Comparison of head impact exposure in practice drills among multiple youth football teams

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Limiting contact in football practice can reduce the number of head impacts a player receives, but further research is needed to inform the modification of optimal drills that mitigate head impact exposure (HIE) while the player develops the skills needed to safely play the game. This study aimed to compare HIE in practice drills among 6 youth football teams and to evaluate the effect of a team on HIE.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>On-field head impact data were collected from athletes (ages 10–13 years) playing on 6 local youth football teams (teams A–F) during all practices using the Head Impact Telemetry System. Video was recorded and analyzed to verify and assign impacts to a specific drill. Drills were identified as follows: dummy/sled tackling, half install, install, install walk through, multiplayer tackle, Oklahoma, one-on-one, open field tackling, other, passing, position skill work, scrimmage, special teams, tackling drill stations, and technique. HIE was quantified in terms of impacts per player per minute (ppm) and peak linear and rotational head acceleration. Generalized linear models were used to assess differences in head impact magnitude and frequency among drills as well as among teams within the most common drills.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Among 67 athlete-seasons, a total of 14,718 impacts during contact practices were collected and evaluated in this study. Among all 6 teams, the mean linear (p &lt; 0.0001) and rotational (p &lt; 0.0001) acceleration varied significantly among all drills. Open field tackling had significantly (p &lt; 0.001) higher mean linear acceleration than all other drills. Multiplayer tackle had the highest mean impact rate (0.35 ppm). Significant variations in linear acceleration and impact rate were observed among teams within specific drills. Team A had the highest mean linear acceleration in install, one-on-one, and open field tackling and the highest mean impact rate in Oklahoma and position skill work. Although team A spent the greatest proportion of their practice on minimal- or no-player versus player contact drills (27%) compared to other teams, they had the highest median (20.2<jats:italic>g</jats:italic>) and 95th percentile (56.4<jats:italic>g</jats:italic>) linear acceleration in practice.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Full-speed tackling and blocking drills resulted in the highest HIE. Reducing time spent on contact drills relative to minimal or no contact drills may not lower overall HIE. Instead, interventions such as reducing the speed of players engaged in contact, correcting tackling technique, and progressing to contact may reduce HIE more effectively.</jats:p></jats:sec>

Repetitive Head Impact Exposure in College Football Following an NCAA Rule Change to Eliminate Two-A-Day Preseason Practices: A Study from the NCAA-DoD CARE Consortium

“…Reducing the intensity of contact practices may be the most effective method to reduce total head impact burden, given the association between daily contact intensity and total preseason head impact burden identified here. This finding is consistent with the recent recommendations by Kelley et al , that concluded reducing the speed of players engaged in contact, correcting tackling technique, and progressing to contact as more effective methods to reduce head impact exposure in youth football 20. Based in part on data presented here, the NCAA did act again in 2018 to reduce total head impact burden by reducing the total number of on-field preseason practices from 29 in 2016 and 2017 to 25 in 2018.…”

Analysis of longitudinal head impact exposure and white matter integrity in returning youth football players

“…Prior studies have also shown that teams, player position, practice drills, and amount of contact can influence HIE. 2,4,[8][9][10]38,41,42 Youth football athletes may have a primary position, but it is common for athletes at this level to play multiple positions throughout the season. It is also likely that their primary position changes from season to season until they begin to specialize at the high school and college levels.…”

“…Athletes were placed on teams based on the national governing association's age and weight requirements. 4,38 The study protocol was approved by the Wake Forest University Health Sciences Institutional Review Board, and participant assent and parental consent were properly obtained for participation in the study. Participation in the study was voluntary.…”

A Comparison of Youth Flag and Tackle Football Head Impact Biomechanics

“…4,9,10 There are many factors that may influence head impact magnitude in football, such as head impact location, 11 playing position, 12,13 and type of practice drill. 12,14,15 In youth football, approximately 8% of head impacts are considered high magnitude by one definition (greater than linear acceleration of 40g 12,14 ), with an association existing between impact magnitude and on-field impact location, position, and practice drill. 12 Ninety-five percent of youth tackle football head impacts are below a range of 47-60g of linear acceleration and 2500-3900 rad/s 2 of rotational acceleration, 4,7,8 although 95% of impacts may be below lower thresholds for younger players (approximately 38g and 2100 rad/s 2 , respectively).…”