Protocol for COACH, an evidence-based intervention for improved head impact safety in youth American football developed using a community-engaged approach.

Subconcussive, repetitive head impacts sustained in collision sports may negatively affect brain health. American football practices are controlled environments amenable to intervention. Engaging community members is essential for successful development, implementation, and sustainability of viable interventions. The objective of this study is to develop and pilot test an evidence-based intervention to reduce head impact exposure in youth American football (i.e., football), using a community-engaged approach. This manuscript describes the co-design of the intervention and associated implementation plan and the study protocol for evaluating the effectiveness and feasibility of the intervention and implementation plan. In the first part of this study, focus groups with parents and coaches, and individual interviews with organizational leaders associated with two teams at the middle school level were conducted. An anonymous survey assessing beliefs and perceptions of non-concussive head impacts was given to parents, coaches, and organizational leaders within the local youth football league. Following the football season, qualitative and quantitative data describing determinants of head acceleration events in football were shared with 12 stakeholders of coaches, league and school administrators, parents, an athletic trainer, and local university player development director. Together, we co-designed COACH (COmmunities Aligned to reduce Concussion and Head impact exposure) and implementation plan using a strategic planning approach. The preliminary effectiveness and feasibility were assessed in the second part of this study. Youth football players participating on the teams in year 1 (control teams) were fitted with mouthpiece-based head kinematic sensors which measure head acceleration events (HAEs). HAEs were collected and quantified during team activities. Preliminary effectiveness of the intervention to reduce HAEs was measured among two new teams pilot testing COACH with mouthpiece-based sensors, while simultaneously monitoring implementation of the intervention. We report our study design and evaluation, and opportunities and challenges with our approach. The results will inform a future full-scale pragmatic trial to assess the implementation and effectiveness of the intervention program. NCT04908930.

On-Field Evaluation of Mouthpiece-and-Helmet-Mounted Sensor Data from Head Kinematics in Football.

PURPOSE: Wearable sensors are used to measure head impact exposure in sports. The Head Impact Telemetry (HIT) System is a helmet-mounted system that has been commonly utilized to measure head impacts in American football. Advancements in sensor technology have fueled the development of alternative sensor methods such as instrumented mouthguards. The objective of this study was to compare peak magnitude measured from high school football athletes dually instrumented with the HIT System and a mouthpiece-based sensor system. METHODS: Data was collected at all contact practices and competitions over a single season of spring football. Recorded events were observed and identified on video and paired using event timestamps. Paired events were further stratified by removing mouthpiece events with peak resultant linear acceleration below 10 g and events with contact to the facemask or body of athletes. RESULTS: A total of 133 paired events were analyzed in the results. There was a median difference (mouthpiece subtracted from HIT System) in peak resultant linear and rotational acceleration for concurrently measured events of 7.3 g and 189 rad/s2. Greater magnitude events resulted in larger kinematic differences between sensors and a Bland Altman analysis found a mean bias of 8.8 g and 104 rad/s2, respectively. CONCLUSION: If the mouthpiece-based sensor is considered close to truth, the results of this study are consistent with previous HIT System validation studies indicating low error on average but high scatter across individual events. Future researchers should be mindful of sensor limitations when comparing results collected using varying sensor technologies.

Characterization of Head Acceleration Exposure During Youth Football Practice Drills.

Many head acceleration events (HAEs) observed in youth football emanate from a practice environment. This study aimed to evaluate HAEs in youth football practice drills using a mouthpiece-based sensor, differentiating between inertial and direct HAEs. Head acceleration data were collected from athletes participating on 2 youth football teams (ages 11-13 y) using an instrumented mouthpiece-based sensor during all practice sessions in a single season. Video was recorded and analyzed to verify and assign HAEs to specific practice drill characteristics, including drill intensity, drill classification, and drill type. HAEs were quantified in terms of HAEs per athlete per minute and peak linear and rotational acceleration and rotational velocity. Mixed-effects models were used to evaluate the differences in kinematics, and generalized linear models were used to assess differences in HAE frequency between drill categories. A total of 3237 HAEs were verified and evaluated from 29 football athletes enrolled in this study. Head kinematics varied significantly between drill categorizations. HAEs collected at higher intensities resulted in significantly greater kinematics than lower-intensity drills. The results of this study add to the growing body of evidence informing evidence-based strategies to reduce head impact exposure and concussion risk in youth football practices.

Characterizing Exposure to Head Acceleration Events in Youth Football Using an Instrumented Mouthpiece.

Understanding characteristics of head acceleration events (HAEs) in youth football is vital in developing strategies to improve athlete safety. This study aimed to characterize HAEs in youth football using an instrumented mouthpiece. Youth football athletes (ages 11-13) participating on two teams were enrolled in this study for one season. Each athlete was instrumented with a mouthpiece-based sensor throughout the season. HAEs were verified on film to ensure that mouthpiece-based sensors triggered during contact. The number of HAEs, peak resultant linear and rotational accelerations, and peak resultant rotational velocity were quantified. Mixed effects models were used to evaluate differences in mean kinematic metrics among all HAEs for session type, athlete position, and contact surface. A total of 5,292 HAEs were collected and evaluated from 30 athletes. The median (95th percentile) peak resultant linear acceleration, rotational acceleration, and rotational velocity was 9.5 g (27.0 g), 666.4 rad s-2 (1863.3 rad s-2), and 8.5 rad s-1 (17.4 rad s-1), respectively. Athletes experienced six (22) HAEs per athlete per session (i.e., practice, game). Competition had a significantly higher mean number of HAEs per athlete per session and mean peak rotational acceleration. Peak resultant rotational kinematics varied significantly among athlete positions. Direct head impacts had higher mean kinematics compared to indirect HAEs, from body collisions. The results of this study demonstrate that session type, athlete position, and contact surface (i.e., direct, indirect) may influence HAE exposure in youth football.