Distribution of Head Acceleration Events Varies by Position and Play Type in North American Football

Abstract

Objective: The goal of this pilot study was to evaluate the number of head acceleration events (HAEs) based on position, play type, and starting stance. Design: Prospective cohort study. Setting: Postcollegiate skill development camp during practice sessions and 1 exhibition game. Participants: Seventy-eight male adult North American football athletes. Independent Variables: A position was assigned to each participant, and plays in the exhibition game were separated by play type for analysis. During the exhibition game, video data were used to determine the effects of the starting position (“up” in a 2-point stance or “down” in a 3- or 4-point stance) on the HAEs experienced by players on the offensive line. Main Outcome Measures: Peak linear acceleration and number of HAEs greater than 20 g (g = 9.81 m/s2) were measured using an xPatch (X2 Biosystems, Seattle, WA). Results: Four hundred thirty-seven HAEs were recorded during practices and 272 recorded during the exhibition game; 98 and 52 HAEs, the greatest number of HAEs by position in the game, were experienced by the offensive and defensive linemen, respectively. Linebackers and tight ends experienced high percentages of HAEs above 60 g. Offensive line players in a down stance had a higher likelihood of sustaining a HAE than players in an up stance regardless of the type of play (run vs pass). Conclusions: Changing the stance of players on the offensive line and reducing the number of full-contact practices will lower HAEs.

On-Field Performance of an Instrumented Mouthguard for Detecting Head Impacts in American Football

“…30 For example, data from wearable head impact sensors obtained onfield can be used to ensure test methodologies are representative of actual loading conditions, to evaluate changes to rules of the game, and to identify drills and game scenarios that may be associated with a greater number of impacts or impacts of higher magnitude. 4,25,36 Currently, numerous, wearable head impact monitoring systems are available for use with varying form factors including impact sensors mounted in helmets, headbands, skin patches, earpieces, mouthguards, and retainers. 6,10,26,29,[31][32][33]40 These systems typically measure or estimate six-degree-of-freedom (6DOF) kinematics of the head during an impact which can be used to assess the severity of the impact and the likelihood of head injury.…”

Effect of Repetitive Head Impacts on Saccade Performance in Canadian University Football Players

“…Accordingly, this study's results may not be generalizable to teams that follow American rules. Head impact frequency can vary within positional groups, 70 depending upon seniority and roster depth. 31 This study measured saccade latencies of all roster depths at different positions, including injured players who did not experience any head impacts.…”

A preliminary model of football-related neural stress that integrates metabolomics with transcriptomics and virtual reality

“…Twenty-three male collegiate American football athletes (mean age = 21 2 years) participated in this study. The selected athletes were all seasoned starters who experience, and have experienced, a high frequency of HAEs throughout the athletic season (i.e., 16/23 athletes were non-speed linemen who sustain a high volume of impacts during practices and games) ( Lee et al., 2020 ; Lehman, 2013 ). Written informed consent was obtained from each participant in accordance with the Pennsylvania State University Institutional Review Board and in alignment with the Declaration of Helsinki.…”

“…Sensors were individually mounted on the inner surface, between the shell and padding, of each active player’s helmet prior to contact practice beginning. To avoid game disruption, no games were monitored; however, previous studies have revealed that most HAEs accumulate from practice sessions, not games ( Lee et al., 2020 ). Sensors were monitored throughout the season for integrity and functionality and outputs included peak translational acceleration (PTA; G-units) and impact location.…”