Head Impact Exposure in College Football after a Reduction in Preseason Practices

Brian D. Stemper*, Alok S. Shah, Jason P. Mihalik, Jaroslaw Harezlak, Steven Rowson, Stefan Duma, Larry D. Riggen, Alison Brooks, Kenneth L. Cameron, Christopher C. Giza, Joshua Goldman, Megan N. Houston, Jonathan Jackson, Gerald McGinty, Steven P. Broglio, Thomas W. McAllister, Michael McCrea

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Introduction Regulatory efforts toward reducing concussion risk have begun to focus on decreasing the number of head impacts (i.e., head impact burden) sustained by athletes in contact sports. To that end, in 2018, the NCAA decreased the number of preseason on-field team activities for Division I teams from 29 to 25. The objective of the current study was to quantify changes in practice schedule and head impact exposure between the 2017 and 2018 football preseasons. Methods Athletes from five NCAA Division I football teams (n = 426) were consented and enrolled. Results On average, athletes participated in 10% fewer contact practices in 2018. However, the effect of this ruling on preseason head impact burden was mixed. Across all athletes, the total preseason head impact burden was essentially the same from 2017 to 2018. However, this study revealed significant team-by-team differences in preseason head impact burden, with one team demonstrating a 35% increase in the average number of recorded head impacts from 2017 to 2018, despite a modest decrease in the number of contact practices. Other teams had similar or decreased head impact burden. Conclusions Team-based differences in total preseason head impact burden were attributable to changes in daily practice schedule, with longer practice durations and more intense contact practice sessions contributing to increases in daily head impact exposure that, in turn, led to greater preseason head impact burden. Results of this study have highlighted the difficulty in decreasing contact sport head impact exposure through rule changes targeted at limiting on-field team activities. Future efforts aimed specifically at contact practice duration, daily head impact exposure, or limiting time in specific drills may be more effective at reducing total preseason head impact burden.

Original languageEnglish
Pages (from-to)1629-1638
Number of pages10
JournalMedicine and Science in Sports and Exercise
Issue number7
StatePublished - 1 Jul 2020
Externally publishedYes


  • American Football
  • Biomechanics
  • Concussion
  • Head Impact Exposure
  • Subconcussive
  • Traumatic Brain Injury


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