Subconcussive Head Impact Biomechanics: Comparing Differing Offensive Schemes

MARTINI, DOUGLAS1; ECKNER, JAMES2,3; KUTCHER, JEFFERY3,4; BROGLIO, STEVEN P.1,3

Medicine & Science in Sports & Exercise: April 2013 - Volume 45 - Issue 4 - p 755–761
doi: 10.1249/MSS.0b013e3182798758
Applied Sciences

Purpose: Recent literature suggests that subconcussive impacts may influence cognitive functioning across the life span. These effects are suggested to manifest as functional and possibly structural changes. Head impact biomechanics during American football have been characterized from the high school to professional level, but style of play has not been considered. The aim of this investigation was to quantify and compare head impact frequencies and magnitudes between two different offensive schemes.

Methods: We investigated the frequencies and magnitudes (linear acceleration [g], rotational acceleration [rad·s−2], and HITsp) of head impacts sustained by 83 high school football athletes, playing for schools using two different offensive schemes. The two schemes comprised a run-first offense (42 athletes) and a pass-first offense (41 athletes). The Head Impact Telemetry System was used to record head impact measures.

Results: A total of 35,620 impacts were recorded across two seasons. Athletes in the run-first offense sustained an average of 456 head impacts per season (41 practices and 9 games), whereas the pass-first offense athletes sustained an average of 304 head impacts per season (44 practices and 9 games). The pass-first offense, however, sustained significantly higher impact magnitudes (P values < 0.05; 28.56g, 1777.58 rad·s−2, and 16.24) than the run-first offense (25.67g, 1675.36 rad·s−2, and 15.48) across a season.

Conclusions: These data provide a first look at how different offensive strategies may influence head impact exposure in football athletes. In the study population, a run-first offense was associated with more frequent head impacts, of smaller magnitude, than a pass-first offense.

1School of Kineisology, Neurotrauma Research Laboratory, University of Michigan, Ann Arbor, MI; 2Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI; 3Michigan NeuroSport, Ann Arbor, MI; and 4Department of Neurology, University of Michigan, Ann Arbor, MI

Address for correspondence: Steven P. Broglio, Ph.D., ATC, School of Kinesiology, University of Michigan, 1402 Washington Heights, Ann Arbor, MI 48109-2013; E-mail: broglio@umich.edu.

Submitted for publication August 2012.

Accepted for publication October 2012.

©2013The American College of Sports Medicine