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The Natural History of Sport-Related Concussion in Collegiate Athletes: Findings from the NCAA-DoD CARE Consortium



Sport-related concussion is recognized as a significant injury with variable recovery rates.


This study defined the acute natural history of sport concussion in male and female collegiate athletes participating in a broad array of sports.


We conducted a prospective, longitudinal investigation among collegiate student athletes (n = 34,709) from 30 academic institutions. Primary outcomes included the time (days) from injury until initiation of a return to participation (RTP) protocol and time from injury until medical clearance for unrestricted RTP.


Concussed athletes (n = 1751, 19.2 years, 63.2% male) participating in 22 different sports began the RTP protocol in a median 6.4 (IQR 3.7–11.8) days. Time to initiate the RTP protocol was lengthened by less frequent post-injury assessments, greater initial post-injury symptom severity, limited contact sports participation, practice/training injuries, and three or more prior concussions. The median total RTP duration was 12.8 (IQR 8.7–20.1) days. Total RTP duration was shorter with ADHD medication usage, males, and greater assessment frequency; while greater initial post-injury symptom severity, practice-/training-related injuries, and three or more prior concussions had longer recoveries.


Although median recovery times are consistent with previous guidelines, it was not until 1 month post-injury that a preponderance of collegiate athletes were cleared to begin the RTP protocol (92%) or cleared for unrestricted sport participation (85%). Intrinsic and extrinsic factors had a small effect, altering recovery trajectories by up to 2 days, suggesting a largely unified approach to post-injury monitoring and management across all athletes. These data represent a shift from previous classification parameters of normal clinical recovery.

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The authors would like to thank Ryan Tierney (Temple University), Patrick O'Donnell (United States Coast Guard Academy), Josh Goldman (University of California at Los Angeles), Kevin Guskiewicz (University of North Carolina at Chapel Hill), Mickey Collins (University of Pittsburgh), Jeff Bazarian (University of Rochester), Laura Lintner (Wake Forest University), Brian Dyhuizen (Wilmington College), Paul Pasquina (Uniformed Services University), Jaroslaw Harezlak, Jody Harland, Janetta Matesan, and Larry Riggen (Indiana University), Nicole L’Heureux and Ashley Rettmann (University of Michigan), Melissa Koschnitzke (Medical College of Wisconsin), Michael Jarrett, Vibeke Brinck, and Bianca Byrne (Quesgen), Thomas Dompier, Christy Collins, Melissa Baker, and Sara Quetant (Datalys Center for Sports Injury Research and Prevention), and the research and medical staff at each of the participating sites.

CARE Consortium Investigators include (alphabetical by institution): April Hoy MS, ATC, CSCS (Azusa Pacific University), Joseph B. Hazzard, EdD, ATC (Bloomsburg University), Louise A. Kelly, PhD (California Lutheran University), John DiFiori, MD (Hospital for Special Surgery), Justus D. Ortega, PhD (Humbolt State University), Nicholas Port, PhD (Indiana University), Margot Putukian (Princeton University), Dianne Langford, PhD and Jane McDevitt PhD, ATC, CSCS (Temple University), Darren Campbell, MD, Jonathan C. Jackson, MD, and Gerald McGinty, PT, DPT (United States Air Force Academy), Carlos Estevez, DPT (United States Coast Guard Academy), Kenneth L. Cameron, PhD, MPH, ATC, Megan N. Houston, PhD, ATC, and Steven J. Svoboda, MD (United States Military Academy), Adam James Susmarski, DO (United States Naval Academy), Chris Giza, MD (University of California at Los Angeles), Holly J. Benjamin, MD (University of Chicago), Thomas W. Kaminski, PhD, ATC and Thomas Buckley, EdD, ATC (University of Delaware), James R. Clugston, MD, MS, CAQSM (University of Florida), Julianne Schmidt, PhD, ATC (University of Georgia), Luis A. Feigenbaum, PT, DPT, ATC (University of Miami), J. T. Eckner, MD (University of Michigan), Jason Mihalik, PhD, CAT(C), ATC (University of North Carolina at Chapel Hill), Jessica Dysart Miles, PhD, ATC (University of North Georgia), Scott Anderson, ATC (University of Oklahoma), Kristy Arbogast, PhD and Christina L. Master, MD, CAQSM (University of Pennsylvania), Anthony P. Kontos, PhD (University of Pittsburgh), Sara P. D. Chrisman, MD, MPH (University of Washington), M. Alison Brooks, MD MPH (University of Wisconsin-Madison), Steve Rowson, PhD and Stefan M. Duma, PhD (Virginia Tech), Chris Miles, MD (Wake Forest University).

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Corresponding author

Correspondence to Steven P. Broglio.

Ethics declarations


Data collection and sharing for this project was conducted with support from the National Collegiate Athletic Association (NCAA) and the Department of Defense (DOD). The U.S. Army Medical Research Acquisition Activity, 820 Chandler Street, Fort Detrick MD 21702-5014, is the awarding and administering acquisition office. This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs, through the Combat Casualty Care Research Program, endorsed by the Department of Defense, through the Joint Program Committee 6/Combat Casualty Care Research Program—Psychological Health and Traumatic Brain Injury Program under Award No. W81XWH1420151. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the Department of Defense.

Author Contributions

SB, TM, MM contributed to the design and implementation of the investigation, drafting and revision of the manuscript; BK contributed to the design and implementation of the investigation, statistical analyses and interpretation, and drafting and revision of the manuscript; MLP and WZ contributed to the statistical analyses and interpretation, and drafting and revision of the manuscript; CARE Consortium Investigators contributed to the implementation of the investigation and revision of the manuscript.

Conflicts of interest/Competing interests

Steven Broglio, Thomas McAllister, Barry Katz, Michelle LaPradd, Wenxian Zhou, and Michael McCrea received funding from the NCAA and the Department of Defense to complete this investigation and to cover travel costs related to the study.

Ethics approval

This study was completed following approval from respective local Institutional Review Boards and the United States Army Human Research Protection Office. This study was conducted in accordance with the Declaration of Helsinki.

Availability of data

Data used in this investigation are available in the Federal Interagency Traumatic Brain Injury Research (FITBIR) Informatics System (

Code availability

The specific analytic coding that was used relies on the data set prepared from the full data set of over 38,000 participants, but the analytic techniques used are standard (e.g. Cox proportional hazards models) and available in all statistical software packages. For those interested, the authors can be contacted for the code and with questions.

Additional information

This article is part of a Collection on The NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium.

The members of “CARE Consortium Investigators” is present in Acknowledgements section.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 749 kb)

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Broglio, S.P., McAllister, T., Katz, B.P. et al. The Natural History of Sport-Related Concussion in Collegiate Athletes: Findings from the NCAA-DoD CARE Consortium. Sports Med (2021).

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