Investigation of Aerobic and Muscular Fitness and Concussion Among Service Academy Cadets at the United States Air Force Academy: Results from the CARE Consortium.

INTRODUCTION: Concussion has become the signature injury facing the U.S. military. However, little is understood about the relationship between military fitness and concussion recovery. The current study examined the recoveries of cadets at a U.S. Service Academy to determine whether preinjury physical fitness improved recovery and whether recovery was associated with post-injury physical fitness measures. METHODS: Participants were enrolled in a longitudinal study of concussion. Aerobic Fitness Test (AFT) and Physical Fitness Test (PFT) data were used to estimate cadet fitness. Survival analysis evaluated significant estimators of concussion recovery time. Linear regression models were used to explore the relationship between recovery duration and change in physical fitness scores. RESULTS: Between 2014 and 2017, 307 (n = 70; 22.80% Women) cadets who had sustained a concussion were enrolled. Preinjury physical fitness was not significantly associated with recovery duration (P > .05). Men and intercollegiate cadets took fewer days to reach recovery milestones. Compared to women, men had greater decrements in the Aerobic Fitness Test total score (P < .05) and increased 1.5-mile time postconcussion (P < .05). Women had greater decreases in push-ups postconcussion compared to males (P < .05). There was a trend for a negative association between days until asymptomatic and change in the Physical Fitness Test score (P = .07). CONCLUSION: Preconcussion physical fitness levels do not appear to impact concussion recovery time among a highly physically fit cohort. Possible methods to reduce the effect of symptom duration on strength-related physical fitness should be investigated along with evaluating reductions in strength as a possible mechanism for postconcussion injury risk.

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets: A Prospective Study From the NCAA and US Department of Defense CARE Consortium.

Importance: Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose. Objective: To investigate acute blood protein levels in military cadets after combative training-associated concussions. Design, Setting, and Participants: This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020. Exposure: Concussion incurred during combative training. Main Outcomes and Measures: Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory. Results: Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point. Conclusions and Relevance: This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.

Test-Retest Reliability of Concussion Baseline Assessments in United States Service Academy Cadets: A Report from the National Collegiate Athletic Association (NCAA)-Department of Defense (DoD) CARE Consortium.

OBJECTIVE: In response to advancing clinical practice guidelines regarding concussion management, service members, like athletes, complete a baseline assessment prior to participating in high-risk activities. While several studies have established test stability in athletes, no investigation to date has examined the stability of baseline assessment scores in military cadets. The objective of this study was to assess the test-retest reliability of a baseline concussion test battery in cadets at U.S. Service Academies. METHODS: All cadets participating in the Concussion Assessment, Research, and Education (CARE) Consortium investigation completed a standard baseline battery that included memory, balance, symptom, and neurocognitive assessments. Annual baseline testing was completed during the first 3 years of the study. A two-way mixed-model analysis of variance (intraclass correlation coefficent (ICC)3,1) and Kappa statistics were used to assess the stability of the metrics at 1-year and 2-year time intervals. RESULTS: ICC values for the 1-year test interval ranged from 0.28 to 0.67 and from 0.15 to 0.57 for the 2-year interval. Kappa values ranged from 0.16 to 0.21 for the 1-year interval and from 0.29 to 0.31 for the 2-year test interval. Across all measures, the observed effects were small, ranging from 0.01 to 0.44. CONCLUSIONS: This investigation noted less than optimal reliability for the most common concussion baseline assessments. While none of the assessments met or exceeded the accepted clinical threshold, the effect sizes were relatively small suggesting an overlap in performance from year-to-year. As such, baseline assessments beyond the initial evaluation in cadets are not essential but could aid concussion diagnosis.

Factors Associated With Delayed Concussion Reporting by United States Service Academy Cadets.

CONTEXT: Approximately half of individuals who sustain a concussion do not immediately report their injuries. Motivators for not reporting include thinking the suspected concussion was not a serious injury and wanting to continue participating in activity. Additionally, military personnel have concerns about how concussions may affect their careers. However, delayed reporting can prolong neurobehavioral recovery. Understanding the frequency of delayed reporting and contributing factors will aid in identifying individuals who may be more likely to delay reporting. OBJECTIVE: To describe the frequency of delayed concussion reporting by service academy cadets and determine if sex, injury setting, sport level, or medical history is capable of predicting delayed reporting. DESIGN: Cohort study. SETTING: Service academies. PATIENTS OR OTHER PARTICIPANTS: A total of 316 patients with concussions were observed from January 2014 to August 2016. MAIN OUTCOME MEASURE(S): All cadets completed an annual concussion baseline collection of demographic, medical history, and sports participation information. Delayed concussion reporting served as the outcome variable. Predictor variables were sex, injury setting, and sport level, as well as concussion, headache, and learning disorder history. Frequencies were calculated to describe the proportion of participants who delayed reporting. Univariable and multivariable logistic regression models were used to assess if the predictor variables were associated with delayed concussion reporting. Odds ratios (ORs) and 95% confidence intervals were calculated for all variables included in the final model. RESULTS: Of the patients with concussion, 51% were classified as delayed reporting. In univariable models, females (OR = 1.70) and National Collegiate Athletic Association cadet-athletes (OR = 1.98) were more likely to delay reporting than males and intramural cadet-athletes, respectively. The multivariable model yielded similar findings. CONCLUSIONS: Roughly half of the cadets who sustained a concussion failed to immediately report their injury. Specifically, our data suggested that female cadets, cadets injured outside of competition, and highly competitive cadet-athletes were almost twice as likely to delay reporting as others.

Concussion-Recovery Trajectories Among Tactical Athletes: Results From the CARE Consortium.

CONTEXT: Assessments of the duration of concussion recovery have primarily been limited to sport-related concussions and male contact sports. Furthermore, whereas durations of symptoms and return-to-activity (RTA) protocols encompass total recovery, the trajectory of each duration has not been examined separately. OBJECTIVE: To identify individual (eg, demographics, medical history), initial concussion injury (eg, symptoms), and external (eg, site) factors associated with symptom duration and RTA-protocol duration after concussion. DESIGN: Cohort study. SETTING: Three US military service academies. PATIENTS OR OTHER PARTICIPANTS: A total of 10 604 cadets at participating US military service academies enrolled in the study and completed a baseline evaluation and up to 5 postinjury evaluations. A total of 726 cadets (451 men, 275 women) sustained concussions during the study period. MAIN OUTCOME MEASURE(S): Number of days from injury (1) until the participant became asymptomatic and (2) to complete the RTA protocol. RESULTS: Varsity athlete cadets took less time than nonvarsity cadets to become asymptomatic (hazard ratio [HR] = 1.75, 95% confidence interval = 1.38, 2.23). Cadets who reported less symptom severity on the Sport Concussion Assessment Tool, third edition (SCAT3), within 48 hours of concussion had 1.45 to 3.77 times shorter symptom-recovery durations than those with more symptom severity. Similar to symptom duration, varsity status was associated with a shorter RTA-protocol duration (HR = 1.74, 95% confidence interval = 1.34, 2.25), and less symptom severity on the SCAT3 was associated with a shorter RTA-protocol duration (HR range = 1.31 to 1.47). The academy that the cadet attended was associated with the RTA-protocol duration (P < .05). CONCLUSIONS: The initial total number of symptoms reported and varsity athlete status were strongly associated with symptom and RTA-protocol durations. These findings suggested that external (varsity status and academy) and injury (symptom burden) factors influenced the time until RTA.

Association of Blood Biomarkers With Acute Sport-Related Concussion in Collegiate Athletes: Findings From the NCAA and Department of Defense CARE Consortium.

Importance: There is potential scientific and clinical value in validation of objective biomarkers for sport-related concussion (SRC). Objective: To investigate the association of acute-phase blood biomarker levels with SRC in collegiate athletes. Design, Setting, and Participants: This multicenter, prospective, case-control study was conducted by the National Collegiate Athletic Association (NCAA) and the US Department of Defense Concussion Assessment, Research, and Education (CARE) Consortium from February 20, 2015, to May 31, 2018, at 6 CARE Advanced Research Core sites. A total of 504 collegiate athletes with concussion, contact sport control athletes, and non-contact sport control athletes completed clinical testing and blood collection at preseason baseline, the acute postinjury period, 24 to 48 hours after injury, the point of reporting being asymptomatic, and 7 days after return to play. Data analysis was conducted from March 1 to November 30, 2019. Main Outcomes and Measures: Glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neurofilament light chain, and tau were quantified using the Quanterix Simoa multiplex assay. Clinical outcome measures included the Sport Concussion Assessment Tool-Third Edition (SCAT-3) symptom evaluation, Standardized Assessment of Concussion, Balance Error Scoring System, and Brief Symptom Inventory 18. Results: A total of 264 athletes with concussion (mean [SD] age, 19.08 [1.24] years; 211 [79.9%] male), 138 contact sport controls (mean [SD] age, 19.03 [1.27] years; 107 [77.5%] male), and 102 non-contact sport controls (mean [SD] age, 19.39 [1.25] years; 82 [80.4%] male) were included in the study. Athletes with concussion had significant elevation in GFAP (mean difference, 0.430 pg/mL; 95% CI, 0.339-0.521 pg/mL; P < .001), UCH-L1 (mean difference, 0.449 pg/mL; 95% CI, 0.167-0.732 pg/mL; P < .001), and tau levels (mean difference, 0.221 pg/mL; 95% CI, 0.046-0.396 pg/mL; P = .004) at the acute postinjury time point compared with preseason baseline. Longitudinally, a significant interaction (group × visit) was found for GFAP (F7,1507.36 = 16.18, P < .001), UCH-L1 (F7,1153.09 = 5.71, P < .001), and tau (F7,1480.55 = 6.81, P < .001); the interaction for neurofilament light chain was not significant (F7,1506.90 = 1.33, P = .23). The area under the curve for the combination of GFAP and UCH-L1 in differentiating athletes with concussion from contact sport controls at the acute postinjury period was 0.71 (95% CI, 0.64-0.78; P < .001); the acute postinjury area under the curve for all 4 biomarkers combined was 0.72 (95% CI, 0.65-0.79; P < .001). Beyond SCAT-3 symptom score, GFAP at the acute postinjury time point was associated with the classification of athletes with concussion from contact controls (ß = 12.298; 95% CI, 2.776-54.481; P = .001) and non-contact sport controls (ß = 5.438; 95% CI, 1.676-17.645; P = .005). Athletes with concussion with loss of consciousness or posttraumatic amnesia had significantly higher levels of GFAP than athletes with concussion with neither loss of consciousness nor posttraumatic amnesia at the acute postinjury time point (mean difference, 0.583 pg/mL; 95% CI, 0.369-0.797 pg/mL; P < .001). Conclusions and Relevance: The results suggest that blood biomarkers can be used as research tools to inform the underlying pathophysiological mechanism of concussion and provide additional support for future studies to optimize and validate biomarkers for potential clinical use in SRC.

The Influence of Self-Reported Tobacco Use on Baseline Concussion Assessments.

INTRODUCTION: Baseline symptom, balance, and neurocognitive scores have become an integral piece of the concussion management process. Factors such as sleep, learning disorders, fitness level, and sex have been linked to differences in performance on baseline assessments; however, it is unclear how tobacco use may affect these scores. The objective of this study was to compare baseline concussion assessment scores between service academy cadets who use and do not use tobacco. METHODS: Cadets completed a standard battery of concussion baseline assessments per standard of care and were classified into two groups: tobacco users (n = 1,232) and nonusers (n = 5,922). Dependent variables included scores on the Balance Error Scoring System, Standardized Assessment of Concussion, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Brief Symptom Inventory-18, and Brief Sensation Seeking Scale (BSSS). Separate Mann-Whitney U-tests were used to compare all baseline assessment scores between groups with an adjusted P-value < 0.004. RESULTS: Cadets that used tobacco performed significantly worse on the impulse control (P < 0.001) section of the ImPACT, reported greater ImPACT symptom severity scores (P < 0.001), and were more likely to take risks as measured by the BSSS (P < 0.001). No differences were detected for Balance Error Scoring System, Standardized Assessment of Concussion, Brief Symptom Inventory-18, and Sport Concussion Assessment Tool-3 symptom scores, verbal memory, visual memory, visual-motor speed, or reaction time on the ImPACT (P > 0.004). CONCLUSIONS: Tobacco users performed significantly worse than tobacco nonusers on the impulse control section of the ImPACT, reported greater symptom severity scores on the ImPACT, and were more likely to take risks as measured by the BSSS. Despite statistical significance, these results should be interpreted with caution, as the overall effect sizes were very small. Future research should examine the influence of tobacco use on recovery post-concussion.

A cohort study to identify and evaluate concussion risk factors across multiple injury settings: findings from the CARE Consortium.

BACKGROUND: Concussion, or mild traumatic brain injury, is a major public health concern affecting 42 million individuals globally each year. However, little is known regarding concussion risk factors across all concussion settings as most concussion research has focused on only sport-related or military-related concussive injuries. METHODS: The current study is part of the Concussion, Assessment, Research, and Education (CARE) Consortium, a multi-site investigation on the natural history of concussion. Cadets at three participating service academies completed annual baseline assessments, which included demographics, medical history, and concussion history, along with the Sport Concussion Assessment Tool (SCAT) symptom checklist and Brief Symptom Inventory (BSI-18). Clinical and research staff recorded the date and injury setting at time of concussion. Generalized mixed models estimated concussion risk with service academy as a random effect. Since concussion was a rare event, the odds ratios were assumed to approximate relative risk. RESULTS: Beginning in 2014, 10,604 (n = 2421, 22.83% female) cadets enrolled over 3 years. A total of 738 (6.96%) cadets experienced a concussion, 301 (2.84%) concussed cadets were female. Female sex and previous concussion were the most consistent estimators of concussion risk across all concussion settings. Compared to males, females had 2.02 (95% CI: 1.70-2.40) times the risk of a concussion regardless of injury setting, and greater relative risk when the concussion occurred during sport (Odds Ratio (OR): 1.38 95% CI: 1.07-1.78). Previous concussion was associated with 1.98 (95% CI: 1.65-2.37) times increased risk for any incident concussion, and the magnitude was relatively stable across all concussion settings (OR: 1.73 to 2.01). Freshman status was also associated with increased overall concussion risk, but was driven by increased risk for academy training-related concussions (OR: 8.17 95% CI: 5.87-11.37). Medical history of headaches in the past 3 months, diagnosed ADD/ADHD, and BSI-18 Somatization symptoms increased overall concussion risk. CONCLUSIONS: Various demographic and medical history factors are associated with increased concussion risk. While certain factors (e.g. sex and previous concussion) are consistently associated with increased concussion risk, regardless of concussion injury setting, other factors significantly influence concussion risk within specific injury settings. Further research is required to determine whether these risk factors may aid in concussion risk reduction or prevention.

Influences of Mental Illness, Current Psychological State, and Concussion History on Baseline Concussion Assessment Performance.

BACKGROUND: A student-athlete's mental state, including history of trait anxiety and depression, or current psychological state may affect baseline concussion assessment performance. PURPOSE: (1) To determine if mental illness (anxiety, depression, anxiety with depression) influences baseline scores, (2) to determine if psychological state correlates with baseline performance, and (3) to determine if history of concussion affects Brief Symptom Inventory-18 (BSI-18) subscores of state anxiety, depression, and somatization. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A sample of 8652 collegiate student-athletes (54.5% males, 45.5% females) participated in the Concussion Assessment, Research and Education (CARE) Consortium. Baseline assessments included a demographic form, a symptom evaluation, Standardized Assessment of Concussion, Balance Error Scoring System, a psychological state assessment (BSI-18), and Immediate Post-concussion Assessment and Cognitive Test. Baseline scores were compared between individuals with a history of anxiety (n = 59), depression (n = 283), and anxiety with depression (n = 68) and individuals without a history of those conditions (n = 8242). Spearman's rho correlations were conducted to assess the relationship between baseline and psychological state subscores (anxiety, depression, somatization) (α = .05). Psychological state subscores were compared between individuals with a self-reported history of concussions (0, 1, 2, 3, 4+) using Kruskal-Wallis tests (α = .05). RESULTS: Student-athletes with anxiety, depression, and anxiety with depression demonstrated higher scores in number of symptoms reported (anxiety, 4.3 ± 4.2; depression, 5.2 ± 4.8; anxiety with depression, 5.4 ± 3.9; no anxiety/depression, 2.5 ± 3.4), symptom severity (anxiety, 8.1 ± 9.8; depression, 10.4 ± 12.4; anxiety with depression, 12.4 ± 10.7; no anxiety/depression, 4.1 ± 6.9), and psychological distress in state anxiety (anxiety, 3.7 ± 4.7; depression, 2.5 ± 3.6; anxiety with depression, 3.8 ± 4.2; no anxiety/depression, 0.8 ± 1.8), depression (anxiety, 2.4 ± 4.0; depression, 3.2 ± 4.5; anxiety with depression, 3.8 ± 4.8; no anxiety/depression, 0.8 ± 1.8), and somatization (anxiety, 2.3 ± 2.9; depression, 1.8 ± 2.8; anxiety with depression, 2.2 ± 2.4; no anxiety/depression, 0.9 ± 1.7). A moderate positive relationship existed between all BSI-18 subscores and total symptom number (n = 8377; anxiety: rs = 0.43, P < .001; depression: rs = 0.42, P < .001; somatization: rs = 0.45, P < .001), as well as total symptom severity (anxiety: rs = 0.43, P < .001; depression: rs = 0.41, P < .001; somatization: rs = 0.45, P < .001). Anxiety, depression, and somatization subscores were greater among student-athletes that self-reported more concussions. CONCLUSION: Clinicians should be cognizant that student-athletes with a history of trait anxiety, depression, and anxiety with depression may report higher symptom score and severity at baseline. Individuals with extensive concussion history may experience greater state anxiety, depression, and somatization.

Descriptive Analysis of a Baseline Concussion Battery Among U.S. Service Academy Members: Results from the Concussion Assessment, Research, and Education (CARE) Consortium.

Introduction: The prevalence and possible long-term consequences of concussion remain an increasing concern to the U.S. military, particularly as it pertains to maintaining a medically ready force. Baseline testing is being used both in the civilian and military domains to assess concussion injury and recovery. Accurate interpretation of these baseline assessments requires one to consider other influencing factors not related to concussion. To date, there is limited understanding, especially within the military, of what factors influence normative test performance. Given the significant physical and mental demands placed on service academy members (SAM), and their relatively high risk for concussion, it is important to describe demographics and normative profile of SAMs. Furthermore, the absence of available baseline normative data on female and non-varsity SAMs makes interpretation of post-injury assessments challenging. Understanding how individuals perform at baseline, given their unique individual characteristics (e.g., concussion history, sex, competition level), will inform post-concussion assessment and management. Thus, the primary aim of this manuscript is to characterize the SAM population and determine normative values on a concussion baseline testing battery. Materials and Methods: All data were collected as part of the Concussion Assessment, Research and Education (CARE) Consortium. The baseline test battery included a post-concussion symptom checklist (Sport Concussion Assessment Tool (SCAT), psychological health screening inventory (Brief Symptom Inventory (BSI-18) and neurocognitive evaluation (ImPACT), Balance Error Scoring System (BESS), and Standardized Assessment of Concussion (SAC). Linear regression models were used to examine differences across sexes, competition levels, and varsity contact levels while controlling for academy, freshman status, race, and previous concussion. Zero inflated negative binomial models estimated symptom scores due to the high frequency of zero scores. Results: Significant, but small, sex effects were observed on the ImPACT visual memory task. While, females performed worse than males (p < 0.0001, pη2 = 0.01), these differences were small and not larger than the effects of the covariates. A similar pattern was observed for competition level on the SAC. There was a small, but significant difference across competition level. SAMs participating in varsity athletics did significantly worse on the SAC compared to SAMs participating in club or intramural athletics (all p's < 0.001, η2 = 0.01). When examining symptom reporting, males were more than two times as likely to report zero symptoms on the SCAT or BSI-18. Intramural SAMs had the highest number of symptoms and severity compared to varsity SAMs (p < 0.0001, Cohen's d < 0.2). Contact level was not associated with SCAT or BSI-18 symptoms among varsity SAMs. Notably, the significant differences across competition level on SCAT and BSI-18 were sub-clinical and had small effect sizes. Conclusion: The current analyses provide the first baseline concussion battery normative data among SAMs. While statistically significant differences may be observed on baseline tests, the effect sizes for competition and contact levels are very small, indicating that differences are likely not clinically meaningful at baseline. Identifying baseline differences and significant covariates is important for future concussion-related analyses to inform concussion evaluations for all athlete levels.

Reconsidering Return-to-Play Times: A Broader Perspective on Concussion Recovery.

BACKGROUND: Return-to-play protocols describe stepwise, graduated recoveries for safe return from concussion; however, studies that comprehensively track return-to-play time are expensive to administer and heavily sampled from elite male contact-sport athletes. PURPOSE: To retrospectively assess probable recovery time for collegiate patients to return to play after concussion, especially for understudied populations, such as women and nonelite athletes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Medical staff at a military academy logged a total of 512 concussion medical records over 38 months. Of these, 414 records included complete return-to-play protocols with return-to-play time, sex, athletic status, cause, and other data. RESULTS: Overall mean return to play was 29.4 days. Sex and athletic status both affected return-to-play time. Men showed significantly shorter return to play than women, taking 24.7 days (SEM, 1.5 days) versus 35.5 days (SEM, 2.7 days) (P < .001). Intercollegiate athletes also reported quicker return-to-play times than nonintercollegiate athletes: 25.4 days (SEM, 2.6 days) versus 34.7 days (SEM, 1.6 days) (P = .002). These variables did not significantly interact. CONCLUSION: Mean recovery time across all groups (29.4 days) showed considerably longer return to play than the most commonly cited concussion recovery time window (7-10 days) for collegiate athletes. Understudied groups, such as women and nonelite athletes, demonstrated notably longer recovery times. The diversity of this sample population was associated with longer return-to-play times; it is unclear how other population-specific factors may have contributed. These inclusive return-to-play windows may indicate longer recovery times outside the population of elite athletes.