Concussions are a prevalent public health concern; however, non-concussive head impacts without signs and symptoms of concussion may have a greater influence on brain health. The objective of this study was to apply components of the health belief model to perceptions of non-concussive head impacts and preventative efforts to reduce head impacts in youth American football and thematically analyze responses across parents with children participating in youth football, coaches, and organizational leaders. Parents, coaches, and organizational leaders of a local youth football league were invited to complete a one-time online anonymous survey assessing football and sport history, knowledge, beliefs, perceived susceptibility, perceived severity, self-efficacy, and demographics. Principal factor analysis was conducted prior to scoring measurements evaluated in this study. Parents perceived the susceptibility and severity of head impacts in football to be greater than coaches and organizational leaders; however, coaches and organizational leaders had greater beliefs and self-efficacy surrounding head impact safety efforts in football compared to parents. Understanding beliefs and perceptions of key stakeholders in the youth football community is critical to the development and implementation of prevention programs aimed at reducing head impact exposure in the sport.

Background Women's Artistic Gymnastics (WAG) is a high-risk sport for concussion, and improved understanding of head kinematics in gymnastics can help inform targeted injury prevention strategies. Objective Characterize head acceleration exposure in WAG. Design Gymnasts were monitored with mouthpiece sensors and time-synchronized video at all practices over an 11-week period. Setting Two local USA Gymnastics club gyms. Participants 18 competitive women's artistic gymnasts ages 11–15 (n=8 beginner-level, n=10 advanced-level) Independent variables Frequency and head kinematics of skills were compared across activity types (i.e., floor, uneven-bars, beam, vault, dance, conditioning, warm-up, basics). Kinematic metrics were compared across the following skill categories: bar-releases, bar-elements, jumps, handsprings, somersaults, somersaults-with-twists, rolls, and inversions. Main Outcome Measurements Peak resultant linear (PLA) and rotational acceleration (PRA), and change in rotational velocity associated with PRA (ΔRV) of skills, and rate of skills per gymnastics activity. Results Median (95th%ile) PLA, PRA, and ΔRV of skills were 5.9 (10.0) g, 147 (427) rad/s2, 5.4 (13.3) rad/s, respectively. On average, gymnasts experienced 2.6 skills per practice with PLA greater than 10 g. Activity type and skill category were significantly associated with PLA, PRA, and ΔRV (all p<0.001). Activity type was associated with skill rate. Floor training had the greatest skill rate (27.8 per 30 min), PLA (7.7 g), and ΔRV (8.7 rad/s). Rolls, commonly performed during floor training, had the greatest PRA (372 rad/s2) and ΔRV (9.8 rad/s). Conclusions Gymnasts frequently perform skills that expose them to head acceleration events at magnitudes and rates similar to other contact sports. Gymnasts perform a high-rate of skills on floor exercise which expose them to relatively high magnitude head acceleration events. Injury prevention strategies in gymnastics should target the reduction of head accelerations during floor training, through safety modifications.

Background Youth represent the greatest number of sports participants but often participate in community organizations with limited resources and volunteer coaches, making implementation and enforcement of injury prevention strategies challenging. Objective Develop an evidence-based multi-component intervention and implementation plan to reduce head impacts and concussion risk in youth American football practices, using a community-engaged and co-design approach. Design A stakeholder team met monthly to co-design an intervention program and implementation plan. Two football teams pilot tested the program. Setting Community youth football league Participants Stakeholder team (n=12) of youth and high school (HS) coaches, league and school administrators, parents, an athletic trainer, and local university player development director. Two youth football team coaches (n=12). Interventions Intervention targets: (1) improve knowledge and skills of coaches in effective practice planning and use of safe drills, (2) change attitudes and beliefs toward contact in practice. The intervention program included use of guided practice plans, resource booklet aligned with state guidelines for contact in practice, pre-season coaches' clinic, and peer mentorship. Main Outcome Measurements Acceptability of Implementation Measure (AIM), Feasibility of Implementation Measure (FIM), minutes of live contact Results Over 5 months, >90% of stakeholders attended program development meetings. HS coaches were identified as key to development and implementation of intervention materials and early adopters. Youth coaches feel the program is acceptable (4.5/5) and feasible (4.4/5) and participation in the program resulted in 69% less time spent on "live" contact per practice in the season's first three weeks compared to controls. Conclusions Community members are willing to engage in co-design of injury prevention strategies for youth sports. Early pilot testing indicates the program is acceptable and feasible among the target population. Engaging community stakeholders is an effective strategy to create and implement evidence-based injury prevention programs in youth sports. Acknowledgements NIH NICHD K25HD101686

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

To identify barriers and strategies to improve enrollment in multi-site pediatric and adolescent concussion studies.

The objective of this study was to evaluate the effect of skill modifications on head motion experienced during women's artistic gymnastics skills. Nine gymnasts (four beginner and five advanced) completed three trials of up to 24 skill progressions, each consisting of a skill and two progressive safety modifications. Gymnasts were instrumented with mouthpiece sensors embedded with an accelerometer and gyroscope collecting motion data at 200, 300, and 500 Hz during each skill performance. Peak-to-peak linear and rotational kinematics during contact phases and peak rotational kinematics during non-contact phases were computed. A mixed-effects model was used to compare differences in modification status nested within skill categories. Timer skills (i.e. drills that simulate performance of a gymnastics skill) resulted in the highest median Delta LA and Delta RA of all skill categories, and 132 skill performances exceeded 10 g Delta LA during a contact phase. Modifications were associated with significant reductions in head kinematics during contact phases of timers, floor skills, bar releases, and vault skills. Gymnasts can be exposed to direct and indirect head accelerations at magnitudes consistent with other youth contact sports, and common safety modifications may be effective at reducing head motion during contact and non-contact phases of gymnastics skills.

There is concern that exposure to soccer headers may be associated with neurological sequelae. Training proper heading technique represents a coachable intervention that may reduce head acceleration exposure. The objective was to assess relationships between heading technique and head kinematics in female youth soccer players. Fourteen players (mean age = 14.4 years) wore instrumented mouthpieces during practices and games. Headers were reviewed by three raters to assign a technique score. Mixed models and LASSO regression evaluated associations of technique with peak linear acceleration (PLA), rotational acceleration (PRA), rotational velocity (PRV), and head impact power ratio (HIP Ratio) while adjusting for session type and ball delivery. Two hundred eighty-nine headers (n = 212 standing, n = 77 jumping) were analyzed. Technique score (p = 0.043) and the technique score - session type interaction (p = 0.004) were associated with PRA of standing headers, whereby each 10-unit increase in technique score was associated with an 8.6% decrease in PRA during games but a 5.1% increase in PRA during practices. Technique was not significantly associated with any other kinematic metrics; however, peak kinematics tended to decrease as technique score increased. LASSO regression identified back extension and shoulder/hip alignment as important predictors of peak kinematics. Additional research on heading technique and head acceleration is recommended.

Grassroots dirt track racing is a foundational part of motorsports with a high risk of severe injury. This study aimed to gather perspectives and experiences of motorsports drivers surrounding safety and head acceleration events experienced during grassroots dirt track racing to inform strategies to improve driver safety. Thirteen drivers (n=9 who primarily race on dirt tracks; n=4 who primarily race on pavement tracks) with prior dirt track racing experience participated in separate, group-specific focus groups and/or one-on-one interviews where video, simulations of head motion, and head acceleration data were shared. Peak kinematics of laps and crash contact scenarios were recorded, and head perturbations (i.e., deviations in head motion relative to its moving -average trajectory) were quantified for each lap and presented through guided discussion. Responses were summarized using Rapid Assessment Process. Audio recordings and field notes were collected from focus groups and interviews and analyzed across 25 domains. Drivers described dirt track racing as short, fast bursts of racing. Benefits of dirt track racing for driver development were described, including learning car control. Drivers acknowledged risks of racing and expressed confidence in safety equipment but identified areas for improvement. Drivers observed lateral bouncing of the head in video and simulations but recognized that such motions were not noticed while racing. Track conditions and track type were identified as factors influencing head perturbations. Mean PLA (5.5 g) and PRV (3.07 rad/s) of perturbations experienced during racing laps and perturbation frequencies of 5 and 7 perturbations per second were reported. Generally, drivers accurately estimated the head acceleration magnitudes but were surprised by the frequency and maximum magnitude of perturbations. Maximum perturbation magnitudes (26.8 g and 19.0 rad/s) were attributed to hitting a "rut" in the dirt. Drivers described sudden stops, vertical loads due to landing from a large height, and impacts to the vehicle frame as crash events they physically feel the most. Summary statistics for crashes (medians = 7.30 g, 6.94 rad/s) were reported. Typical impact magnitudes measured in other sports (e.g., football) were provided for context. Upon reviewing the biomechanics, drivers were surprised that crash accelerations were relatively low compared to other contact/collision sports. Pavement drivers noted limited safety features in dirt track racing compared to pavement, including rigidity of vehicle frames, seat structure, seatbelt integration, and lack of oversight from sanctioning bodies. Most drivers felt seat inserts and head and neck restraints are important for injury prevention; however, usage of seat inserts and preferred head and neck restraint system differed among drivers. Drivers described their perspectives and experiences related to safety and identified strategies to improve safety in grassroots dirt track racing. Drivers expressed support for future safety research.

Motorsport athletes experience head acceleration loading during crashes; however, there is limited literature quantifying the frequency and magnitude of these loads, particularly at the grassroots level of the sport. Understanding head motion experienced during crash events in motorsport is necessary to inform interventions to improve driver safety. This study aimed to quantify and characterize driver head and vehicle kinematics during crashes in open-wheel grassroots dirt track racing. Seven drivers (ages 16-22, n = 2 female) competing in a national midget car series were enrolled in this study over two racing seasons and were instrumented with custom mouthpiece sensors. Drivers' vehicles were outfitted with an incident data recorder (IDR) to measure vehicle acceleration. Forty-one crash events were verified and segmented into 139 individual contact scenarios via film review. Peak resultant linear acceleration (PLA) of the vehicle and PLA, peak rotational acceleration (PRA), and peak rotational velocity (PRV) of the head were quantified and compared across the part of the vehicle contacted (i.e., tires or chassis), the vehicle location contacted (e.g., front, left, bottom), the external object contacted (i.e., another vehicle, wall, or the track), and the principal direction of force (PDOF). The median (95th percentile) PLA, PRA, and PRV of the head and PLA of the vehicle were 12.3 (37.3) g, 626 (1799) rad/s2, 8.92 (18.6) rad/s, and 23.2 (88.1) g, respectively. Contacts with a non-horizontal PDOF (n = 98, 71%) and contact with the track (n = 96, 70%) were common in the data set. Contact to the left side of the vehicle, with the track, and with a non-horizontal PDOF tended to have the greatest head kinematics compared to other factors in each sub-analysis. Results from this pilot study can inform larger studies of head acceleration exposure during crashes in the grassroots motorsports environment and may ultimately support evidence-based driver safety interventions.

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.

Treatment of youth concussion during the acute phase continues to evolve, and this has led to the emergence of guidelines to direct care. While symptoms after concussion typically resolve in 14-28 days, a portion (∼20%) of adolescents endorse persistent post-concussive symptoms (PPCS) beyond normal resolution. This report outlines a study implemented in response to the National Institute of Neurological Diseases and Stroke call for the development and initial clinical validation of objective biological measures to predict risk of PPCS in adolescents. We describe our plans for recruitment of a Development cohort of 11- to 17-year-old youth with concussion, and collection of autonomic, neurocognitive, biofluid, and imaging biomarkers. The most promising of these measures will then be validated in a separate Validation cohort of youth with concussion, and a final, clinically useful algorithm will be developed and disseminated. Upon completion of this study, we will have generated a battery of measures predictive of high risk for PPCS, which will allow for identification and testing of interventions to prevent PPCS in the most high-risk youth.

Soccer, one of the most popular sports in the world, has one of the highest rates of sports-related concussions. Additionally, soccer players are frequently exposed to nonconcussive impacts from intentionally heading the ball, a fundamental component of the sport. There have been many studies on head impact exposure in soccer, but few focus on soccer practices or practice activities. This study aimed to characterize the frequency and magnitude of head impacts in National Collegiate Athletic Association Division I female soccer practice activities using a custom-fit instrumented mouthpiece. Sixteen players were instrumented over the course of 54 practice sessions. Video analysis was performed to verify all mouthpiece-recorded events and classify practice activities. Category groupings of practice activities include technical training, team interaction, set pieces, position-specific, and other. Differences in head impact rates and peak resultant kinematics were observed across activity types and category groupings. Technical training had the highest impact rate compared to other category groupings. Impacts occurring during set piece activities had the highest mean kinematic values. Understanding drill exposure can help inform coaches on training plans aimed to reduce head impact exposure for their athletes.

Abstract Objective The objective of this study was to utilize an instrumented mouthpiece sensor to characterize head kinematics experienced by grassroots dirt track race car drivers. Methods Four dirt track race car drivers (ages 16–19) were instrumented with custom mouthpiece sensors capable of accurately measuring head motion during racing. Sensors were deployed before races and recorded tri-axial linear acceleration and rotational velocity for approximately 10 min at 200 Hz. Film review was performed to identify data associated with racing laps. For each lap, moving average kinematics were computed and subtracted from the head motion signals to obtain ‘adjusted’ head motion accounting for lower frequency variance due to periodic motion around the track. From adjusted data, linear and angular head perturbations (i.e., deviations from moving average) were extracted using a custom algorithm. Results Data was collected during 400 driver-races. A total of 2438 laps were segmented from mouthpiece recordings. The median (95th percentile) peak linear acceleration, rotational velocity, and rotational acceleration of all laps were 5.33 (8.28) g, 2.89 (4.60) rad/s, and 179 (310) rad/s2, respectively. Angular perturbations occurred most frequently about the anterior-posterior axis (median lap frequency = 6.39 Hz); whereas linear perturbations occurred most frequently in the inferior-superior direction (7.96 Hz). Nine crash events were recorded by the mouthpiece sensors. The median (95th percentile) peak head kinematics of these events were 13.4 (36.6) g, 9.67 (21.9) rad/s, and 630 (1330) rad/s2. Conclusions Mouthpiece sensors can be used to measure head kinematics during active racing. Laps, head perturbations, and crashes may be useful units of observation to describe typical head kinematic exposure experienced by drivers while racing. Subsequent research is needed to understand the associations between repetitive racing exposure and neurological function. Higher magnitude events (i.e., crashes) are not uncommon and may result in concussion or more severe injury. Results represent novel characterizations of head kinematic exposure experienced in a dirt track racing environment. This information may inform evidence-based strategies (e.g., vehicle/seat design) to improve driver safety.

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.

This study evaluated head impact exposure (HIE) metrics in relation to individual-level determinants of HIE. Youth (n = 13) and high school (n = 21) football players were instrumented with the Head Impact Telemetry (HIT) system during one season. Players completed the Trait-Robustness of Self-Confidence Inventory (TROSCI), Sports Climate Questionnaire (SCQ), and Competitive Aggressiveness and Anger Scale (CAAS), measuring self-confidence, perceived coach support, and competitive aggressiveness, respectively. Relationships between HIE metrics (number of impacts, median and 95th percentile accelerations, and risk-weighted exposure (RWE)) and survey scores were evaluated using linear regression analysis. For middle school athletes, TROSCI scores were significantly negatively associated with the number of competition impacts and the mean number of impacts per player per competition. SCQ scores were significantly positively associated with median linear acceleration during practice. CAAS scores were not significantly associated with biomechanical metrics at either level of play. Perceived coach support and self-confidence might influence HIE among middle school football players. Football athletes' competitive aggressiveness may have less influence their HIE than other factors.

Although most head impacts in soccer are headers, limited knowledge exists about how header magnitude varies by on-field scenario. This study aimed to compare head kinematics during on-field headers by play state (i.e., corner kick, goal kick, free kick, throw-in, drill, or live ball), intent (i.e., pass, shot, or clearance), and outcome (i. e., successful or unsuccessful). Fifteen female collegiate soccer players were instrumented with mouthpiece-based head impact sensors during 72 practices and 24 games. A total of 336 headers were verified and contextualized via film review. Play state was associated with peak linear acceleration, rotational acceleration, and rotational velocity (all p < .001) while outcome was associated with peak linear acceleration (p < .010). Header intent was not significantly associated with any kinematic metric. Headers during corner kicks (22.9 g, 2189.3 rad/s(2), 9.87 rad/s), goal kicks (24.3 g, 2658.9 rad/s(2), 10.1 rad/s), free kicks (18.0 g, 1843.3 rad/s(2), 8.43 rad/s), and live balls (18.8 g, 1769.7 rad/s(2), 8.09 rad/s) each had significantly greater mean peak linear acceleration (all p < .050), rotational acceleration (all p < .001), and rotational velocity (all p < .001) than headers during drills (13.0 g, 982.4 rad/s(2), 5.28 rad/s). Headers during goal kicks also had a significantly greater mean rotational acceleration compared to headers during live ball scenarios (p < .050). Successful headers (18.3 g) had a greater mean peak linear acceleration compared to unsuccessful headers (13.8 g; p < .010). Results may help inform efforts to reduce head impact exposure in soccer.

BACKGROUND Although children 10-17 years can be hired to work in agriculture, little research has addressed possible musculoskeletal injuries. Children may be at particular risk for these injuries because of the repetitive and load bearing nature of work tasks. Existing research relies on child workers to self-report musculoskeletal injuries. METHODS In 2017, 202 Latinx child farmworkers ages 10-17 employed across North Carolina completed survey interviews. In 2018, 145 of these children (94 [64.8%] current farmworkers) completed a physical examination and second interview. The examination obtained findings for upper and lower extremity as well as back injuries. RESULTS Positive indicators for musculoskeletal symptoms were few in either current or former child farmworkers. The knee was most common site for positive indicators with 15.4% of children having at least one. Combining all anatomical sites, 29.0% of children had at least one positive indicator, with no significant difference between current and former farmworkers. Overall, boys had significantly more indicators of knee injuries than girls (21.3% vs. 4.1%), indicators of ankle injuries were found only in the youngest workers (9.5% of children 11-13 years), and significantly fewer current farmworkers had indicators of lower back injuries than former farmworkers (6.4% vs. 17.7%). CONCLUSIONS Expectations of injuries come from previous studies using child farmworker self-reports, adult farmworker injury rates, and sports medicine pediatric findings. Hired child farmworkers may not perform activities as repetitious and load-bearing as children in sports training or adult farmworkers. Additional research using physical examination is needed to confirm these findings.