The Relationship Between Position, Impact Magnitude and Cumulative Impact Burden in NCAA Division I Football Players

GOALS/ OBJECTIVES: The goal of this study was to investigate and identify the potential differences of average impact magnitudes (AIM) and cumulative impact burden (CIB) between positions (line vs. skill) and participation settings (games vs. practice) during the course of a single football season. INTRODUCTION: Accelerations to the brain result in diffuse deformation of axons, if these accelerations are severe enough they can result in a concussion. (Kilnic, 2013; Thomas, 2015) Over 1.6 million sports-related concussions occur annually, and football players may account for as high as 47% of all sports-related concussions. (Langlois, 2006; Marar,2012). Previous research has established that linear accelerations (LA) of a single concussion -resulting impact does not correlate with the clinical severity of the concussion. (Guskiewicz, 2007; Broglio, 2011; McCaffrey, 2007) Research has however, established that significant differences of impact frequency exist between difference positions. (Mihalik, 2007; Broglio 2009) Furthermore, research has established that players who sustained a higher frequency of impacts, especially to the front of the head, were more likely to have deficits with function MRI‰Ûªs. (Talavage, 2010; Breedlove, 2012). While frequency of impacts has been observed, cumulative impact burden (the total exposure to linear accelerations) has not been established. Therefore the purpose of this study was to investigate potential differences of average impact magnitude (AIM) and cumulative impact burden (CIB) among position, and participation setting. METHODS: Thirty-two NCAA Division I football players were fitted with Head Impact Telemetry (HIT) System sensors to measure acceleration forces associated with a head impact (player vs. player or contact with ground). Impact magnitudes were recorded for all head impacts with a LA above 10 g during the 2014‰ÛÓ2015 competitive football season. To obtain AIM, each session’s recorded LA’s were averaged. Similarly, each practices or games recorded LA’s were totaled to yield the CIB. For statistical analysis, players were dichotomized into two groups: line-position players (LINE), which consisted of offensive and defensive linemen and skill position players (SKILL), which consisted of running backs, wide receivers, linebackers, defensive backs, and quarterbacks. AIM and CIB of LINE and SKILL was compared between practices and games using a paired sample t-test. Differences in AIM and CIB between positions (LINE and SKILL) were compared using an independent sample t-test. RESULTS: Position demographics were as followed: SKILL: n=20, and LINE: n= 11. When comparing LINE and SKILL, no significant difference was found in AIM among practices (p=0.185) and competition (p=0.712). LINE had over three times CIB in both practices (26,056.67g vs. 23,078.94g,