The Effect of Bye Weeks on Injury Event Rates in the Canadian Football League.

OBJECTIVE: To determine the effect of bye weeks (no practices or games) on the injury event rate in the Canadian Football League (CFL). DESIGN: Historical (retrospective) cohort study. SETTING: CFL. PARTICIPANTS: CFL athletes between 2011 and 2018. INTERVENTION: CFL pseudorandom assignment of bye weeks each season (2011-2013: 1; 2014-2017: 2; 2018: 3). MAIN OUTCOME MEASURES: Game injury incident rate ratio (IRR) in the week following a bye week compared with non-bye weeks. Sensitivity analyses: IRR for the 2 and 3 weeks following a bye week. We conducted exploratory analyses for combined game and practice injury events because we did not have the number of players exposed during practice. RESULTS: The IRR was 0.96 (0.87-1.05), suggesting no meaningful effect of a bye week on the post-bye week game injury event rate. We obtained similar results for cumulative game injury events for subsequent weeks: IRR was 1.02 (0.95-1.10) for the 2 weeks following the bye week and 1.00 (0.93-1.06) for the 3 weeks following the bye week. The results were similar with 1, 2, or 3 bye weeks. However, the combined game and practice injury event rate was increased following the bye week [IRR = 1.14 (1.05-1.23)]. These results are expected if the break period results in medical clearance for preexisting injuries; increasing pain in these locations following the bye week would now be considered new injuries instead of "exacerbations." CONCLUSIONS: Bye weeks do not appear to meaningfully reduce the injury event rate. Furthermore, there was no injury reduction when adding additional bye weeks to the schedule.

Symptom Exacerbation and Adverse Events during a Randomized Trial of Early-stage Concussion Rehabilitation.

CONTEXT: Few studies utilize randomized clinical trials (RCT) to quantify clinical intervention safety of rehabilitation after sport-related concussion across sport levels. OBJECTIVE: Describe symptom exacerbation and adverse events (AEs) associated with two concussion rehabilitation interventions. DESIGN: Cluster Randomized Controlled Trial (XXX). SETTING: Sports medicine clinic and field settings. PARTICIPANTS: The RCT enrolled 251 concussed athletes (median age=20 years; female n=48) across 28 sites from New Zealand professional rugby (n=31), Canadian professional football (n=52), United States (U.S.)/Canadian colleges (n=128) and U.S. high schools (n=40). INTERVENTIONS: Two medically supervised interventions: 1) Enhanced Graded Exertion (EGE): international return to sport strategy and sport specific activities only (EGE-only n=119) and 2) Multidimensional Rehabilitation (MDR) followed by EGE: early symptom-directed exercises once symptoms were stable, followed by EGE after symptoms resolved (MDR+EGE n=132). MAIN OUTCOME MEASURES: Primary outcomes were intrasession total symptom severity score exacerbation and significant intersession (increase 10+ severity points) sustained total symptom severity exacerbation, each measured with a Postconcussion Symptom Scale (132 total severity points on scale). Reported AEs were also described. Activity-based rehabilitation sessions (n=1437) were the primary analysis unit. Frequencies, proportions, medians, and Interquartile Ranges (IQRs) were calculated for outcomes by treatment group. RESULTS: The 251 post-injury participants completed 1437 (MDR+EGE=819, EGE-only=618) activity-based intervention sessions. A total of 110 and 105 participants contributed data (those missing had no documented session data) to at least 1 activity-based session in the MDR+EGE and EGE-only arms respectively. Intrasession symptom exacerbations were equivilantly low in MDR+EGE and EGE-only arms (MDR+EGE: 16.7%, 95% CI:14.1%,19.1%; EGE-only: 15.7%, 95% CI: 12.8%,18.6%). In total, 9/819 MDR+EGE sessions (0.9%) and 1/618 EGE-only sessions (0.2%) resulted in a pre- to post-session symptom exacerbation beyond a 10+ severity point increase; 8/9 resolved to <10 points by the next session. Two study-related AEs (1 in each arm) were reported. CONCLUSIONS: Participants in MDR+EGE and EGE-only activities reported equivalently low rates of symptom exacerbation.

Acute evaluation of sport-related concussion and implications for the Sport Concussion Assessment Tool (SCAT6) for adults, adolescents and children: a systematic review.

OBJECTIVES: To systematically review the scientific literature regarding the acute assessment of sport-related concussion (SRC) and provide recommendations for improving the Sport Concussion Assessment Tool (SCAT6). DATA SOURCES: Systematic searches of seven databases from 2001 to 2022 using key words and controlled vocabulary relevant to concussion, sports, SCAT, and acute evaluation. ELIGIBILITY CRITERIA: (1) Original research articles, cohort studies, case-control studies, and case series with a sample of >10; (2) ≥80% SRC; and (3) studies using a screening tool/technology to assess SRC acutely (<7 days), and/or studies containing psychometric/normative data for common tools used to assess SRC. DATA EXTRACTION: Separate reviews were conducted involving six subdomains: Cognition, Balance/Postural Stability, Oculomotor/Cervical/Vestibular, Emerging Technologies, and Neurological Examination/Autonomic Dysfunction. Paediatric/Child studies were included in each subdomain. Risk of Bias and study quality were rated by coauthors using a modified SIGN (Scottish Intercollegiate Guidelines Network) tool. RESULTS: Out of 12 192 articles screened, 612 were included (189 normative data and 423 SRC assessment studies). Of these, 183 focused on cognition, 126 balance/postural stability, 76 oculomotor/cervical/vestibular, 142 emerging technologies, 13 neurological examination/autonomic dysfunction, and 23 paediatric/child SCAT. The SCAT discriminates between concussed and non-concussed athletes within 72 hours of injury with diminishing utility up to 7 days post injury. Ceiling effects were apparent on the 5-word list learning and concentration subtests. More challenging tests, including the 10-word list, were recommended. Test-retest data revealed limitations in temporal stability. Studies primarily originated in North America with scant data on children. CONCLUSION: Support exists for using the SCAT within the acute phase of injury. Maximal utility occurs within the first 72 hours and then diminishes up to 7 days after injury. The SCAT has limited utility as a return to play tool beyond 7 days. Empirical data are limited in pre-adolescents, women, sport type, geographical and culturally diverse populations and para athletes. PROSPERO REGISTRATION NUMBER: CRD42020154787.

The Influence of Time of Season on Injury Rates and the Epidemiology of Canadian Football Injuries.

OBJECTIVE: To describe injury rates and injury patterns in the Canadian Football League (CFL) according to time during the season, player position, injury type, and injury location. DESIGN: Prospective, cohort study. SETTING AND PARTICIPANTS: Eight seasons from CFL injury surveillance database. INDEPENDENT VARIABLES: Depending on the analysis, time of season (preseason, regular, and playoffs), player position, injury type, and injury location. MAIN OUTCOME MEASURES: Medical attention and time-loss injury rates per 100 athletes at risk (AAR), and prevalence of time-loss injuries per week. RESULTS: The average game injury rate was 45.2/100 AAR medical attention injuries and 30.7/100 AAR time-loss injuries. Injury rates declined by 1% per week over the season for both medical attention (rate ratio = 0.99) and time-loss (rate ratio = 0.99) injuries, with a substantial decline during the playoffs compared with preseason (rate ratio = 0.70-0.77). The number of ongoing time-loss injuries increased over the course of the regular season. Quarterbacks, offensive backs, and linebackers had the highest game injury rates. Joint/ligament and muscle/tendon injuries were the most common injury types for games and practices, respectively. The lower extremity was the most commonly affected area, specifically the lower leg/ankle/foot and hip/groin/thigh. CONCLUSIONS: There was a 1% decline in injury rate per week during the season and a 30% decline during the playoffs. The number of ongoing time-loss injuries increased over the regular season. Current results can aid league officials and medical staff in making evidence-based decisions concerning player safety and health.

Methodology and Implementation of a Randomized Controlled Trial (RCT) for Early Post-concussion Rehabilitation: The Active Rehab Study.

Background: Sports-related concussion (SRC) is a complex injury with heterogeneous presentation and management. There are few studies that provide guidance on the most effective and feasible strategies for recovery and return to sports participation. Furthermore, there have been no randomized studies of the feasibility, safety, and efficacy of early rehabilitation strategies across multiple sports and age groups. This international cluster-randomized pragmatic trial evaluates the effectiveness of early multi-dimensional rehabilitation integrated with the current return to sport strategy vs. the current return to sport strategy alone. Methods: The study is a cluster-randomized pragmatic trial enrolling male and female athletes from 28 sites. The sites span three countries, and include multiple sports, levels of play (high school, college, and professional), and levels of contact. The two study arms are Enhanced Graded Exertion (EGE) and Multidimensional Rehabilitation (MDR). The EGE arm follows the current return to sport strategy and the MDR arm integrates early, MDR strategies in the context of the current return to sport strategy. Each arm employs a post-injury protocol that applies to all athletes from that site in the event they sustain a concussion during their study enrollment. Participants are enrolled at pre-season baseline. Assessment timepoints include pre-season baseline, time of injury (concussion), 24-48 h post-injury, asymptomatic, and 1-month post-injury. Symptoms and activity levels are tracked post injury through the return to play process and beyond. Injury and recovery characteristics are obtained for all participants. Primary endpoints include time to medical clearance for full return to sport and time to become asymptomatic. Secondary endpoints include symptom, neurocognitive, mental status, balance, convergence insufficiency, psychological distress, and quality of life trajectories post-injury. Discussion: Outputs from the trial are expected to inform both research and clinical practice in post-concussion rehabilitation across all levels of sport and extend beyond civilian medicine to care for military personnel. Ethics and Dissemination: The study is approved by the data coordinating center Institutional Review Board and registered at clinicaltrials.gov. Dissemination will include peer-reviewed publications, presentation to patients and public groups, as well as dissemination in other healthcare and public venues of interest. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02988596 Trial Funding: National Football League.

King Devick computerized neurocognitive test scores in professional football players with learning and attentional disabilities.

OBJECTIVE: This study examined outcomes from the King Devick (K-D) in athletes with Learning Disabilities (LD) and attention disorders (ADHD). METHODS: A total of 574 professional football players from the Canadian Football League (CFL) completed baseline evaluations with computerized neurocognitive testing (CNT) prior to the 2016 competitive season. Player age, education, history of concussion, LD, and ADHD were analyzed for K-D and Immediate Post Concussion Assessment and Cognitive Testing (ImPACT) performance. A series of analyses of co-variance (ANCOVA's) were used to compare participants with a history of LD and ADHD with history of concussion as a co-variate. RESULTS: Approximately 5% of participants reported a diagnosed history of LD and 13% with ADHD. Performance on the K-D test was not significantly correlated with age, education, or history of concussion but was significantly correlated with history of LD and ADHD. Participants with LD performed approximately 6.9 s slower on the K-D test (t[563] = 4.70, p. = 0.0003) and participants with ADHD were approximately 2 s slower (t[572] = 2.04, p. = 0.04). CONCLUSIONS: Results indicated that players with a history of diagnosed LD and ADHD performed slower on the K-D test in comparison to athletes with no history of diagnoses. The results of this study underscore the importance of recognizing individualized outcomes when using the K-D.

Sideline Concussion Assessment: The King-Devick Test in Canadian Professional Football.

Sideline assessment tools are an important component of concussion evaluations. To date, there has been little data evaluating the clinical utility of these tests in professional football. The purpose of this study was to evaluate the clinical utility of the King-Devick (K-D) test in evaluating concussions in professional football players. Baseline data was collected over two consecutive seasons in the Canadian Football League as part of a comprehensive medical baseline evaluation. A pilot study with the K-D test began in 2015 with 306 participants and the next year (2016) there were 917 participants. In addition, a sample of 64 participants completed testing after physical exertion (practice or game). Participants with concussion demonstrated significantly higher (slower) results compared with baseline and the exercise group (F[2,211] = 5.94; p = 0.003). The data revealed a specificity of 84% and sensitivity of 62% for our sample. Reliability from season to season was good (intraclass correlation coefficient [ICC] 2,1 = 0.88; 95% confidence interval [CI]: 0.83, 0.91). On average, participants improved performances by a mean of 1.9 sec (range, -26.6 to 23.8) in subsequent years. High reliability was attained in the exercise group. (ICC2,1 = 0.93; 95% CI: 0.89, 0.96). The K-D test presents as a reliable measure although sensitivity and specificity data from our sample indicate it should be used in conjunction with other measures for diagnosing concussion. Further research is required to identify stability of results over multiple usages.

Does Game Participation Impact Cognition and Symptoms in Elite Football Players?

OBJECTIVE: To measure neurocognitive functioning in college and professional football players after game participation. STUDY DESIGN: Retrospective, cross-sectional cohort design. PARTICIPANTS: Ninety-four male university and professional football players. INTERVENTION: All participants completed Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) testing at baseline, and either at postconcussion (group 1) or postgame (group 2) participation. MAIN OUTCOME MEASURES: Results from the 5 ImPACT composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time and Impulse Control) and Total Symptom Score. RESULTS: Repeated-measures analysis of variance demonstrated a significant main effect for time (improvements) in 3 of 5 domains for the postconcussion group, but no improvements in the postgame group. The postconcussion group presented with significantly improved results on 4 of 5 ImPACT domains compared with the postgame group at the follow-up time interval. CONCLUSIONS: Participation in a football game with potential cumulative head contacts did not yield increased symptoms or cognitive impairment. However, the absence of improvement in cognitive functioning in noninjured football players, which was found in those players who were returned to play after an injury, may suggest that there is a measureable impact as a result of playing football.

A qualitative review of sports concussion education: prime time for evidence-based knowledge translation.

BACKGROUND: Educating athletes, coaches, parents and healthcare providers about concussion management is a public health priority. There is an abundance of information on sports concussions supported by position statements from governing sport and medical organisations. Yet surveys of athletes, parents, coaches and healthcare providers continue to identify multiple barriers to the successful management of sports concussion. To date, efforts to provide education using empirically sound methodologies are lacking. PURPOSE: To provide a comprehensive review of scientific research on concussion education efforts and make recommendations for enhancing these efforts. STUDY DESIGN: Qualitative literature review of sports concussion education. METHODS: Databases including PubMed, Sport Discus and MEDLINE were searched using standardised terms, alone and in combination, including 'concussion', 'sport', 'knowledge', 'education' and 'outcome'. RESULTS: Studies measuring the success of education interventions suggest that simply presenting available information may help to increase knowledge about concussions, but it does not produce long-term changes in behaviour among athletes. Currently, no empirical reviews have evaluated the success of commercially available sports concussion applications. The most successful education efforts have taken steps to ensure materials are user-friendly, interactive, utilise more than one modality to present information and are embedded in mandated training programmes or support legislation. Psychosocial theory-driven methods used to understand and improve 'buy in' from intended audiences have shown promise in changing behaviour. CONCLUSIONS: More deliberate and methodologically sound steps must be taken to optimise education and knowledge translation efforts in sports concussion.

Exploring minor hockey players' knowledge and attitudes toward concussion: implications for prevention.

OBJECTIVE: To evaluate minor hockey players' attitudes and knowledge about sport concussions. PARTICIPANTS: Male and female Pee Wee, Bantam, and Midget level players (n = 183) participating in minor hockey and a comparison group of non-hockey players (n = 57). DESIGN: Survey. MAIN MEASURES: Player knowledge and attitudes were evaluated with a standardized questionnaire developed for the purpose of this study. Descriptive statistics including cross-tabulations and proportion comparisons were used to report the data. RESULTS: Players had foundational knowledge about concussions; however, more than half underestimated the prevalence and more than 30% were unaware of return to play protocols. Although nearly all players knew what they "should" do when concussed, 33% did not follow recommendations. Players reported more concern and appreciation of the seriousness of concussion than non-players, but they tended to minimize their vulnerability. The most common and helpful information sources were parents, doctors, and coaches, and therefore knowledge translation efforts should target theses audiences. CONCLUSION: Young athletes continue to demonstrate gaps in their knowledge of concussions. In addition, attitudes toward concussion suggest a developmental trajectory with younger athletes being most likely to ignore current recommended guidelines.

Does an individual's fitness level affect baseline concussion symptoms?

CONTEXT: Variables that may influence baseline concussion symptoms should be investigated. OBJECTIVE: To evaluate the effect of physical fitness on self-report of baseline concussion symptoms in collegiate athletes and students. DESIGN: Controlled laboratory study. PATIENTS OR OTHER PARTICIPANTS: A total of 125 undergraduates, including 95 collegiate athletes and 30 recreational athletes (83 males, 42 females). INTERVENTION(S): Participants completed the Standardized Concussion Assessment Tool 2 (SCAT2; symptom report) at baseline, within 10 minutes of completing the Leger test, and within 24 hours of the initial baseline test. The Leger (beep) test is a shuttle-run field test used to predict maximal aerobic power. MAIN OUTCOME MEASURE(S): The total symptom score on the SCAT2 was calculated and analyzed with a repeated-measures analysis of variance. A linear regression analysis was used to determine if 3 variables (sport type, sex, or fitness level) accounted for a significant amount of the variance in the baseline symptom report. RESULTS: Participants reported more symptoms postactivity but fewer symptoms at 24 hours compared with baseline, representing a time effect in our model (F2,234 = 47.738, P < .001). No interactions were seen among the independent variables. We also found an effect for fitness level, with fitter individuals reporting fewer symptoms at all 3 time intervals. The regression analysis revealed that fitness level accounted for a significant amount of the variance in SCAT2 symptoms at baseline (R (2) = 0.22, F3,121 = 11.44, P < .01). CONCLUSIONS: Fitness level affected the baseline concussion symptom report. Exercise seems to induce concussion symptom reporting, and symptom severity may be a function of an athlete's level of conditioning. Sports medicine professionals should consider an athlete's level of fitness when conducting baseline concussion symptom assessments.

Assessment of symptoms in a concussion management programme: method influences outcome.

CONTEXT: Monitoring of subjective symptoms is the foundation of all sport concussion management programmes. The purpose of this study is to examine methodological variables that impact symptom reporting during baseline testing. OBJECTIVE: To investigate how the administration method of a concussion assessment tool (self-report vs interview) affects the report of symptoms. DESIGN, SETTING AND PARTICIPANTS: This was a cross-sectional, semi-randomized study of 117 athletes. MAIN OUTCOME MEASUREMENTS: Subjects completed the Post-Concussion Scale during pre-season evaluations. RESULTS: A two-factor ANOVA revealed a significant difference in total symptom scores (p = 0.02) and number of endorsed symptoms (p = 0.02) across administration modes. Athletes had a greater total symptom score and reported a greater number of symptoms in the self-administration condition than in the interview condition. Furthermore, there was a significant difference in symptom reporting across interviewer gender. Athletes endorsed more symptoms when the interviewer was a woman. CONCLUSIONS: Because the method of collecting symptoms, as well as interviewer gender, can impact test results, self-report measures may be a better way of obtaining consistent results. Clinicians and researchers should be aware that both the nature and extent of symptom reporting is greater when using questionnaires than when athletes are interviewed.