in Calgary, Canada participated in 2016-2017 (control; season 1) and 2017-2018 (intervention; season 2). The control season included a standard-of-practice warm-up. In season 2, a SHRed Injuries Basketball coach workshop was completed by participating team coaches. Teams were randomized by school/club to an unsupervised or a supervised (weekly supervision by study personnel) implementation of the coach-delivered SHRed Injuries Basketball program. The 10-minute SHRed Injuries Basketball program included 13 exercises (ie, aerobic, agility, strength, balance). All-complaint ankle and knee injuries were collected weekly using validated injury surveillance. Multilevel, multivariable Poisson regression analyses (considering important covariates, clustering by team and individual, and offset by exposure hours) estimated incidence rate ratios (IRRs) by intervention group (season 1 versus season 2) and secondarily considered the control versus completion of the SHRed Injuries Basketball program, unsupervised and supervised.Sixty-three teams (n = 502 players) participated in season 1 and 31 teams (n = 307 players: 143 unsupervised, 164 supervised) participated in season 2. The SHRed Injuries Basketball program was protective against all-complaint knee and ankle injuries (IRR = 0.64; 95% confidence interval [CI]: 0.51, 0.79). Unsupervised (IRR = 0.62; 95% CI: 0.47, 0.83) and supervised (IRR = 0.64; 95% CI: 0.49, 0.85) implementations of the SHRed Injuries Basketball program had similar protective effects.The SHRed Injuries Basketball program was associated with a 36% lower rate of ankle and knee injuries. Neuromuscular training warm-ups are recommended as the minimal standard of practice for injury prevention in youth basketball.

Rugby Union is team-based collision sport with increasing global popularity, particularly in the women's game. Despite this, there is currently no evidence demonstrating the frequency of match events outside of the international game. Therefore, the aim of this study is to outline the frequency and distribution of match events in non-international female rugby union to both outline the demands placed on players and to assess the patterns of play for future injury prevention strategies. Forty-eight games from three seasons of varsity rugby were coded and rates of events per match were calculated. Average ball in play percentage was 51%. The tackle was the most frequent contact match event [280.0 (95% CIs: 270.2-289.7)] while passes were the most frequent non-contact match events [323.2 (95% CIs: 311.8-334.5)]. The distribution of events across match quarter was largely consistent and neither the fixture type, nor the season was consistently associated with differences in match event count per game. This study provides the first analysis of match events outside of international game and provides a useful reference for coaches in preparation of players as well as comparable data for the women's game when informing decision making on injury prevention.

The aim of this study was to investigate sport-related injury rates, types, locations, and mechanisms in female youth team sports. This was a secondary analysis of a cross-sectional study. An anonymous online survey was administered to high school students (ages 14-19) in Alberta, Canada. The survey included questions regarding demographic information, sport participation and self-reported injuries sustained in the past year. Results were analyzed for girls who reported playing a top ten team sports for female participation. For girls participating in team sports, the overall injury rate was 55.5 injuries/100 participants/year. The rate of at least one concussion was 9.4 concussions/100 participants/year. Injury and concussion rates were highest in ringette (Injury rate=42.9 injuries/100 participants/year, Concussion rate=19.0 concussions/100 participants/year) and rugby (Injury rate=40.0, Concussion rate=15.3). The top three most serious injury locations were the knee (24.7%), ankle (21.6%) and head (16.1%). The most common injury types were joint/ligament sprain (26.71%), fracture (13.0%) and concussion (11.8%). Contact mechanisms accounted for 73.4% of all serious injuries reported in girls team sports. Team sport injury rates are high in female youth team sports. Specific consideration of sport-specific injury rates, types and mechanisms in girls’ team sports will inform development and evaluation of targeted sport-specific prevention strategies.

OBJECTIVES To describe injury and concussion rates and mechanisms in female high school rugby players. DESIGN Two-year prospective cohort study. SETTING High school rugby. PARTICIPANTS Participants included 214 female High school rugby players (year 1) and 207 female High school players (year 2) from the Calgary Senior High School Athletics Association 2018 and 2019 rugby competition. INTERVENTION None. MAIN OUTCOME MEASURES Match and training injury and concussion. Injury definition included any injury resulting in time loss, inability to complete a session, and/or requiring medical attention. Details of reported injuries were collected on injury report forms and validated by a certified athletic therapist on a validated online injury surveillance platform. Exposure hours for players were tracked using paper or virtual weekly exposure forms by team designates. RESULTS A match incidence rate (IR) = 93.7 injuries/1000 match hours (95% confidence intervals (CI): 78.6-11.7) and training IR = 5.3 injuries/1000 training hours (95% CI: 4.0-6.9) were estimated. The tackle accounted for 109 (70%) match and 37 (44%) training injuries. Tackling was the most frequent mechanism of injury (IR = 37.5 injuries/1000 match hours, 95% CI: 27.5-51.8 and 1.2 injuries/1000 training hours, 95% CI: 0.7-2.4). Sixty-two match concussions (IR = 37.5 concussions/1000 match hours, 95% CI: 26.8-52.3) and 16 training concussions (IR = 1.0 concussions/1000 training hours, 95% CI: 0.7-1.4) occurred. Of 78 reported concussions, 78% for match and 56% for training were physician diagnosed. Tackling was the most frequent mechanism of concussion in matches (IR = 18.1 concussions/1000 match hours, 95% CI:11.4-28.6). CONCLUSIONS Injury and concussion rates in female high school rugby are high. The tackle accounted for the highest proportion of injuries. Prevention strategies (eg, tackle policy change, tackle-training programs, and neuromuscular training) should be explored to increase sport safety.

Background Youth sports participation is encouraged for proposed physical and psychological benefits. However early sport specialization and the potentially negative consequences may be a cause for concern. Purpose To describe sport specialization in Canadian youth and investigate associations with previous injury and physical performance. Study design Cross-sectional study. Methods Junior high school students (grades 7-9, ages 11-16) were invited to participate. All participants completed a questionnaire capturing specialization level (low, moderate, high; based on year-round training, exclusion of other sports, and single-sport training) and injury history in the previous 12-months. Additionally, all participants completed physical performance measures including vertical jump (cm), predicted VO2max (mL/kg/min), single-leg balance (secs) and Y-Balance composite score (%). Logistic regression examined the association between school grade, school size, sex and sport specialization (Objective 1) and the association between sport specialization and injury history (Objective 2). Multivariable linear regression analyses (4) assessed associations between sport specialization category and physical performance measures (Objective 3). Results Two hundred and thirty-eight students participated in the study. Eighteen percent of participants reported high specialization, with no significant associations between sex, grade or school size and specialization category. There was no significant difference in the odds of sustaining previous injury between participants reporting moderate (odds ratio [OR]=1.94, 95% CI 0.86-4.35) or high (OR=2.21, 95% CI 0.43-11.37) compared to low specialization. There were no significant differences in vertical jump height (mean diff [MD] = -0.4 to 2.1cm), predicted VO2max (MD = 2.2 to 3.1mL/kg/min), single leg balance (MD = 0.5 to 1.9sec) or Y-balance (MD = 0.6 to 7.0%) between sport specialization categories. Conclusions Sport specialization exists in Canadian junior high schools but may be less common than previously reported and it was not associated with sex, grade, or school size. Level of specialization was not associated with history of injury nor a range of physical performance measures. Level of Evidence Level 3

Magnetic resonance imaging (MRI) can provide a number of measurements relevant to sport-related concussion (SRC) symptoms; however, most studies to date have used a single MRI modality and whole-brain exploratory analyses in attempts to localize concussion injury. This has resulted in highly variable findings across studies due to wide ranging symptomology, severity and nature of injury within studies. A multimodal MRI, symptom-guided region-of-interest (ROI) approach is likely to yield more consistent results. The functions of the cerebellum and basal ganglia transcend many common concussion symptoms, and thus these regions, plus the white matter tracts that connect or project from them, constitute plausible ROIs for MRI analysis. We performed diffusion tensor imaging (DTI), resting-state functional MRI, quantitative susceptibility mapping (QSM), and cerebral blood flow (CBF) imaging using arterial spin labeling (ASL), in youth aged 12-18 years following SRC, with a focus on the cerebellum, basal ganglia and white matter tracts. Compared to controls similar in age, sex and sport (N = 20), recent SRC youth (N = 29; MRI at 8 ± 3 days post injury) exhibited increased susceptibility in the cerebellum (p = 0.032), decreased functional connectivity between the caudate and each of the pallidum (p = 0.035) and thalamus (p = 0.021), and decreased diffusivity in the mid-posterior corpus callosum (p < 0.038); no changes were observed in recovered asymptomatic youth (N = 16; 41 ± 16 days post injury). For recent symptomatic-only SRC youth (N = 24), symptom severity was associated with increased susceptibility in the superior cerebellar peduncles (p = 0.011) and reduced activity in the cerebellum (p = 0.013). Fewer days between injury and MRI were associated with reduced cerebellar-parietal functional connectivity (p < 0.014), reduced activity of the pallidum (p = 0.002), increased CBF in the caudate (p = 0.005), and reduced diffusivity in the central corpus callosum (p < 0.05). Youth SRC is associated with acute cerebellar inflammation accompanied by reduced cerebellar activity and cerebellar-parietal connectivity, as well as structural changes of the middle regions of the corpus callosum accompanied by functional changes of the caudate, all of which resolve with recovery. Early MRI post-injury is important to establish objective MRI-based indicators for concussion diagnosis, recovery assessment and prediction of outcome.

Background Collision sport participation rates among high school youth in Canada are high. While participation is beneficial for physical and mental well-being, the rates of injury in these sports are high. Aims This study aims to compare injury rates and profiles across four common youth collision sports (ice hockey, tackle football, lacrosse, rugby). Methods Data from a cross-sectional questionnaire of 2029 high school youth were used to identify male collision sport participants to be included in this secondary analysis (n = 360). Results Of the 2029 students who completed the questionnaire, 360 participated in collision-based sports [Ages: 14 (5%), 15 (41%), 16 (25%), 17 (26%), 18 (3%)]. The rates of injury ranged from 12.7 injuries/100 participants/year (rugby) to 33.1 injuries/100 participants/year (ice hockey). Concussion rates ranged from 12.4 (football) to 15.8 (ice hockey) concussions/100 participants/year. Similarities existed in the profile of injuries between sports, with most injuries occurring due to contact with another player (range 57.0% to 87.5%). Injuries to the head (33.3%), wrist/hand (16.0%), shoulder (12.8%), and knee (12.0%) were the most prevalent injury type. Substantial differences in previous playing experience existed between sports. Discussion The high rate of injury and concussion reported across each of these sports highlights the need for the introduction of primary prevention strategies in these sports aimed to reduce the risk of injury.

It is believed youth snow-sports injuries are preventable through adequate safety education. This study evaluated the effectiveness of a ski and snowboard injury prevention video on youth safety knowledge. A cluster randomized controlled trial was conducted among grade 2-9 students participating in a ski-snowboard school program. The intervention group watched a new injury prevention video. The control group watched the general ski-area orientation video. Students completed a 15-question ski-snowboard safety test before, immediately after, and one month after viewing. Within-subject difference between the pre- and post-questionnaire scores was calculated. Linear mixed-effects model assessed difference in knowledge change scores. 1034 students (seven intervention; 10 control schools) were enrolled. Pre- to-post-test knowledge increased by an average of 1.91 in the intervention (n = 388) and 0.10 points in the control (n = 646). The difference between the immediate and one-month post-test was 0.17 for the intervention (n = 122) and 0.60 for the control (n = 130). The mean change score for the immediate post-test was greater in the intervention (1.77; 95% CI: 1.52-2.03). The mean change score between the immediate and one-month post-test was lower (−0.55; 95% CI: −1.07 to 0.02) for the intervention compared with the control. The findings showed a ski-snowboard safety video can increase knowledge immediately after viewing within a school-aged population.

Context Causes of anterior knee pain (AKP) in jumping athletes include patellofemoral pain and patellar tendinopathy. The differential diagnosis of AKP is challenging, with variations in clinical presentations. No previous research has used pain location to describe AKP in basketball players. Objective To (1) describe the prevalence and pain distribution of AKP in collegiate basketball players and (2) report the prevalence of focal inferior pole pain using 2 outcome measures. Design Cross-sectional study. Setting University and collegiate basketball facilities in Alberta, Canada. Patients or Other Participants A total of 242 collegiate basketball athletes (138 women, 104 men). Main Outcome Measure(s) The single-legged decline squat test (SLDS) was used to capture pain location via pain mapping (dichotomized as focal or diffuse) and pain severity (numeric rating scale). The Oslo Sports Trauma Research Centre Knee questionnaire (OSTRC-Knee) and adapted version for patellar tendinopathy (OSTRC-Patellar Tendinopathy Questionnaire [OSTRC-P]) were used to report the prevalence of AKP and patellar tendinopathy, respectively. Focal inferior pole pain during the SLDS was used to classify patellar tendinopathy. Results Of the 242 players, 146 (60%) reported pain with the SLDS (unilateral = 64 [26%]; bilateral = 82 [34%]). A total of 101 (43%) described knee pain using the OSTRC-Knee. Pain mapping captured the variability in pain locations. Diffuse pain was more prevalent (left, 70%; right, 72%) than focal pain (left, 30%; right, 28%). Low prevalence of patellar tendinopathy was noted using the OSTRC-P (n = 21, 8.7%) and inferior pole pain during the SLDS (n = 25, 10.3%). Conclusions Diffuse AKP was common in Canadian basketball players; however, pain mapped to the inferior pole of the patella was not common. Few players reported tendinopathy using the OSTRC-P, suggesting that patellar tendinopathy was not a primary knee pain presentation in this jumping cohort. Pain location, rather than the presence or severity of pain alone, may better describe the clinical presentation of AKP in jumping athletes.

OBJECTIVE Juvenile idiopathic arthritis (JIA) is associated with altered body structure and function outcomes that may expose youth with JIA to a greater risk of secondary joint injury. This study aimed to examine differences in vertical drop jump (VDJ) biomechanics for youth with JIA and healthy youth (control group). METHODS The present study was a matched pair cohort study. Youth with JIA (n = 30) and their age- and sex-matched control peers participated in this ethics-approved study. Lower-extremity biomechanics information was obtained using a motion analysis system (Motion Analysis) and 2 force plates (AMTI). Biomechanics outcomes included hip, knee, and ankle joint angles, ground reaction forces (GRF), and VDJ phase durations. Other outcomes included disease activity, physical disability, and sports participation. Matched pairs data (JIA-control) were analyzed using a multivariate random coefficient model (version 3.5.0, R Core Team; joint angles, potential confounders) and paired samples t-tests with Bonferroni correction (α = 0.0125; GRF, VDJ phase durations). RESULTS Youth with JIA had low disease activity, pain, and disability scores. Youth with JIA maintained a more erect posture at the hip (β = -4.0°, P = 0.004), knee (β = 7.5°, P = 0.004) and ankle (β = -2.6°, P = 0.001). GRF and phase durations outcomes did not meet criteria for significant differences. Knee extension increased with participant age (β = -1.0°, P = 0.002), while female participants displayed greater hip flexion (β = -6.6°, P = 0.001) and less ankle dorsiflexion (β = 2.3°, P = 0.006). CONCLUSION This study provides evidence for a stiff knee landing strategy by youth with JIA. These findings inform targets for physical therapy management to mitigate the risks of a secondary joint injury in sports participation.

Secondary consequences of juvenile idiopathic arthritis (JIA) may impact long-term health outcomes. This study examined differences in physical activity, cardiorespiratory fitness, adiposity, and functional performance in children and adolescents with JIA compared to their typically developing (TD) peers. Participants with JIA (n = 32; 10–20 years old) and their TD peers (n = 35) volunteered for assessments of: daily moderate-to-vigorous physical activity (MVPA, body-worn accelerometer); peak oxygen consumption (VO2 Peak, incremental bike test); fat mass index (FMI, dual-energy X-ray absorptiometry); and triple-single-leg-hop (TSLH) distance. Statistical analyses were performed in R using four linear mixed-effect models with Bonferroni adjustment (⍺ = 0.0125). Fixed effects were group, sex, and age. Participant clusters based on sex and age (within 1.5 years) were considered as random effects. Participants with JIA displayed lower mean daily MVPA than their TD peers [p = 0.006; β (98.75% CI); −21.2 (−40.4 to −2.9) min]. VO2 Peak [p = 0.019; −1.4 (−2.5 to −0.2) ml/kg/min] decreased with age. Females tended to have lower VO2 Peak [p = 0.045; −6.4 (−13.0 to 0.4) ml/kg/min] and greater adiposity [p = 0.071; 1.4 (−0.1 to 3.0) kg/m2] than males. The findings support the need for strategies to promote MVPA participation in children and adolescents with JIA. Sex and age should be considered in research on the consequences of JIA.