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Sport-related concussions (SRCs) are prevalent in high school (HS) sports, though the determinants of, and relationships between concussion symptoms in this population remain relatively unknown. We analysed SRC data captured within the HS RIO injury surveillance system during 2014/15-2018/19. We used Generalized Estimating Equations to simultaneously assess covariate predictors of symptom presentations and identify pairwise symptom associations and employed multivariable ordinal logistic regressions to determine symptom resolution time (SRT) predictors. Among the 8,969 concussions assessed, headaches (94.3%) and dizziness (73.3%) were the most prevalently reported symptoms. In 5,953 boys' concussion assessed, class year, event type and injury mechanism emerged as determinants of various concussion symptoms, while in 3,016 girls' concussions assessed, class year, event type, injury mechanism, and sport type emerged as significant symptom determinants. In both groups, difficulty concentrating, sensitivity to light, sensitivity to noise, and disorientation were symptoms with the strongest associations with other symptoms. Odds of longer SRT were higher with greater endorsement (i.e. counts) of the subset of symptoms with strongest cross-domain associations (OR adj.  = 1.35; 95% CI = [1.30, 1.40]). Our findings provide valuable information for informing sideline and follow-up clinical concussion assessment algorithms in high school athletes.

Concussion has been described in the United States (US) collegiate student-athlete population, but female-specific findings are often underrepresented and underreported. Our study aimed to describe female collegiate student-athletes' initial injury characteristics and return to activity outcomes following concussion. Female collegiate student-athletes (n = 1393) from 30-US institutions experienced a concussion and completed standardized, multimodal concussion assessments from pre-injury through unrestricted return to play (uRTP) in this prospective, longitudinal cohort study. Initial injury presentation characteristics, assessment, and return to activity outcomes [<48-h (acute), return to learn, initiate return to play (iRTP), uRTP] were collected. We used descriptive statistics to report injury characteristics, return to activity outcomes, and post-injury assessment performance change categorization (worsened, unchanged, improved) based on change score confidence rank criteria across sport contact classifications [contact (n = 661), limited (n = 446), non-contact (n = 286)]. The median (25th to 75th percentile) days to return to learn was 6.0 (3.0-10.0), iRTP was 8.1 (4.8-13.8), and uRTP was 14.8 (9.9-24.0), but varied by contact classification. Across contact levels, the majority experienced worse SCAT total symptom severity (72.8-82.6%), ImPACT reaction time (91.2-92.6%), and BSI-18 total score (45.2-51.8%) acutely relative to baseline, but unchanged BESS total errors (58.0-60.9%), SAC total score (71.5-76.1%), and remaining ImPACT domains (50.6-66.5%). Our findings provide robust estimates of the typical female collegiate student-athlete presentation and recovery trajectory following concussion, with overall similar findings to the limited female collegiate student-athlete literature. Overall varying confidence rank classification was observed acutely. Our findings provide clinically-relevant insights for athletes, clinicians, researchers, and policymakers to inform efforts specific to females experiencing concussion., (© 2023. The Author(s) under exclusive licence to Biomedical Engineering Society.)

Sporting helmets contain force attenuating materials which reduce traumatic head injury risk and may influence sport-related concussion (SRC) sequelae. The purpose of this study was to examine the association of sport helmet status with SRC-clinical presentation and recovery trajectories in men's collegiate athletes. Sport helmet status was based on the nature of sports being either helmeted/non-helmeted. 1070 SRCs in helmeted (HELM) sports (Men's-Football, Ice Hockey, and Lacrosse), and 399 SRCs in non-helmeted (NOHELM) sports (Men's-Basketball, Cheerleading, Cross Country/Track & Field, Diving, Gymnastics, Soccer, Swimming, Tennis, and Volleyball) were analyzed. Multivariable negative binomial regression models analyzed associations between sport helmet status and post-injury cognition, balance, and symptom severity, adjusting for covariate effects (SRC history, loss of consciousness, anterograde/retrograde amnesia, event type). Kaplan-Meier curves evaluated median days to: initiation of return to play (iRTP) protocol, and unrestricted RTP (URTP) by sport helmet status. Log-rank tests were used to evaluate differential iRTP/URTP between groups. Two independent multivariable Weibull accelerated failure time models were used to examine differential iRTP and URTP between groups, after adjusting for aforementioned covariates and symptom severity score. Overall, the median days to iRTP and URTP was 6.3 and 12.0, respectively, and was comparable across NOHELM- and HELM-SRCs. Post-injury symptom severity was lower (Score Ratio 0.90, 95%CI 0.82, 0.98), and cognitive test performance was higher (Score Ratio 1.03, 95%CI 1.02, 1.05) in NOHELM-compared to HELM-SRCs. Estimated time spent recovering to iRTP/URTP was comparable between sport helmet status groups. Findings suggest that the grouping of sports into helmeted and non-helmeted show slight differences in clinical presentation but not recovery., (© 2024. The Author(s) under exclusive licence to Biomedical Engineering Society.)

Mild traumatic brain injury (mTBI) has been described in the United States (US) military service academy cadet population, but female-specific characteristics and recovery outcomes are poorly characterized despite sex being a confounder. Our objective was to describe female cadets' initial characteristics, assessment performance, and return-to-activity outcomes post-mTBI. Female cadets (n = 472) from the four US military service academies who experienced a mTBI completed standardized mTBI assessments from pre-injury to acute initial injury and unrestricted return-to-duty (uRTD). Initial injury presentation characteristics (e.g., delayed symptoms, retrograde amnesia) and return-to-activity outcomes [i.e., return-to-learn, initiate return-to-duty protocol (iRTD), uRTD] were documented. Descriptive statistics summarized female cadets' injury characteristics, return-to-activity outcomes, and post-mTBI assessment performance change categorization (worsened, unchanged, improved) relative to pre-injury baseline using established change score confidence rank criteria for each assessment score. The median (interquartile range) days to return-to-learn (n = 157) was 7.0 (3.0-14.0), to iRTD (n = 412) was 14.7 (8.6-25.8), and to uRTD (n = 431) was 26.0 (17.7-41.8). The majority experienced worse SCAT total symptom severity (77.8%) and ImPACT reaction time (97.0%) acutely < 24-h versus baseline, but unchanged BESS total errors (75.2%), SAC total score (72%), BSI-18 total score (69.6%), and ImPACT verbal memory (62.3%), visual memory (58.4%), and visual motor speed (52.5%). We observed similar return-to-activity times in the present female cadet cohort relative to the existing female-specific literature. Confidence ranks categorizing post-mTBI performance were heterogenous and indicate multimodal assessments are necessary. Our findings provide clinically relevant insights to female cadets experiencing mTBI across the US service academies for stakeholders providing healthcare., (© 2023. The Author(s) under exclusive licence to Biomedical Engineering Society.)

The Sport Concussion Assessment Tool (SCAT) is the most widely used tool following sport-related concussion (SRC). Initial SCAT symptom burden is a strong predictor of recovery in collegiate athletes; however, it is unknown if symptom presentation varies within the acute (<48 h) post-SRC phase. The purpose of this cohort study was to examine acute SRC symptom presentation among the National Collegiate Athletic Association (NCAA) athletes. Concussed NCAA varsity athletes ( n = 1,780) from 30 universities across the United States, which participated in the Concussion Assessment, Research, and Education (CARE) Consortium, were included. Time of injury occurrence and SCAT administration data were recorded, from which time-to-SCAT (hours, continuous) was calculated. The main outcome was SCAT total symptom severity [(TSS), 0-126]. Multivariable negative binomial regression was used to examine the association between time (hours) since injury and TSS. Covariates included sex, previous concussion, sport contact level, amnesia/loss of consciousness, immediate reporting of injury, and injury situation. A random effect (person level) accounted for multiple assessments. TSS score ratios (SR) with associated 95% confidence intervals (CI) were provided. The SCAT was administered an average of 14 (25th-75th percentile: 1.2-24) hours post-SRC, and average TSS was 27.35 ± 21.28 across all participants. Time-to-SCAT was associated with a 1% decrease in TSS after adjusting for covariate effects (SR: 0.99, 95% CI: 0.99-0.99, p < 0.001). Overall, we observed a small, but significant decrease in TSS with each hour post-SRC. Assessing a concussed athlete once in the acute phase will likely provide a sufficient sense of their symptomatic well-being, as measures did not fluctuate dramatically. Future research should aim to examine how acute symptom evolution influences recovery metrics.

Context: Understanding former professional football players engagement with health promoting behaviors (physical exercise, high quality diet, and good sleep hygiene) will be helpful for developing lifestyle interventions to improve their feelings of well-being, a relatively understudied facet of health among this population., Objective: Examine associations among health-promoting behaviors and subjective outcomes related to well-being among former National Football League (NFL) players., Design: Cross-sectional., Setting: Online or hard-copy survey., Patients or Other Participants: Former NFL players., Main Outcome Measures: Self-reported health-promoting behaviors (exercise frequency, diet quality, sleep duration and disturbance) and factors related to well-being (PROMIS ® Meaning and Purpose [MP], Self-Efficacy [SE], Ability to Participate in Social Roles and Activities [SRA]). Multivariable linear regression models were fit for each well-being-related factor with health-promoting behaviors as explanatory variables alongside select demographic, behavioral, and functional covariates. Models were fit for the full sample and separately for individual age groups: <30 years; 30-39 years; 40-49 years; 50-59 years; 60-69 years; and 70+ years., Results: A total of 1,784 former NFL players (aged 52.3±16.3 years) completed the survey. Lower sleep disturbance was associated with better MP (β[standard error]=-0.196[0.024]), SE (β[standard error]=-0.185[0.024]), and SRA (β[standard error]=-0.137[0.017]) in the full sample and almost all the individual age groups. More frequent moderate-to-vigorous exercise was associated with higher MP (β[standard error]=0.068[0.025]) and SRA (β[standard error]=0.151[0.065]) in the full sample, and with better MP, SE, and SRA among select middle-aged groups (between 40-69 years old). Diet quality, resistance training exercise frequency, other wellness activity frequency, and sleep duration were not associated with well-being-related factors in the full-group and sparse significant associations were observed in individual age group models., Conclusions: Lower sleep disturbance and more frequent moderate-to-vigorous exercise frequency may be important targets for improving overall health and well-being among former NFL players.

Previous studies on pain experiences in retired contract sport athletes have been cross-sectional, leaving gaps in our understanding of the evolution of pain interference (PI) and factors that influence trajectories decades after sport discontinuation. This study investigated the longitudinal course of PI in former male National Football League (NFL) players over a 19-year period following sport discontinuation and examined factors influencing overall levels and trajectories of PI. Former NFL players completed health surveys in 2001, 2010, and 2019, with PI ratings measured using the 36-Item Short Form Health Survey (2001 and 2010) and the Patient-Reported Outcomes Measurement Information System (2019). Unconditional latent growth curve models analyzed overall PI severity and trajectories. Conditional latent growth curve models explored the influence of musculoskeletal injuries, osteoarthritis (OA), and depression diagnosis on PI. Over 19 years (N = 338; mean age = 48.96 ± 9.35), PI significantly increased (slope = .179, P < .001; mean Patient-Reported Outcomes Measurement Information System PI t-scores 2001 = 54.19, 2010 = 54.64, 2019 = 57.38). Cumulative musculoskeletal injuries (B = .092, P < .001) and baseline depression diagnosis (B = 4.463, P < .001) were associated with overall PI levels but not change over time. OA was significantly associated with overall PI levels (B = 6.536, P < .001) and trajectory (B = -.253, P < .001); those endorsing OA in 2001 had lower PI increases over 19 years. The body region of injury and level of play during injuries mirrored overall injury effects. PI mildly increased over 19 years, with multiple factors independently influencing overall PI levels. Enhancing former contact sport athletes' daily functionality may be achieved through holistic biopsychosocial interventions addressing musculoskeletal injuries, OA, and depression. Future research should identify factors influencing elevated trajectories of long-term PI post-sport discontinuation. PERSPECTIVE: This study assessed PI in former NFL athletes over 2 decades, revealing notable interindividual variability in trajectories over time. Musculoskeletal injuries, depression, and OA correlated with overall PI. Prevention and intervention in these 3 areas present the potential to improve disruptions in daily living due to pain in former athletes., Competing Interests: Disclosures This study (NFL-LONG) was funded by the National Football League (NFL). Dr. Brett reports grants from the National Institute on Aging and the National Institute of Neurological Disorders and Stroke, and honoraria for conference presentations. Dr. Chandran discloses research funding from the National Collegiate Athletic Association as the Director of the NCAA Injury Surveillance Program, and separately from the Atlantic Coast Conference Center for Research on Intercollegiate Athletics, and the University of North Carolina Translational and Clinical Sciences Institute; he also discloses receiving honoraria from the Sports Neuropsychological Society as well as the American Medical Society for Sports Medicine. Dr. Kerr reports grants from the National Institutes of Health, the Centers for Disease Control and Prevention, and the National Football League. Dr. Lempke reports grants from the Eastern Athletic Trainers’ Association, National Athletic Trainers’ Association, and VALD. Dr. Walton reports grant funding from the U.S. Departments of Defense and Veterans Affairs, and unpaid work on projects funded by the National Collegiate Athletic Association, and reports honoraria for conference presentations from the National Athletic Trainers’ Association. Dr. DeFreese reports grants from the Atlantic Coast Conference and the Association for Applied Sport Psychology. Dr. Echemendia is a paid consultant for the National Hockey League and co-chair of the National Hockey League/National Hockey League Players Association Concussion Subcommittee and Major League Soccer, and provides testimony in matters related to mTBI. Dr. Guskiewicz reports compensation from the National Collegiate Athletic Association for other services and grants from Boston Children's Hospital (sub-award from the National Football League). Dr. Meehan receives royalties from ABC-Clio Publishing, Springer International, and Wolters Kluwer. His research is funded by philanthropic support from the National Hockey League Alumni Association through the Corey C. Griffin Pro-Am Tournament and a grant from the National Football League. Dr. McCrea reports researching funding for the Medical College of Wisconsin from the National Institutes of Health, Department of Defense, Department of Veterans Affairs, Centers for Disease Control and Prevention, National Football League, National Collegiate Athletic Association, and Abbott Laboratories. He previously served as a consultant to Neurotrauma Sciences, Inc and is a clinical consultant to the Green Bay Packers professional football club. He also reports honoria and travel support for professional speaking engagements. Dr. Mannix reports grants from the U.S. Department of Defense, the NFL Foundation, and the National Institute of Neurological Disorders and Stroke., (Copyright © 2024 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Objective: To (1) characterize lifetime mild traumatic brain injury (TBI) exposures among male and female US military service members and Veterans (SMVs) and (2) evaluate sex-related differences in mild TBI exposures., Setting: Clinical research laboratory., Participants: Participants were enrolled in the ongoing Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) Prospective Longitudinal Study., Design: Cross-sectional., Main Measures: Lifetime history of mild TBI was measured via structured interview. All mild TBI characteristics were collected as part of this interview, including total lifetime number; environment (deployment vs. non-deployment); timing of injury (relative to military service and age); and mechanism of injury (blast-related vs. non-blast)., Results: Most participants (n = 2323; 87.5% male; 79.6% Veteran) reported ≥1 lifetime mild TBI (n = 1912; 82%), among whom, many reported ≥2 lifetime mild TBIs. Female SMVs reported fewer total lifetime mild TBIs than male participants (P < 0.001), including fewer deployment-related (P < 0.001) and non-deployment (P < 0.001) mild TBIs. There were significant sex differences for total number of mild TBIs sustained before (P = 0.005) and during (P < 0.001) military service but not after separation from military service (P = 0.99). Among participants with a lifetime history of mild TBI, female SMVs were less likely to report ≥2 mTBIs (P = 0.003); however, male SMVs were more likely to report a mild TBI during military service (P = 0.03), including combat-related mild TBI (P < 0.001) and mild TBI involving blast (P < 0.001)., Conclusions: These findings inform clinical and research efforts related to mild TBI in US military SMVs. It may not be sufficient to simply measure the total number of mild TBIs when seeking to compare clinical outcomes related to mild TBI between sexes; rather, it is important to measure and account for the timing, environment, and mechanisms associated with mild TBIs sustained by female and male SMVs., Competing Interests: Conflicts of Interest: Samuel R. Walton: Dr Walton reports separate funding support from the DoD & VA for projects related to the LIMBIC-CENC study; honorarium and conference travel support from the National Athletic Trainers’ Association and UCLA; serves in unpaid leadership roles with the World Federation of Athletic Training and Therapy (WFATT) and the Concussion in Sport Group (CISG); Jessie R. Oldham: Dr. Oldham receives support from the Thrasher Research Fund and National Institute of Arthritis and Musculoskeletal Skin Diseases (8K12AR084233-03); Benjamin L. Brett: Dr. Brett reports funding support from the NIA and NINDS, as well as honoraria and travel support as conference presentations; Elisabeth A. Wilde: Dr. Wilde receives grant funding support from the US Department of Veterans Affairs and the Department of Defense (related to this work and cited below) and from the National Institutes of Health (NINDS), and Vielight, Inc. (unrelated to this work); Rosemay A. Remigio-Baker:Dr. Remigio-Baker is a contractor from Compass Government Solutions that support the Traumatic Brain Injury Center of Excellence; Mary J. Pugh: Dr. Pugh reports separate funding support from the DoD & VA for projects not related to the LIMBIC-CENC study; Randel L. Swanson: Dr. Swanson reports separate funding support from the VA for a project related to the LIMBIC-CENC study and funding from the DoD and VA for projects not related to the LIMBIC-CENC study. Dr. Swanson was supported, in part, by the United States Department of Veterans Affairs Rehabilitation Research and Development Service under Award Number IK2 RX00365; Monique R. Pappadis: Receives grant funding support from the NIH/NIA (K01AG065492), NIMHD (L60MD009326L), and NIDILRR (90DPTB0025). Tara A. Austin, Olivia D. Cetin, Landon B. Lempke, Zhining Ou, Sreekanth Kamineni, Sarah L. Martindale, Maya E. O’Neil, David X. Cifu, and William C. Walker: declared no conflict of interest to disclose., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Concussion evaluations use a multidimensional assessment to evaluate unique patient function dimensions (e.g., subjective symptoms differ from balance assessments), but the overarching latent factor structure has not been empirically substantiated. Our objective was to determine the cumulative latent factor structure of pre-injury baseline and acute (<48-h) post-concussion assessment battery outcomes, and determine measurement equivalence among common factors in collegiate student-athletes. Methods: Collegiate student-athletes at baseline ( n  = 21,865) and post-concussion ( n  = 1,537) across 25-institutions completed standardized assessments. Individual items were used from the baseline and post-concussion assessments and consisted of: Sport Concussion Assessment Tool, Brief Symptom Inventory-18, Standardized Assessment of Concussion, Balance Error Scoring System, Immediate Post-Concussion Assessment and Cognitive Test, and vestibular-ocular motor screening. Exploratory factor analysis was used on half the baseline data, and confirmatory factor analysis on the remaining baseline data and post-concussion data separately. Measurement equivalence was assessed between sex, sport contact classification, concussion history, and time. Results: A 10-factor exploratory model was established and comprised of: depression, somatic, vestibulo-ocular, headache, postural stability, neurocognition, emotional, fatigue, cognitive, consciousness clouding. The 10-factor model was confirmed at baseline and post-concussion with strong measurement equivalence between timepoints. Strong to strict measurement equivalence was observed for sex, sport contact classification, and concussion history at both timepoints separately. Conclusion: Our findings established a robust 10-factor latent factor model equivalent across timepoints and common factors among healthy and concussed collegiate athletes. Clinicians can use these findings to target specific factors while reducing redundant elements to provide efficient, comprehensive post-concussion assessments.

Context: Dual-task (simultaneous cognitive-motor activities) assessments have been adapted into reliable and valid clinical concussion measures. However, abundant motor and cognitive variations leave researchers and clinicians uncertain about which combinations elicit the intended dual-task effect. Our objective was to examine differences between commonly employed dual-task motor and cognitive combinations among healthy, college-aged individuals., Design: Cross-sectional laboratory study., Methods: Twenty participants (age: 21.3 [2.4] y; height: 176.0 [9.1] cm; mass: 76.0 [16.4] kg; 20% with concussion history) completed 4 motor tasks (gait, tandem gait, single-leg balance, and tandem balance) under 5 cognitive conditions (single task, subtraction, month reversal, spelling backward, and visual Stroop) in a research laboratory. The motor performance outcomes were spatiotemporal variables for gait and tandem gait and center of pressure path length (in centimeters) for single-leg and tandem balance. Cognitive outcomes were response rate (responses/second) and cognitive accuracy. We used separate repeated-measures analyses of variance for each motor and cognitive outcome with post hoc Tukey t tests., Results: Gait velocity, gait stride length, and tandem gait velocity demonstrated significant cognitive-motor interactions (P's < .001) such that all dual-task conditions resulted in varyingly slower or shorter movement than single task. Conversely, single-leg balance (P = .627) and tandem balance (P = .434) center of pressure path length did not significantly differ among the dual-task cognitive conditions or relative to single task. Statistically significant cognitive-motor interactions were observed only for spelling backward accuracy (P = .004) and response rates for spelling backward, month reversal, and visual Stroop (P's < .001) such that worse accuracy, but faster response rates, occurred during motor tasks., Conclusions: Gait and tandem gait motor tasks accompanied with spelling backward or subtraction cognitive tasks demonstrated consistently strong dual-task effects and, therefore, may be the best suited for clinical and research use following concussion.

Objectives: The purpose of this study was to determine sex differences in recovery trajectories of assessments for sport-related concussion using Concussion Assessment, Research and Education (CARE) Consortium data., Methods: National Collegiate Athletic Association athletes (N = 906; 61% female) from sex-comparable sports completed a pre-season baseline assessment and post-sport-related concussion assessments within 6 h of injury, 24-48 h, when they initiated their return to play progression, when they were cleared for unrestricted return to play, and 6 months post-injury. Assessments included the Standardized Assessment of Concussion, Balance Error Scoring System, Brief Symptom Inventory-18, Immediate Post-concussion Assessment and Cognitive Testing (ImPACT), Sport Concussion Assessment Tool-3 symptom evaluation, Clinical Reaction Time, King-Devick test, Vestibular Ocular Motor Screen, 12-item Short-Form Health Survey, Hospital Anxiety and Depression Scale, and Satisfaction with Life Scale., Results: Only the Vestibular Ocular Motor Screen Total Symptom Score at the 24-48 h timepoint (p = 0.005) was statistically significantly different between sexes. Specifically, female athletes (mean = 60.2, 95% confidence interval [CI] 51.5-70.4) had higher Vestibular Ocular Motor Screen Total Symptom Scores than male athletes (mean = 36.9, 95% CI 27.6-49.3), but this difference resolved by the time of return-to-play initiation (female athletes, mean = 1.8, 95% CI 1.1-2.9; male athletes, mean = 4.1, 95% CI 1.5-10.9)., Conclusions: Sport-related concussion recovery trajectories for most assessments were similar for female and male National Collegiate Athletic Association athletes except for Vestibular Ocular Motor Screen symptoms within 48 h of sport-related concussion, which was greater in female athletes. Female athletes had a greater symptom burden across all timepoints, suggesting that cross-sectional observations may indicate sex differences despite similar recovery trajectories., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Objective: Investigate the relationships between concussion history and years of football participation (repetitive head impact proxy) with alcohol use across multiple decades in former professional football players., Methods: Participants (n = 348; mean age = 49.0 ± 9.4) completed health questionnaires in 2001 and 2019, which included self-reported concussion history and years of participation. Alcohol use frequency and amount per occasion were reported for three timepoints: during professional career, 2001, and 2019. Ordinal logistic regression models were fit to test associations of concussion history and years of participation with alcohol use at each timepoint., Results: There were no significant associations between either concussion history or years of football participation with alcohol use (frequency and amount per occasion) at any timepoint. Effect estimates for concussion history and years of football participation with alcohol use were generally comparable across timepoints., Conclusions: Later life alcohol use by former American football players is not associated with concussion history or years of exposure to football., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Background: Growing evidence indicates early exercise may improve symptoms and reduce clinical recovery time after concussion, but research examining collegiate student-athletes is scarce., Objective: The aim of this study was to compare symptom recovery time, clinical recovery time, and persisting post-concussion symptom (i.e., symptoms ≥ 28 days) prevalence by the timing of light exercise initiation before the graded return to play (RTP) protocol among concussed participants., Methods: Collegiate student-athletes (n = 1228; age 18.4 ± 0.9 years; 56.5% male, 76.3% division I; 33.7% ≥ 1 prior concussion) across 30 institutions enrolled in the CARE Consortium completed post-concussion assessments and were monitored over time. Symptom recovery (days from injury to symptom resolution) and clinical recovery (days from injury to return to play protocol completion) was determined by the student-athletes' clinicians. Student-athletes were categorized by timing of light exercise initiation. Early (< 2 days post-concussion; n = 161), typical (3-7 days post-concussion; n = 281), and late exercise (≥ 8 days post-concussion; n = 169) groups were compared with the no-exercise group (n = 617; i.e., did not exercise prior to beginning the RTP protocol) for all analyses. Multivariable Cox regression models with hazard ratios (HR) and survival curves and a multivariable binomial regression model with prevalence ratios (PR) compared recovery outcomes between exercise groups while accounting for covariates., Results: Compared to the no-exercise group, the early exercise group was 92% more probable to experience symptom recovery (HR 1.92; 95% CI 1.57-2.36), 88% more probable to reach clinical recovery (HR 1.88; 95% CI 1.55-2.28) and took a median of 2.4 and 3.2 days less to recover, respectively. The late exercise group relative to the no-exercise group was 57% less probable to reach symptom recovery (HR 0.43; 95% CI 0.35-0.53), 46% less probable to achieve clinical recovery (HR 0.54; 95% CI 0.45-0.66) and took 5.3 days and 5.7 days more to recover, respectively. The typical exercise group did not differ in hazard for symptom or clinical recovery (p ≥ 0.329) compared with the no-exercise group. The prevalence of persisting post-concussion symptoms in the combined sample was 6.6%. Early exercise had 4% lower prevalence (PR 0.96, 95% CI 0.94-0.99) and typical exercise had 3% lower prevalence (PR 0.97, 95% CI 0.94-0.99) of persisting post-concussion symptoms, while the late exercise group had an elevated prevalence (PR 1.11, 95% CI 1.04-1.18) compared with the no-exercise group., Conclusion: Exercise < 2 days post-concussion was associated with more probable and faster symptom and clinical recovery, and lower persisting post-concussion symptom prevalence. When considering our findings and existing literature, qualified clinicians may implement early exercise into their clinical practice to provide therapeutic treatment and improve student-athlete recovery., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Context: Single- and dual-task walking gait assessments have been used to identify persistent movement and cognitive dysfunction among athletes with concussions. However, it is unclear whether previous ankle sprain injuries confound these outcomes during baseline testing. The purpose of this study was to determine the effects of (1) ankle sprain history and (2) time since prior ankle sprain injury on single- and dual-task spatiotemporal gait outcomes and cognitive measures., Design: Cross-sectional study., Methods: We assessed 60 college Division-I athletes (31 with ankle sprain history; 13 females and 18 males, 19.3 [0.8] y; 29 with no ankle sprain history, 14 females and 15 males, 19.7 [0.9] y) who completed injury history forms and underwent concussion baseline testing. Athletes completed single- and dual-task gait assessments by walking back and forth along an 8-m walkway for 40 seconds. Athletes wore a smartphone with an associated mobile application on their lumbar spine to record spatiotemporal gait parameters and dual-task cognitive performance. Separate multivariate analyses of variance were used to assess the effects of ankle sprain injury history on spatiotemporal measures, gait variability, and cognitive performance. We performed a multivariate regression subanalysis on athletes who reported time since injury (n = 23) to assess temporal effects on gait and cognitive performance., Results: Athletes with and without a history of ankle sprains had comparable spatiotemporal and gait variability outcomes during single- (P = .42; P = .13) and dual-task (P = .75; P = .55) conditions. Additionally, ankle sprain injury history did not significantly influence cognitive performance (P = .35). Finally, time since ankle sprain did not significantly affect single- (P = .75) and dual-task gait (P = .69), nor cognitive performance (P = .19)., Conclusions: Ankle sprain injury history did not significantly alter spatiotemporal gait outcomes nor cognitive performance during this common clinical assessment. Future studies may consider including athletes with ankle sprain injury history during concussion assessments.

Abstract: This prospective cohort study aimed to determine whether preinjury characteristics and performance on baseline concussion assessments predicted future concussions among collegiate student-athletes. Participant cases (concussed = 2529; control = 30,905) completed preinjury: demographic forms (sport, concussion history, sex), Immediate Post-Concussion Assessment and Cognitive Test, Balance Error Scoring System, Sport Concussion Assessment Tool symptom checklist, Standardized Assessment of Concussion, Brief Symptom Inventory-18 item, Wechsler Test of Adult Reading, and Brief Sensation Seeking Scale. We used machine-learning logistic regressions with area under the curve, sensitivity, and positive predictive values statistics for univariable and multivariable analyses. Primary sport was determined to be the strongest univariable predictor (area under the curve = 64.3% ± 1.4, sensitivity = 1.1% ± 1.4, positive predictive value = 4.9% ± 6.5). The all-predictor multivariable model was the strongest (area under the curve = 68.3% ± 1.6, sensitivity = 20.7% ± 2.7, positive predictive value = 16.5% ± 2.0). Despite a robust sample size and novel analytical approaches, accurate concussion prediction was not achieved regardless of modeling complexity. The strongest positive predictive value (16.5%) indicated only 17 of every 100 individuals flagged would experience a concussion. These findings suggest preinjury characteristics or baseline assessments have negligible utility for predicting subsequent concussion. Researchers, healthcare providers, and sporting organizations therefore should not use preinjury characteristics or baseline assessments for future concussion risk identification at this time., Competing Interests: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Wearable accelerometry devices quantify on-field frequency and severity of head impacts to further improve sport safety. Commonly employed post-data collection cleaning techniques may affect these outcomes., Objective: Our purpose was to compare game impact rates and magnitudes between three different cleaning levels (Level-1: impacts recorded within start and end times, Level-2: impacts during pauses/breaks removed, Level-3: video verified) for male youth tackle football., Methods: Participants ( n  = 23, age = 10.9 ± 0.3 yrs, height = 150.0 ± 8.3 cm, mass = 41.6 ± 8.4 kg) wore Triax SIM-G sensors throughout Fall 2019. Impact rates, ratios (IRRs), and 95% confidence intervals (95%CI) were used to compare levels. Random-effects general linear models were used to compare peak linear acceleration (PLA;g) and angular velocity (PAV;rads/s)., Results: Level-1 resulted in higher impact rates (4.57; 95%CI = 4.14-5.05) compared to Level-2 (3.09; 95%CI = 2.80-3.42; IRR = 1.48; 95%CI = 1.34-1.63) and Level-3 datasets (2.56; 95%CI = 2.30-2.85; IRR = 1.78; 95%CI = 1.60-1.98). Level-2 had higher impact rates compared to Level-3 (1.21; 95%CI = 1.08-1.35). Level-1 resulted in higher PAV than Level-2 and Level-3 ( p  < 0.001) datasets. PLA did not differ across datasets ( p  = 0.296)., Conclusions: Head impact data should be filtered of pauses/breaks, and does not substantially differ outcome estimates compared to time-intensive video verification.

Background: Current medical practices and recommendations largely ignore the safety of postconcussion driving, even though commonly used measures of neurocognition, balance, and vestibulo-ocular function show impairment., Purpose: To compare simulated driving between patients with concussion and controls throughout concussion recovery using a case-control design., Study Design: Cohort study; Level of evidence, 2., Methods: A total of 26 concussed and 23 control Division I collegiate athletes completed a driving simulation assessment at 3 time points (within 72 hours, asymptomatic, and return to sport). Cumulative driving simulation outcome variables included total number of collisions, speed exceedances, stop signs missed, lane excursions, total drive time, percentage of time over the speed limit, and percentage of time out of the lane. The mean speed, standard deviation of speed (SDS), lateral lane position, and standard deviation of lateral lane position (SDLP) were examined for each of the 11 drive segments. Outcomes were compared using generalized linear mixed models with random intercepts by participant with Poisson or normal distributions., Results: Within 72 hours of injury, the concussion group committed more lane excursions (median difference, 2; P = .003), exhibited greater SDS while avoiding a child pedestrian crossing the road (Cohen d = 0.73; P = .011), drove ~7 inches (~18 cm) closer to the centerline during a residential left curve ( d = 0.90; P = .015), and had greater SDLP while navigating around a car crash compared with controls ( d = 0.72; P = .016). When asymptomatic, the concussion group committed fewer speed exceedances (median difference, 2; P = .002) and had lower SDLP while navigating through a traffic light compared with controls ( d = 0.60; P = .045). No differences were evident at return to sport. Groups did not differ in total collisions at any time point., Conclusion: The concussion group showed more impaired driving patterns within 72 hours of injury, drove more conservatively once asymptomatic, and had similar driving performance at the time they returned fully to sport. Clinicians should consider these findings when discussing driving with patients acutely after concussion. Further research is needed to determine whether on-road collision risk is elevated after concussion.

Context: Postconcussion reaction time deficits are common, but existing assessments lack sport-related applicability. We developed the Standardized Assessment of Reaction Time (StART) tool to emulate the simultaneous cognitive and motor function demands in sport, but its reliability is unestablished., Objectives: To determine the intrarater, interrater, and test-retest reliability of StART and to examine the dual-task effect, time effect, and relationships between StART and computerized and laboratory-based functional reaction time assessments., Design: Prospective cohort study., Setting: Clinical laboratory., Patients or Other Participants: Twenty healthy, physically active individuals (age = 20.3 ± 1.8 years, females = 12, no concussion history = 75%)., Main Outcome Measure(s): Participants completed the StART, computerized reaction time (Stroop task via CNS Vital Signs), and laboratory-based jump landing and cutting reaction time under single-task and dual-task (subtracting by 6s or 7s) cognitive conditions at 2 testing sessions a median of 7 days apart. We used intraclass correlation coefficients (ICCs), repeated-measure analysis of variance, and Pearson r correlations to address our aims., Results: Overall, good to strong interrater (ICC [2,k] range = 0.83-0.97), intrarater (ICC [3,k] range = 0.91-0.98), and test-retest (ICC [3,k] range = 0.69-0.89) reliability were observed. A significant reaction time assessment-by-cognitive condition interaction was present (P = .018, ηp2 = 0.14), with StART having the largest dual-task effect. Main time effects for dual-task conditions were seen across all reaction time assessments (mean difference = -25 milliseconds, P = .026, ηp2 = 0.08) with improved performance at the second testing session. No StART outcomes correlated with computerized reaction time (P > .05), although some correlated with single-task (r range = 0.42-0.65) and dual-task (r range = 0.19-0.50) laboratory cutting reaction time., Conclusions: The StART demonstrated overall reliable performance relative to other reaction time measures. Reliability coupled with a strong dual-task effect indicates that StART is a valid measure for examining functional reaction time and may have future utility for sport-related concussion return-to-play decision-making., (© by the National Athletic Trainers’ Association, Inc.)

Background: The age of first exposure (AFE) to American football participation is a growing concern for late-life function. Mixed evidence exists surrounding AFE and may be attributed to varied methods employed across studies., Objective: To examine the associations between AFE to American football participation with measures of cognitive, behavioral, and physical function and brain-related medical diagnoses across age categories among former National Football League players., Methods: We conducted a cross-sectional survey of 1784 former players (age: 52.3 ± 16.3 years, AFE: 11.3 ± 2.9 years, years of football: 17.5 ± 4.5 years, 86.9% ≥ one lifetime concussion). Players completed a general health questionnaire recording demographics, football playing history (including AFE), and diagnoses (anxiety, depression, any form of dementia, mild cognitive impairment). Players completed Patient-Reported Outcomes Measurement Information System (PROMIS) measures assessing domains of cognitive and physical function, anxiety, depression, sleep disturbance, pain interference, and emotional-behavioral dyscontrol. Multivariable linear and binomial regression models were used to examine the associations of AFE and age with PROMIS outcomes and diagnoses, respectively., Results: No significant AFE by age interactions were detected for PROMIS outcomes (p ≥ 0.066) or diagnoses (p ≥ 0.147). Younger AFE associated with higher PROMIS scores of anxiety (B = - 0.22, p = 0.016), depression (B = - 0.22, p = 0.010), sleep disturbances (B = - 0.16, p = 0.007), pain interference (B = - 0.19, p = 0.014), and emotional-behavioral dyscontrol (B = - 0.22, p = 0.019). Age was associated with all PROMIS outcomes (p ≤ 0.042). AFE was not associated with the prevalence of anxiety, depression, dementia, or mild cognitive impairment (p ≥ 0.449), while age was (p ≤ 0.013)., Conclusions: AFE was significantly associated with PROMIS outcomes, albeit low-strength associations (i.e., effect sizes), but not with diagnoses. Our findings indicate AFE is a significant but minor contributing factor for health-related quality of life in this cohort. Future work should incorporate additional characterizations of cumulative head impacts and related factors when examining long-term outcomes associated with football participation., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Abstract: Shumski, EJ, Lempke, LB, Johnson, RS, Oh, J, Schmidt, JD, and Lynall, RC. Jump height and hip power decrease during cognitive loading regardless of sex: implications for sport performance metrics. J Strength Cond Res 37(4): 793-798, 2023-Sex and cognitive loading separately influence jumping performance. However, it is unknown how cognitive loading influences jump performance and how sex and cognitive loading interact. The purpose of our study was to determine if an interaction existed between sex and cognitive loading for the dependent variables jump height, ground contact time, reactive strength index, vertical stiffness, impulse, and lower extremity joint power during a double limb drop vertical jump. Twenty-one male (23.2 ± 2.5 years, 180.8 ± 8.4 cm, 80.4 ± 10.2 kg) and 20 female (21.7 ± 1.0 years, 163.7 ± 8.2 cm, 61.2 ± 9.4 kg) physically active individuals participated. Subjects jumped from a 30 cm box placed 50% of their height away from 2 force plates under single-task and dual-task (serial 6s or 7s) conditions. Separate 2 × 2 analyses of variance were used for all dependent variables (α = 0.05) with Bonferroni post hoc mean differences and 95% confidence intervals (CIs). There were no significant interactions for any outcomes ( p ≥ 0.190). Condition main effects demonstrated subjects jumped significantly higher (1.84 cm, 95% CI = 0.68-3.01, d = 0.26, p = 0.003) and with greater hip power (0.29 Watts·BW -1 ·HT -1 , 95% CI = 0.04-0.54, d = 0.21, p = 0.025) during single task compared with dual task. Sex main effects revealed males jumped higher (9.88 cm, 95% CI = 7.00-12.77, d = 2.17, p < 0.001), with greater reactive strength index (0.29, 95% CI = 0.17-0.41, d = 1.52, p < 0.001), greater ankle power (3.70 Watts·BW -1 ·HT -1 , 95% CI = 2.26-5.13, d = 1.64, p < 0.001), and greater knee power (5.00 Watts·BW -1 ·HT -1 , 95% CI = 3.25-6.75, d = 1.82, p < 0.001) compared with females. Jump performance is influenced by sex and dual-task conditions but not their interaction. To optimize jumping performance, testing should be completed without distractions (single task) to decrease cognitive loading., (Copyright © 2022 National Strength and Conditioning Association.)

Context: With growing concerns surrounding exposure to head impacts in youth tackle football, players and parents must understand the exposure level when assenting and consenting to participate., Objective: To determine whether youth football players and parents could estimate on-field head-impact frequency, severity, and location., Design: Prospective cohort study., Setting: Football field., Patients or Other Participants: We administered a 10-question head-impact estimation tool to parents (n = 23; mean age = 36.5 years [95% CI = 31.7, 37.3 years]) and players (n = 16 boys; mean age = 11.1 years [95% CI = 10.3, 11.8 years])., Main Outcome Measure(s): Player on-field head-impact exposure was captured using the Triax SIM-G system. We determined the accuracy between player and parent estimates relative to on-field head-impact exposures using κ and weighted κ values., Results: Youth tackle football players and parents did not accurately estimate on-field head-impact frequency (κ range = -0.09 to 0.40), severity (κ range = -0.05 to 0.34), or location (κ range = -0.30 to 0.13). Players and parents overestimated head-impact frequency in practices but underestimated the frequency in games. Both groups overestimated head-impact severity, particularly in games. Most players and parents underestimated the number of head impacts to the top of the head, particularly during practices., Conclusions: Underestimations of head-impact frequency in games and to the top of the head suggest that informed consent processes aimed at educating players and parents should be improved. Overestimations of head-impact frequency in practices and severity may explain declining rates of youth tackle football participation., (© by the National Athletic Trainers' Association, Inc.)

Context: Certified athletic therapists in Ireland and Canada serve essential concussion assessment and management roles, but their health care practices and concussion knowledge have not been established., Objective: To examine Irish and Canadian athletic therapist cohorts' (1) concussion knowledge, (2) current concussion assessment and management techniques across all job settings, and (3) the association of concussion assessment and management practices with years of clinical experience and highest degree attained., Design: Cross-sectional cohort study., Setting: Online survey., Patients or Other Participants: Licensed Irish (49.7%, n = 91/183) and Canadian (10.1%, n = 211/2090) athletic therapists., Main Outcome Measure(s): Athletic therapists completed an online survey assessing their demographics, concussion knowledge (symptom recognition, patient-clinician scenarios), frequency of concussions assessed annually, and assessment and return-to-play (RTP) measures using a modified, previously validated survey. Symptom recognition consisted of 20 (8 true, 12 false) items on recognition of signs and symptoms that were scored as total correct. Descriptive statistics and odds ratios were used to examine survey responses where appropriate., Results: Irish (86.8%, n = 46/53) and Canadian (93.4%, n = 155/166) athletic therapists indicated RTP guidelines were the most common method for determining RTP. Symptom recognition scores were 72.8% ± 17.0% among Irish and 76.6% ± 17.0% among Canadian athletic therapists. Irish (91.2%, n = 52/57) and Canadian (90.4%, n = 161/178) athletic therapists reported standardized sideline assessments as the most used concussion assessment method. Irish and Canadian athletic therapists' use of 2-domain (Irish: 38.6% [n = 22/57]; Canadian: 73.6% [n = 131/178]) and 3-domain (Irish: 3.5% [n = 2/57]; Canadian: 19.7% [n = 35/178]) minimum assessments (ie, symptoms, balance, or neurocognitive) was not associated with education or clinical experience (P ≥ .07), except for Canadian athletic therapists with master's degrees having greater odds of completing 2-domain assessments at initial evaluation than those with bachelor's degrees (odds ratio = 1.80; 95% CI = 1.41, 1.95)., Conclusions: Irish and Canadian athletic therapists demonstrated similar concussion knowledge; however, most did not fully adhere to international consensus guidelines for concussion assessment as evidenced by low 2- and 3-domain assessment use. Athletic therapists should aim to implement multidimensional concussion assessments to ensure optimal health care practices and patient safety., (© by the National Athletic Trainers' Association, Inc.)

Objective: Balance impairments may suggest somatosensory disruption beyond concussion clinical recovery, but somatosensory subsystems have never been directly assessed. Our objective was to examine somatosensory function between individuals with a concussion and healthy matched-controls at acute (<7 days) and asymptomatic (<72 hours of being symptom-free) time points., Setting: Laboratory., Participants: Participants with a concussion and matched controls ( n = 24; 58% male, age: 19.3 ± 1.1 years, mass: 70.3 ± 16.4 kg, height: 177.3 ± 12.7 cm)., Design: Prospective cohort., Main Measures: Somatosensory assessments on the dominant limb at both time points included: (1) plantar touch sensation threshold via Semmes-Weinstein monofilaments, (2) plantar pressure pain threshold via algometry, and (3) knee absolute passive joint repositioning (PJR) error via Biodex across 3 arcs (105°-75°, 30°-60°, 90°-45° knee-flexion). We used mixed-model analyses of variance, post hoc Tukey honestly significant difference t tests with mean difference, 95% CI, and Hedges' g effect sizes to examine outcomes., Results: Touch sensation had a group effect with the concussion cohort needing 0.95 grams of force (gf) more relative to controls (95% CI: 0.03 to 1.87; P = .043). No touch sensation interaction was present, but medium and large effects were observed for greater gf needed among the concussed cohort at the acute (1.11 gf; 95% CI: 0.17 to 2.05; g = 0.96) and asymptomatic time points (0.79 gf; 95% CI: -0.15 to 1.73; g = 0.73). No plantar pressure pain threshold effects were observed ( P ≥ .311), with negligible pressure difference magnitudes at the acute (0.26 pound force [lbf]/cm 2 ; 95% CI: -1.54 to 2.06; g = 0.13) and medium magnitudes at the asymptomatic time points (0.99 lbf/cm 2 ; 95% CI: -0.81 to 2.80; g = 0.42) for the concussed cohort needing more pressure to detect pain. The 30° to 60° PJR had a time effect, with asymptomatic time point having 3.12° better accuracy (95% CI: 1.23° to 5.02; P = .002). The concussed cohort had small-to-medium magnitude differences relative to controls at the acute time point for PJR during 105° to 75° (0.89°; g = 0.30) and 90° to 45° (0.62°; g = 0.17), but not 30° to 60° (-1.75°; g = -0.40)., Conclusions: Individuals with a concussion exhibited large effects for diminished plantar touch sensation and small to medium effects for inhibited plantar pressure pain sensation compared with controls, which may indicate altered somatosensory function. Negligible PJR differences suggest knee joint position sense is not altered post-concussion. Pre- and postconcussion examination is warranted to understand causal somatosensory mechanisms., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Context: Aberrant movement patterns among individuals with concussion history have been reported during sport-related movement. However, the acute postconcussion kinematic and kinetic biomechanical movement patterns during a rapid acceleration-deceleration task have not been profiled and leaves their progressive trajectory unknown. Our study aimed to examine single-leg hop stabilization kinematics and kinetics between concussed and healthy-matched controls acutely (≤7 d) and when asymptomatic (≤72 h of symptom resolution)., Design: Prospective, cohort laboratory study., Methods: Ten concussed (60% male; 19.2 [0.9] y; 178.7 [14.0] cm; 71.3 [18.0] kg) and 10 matched controls (60% male; 19.5 [1.2] y; 176.1 [12.6] cm; 71.0 [17.0] kg) completed the single-leg hop stabilization task under single and dual task (subtracting by 6's or 7's) at both time points. Participants stood on a 30-cm tall box set 50% of their height behind force plates while in an athletic stance. A synchronized light was illuminated randomly, queuing participants to initiate the movement as rapidly as possible. Participants then jumped forward, landed on their nondominant leg, and were instructed to reach and maintain stabilization as fast as possible upon ground contact. We used 2 (group) × 2 (time) mixed-model analyses of variance to compare single-leg hop stabilization outcomes separately during single and dual task., Results: We observed a significant main group effect for single-task ankle plantarflexion moment, with greater normalized torque (mean difference = 0.03 N·m/body weight; P = .048, g = 1.18) for concussed individuals across time points. A significant interaction effect for single-task reaction time indicated that concussed individuals had slower performance acutely relative to asymptomatic (mean difference = 0.09 s; P = .015, g = 0.64), while control group performance was stable. No other main or interaction effects for single-leg hop stabilization task metrics were present during single and dual task (P ≥ .051)., Conclusions: Greater ankle plantarflexion torque coupled with slower reaction time may indicate stiff, conservative single-leg hop stabilization performance acutely following concussion. Our findings shed preliminary light on the recovery trajectories of biomechanical alterations following concussion and provide specific kinematic and kinetic focal points for future research.

Context: Clinical reaction-time (RT) measures are frequently used when examining patients with concussion but do not correlate with functional movement RT. We developed the Standardized Assessment of RT (StART) to emulate the rapid cognitive demands and whole-body movement needed in sport., Objective: To assess StART differences across 6 cognitive-motor combinations, examine potential demographic and health history confounders, and provide preliminary reference data for healthy collegiate student-athletes., Design: Prospective, cross-sectional study., Setting: Clinical medicine facilities., Patients or Other Participants: A total of 89 student-athletes (56 [62.9%] men, 33 [37.1%] women; age = 19.5 ± 0.9 years, height = 178.2 ± 21.7 cm, mass = 80.4 ± 24 kg; no concussion history = 64 [71.9%])., Main Outcome Measure(s): Student-athletes completed health history questionnaires and StART during preseason testing. The StART consisted of 3 movements (standing, single-legged balance, and cutting) under 2 cognitive states (single task and dual task [subtracting by 6's or 7's]) for 3 trials under each condition. The StART trials were calculated as milliseconds between penlight illumination and initial movement. We used a 3 × 2 repeated-measures analysis of variance with post hoc t tests and 95% CIs to assess StART cognitive and movement differences, conducted univariable linear regressions to examine StART performance associations, and reported StART performance as percentiles., Results: All StART conditions differed (P ≤ .03), except single-task standing versus single-task single-legged balance (P = .36). Every 1-year age increase was associated with an 18-millisecond (95% CI = 8, 27 milliseconds) slower single-task cutting RT (P < .001). Female athletes had slower single-task (15 milliseconds; 95% CI = 2, 28 milliseconds; P = .02) and dual-task (28 milliseconds; 95% CI = 2, 55 milliseconds; P = .03) standing RT than male athletes. No other demographic or health history factors were associated with any StART condition (P ≥ .056)., Conclusions: The StART outcomes were unique across each cognitive-motor combination, suggesting minimal subtest redundancy. Only age and sex were associated with select outcomes. The StART composite scores may minimize confounding factors, but future researchers should consider age and sex when providing normative data., (© by the National Athletic Trainers' Association, Inc.)

Objective: To examine the relationships and latent factors within the Standardized Assessment of Reaction Time (StART), and between StART and current clinical assessments., Design: Cross-sectional study., Setting: Clinical medicine facility., Participants: Eighty-nine healthy collegiate student-athletes (63% male, age: 19.5 ± 0.9 years, 28% ≥1 concussion history)., Assessment of Risk Factors: Student-athletes completed StART and clinical assessments during preinjury testing., Main Outcome Measures: Standardized Assessment of Reaction Time consisted of 3 conditions (standing, single-leg balance, cutting) under 2 cognitive states (single task and dual task) for 3 trials each condition. Clinical assessments were the Sport Concussion Assessment Tool (SCAT) symptom checklist, Standardized Assessment of Concussion (SAC), tandem gait (single task and dual task), and Immediate PostConcussion Assessment and Cognitive Testing (ImPACT). We used Pearson- r correlation coefficients and exploratory factor analysis (EFA) to examine relationships and latent factors between StART and clinical assessments., Results: Null to moderate correlations presented among the StART outcomes (r range: 0.06-0.70), and null to small correlations between StART and clinical assessments (r range: -0.16 to 0.34). The three-factor EFA for solely StART explained 70.6% total variance: functional movement (cutting), static dual-task (standing and single-leg balance), and static single task (standing and single-leg balance). The five-factor EFA for StART and clinical assessments explained 65.8% total variance: gait (single-task and dual-task tandem gait), functional movement (StART single-task and dual-task cutting), static dual-task (StART standing, single-leg balance), neurocognitive (ImPACT verbal memory, visual memory, visual-motor speed), and static single task (StART standing, single-leg balance). No other outcomes met the factor loading threshold., Conclusions: StART displayed 3 distinct categories and had minimal redundancy within its subtests. StART did not meaningfully correlate with clinical assessments, suggesting that StART provides unique information by examining more functional, reactive movement., Competing Interests: The research reported in this work was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under Award Number R01NS100952. Separate from this study, Dr. Howell has received research support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (R03HD094560), the National Institute of Neurological Disorders and Stroke (R01NS100952, R03HD094560, and R43NS108823), MINDSOURCE Brain Injury Network, and the Tai Foundation. All other authors have no other conflicts of interest related to this manuscript to report outside the acknowledged funding sources. Dr. Meehan receives royalties from (1) ABC-Clio publishing for the sale of his books, Kids, Sports, and Concussion: A guide for coaches and parents, and Concussions; (2) Springer International for the book Head and Neck Injuries in Young Athlete; and (3) Wolters Kluwer for working as an author for UpToDate. His research is funded, in part, by philanthropic support from the National Hockey League Alumni Association through the Corey C. Griffin Pro-Am Tournament and a grant from the National Football League. The authors report no other relevant conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Racial and ethnic differences in emergency department (ED) visits have been reported among adolescent patients but are unsubstantiated among adults. Therefore, our purpose in this study was to examine the relationship between race/ethnicity and adult ED visits for concussions, their injury mechanisms, and computed tomography (CT) scan use among a nationally representative sample., Methods: We used the National Hospital Ambulatory Medical Care Survey database from 2010-2015 to examine 63,725 adult (20-45 years old) patient visits, representing an estimated 310.6 million visits presented to EDs. Of these visits, 884 (4.5 million national estimate) were diagnosed with a concussion. Visit records detailed patient information (age, sex, race/ethnicity, geographic region, primary payment type), ED visit diagnoses, injury mechanism (sport, motor vehicle, fall, struck by or against, "other"), and head CT scan use. The primary independent variable was race/ethnicity (non-Hispanic Asian, non-Hispanic Black or African American, Hispanic/Latinx, non-Hispanic multiracial or another, and non-Hispanic White). We used multivariable logistic and multinomial regression models with complex survey sampling design weighting to examine the relationship between concussion ED visits, injury mechanisms, and CT scan use separately by race/ethnicity while accounting for covariates., Results: There were no associations between race/ethnicity and concussion diagnosis among adult ED visits after accounting for covariates. Relative to sports-related injuries, non-Hispanic Black or African American patient visits were associated with a motor vehicle (OR = 2.69, 95% CI: 1.06-6.86) and "other" injury mechanism (OR = 4.58, 95% CI: 1.34-15.69) compared to non-Hispanic White patients. Relative to sports-related injuries, non-Hispanic Asian, multiracial, or patients of another race had decreased odds of falls (OR = 0.20, 95% CI: 0.04-0.91) and "other" injuries (OR = 0.09, 95% CI: 0.01-0.55) compared to non-Hispanic White patients. The odds of a CT scan being performed were significantly lower among Hispanic/Latinx patient visits relative to non-Hispanic White patients (OR = 0.52, 95% CI: 0.30-0.91), while no other race/ethnicity comparisons differed., Conclusion: Our findings indicate that the overarching concussion ED visit likelihood may not differ by race/ethnicity in adults, but the underlying mechanism causing the concussion and receiving a CT scan demonstrates considerable differences. Prospective future research is warranted to comprehensively understand and intervene in the complex, multi-level race/ethnicity relationships related to concussion health care to ensure equitable patient treatment., Competing Interests: Author ZK reports current and previous funding from CDC, DoD, NFL, and NIH. Author RM acknowledges support from the National Institute of Neurologic Disorders and Stroke (U01NS096835), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NS115942-01A1), the Department of Defense (W81XWH1920011), and Abbott Pharmaceuticals. Author WM receives royalties from (1) ABC-Clio publishing for the sale of his books, Kids, Sports, and Concussion: A guide for coaches and parents and Concussions; (2) Springer International for the book Head and Neck Injuries in Young Athletes and (3) Wolters Kluwer for working as an author for UpToDate separate from this study. His research was funded, in part, by philanthropic support from the National Hockey League Alumni Association through the Corey C. Griffin Pro-Am Tournament and a grant from the National Football League. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lempke, Kerr, Melvin, Walton, Wallace, Mannix, Meehan and Ward.)

Context: Neuromuscular function is altered acutely following concussion and theoretically linked to the subsequent postconcussion musculoskeletal injury risk. Existing research has only examined voluntary muscle activation, limiting mechanistic understanding. Therefore, our study aimed to examine voluntary and involuntary muscle activation between college-aged, concussed individuals when symptom-free and healthy matched controls., Design: Prospective, cross-sectional cohort laboratory study., Methods: Concussed and healthy participants (n = 24; 58% male, age: 19.3 [1.1] y, mass: 70.3 [16.4] kg, height: 177.3 [12.7] cm) completed the superimposed burst (SB) neuromuscular assessment on their dominant limb within 72 hours after self-reporting asymptomatic (22.4 [20.2] d postinjury). Unnormalized and bodyweight-normalized quadriceps maximal voluntary isometric contraction torque (in newton meters), unnormalized and bodyweight-normalized electrically stimulated SB torque, pain (numeric 1-10) during SB, and the central activation ratio (in percentage) were assessed via the SB. Parametric and nonparametric analyses, 95% confidence intervals (95% CIs), and Hedges g (parametric) and Spearman ρ (nonparametric) effect sizes were used to examine group differences (α = .05)., Results: The maximal voluntary isometric contraction torque (concussed: 635.60 N·m [300.93] vs control: 556.27 N·m [182.46]; 95% CI, -131.36 to 290.02; P = .443; d = 0.33), SB torque (concussed: 203.22 N·m [97.17], control: 262.85 N·m [159.07]; 95% CI, -171.22 to 51.97; P = .280; d = -0.47), and central activation ratio (concussed: 72.16% [17.16], control: 70.09% [12.63]; 95% CI, -10.68 to 14.83; P = .740; d = 0.14) did not differ between the concussed and control groups regardless of bodyweight normalization (P ≥ .344). Pain during the SB was significantly higher with a medium effect for participants with a concussion versus healthy controls (concussed: median = 7, control: median = 5; P = .046; ρ = -0.42)., Discussion: These findings suggest concussed participants do not have statistically altered voluntary or involuntary quadricep neuromuscular function once asymptomatic compared with controls. Therefore, the elevated postconcussion musculoskeletal injury risk may not be attributed to lower-extremity muscle activation. Concussed participants displayed greater pain perception during the SB, which suggests somatosensory or perception changes requiring further examination.

Objective: To describe concussion characteristics among general college students and compare postinjury outcomes to intercollegiate student athletes., Design: Retrospective cohort., Setting: Large university in the Southeast region of the United States., Participants: A total of 179 (N=179) college students' (female=120; 67.0%; 23.9±3.9 years) and 49 athletes' (female=28, 57.1%;19.3±1.3 years) medical records were examined. Participants self-reported injury mechanism, health history information, and completed clinical assessments acutely (<7 days postinjury)., Main Outcome Measures: Descriptive statistics were calculated for each group. Concussion outcomes between students with and without certain health history diagnoses were assessed using separate t tests. We conducted univariate regression analyses to determine if sex, age, and time from concussion to first clinical assessment were significant predictors of clinical outcomes. Statistically significant variables were included as covariates in a series of 1-way analyses of covariance to identify differences in balance, symptom severity, total symptom presence, and neurocognitive domain performance between students and athletes. Fisher exact tests were used to compare health history information between groups (α<0.05)., Results: Among students, 24% reported sustaining a concussion while participating in recreational sports, and 27% of impacts occurred to the back of the head. Students had higher proportions of headache, migraine, anxiety, and depression (P<.05). Students reported greater total symptom presence (P=.006) and performed worse on the computerized neurocognitive test domain score for complex attention (P=.015) relative to athletes., Conclusions: These findings highlight the need for better access to medical care for non- National Collegiate Athletic Association sanctioned athletes because of a large proportion of concussions in the student sample being sustained during sports participation. Identifying common injury mechanisms can provide clinicians with powerful information to improve evaluation and treatment models., (Published by Elsevier Inc.)

Background: Concussion pre-injury (i.e., baseline) assessments serve as a benchmark comparison point in the event an individual sustains a concussion and allows clinicians to compare to post-injury measures. However, baseline assessments must reflect the individual's true and most optimized performance to serve as a useful comparison. Mental fatigue and motivation throughout baseline testing may alter individual assessment performance, indicating an order of administration (OoA) may play an influential role in assessment outcomes., Objective: To examine the influence concussion baseline battery OoA has on symptom, postural stability, cognitive screening, and computerized neurocognitive test outcomes., Methods: We employed a retrospective observational cohort study to examine healthy collegiate student-athletes and military cadets (n = 2898, 19.0 ± 1.4 years, 66.1% male, 75.6% white, 54.4% Division-I) baseline assessment performance on the Sport Concussion Assessment Tool (SCAT; total symptom number and severity), Balance Error Scoring System (BESS; total error scores), Standardized Assessment of Concussion (SAC; total score), and Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) domain scores (verbal and visual memory, visual-motor speed, reaction time). Assessments were binned to beginning, middle, or end tertiles based upon OoA. We used one-way ANOVAs with Tukey post-hoc t tests, 95% confidence intervals (CI), and Cohen's d effect sizes for significant models (α = 0.05)., Results: SCAT total symptom number (mean difference = 2.23; 95% CI 1.76-2.70; d = 0.49, p < 0.001) and severity (mean difference = 5.58; 95% CI 4.42-6.74; d = 0.50; p < 0.001) were lower when completed at the end of baseline testing compared to the middle. Total BESS errors were 1.06 lower when completed at the middle relative to the end (95% CI 0.43-1.69; d = 0.17; p = 0.001). Total SAC scores were better at the beginning relative to middle (mean difference = 0.58; 95% CI 0.25-0.90; d = 0.33; p < 0.001) and end (mean difference = 0.44; 95% CI 0.16-0.73; d = 0.24; p = 0.001). Verbal memory, visual memory, and reaction time performance were highest at the beginning (p ≤ 0.002), while visual-motor speed performance was highest at the middle (p = 0.001)., Conclusion: Completing baseline assessments in the order of (1) ImPACT, (2) SAC, (3) BESS, and (4) SCAT symptom checklist may improve performance across assessments collectively. Clinicians and researchers should consider completing baseline assessments in this order when possible to potentially aid in optimizing concussion baseline assessment performance and maximize post-concussion comparisons., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Concussion education have served as a keystone for improving concussion reporting. Numerous factors affecting concussion reporting have been explored; however, the role of socioeconomic status (SES) in reporting has not been established. We examined the influence of SES and academic achievement (high-school grade point average [HS-GPA] and American College Testing [ACT] composite scores) on athletes' concussion-reporting intentions and behaviors. A cross-sectional study was employed among 191 athletes (94 female; age 19.3 ± 1.2 years). Athletes reported SES metrics (parental education and occupation, household income, HS-GPA, and ACT composite score) prior to their athletic season and completed a survey assessing symptom- and concussion-reporting intentions. Symptom- and concussion-reporting behaviors were assessed among athletes who experienced a concussion within the past year. SES was determined using the Hollingshead Four-Factor Index grouping athletes into SES strata. Athletes were grouped into low/high categories for academic achievement and household income variables. The 191 athletes were included for symptom- and concussion-reporting intentions analyses, while 46 and 41 were included for symptom- and concussion-reporting behavior, respectively. Nonparametric statistics with false discovery rate adjusted p values were employed. We found symptom- and concussion-reporting intentions, and symptom- and concussion-reporting behaviors were not significantly different based on SES strata (all p values ≥.64), household income (all p values ≥.64), HS-GPA (all p values ≥.24), or ACT scores (all p values ≥.25). Overall, SES and academic achievement may not play a role in understanding concussion reporting among middle- to high-SES collegiate athletes. Implementing policies targeting certain SES and academic levels might be an ineffective health care strategy for increasing reporting.

Background: Youth flag football participation has rapidly grown and is a potentially safer alternative to tackle football. However, limited research has quantitatively assessed youth flag football head impact biomechanics., Purpose: To describe head impact biomechanics outcomes in youth flag football and explore factors associated with head impact magnitudes., Study Design: Cross-sectional study; Level of evidence, 3., Methods: We monitored 52 player-seasons among 48 male flag football players (mean ± SD; age, 9.4 ± 1.1 years; height, 138.6 ± 9.5 cm; mass, 34.7 ± 9.2 kg) across 3 seasons using head impact sensors during practices and games. Sensors recorded head impact frequencies, peak linear ( g ) and rotational (rad/s 2 ) acceleration, and estimated impact location. Impact rates (IRs) were calculated as 1 impact per 10 player-exposures; IR ratios (IRRs) were used to compare season, event type, and age group IRs; and 95% CIs were calculated for IRs and IRRs. Weekly and seasonal cumulative head impact frequencies and magnitudes were calculated. Mixed-model regression models examined the association between player characteristics, event type, and seasons and peak linear and rotational accelerations., Results: A total of 429 head impacts from 604 exposures occurred across the study period (IR, 7.10; 95% CI, 4.81-10.50). Weekly and seasonal cumulative median head impact frequencies were 1.00 (range, 0-2.63) and 7.50 (range, 0-21.00), respectively. The most frequent estimated head impact locations were the skull base (n = 96; 22.4%), top of the head (n = 74; 17.2%), and back of the head (n = 66; 15.4%). The combined event type IRs differed among the 3 seasons (IRR range, 1.45-2.68). Games produced greater IRs (IRR, 1.24; 95% CI, 1.01-1.53) and peak linear acceleration (mean difference, 5.69 g; P = .008) than did practices. Older players demonstrated greater combined event-type IRs (IRR, 1.46; 95% CI, 1.12-1.90) and increased head impact magnitudes than did younger players, with every 1-year age increase associated with a 3.78 g and 602.81-rad/s 2 increase in peak linear and rotational acceleration magnitude, respectively ( P ≤ .005)., Conclusion: Head IRs and magnitudes varied across seasons, thus highlighting multiple season and cohort data are valuable when providing estimates. Head IRs were relatively low across seasons, while linear and rotational acceleration magnitudes were relatively high.

Background: This study determined the effect of video-verified collision characteristics on head impact magnitudes in male youth tackle football., Methods: Participants (n = 23, age = 10.9 ± 0.3 years, height = 150.0 ± 8.3 cm, mass = 41.6 ± 8.4 kg) wore Triax Sim-G sensors throughout the fall 2019 season. Ten filmed games were used to identify nine different collision characteristics: mechanism, preparedness, head direction, struck versus striking activity, stance, play type, closing distance, penalty, and quarter. Random-effects general linear models and Cohen d effect sizes were used to examine differences in log-transformed peak linear (PLA; g) and rotational (PRA; rad/s 2 ) accelerations across characteristics. The 10 games produced 533 total video-verified impacts and 23.2 ± 7.2 impacts per athlete., Results: PLA (P range: 0.107 to 0.923) and PRA (P range: 0.057 to 0.768) did not differ across characteristics. Struck players (3370 rads/s 2, 95% confidence interval [CI] = 2986 to 3808) had a small effect for higher PRA compared with striking players (3037 rads/s 2, 95% CI = 2713 to 3404, d = 0.251), but negligible effect for simultaneous struck-striking players (3340 rad/s 2, 95% CI = 2945 to 3792, d = 0.018). Fourth quarter impacts (3490 rads/s 2, 95% CI = 3083 to 3951) had a small effect for higher PRA compared with first (2945 rads/s 2, 95% CI = 2596 to 3337, d = 0.404), second (3196 rads/s 2, 95% CI = 2832 to 3604, d = 0.219), and third quarters (3241 rads/s 2, 95% CI = 2841 to 3699, d = 0.144)., Conclusion: Youth tackle football characteristics did not significantly affect head impact magnitudes during games. More research is needed to explore additional factors that could be modified for sport safety rather than mitigating impact mechanism., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Context: Basketball has remained a popular sport for players and spectators in the United States since before the first National Collegiate Athletic Association men's championship tournament in 1939., Background: Routine examinations of men's basketball injuries are important for identifying emerging temporal patterns., Methods: Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program during 2014-2015 through 2018-2019 athletic seasons were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differences in injury rates., Results: The overall injury rate was 7.28 per 1000 athlete exposures, with competition rates twice those of practices (injury rate ratio = 2.07; 95% CI = 1.93, 2.22). Injuries to the ankle (22.2%), knee (13.0%), head/face (11.3%), and hand/wrist (10.1%) accounted for most reported injuries, with sprains (30.4%), contusions (14.3%), and strains (13.9%) most commonly reported. Ankle sprain rates initially trended upward and decreased between 2017-2018 and 2018-2019; concussion rates remained relatively stable during 2014-2015 through 2018-2019., Conclusions: Findings suggest that common injury rates are trending downward relative to previous study findings., (© by the National Athletic Trainers' Association, Inc.)

Context: Frequent inspection of sports-related injury epidemiology among National Collegiate Athletic Association (NCAA) women's basketball student-athletes is valuable for identifying injury-related patterns., Background: Emerging patterns in epidemiology of NCAA women's basketball injuries are unknown though general sports medicine practices, and playing rules and regulations have evolved in recent years., Methods: Athlete exposures (AEs) and injury incidence data were reported to the NCAA Injury Surveillance Program between 2014-2015 and 2018-2019. Injury counts, rates, and proportions were used to examine injury characteristics, and injury rate ratios (IRRs) were used to assess injury rate differences., Results: Practice and competition injury rates were 5.93 and 10.35 per 1000 AEs, respectively. Preseason injury rates were higher than regular (IRR = 1.41; 95% CI = 1.31, 1.53) and postseason (IRR = 3.12; 95% CI = 2.39, 4.07). Ankle sprains (14.3%), concussions (7.5%), and anterior cruciate ligament tears (2.5%) were the most commonly reported injuries., Summary: Higher rates of practice and competition injuries, as well as ankle sprains, were observed relative to previous reports; continuous monitoring is necessary to identify potential contributing factors to these trends., (© by the National Athletic Trainers' Association, Inc.)

Context: Women's volleyball is a globally popular sport with widespread participation at the National Collegiate Athletic Association (NCAA) level., Background: Routine examinations of NCAA women's volleyball injuries are important for recognizing emerging injury-related patterns in this population., Methods: Exposure and injury data collected in the NCAA Injury Surveillance Program during the 2014-2015 through 2018-2019 athletic years were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differences in injury rates., Results: The overall injury rate was 6.73 per 1000 athlete-exposures. Knee (14.6%) and ankle (13.8%) injuries accounted for the largest proportion of all reported injuries, and most injuries were attributed to overuse (26.1%) or noncontact (22.7%) mechanisms. Lateral ankle ligament complex tears (11.1%) and concussions (7.3%) were the most commonly reported specific injury., Summary: Results indicate an increasing burden of practice-related injuries and the need to further examine overuse injuries. Lower-extremity injury prevention strategies and mechanisms of concussion also warrant further attention., (© by the National Athletic Trainers' Association, Inc.)

Context: Reaction time is commonly assessed postconcussion through a computerized neurocognitive battery. Although this measure is sensitive to postconcussion deficits, it is not clear if computerized reaction time reflects the dynamic reaction time necessary to compete effectively and safely during sporting activities. Functional reaction time assessments may be useful postconcussion, but reliability must be determined before clinical implementation., Objective: To determine the test-retest reliability of a functional reaction time assessment battery and to determine if reaction time improved between sessions., Design: Cohort., Setting: Laboratory., Participants: Forty-one participants (21 men and 20 women) completed 2 time points. Participants, on average, were 22.5 (2.1) years old, 72.5 (11.9) cm tall, had a mass of 71.0 (13.7) kg, and were mostly right leg and hand dominant (92.7%)., Interventions: Participants completed 2 clinical reaction time tests (computerized Stroop and drop stick) and 5 functional reaction time tests (gait, jump landing, single-leg hop, anticipated cut, and unanticipated cut) across 2 sessions. Drop stick and functional reaction time assessments were performed in single (motor task only) and dual task (motor task with cognitive task)., Main Outcome Measures: Reaction time (in seconds) was calculated during all assessments. Test-retest reliability was determined using 2-way mixed-effects intraclass correlation coefficients (3, k). Paired samples t tests compared mean reaction time between sessions., Results: Test-retest reliability was moderate to excellent for all reaction time outcomes (intraclass correlation coefficients [3, k] range = .766-.925). Several statistically significant between-session mean differences were observed, but effect sizes were negligible to small (d range = 0.05-0.44)., Conclusions: The functional reaction time assessment battery displayed similar reliability to the standard computerized reaction time assessment battery and may provide important postinjury information, but more research is needed to determine clinical utility.

Background: Recent literature has indicated altitude may be a protective factor for concussion but it is unknown whether altitude or heat index affects recovery., Objective: To examine whether on-field heat index and altitude at the time of injury alter acute (< 48 h) concussion assessments, days-to-asymptomatic, and days-to-return-to-play in collegiate athletes following concussion., Methods: Collegiate athletes (n = 187; age = 19.7 ± 1.4 years; male = 70.6%) underwent baseline assessments across 30 universities and experienced a concussion in this retrospective cohort study. Altitude (m) and heat index (°C) at the time and location of injury were determined using valid online database tools. Acute concussion assessments included the Sport Concussion Assessment Tool (SCAT) symptom inventory, Balance Error Scoring System (BESS), and the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). We used multiple linear regression models to determine whether heat index and altitude predicted each acute assessment outcome, days-to-asymptomatic, and days-to-return-to-play., Results: Collegiate athletes were concussed at a 181.1 m (range - 0.6 to 2201.9 m) median altitude and 17.8 °C (range - 6.1 to 35.6 °C) median heat index. Altitude did not predict (p ≥ 0.265) any outcomes. Every one-degree increase in heat index reduced days-to-asymptomatic (p = 0.047; R 2  = 0.06) and days-to-return-to-play (p = 0.006; R 2  = 0.09) by 0.05 and 0.14 days, respectively. Heat index and altitude did not explain significant variance in SCAT, BESS, and ImPACT composite scores (p's = 0.20-0.922)., Conclusion: Our findings suggest that on-field altitude and heat index at the time of injury do not contribute to clinically meaningful changes on acute assessments or concussion recovery. On-field altitude and heat index do not appear to significantly alter assessment outcomes or clinical recovery, suggesting that environmental factors at altitudes below < 2500 m are negligible outcomes for researchers and clinicians to consider post-concussion.

Background: Concussed patients have impaired reaction time (RT) and cognition following injury that may linger and impair driving performance. Limited research has used direct methods to assess driving-RT post-concussion. Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT's relationship with traditional computerized neurocognitive testing (CNT) domains., Methods: We employed a cross-sectional study among 14 concussed (15.9 ± 9.8 days post-concussion, mean ± SD) individuals and 14 healthy controls matched for age, sex, and driving experience. Participants completed a driving simulator and CNT (CNS Vital Signs) assessment within 48 h of symptom resolution. A driving-RT composite (ms) was derived from 3 simulated driving scenarios: stoplight (green to yellow), evasion (avoiding approaching vehicle), and pedestrian (person running in front of vehicle). The CNT domains included verbal and visual memory; CNT-RT (simple-, complex-, Stroop-RT individually); simple and complex attention; motor, psychomotor, and processing speed; executive function; and cognitive flexibility. Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups, Pearson correlations (r) examined driving RT and CNT domain relationships among cohorts separately, and p values were controlled for false discovery rate via Benjamini-Hochberg procedures (α = 0.05)., Results: Concussed participants demonstrated slower driving-RT composite scores than controls (mean difference = 292.86 ms; 95% confidence interval (95%CI): 70.18-515.54; p = 0.023; d = 0.992). Evasion-RT (p = 0.054; d = 0.806), pedestrian-RT (p = 0.258; d = 0.312), and stoplight-RT (p = 0.292; d = 0.585) outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits. Among concussed individuals, driving-RT outcomes did not significantly correlate with CNT domains (r-range: -0.51 to 0.55; p > 0.05). No correlations existed between driving-RT outcomes and CNT domains among control participants either (r-range: -0.52 to 0.72; p > 0.05)., Conclusion: Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns. Driving-RT and CNT-RT measures correlated moderately but not statistically, which indicates that CNT-RT is not an optimal surrogate for driving RT., Competing Interests: Competing interests The authors declare that they have no competing interests., (Copyright © 2020. Production and hosting by Elsevier B.V.)

Context: Laboratory-based movement assessments are commonly performed without cognitive stimuli (ie, single-task) despite the simultaneous cognitive processing and movement (ie, dual task) demands required during sport. Cognitive loading may critically alter human movement and be an important consideration for truly assessing functional movement and understanding injury risk in the laboratory, but limited investigations exist., Objective: To comprehensively examine and compare kinematics and kinetics between single- and dual-task functional movement among healthy participants while controlling for sex., Design: Cross-sectional study., Setting: Laboratory. Patients (or Other Participants): Forty-one healthy, physically active participants (49% female; 22.5 ± 2.1 y; 172.5 ± 11.9 cm; 71.0 ± 13.7 kg) enrolled in and completed the study., Intervention(s): All participants completed the functional movement protocol under single- and dual-task (subtracting by 6s or 7s) conditions in a randomized order. Participants jumped forward from a 30-cm tall box and performed (1) maximum vertical jump landings and (2) dominant and (3) nondominant leg, single-leg 45° cuts after landing., Main Outcome Measures: The authors used mixed-model analysis of variances (α = .05) to compare peak hip, knee, and ankle joint angles (degrees) and moments (N·m/BW) in the sagittal and frontal planes, and peak vertical ground reaction force (N/BW) and vertical impulse (Ns/BW) between cognitive conditions and sex., Results: Dual-task resulted in greater peak vertical ground reaction force compared with single-task during jump landing (mean difference = 0.06 N/BW; 95% confidence interval [CI], 0.01 to 0.12; P = .025) but less force during dominant leg cutting (mean difference = -0.08 N/BW; 95% CI, -0.14 to -0.02; P = .015). Less hip-flexion torque occurred during dual task than single task (mean difference = -0.09 N/BW; 95% CI, -0.17 to -0.02). No other outcomes were different between single and dual task (P ≥ .053)., Conclusions: Slight, but potentially important, kinematic and kinetic differences were observed between single- and dual-task that may have implications for functional movement assessments and injury risk research. More research examining how various cognitive and movement tasks interact to alter functional movement among pathological populations is warranted before clinical implementation.

Purpose: This study aimed to examine the association between clinical and functional reaction time (RT) assessments with and without simultaneous cognitive tasks among healthy individuals., Methods: Participants (n = 41, 49% female; 22.5 ± 2.1 yr; 172.5 ± 11.9 cm; 71.0 ± 13.7 kg) completed clinical (drop stick, Stroop) and functional (gait, jump landing, single-leg hop, anticipated cut, unanticipated cut) RT assessments in random order. All RT assessments, except Stroop and unanticipated cut, were completed under single- (movement only) and dual-task conditions (movement and subtracting by 6s or 7s). Drop stick involved catching a randomly dropped rod embedded in a weighted disk. Stroop assessed RT via computerized neurocognitive testing. An instrumented walkway measured gait RT when center-of-pressure moved after random stimulus. All other functional RT assessments involved participants jumping forward and performing a vertical jump (jump landing), balancing on one leg (single-leg hop), or a 45° cut in a known (anticipated cut) or unknown (unanticipated cut) direction. RT was determined when the sacrum moved following random visual stimulus. Pearson correlation coefficients and a 5 × 2 repeated-measures ANOVA compared RT assessments and cognitive conditions., Results: Stroop RT outcomes did not significantly correlate with functional RT assessments (r range = -0.10 to 0.24). A significant assessment by cognitive task interaction (F4,160 = 14.01; P < 0.001) revealed faster single-task RT among all assessments compared with dual-task (mean differences, -0.11 to -0.09 s; P < 0.001), except drop stick (P = 0.195). Single-leg hop (0.58 ± 0.11 s) was significantly slower compared with jump landing (0.53 ± 0.10 s), anticipated cut (0.49 ± 0.09 s), gait (0.29 ± 0.07 s), and drop stick (0.21 ± 0.03 s; P values ≤ 0.001). Dual-task assessments were significantly slower than single-task assessments (mean difference, 0.08 s; P < 0.001)., Conclusions: Clinical and functional RT assessments were not correlated with each other, suggesting that sport-like RT is not being assessed after concussion. Functional and dual-task RT assessments may add clinical value and warrant further exploration after concussion.

Context: Athletic trainers (ATs) are heavily involved in concussion assessment and return-to-play (RTP) decision making. Despite ATs' crucial role, few researchers have directly examined ATs' knowledge of concussions or whether concussion knowledge or clinical experience affects clinical concussion-management practices., Objective: To determine the overall concussion knowledge of ATs and whether concussion knowledge and clinical experience affect concussion-assessment and -management practices., Design: Cross-sectional study., Setting: Online survey., Patients or Other Participants: Random convenience sample of 8725 (15.0% response rate [1307/8725]; certified, 14.8 ± 10.6 years) ATs surveyed from the National Athletic Trainers' Association membership., Main Outcome Measure(s): The survey collected demographics, concussion-assessment and -management tools used, and concussion knowledge (patient-clinician scenarios, signs and symptoms recognition). We used multiple logistic regression models to determine the odds ratios (ORs) for using assessment and management tools based on signs and symptoms recognition and years of clinical experience., Results: The ATs correctly identified 78.0% ± 15.1% of concussion signs and symptoms. Approximately 46% (357/770) of ATs indicated an athlete could RTP if the athlete stated he or she had a "bell rung." Every additional year of clinical experience decreased the odds of using standardized sideline-assessment tools by 3% (OR = 0.97, 95% Confidence Interval [CI] = 0.95, 0.99). The odds of using standardized sideline tools (OR = 0.98, 95% CI = 0.96, 0.99) and symptom checklists (OR = 0.98, 95% CI = 0.97, 0.99) for RTP assessment were significantly decreased for each additional year of clinical experience. No other tools used for RTP assessment were influenced by signs and symptoms recognition (P ≥ .136) or clinical experience (P ≥ .158)., Conclusions: The ATs with greater clinical experience had lower odds of using concussion-assessment and -management tools. Athletic trainers should frequently review and implement current consensus guidelines into clinical practice to improve concussion recognition and prevent improper management., (© by the National Athletic Trainers' Association, Inc.)

Background: Reaction time (RT) deficits are reported following concussion, but it is unknown when these deficits normalize to pre-injury status. It is also unclear how factors such as RT measurement technique and participant characteristics influence post-concussion RT., Objective: The purpose of this systematic review and meta-analysis was to (1) characterize acute post-concussion (0-3 days) RT impairments, (2) examine RT recovery over time, and (3) explore moderating factors related to acute RT impairment following concussion., Methods: Database searches (PubMed, CINAHL, EBSCOhost) were conducted according to PRISMA guidelines for articles published in English from January 2002 to March 2019. Studies compared baseline-to-post-injury RT within individuals (within-subject) and/or RT in concussed individuals to non-concussed controls (between-subject). Sixty studies met inclusion criteria, reporting on a total of 9688 participants with 214 discrete RT effects (Hedges' d; between-subject: N = 29, k = 129; within-subject: N = 42, k = 85). Of the 214 effects, 93 occurred in the acute (0-3 days) post-injury timeframe (k = 47 between-subject). Numerous demographic [sex, age, concussion history, population type (athlete, military, and general population), athlete level (high school, college), and sport], and method-based (RT test and measure type, computerized neurocognitive testing platform, concussion definition, and time post-injury) moderators were examined for mean effect influence. Mixed-effects multi-level modeling with restricted-maximum-likelihood estimation was used to account for nested effects and high heterogeneity for the pooled effect size (D+)., Results: Significant medium-magnitude RT deficits were observed acutely for between- (D+ = - 0.7279, 95% CI - 0.9919, - 0.4639, I 2  = 88.66, p < 0.0001) and within-subject (D+ = - 0.7472, 95% CI - 0.9089, - 0.5855, I 2  = 89.21, p < 0.0001) effect models. RT deficits were present at the sub-acute and intermediate-term timeframes for between-subject effects (sub-acute: D+ = - 0.5655, 95% CI - 0.6958, - 0.4352, p < 0.0001; intermediate-term: D+ = - 0.3219, 95% CI - 0.5988, - 0.0450, p = 0.0245). No significant RT mean effect was observed for the between-subject model at the long-term timeframe, indicating RT recovery among concussed participants relative to controls (D+ = 0.3505, 95% CI - 0.4787, 1.1797, p = 0.3639). Sex was a significant moderator for between-subject effects, with every 1% male sample size increase demonstrating - 0.0171 (95% CI - 0.0312, - 0.0029, p = 0.0193) larger RT deficits. Within-subject effect models resulted in RT measure type (simple: [D+ = - 0.9826] vs. mixed: [D+ = - 0.6557], p = 0.0438) and computerized neurocognitive testing platforms (ANAM: [D+ = - 0.3735] vs. HeadMinder CRI: [D+ = - 1.4799] vs. ImPACT: [D+ = - 0.6749], p = 0.0004) having significantly different RT-deficit magnitudes. No other moderators produced significantly different RT-deficit magnitudes (between-subject: [p ≥ 0.0763], within-subject: [p ≥ 0.1723])., Conclusions: Robust RT deficits were observed acutely following concussion. Minimal magnitude differences were noted when comparing between- and within-subject effects, suggesting that pre-injury baselines may not add clinical value in determining post-injury RT impairment. RT deficits persisted up till the intermediate-term (21-59 days post-injury) timeframe and indicate lingering deficits exist. Mean effect size differences were observed between RT measure types and computerized neurocognitive testing platforms; however, all categories displayed negative effects consistent with impaired RT following concussion. Clinical interpretation suggests that measuring RT post-concussion is more important than considering the RT method employed so long as reliable and valid tools are used. PROSPERO Registration #CRD42019119323.

Context: Athletic trainers (ATs) are often the first health care providers to conduct concussion assessments and carry out postinjury management. Best practices for concussion evaluation and management have changed rapidly in recent years, outdating previous reports of ATs' concussion practices., Objective: To examine ATs' current concussion-assessment and -management techniques., Design: Cross-sectional study., Setting: Web-based survey., Patients or Other Participants: A random convenience sample of 8777 ATs (response rate = 15.0% [n = 1307]; years certified = 15.0 ± 10.6) from the National Athletic Trainers' Association membership., Main Outcome Measure(s): Survey Web links were e-mailed to prospective participants, with 2 follow-up e-mails sent by the National Athletic Trainers' Association. The survey collected demographic information, the number of concussions assessed, the concussion-recovery patterns, and the assessment and return-to-participation (RTP) decision-making methods used., Results: The ATs reported assessing a median of 12.0 (range = 0-218) concussions per year. A total of 95.3% (953/1000) ATs cited clinical examination as the most frequently used concussion-assessment tool, followed by symptom assessment (86.7%; 867/1000). A total of 52.7% (527/1000) ATs described a 3-domain minimum multidimensional concussion-assessment battery. Published RTP guidelines were the most common RTP decision-making tool (91.0%; 864/949), followed by clinical examination (88.2%; 837/949). The ATs with master's degrees were 1.36 times (95% confidence interval [CI] = 1.02, 1.81) more likely to use a 3-domain concussion-assessment battery than ATs with only bachelor's degrees (χ 2 = 4.44, P = .05). Collegiate ATs were 2.12 (95% CI = 1.59, 2.84) and 1.63 (95% CI = 1.03, 2.59) times more likely to use a 3-domain concussion-assessment battery than high school and clinic-based ATs, respectively (χ 2 = 26.29, P < .001)., Conclusions: Athletic trainers were using the clinical examination, standardized assessment tools, and a 3-domain concussion-assessment-battery approach more frequently in clinical practice than previously reported. However, despite practice improvements, nearly half of ATs were not using a 3-domain minimum concussion-assessment battery. Clinicians should strive to implement multidimensional concussion assessments in their practices to ensure optimal diagnosis and management.

Our purpose was to describe the youth flag football head impact burden and make comparisons with youth tackle football. Head impact frequency and magnitude (linear acceleration [g], rotational acceleration [rad/s 2 ]) were collected from 25 tackle and 25 flag youth football players over one season. Athlete exposure (AE) was defined as one player participating in one session. Head impact rates (IR) were calculated and impact rate ratios (IRR) were used to compare youth tackle and flag football. Random-intercept generalized logit models with odds ratios compared the probabilities of sustaining an impact with a linear acceleration of 20.00-29.99 g , 30.00-39.99 g , and ≥40.00 g against the reference of 14.00-19.99 g and an impact with a rotational acceleration of 2500.00-7499.99 rad/s 2 or ≥7500.00 rad/s 2 against the reference of ≤2499.99 rad/s 2 between youth flag and tackle football. We observed 1908 tackle football head impacts (735 in games, 38.5%) across 624 AE and 169 flag football head impacts (101 in games, 59.8%) across 255 AE. Youth tackle football players experienced higher overall IR (3.06, 95% confidence interval [CI]: 2.61, 3.58; IRR = 4.61, 95% CI: 3.94, 5.40) compared with flag football (IR = 0.66, 95% CI: 0.57, 0.78). Youth flag football players had lower odds of sustaining impacts >20 g but higher odds of sustaining impacts between 2500.00-7499.99 rad/s 2 compared with youth tackle players. Our preliminary sample of youth flag football players sustained less frequent head impacts at higher rotational accelerations than tackle football players. Flag football is considered a limited-contact sport, but little is known about the true head impact burden. Our findings may be important for policymakers when debating potential changes to youth football participation.

Primary objective : To describe and compare athletic trainer (AT) post-concussion driving management practices and opinions. Research design : Cross-sectional. Methods & procedures : A survey was sent via email to 8,723 ATs (10.8% response rate[945/8723]) to capture demographics, management practices, and opinions (agreement on a seven-point Likert scale). We used Kruskal-Wallis tests to compare the percentage of patients instructed to refrain from driving across the highest earned a degree, setting, and years certified (alpha = 0.05). Main outcomes & results : When asked whether they recommended patients with concussion refrain from driving, 58.5%(n = 553/945) of ATs responded "sometimes", 37.9%(n = 358/945) responded "always", and 3.6%(n = 34/945) responded "never". ATs responding "sometimes" or "always" estimated that they instruct 57.6 ± 37.6% of patients with concussion to refrain from driving. ATs most commonly: recommended that patients refrain from driving until symptom resolution(44.7%,n = 399/892); utilized their clinical exam (patient interview/history) to determine when a patient could resume driving(64.9%,n = 579/892); and provided instructions verbally(94.2%,n = 840/892). High school(60.5 ± 37.6%) and clinical ATs(66.5 ± 31.2%) trended toward higher percentages of patients they instruct to refrain from driving relative to college(52.3 ± 38.2%; χ 2 (2) = 5.92, p = .052). Conclusions : ATs recommend driving restrictions to some, but not all, patients with concussion. Overall, ATs recognize post-concussion driving dangers, but do not strongly endorse refraining from driving after a concussion. High school and clinical ATs may manage more adolescent novice drivers and, therefore, act more conservatively.

Post-concussion driving restrictions are eminent, but we lack understanding of current behaviors and opinions about driving following concussion among populations at risk of concussion. We aimed to describe post-concussion driving behaviors and opinions among collegiate student-athletes. Student-athletes completed a survey (response rate = 45.3%, 223/492) regarding their post-concussion driving behaviors and opinions. Response frequencies and percentages are presented. Student-athletes self-reported a total of 169 lifetime concussions (0.76 ± 1.02 each). Of the 169 concussions, 52.1% (88/169) were diagnosed and 52.7% (89/169) occurred while the student-athlete possessed a valid driver's license. Student-athletes refrained from driving following 43.8% (39/89) of the concussive events. Student-athletes who refrained most commonly did so for only 24-48 h (20.5%, 8/39) and because a health care provider advised them to (33.3%, 13/39). Student-athletes most commonly reported that they would feel "very unsafe" driving a car immediately following injury (38.4%, 84/219). When asked whether driving restrictions would influence their decision to report the injury to a health care provider, 7.9% reported that it "definitely would" (17/214), 26.6% "probably would" (57/214), 17.8%"neutral" (38/214), 24.8% "probably would not" (53/214), and 22.9% "definitely would not" (49/214). Despite generally believing that driving immediately following a concussion is unsafe, a majority of student-athletes did not refrain from driving at any point following their previous concussions. Post-concussion driving restrictions may have some influence on student-athletes' decisions to report the injury to a health care provider. Health care providers play a critical role in post-concussion driving restriction, but lack standardized recommendations to guide their care.