Frequency and Location of Head Impact Exposures in Individual Collegiate Football Players

Abstract

Context: Measuring head impact exposure is a critical step toward understanding the mechanism and prevention of sportrelated mild traumatic brain (concussion) injury, as well as the possible effects of repeated subconcussive impacts.Objective: To quantify the frequency and location of head impacts that individual players received in 1 season among 3 collegiate teams, between practice and game sessions, and among player positions.Design: Cohort study. Setting: Collegiate football field. Patients or Other Participants: One hundred eighty-eight players from 3 National Collegiate Athletic Association football teams.Intervention(s): Participants wore football helmets instrumented with an accelerometer-based system during the 2007 fall season.Main Outcome Measure(s): The number of head impacts greater than 10g and location of the impacts on the player's helmet were recorded and analyzed for trends and interactions among teams (A, B, or C), session types, and player positions using Kaplan-Meier survival curves.Results: The total number of impacts players received was nonnormally distributed and varied by team, session type, and player position. The maximum number of head impacts for a single player on each team was 1022 (team A), 1412 (team B), and 1444 (team C). The median number of head impacts on each team was 4.8 (team A), 7.5 (team B), and 6.6 (team C) impacts per practice and 12.1 (team A), 14.6 (team B), and 16.3 (team C) impacts per game. Linemen and linebackers had the largest number of impacts per practice and per game. Offensive linemen had a higher percentage of impacts to the front than to the back of the helmet, whereas quarterbacks had a higher percentage to the back than to the front of the helmet.Conclusions: The frequency of head impacts and the location on the helmet where the impacts occur are functions of player position and session type. These data provide a basis for quantifying specific head impact exposure for studies related to understanding the biomechanics and clinical aspects of concussion injury, as well as the possible effects of repeated subconcussive impacts in football.

White Matter Changes and Confrontation Naming in Retired Aging National Football League Athletes

“…Concussion history was accumulated from selfreports, and were classified using the American Academy of Neurology (AAN) Practice Parameter guidelines for grading concussion. 32 Concussion severity ranged from brief periods of confusion to loss of consciousness for several hours. Seven of the athletes met clinical criteria for mild cognitive impairment (MCI).…”

“…White matter pathway disruption as assessed by FA has been correlated with performance on some neuropsychological tasks, 16,29,30 including naming performance. 31 Professional football players who experienced subconcussive head impacts 32,33 may be susceptible to increased risk for progressive cognitive decline and affective disorders 34,35 with aging. 32,33 A subconcussive impact is defined as any blow to the head that does not result in a concussion.…”

“…31 Professional football players who experienced subconcussive head impacts 32,33 may be susceptible to increased risk for progressive cognitive decline and affective disorders 34,35 with aging. 32,33 A subconcussive impact is defined as any blow to the head that does not result in a concussion. This type of impact is innately entwined with high-risk sports and is often difficult to discern.…”

Impact on the head during collisions between university American football players - focusing on the number of head impacts and linear head acceleration -

“…While these studies on injuries are significant, they did not consider other factors related to concussions, such as the frequency of head collisions and their impact point, magnitude, and cumulative number. In other words, when calculating the injury rates, these studies did not account for players who received head collision impacts of dif-*Correspondence: fukuda.takashi.gm@u.tsukuba.ac.jp ferent frequencies and magnitudes but did not get injured 10,11) . Therefore, in order to understand concussions, it is important to obtain a detailed understanding of head collisions.…”

“…In the 2000s, many researchers started to use a headimpact telemetry system (HITS, Simbex, Lebanon NH) equipped with an acceleration sensor installed inside a Riddell (Elyria, OH) helmet to collect real-time headacceleration data during head collisions between American football players [9][10][11][12][13][19][20][21][22][23][24][25][26][27][28] . The data collected by HITS is transmitted to a PC application in real time via a sideline response system (Riddell, Chicago, IL).…”