Drill-Specific Head Impacts in Collegiate Football Practice: Implications for Reducing "Friendly Fire" Exposure

Abstract

This study investigated drill-specific head impact biomechanics in a Division 1 collegiate football team using the Head Impact Telemetry System (HITS). A total of 32,083 impacts were recorded across 2 years of practices. Precise tracking of instrumented athletes, head impacts, and drill participation allowed quantification of hits sustained per person per minute (H/P/M) for each specific drill. We found significant H/P/M variability between 14 drills and player position, ranging from 0.02 to 0.41 H/P/M for Linemen and 0.01 to 0.15 H/P/M for Non-Linemen. Impact magnitude data are also reported for practice term (Spring, Training Camp, In-Season) and dress-type (Helmets Only, Spyders, Shells, Full Pads). Recommendations for shortening high-risk drills, based on H/P/M drill impact frequencies, suggest possible "friendly fire" reductions of 1000 impacts for Linemen and 300 impacts for Non-Linemen over their collegiate career. Over 80% of potentially avoidable head impacts were attributable to just three drills-"Team Run," "Move the Field," and "Team." Recommending drill-specific modifications based on practical considerations (the drill's impact frequency, dress-types when performing the drill, and duration) could improve acceptance from coaches and efficiently reduce head impact exposure without drastically altering overall practice structure.

Keywords: Concussion; Football practice drills; HIT System; Impact frequency; Repetitive head impact exposure; Subconcussive.