Baseline vulnerable road user injury risk in multiple U.S. dense urban driving environments.

Objective: Understanding and modeling baseline driving safety risk in dense urban areas represents a crucial starting point for automated driving system (ADS) safety impact analysis. The purpose of this study was to leverage naturalistic vulnerable road user (VRU) collision data to quantify collision rates, crash severity, and injury risk distributions in the absence of objective injury outcome data.

Methods: From over 500 million vehicle miles traveled, a total of 335 collision events involving VRUs were video verified and reconstructed (126 pedestrians, 144 cyclists, and 65 motorcyclists).

Bridging the gap: Mechanistic-based cyclist injury risk curves using two decades of crash data.

Objective: Injury risk curves are vital in quantifying the relative safety consequences of real-world collisions. Previous injury risk curves for bicycle-passenger vehicle crashes have predominantly focused on frontal impacts. This creates a gap in cyclist injury risk assessment for other geometric crash configurations.

Passenger and heavy vehicle collisions with pedestrians: Assessment of injury mechanisms and risk.

Objective: Automated Driving System (ADS) fleets are currently being deployed in several dense-urban operational design domains within the United States. In these dense-urban areas, pedestrians have historically comprised a significant portion, and sometimes the majority, of injury and fatal collisions. An expanded understanding of the injury risk in collision events involving pedestrians and human-driven vehicles can inform continued ADS development and safety benefits evaluation.

Head Impact Exposure in Youth and Collegiate American Football.

The relationship between head impact and subsequent brain injury for American football players is not well-defined, especially for youth. The objective of this study is to quantify and assess Head Impact Exposure (HIE) metrics among youth and collegiate football players. This multi-season study enrolled 639 unique athletes (354 collegiate; 285 youth, ages 9-14), recording 476,209 head impacts (367,337 collegiate; 108,872 youth) over 971 sessions (480 collegiate; 491 youth).

Relating on-field youth football head impacts to pneumatic ram laboratory testing procedures.

A youth-specific football helmet testing standard has been proposed to address the physical and biomechanical differences between adult and youth football players. This study sought to relate the proposed youth standard-defined laboratory impacts to on-field head impacts collected from youth football players. Head impact data from 112 youth football players (ages 9-14) were collected through the use of helmet-mounted accelerometer arrays.

RELIABILITY OF CENTER OF PRESSURE-BASED MEASURES DURING DUAL-TASK POSTURAL CONTROL TESTING IN A YOUTH POPULATION.

Background: Dual-task assessments can identify changes in postural control during recovery from a concussion. However, developing postural control in children presents a challenge when using adult balance assessments to examine children.

Purpose: The purpose of this study was to investigate the reliability of a cognitive dual-task postural control testing protocol among a youth sample with no history of concussion or exposure to head impacts.

Concussion Risk Between Individual Football Players: Survival Analysis of Recurrent Events and Non-events.

Concussion tolerance and head impact exposure are highly variable among football players. Recent findings highlight that head impact data analyses need to be performed at the subject level. In this paper, we describe a method of characterizing concussion risk between individuals using a new survival analysis technique developed with real-world head impact data in mind.

Neuropsychological Change After a Single Season of Head Impact Exposure in Youth Football.

Objectives: Head impact exposure (HIE) in youth football is a public health concern. The objective of this study was to determine if one season of HIE in youth football was related to cognitive changes.

Method: Over 200 participants (ages 9-13) wore instrumented helmets for practices and games to measure the amount of HIE sustained over one season.

Quantifying Youth Football Helmet Performance: Assessing Linear and Rotational Head Acceleration.

Youth football helmet testing standards have served to largely eliminate catastrophic head injury from the sport. These standards, though, do not presently consider concussion and do not offer consumers the capacity to differentiate the impact performance of youth football helmets. This study adapted the previously developed Summation of Tests for the Analysis of Risk (STAR) equation for youth football helmet assessment.

Psychometric properties of the standardized assessment of concussion in youth football: Validity, reliability, and demographic factors.

The objective of this study was to determine the psychometrics (reliability, validity) of the original Standardized Assessment of Concussion (SAC) in a youth sample (ages 11 to 13). Demographic factors of race, level of vocabulary knowledge, mother's level of education were also considered. Over 150 youth football athletes completed the SAC and a brief battery of NIH Toolbox cognitive tests as part of a larger study on biomechanical factors in youth sport concussion.

Do American Youth Football Players Intentionally Use Their Heads for High-Magnitude Impacts?

Background: Concern for head injuries is widespread and has been reported by the media to be the number one cause of decreased participation in football among the American youth population. Identifying player mechanisms associated with intentional, or purposeful, head impacts should provide critical data for rule modifications, educational programs, and equipment design.

Purpose: To investigate the frequency of intentional and unintentional head impacts and to examine the player mechanisms associated with intentional high-magnitude head impacts by comparing the impact mechanism distributions among session type, player position, and ball possession.

Development of a Concussion Risk Function for a Youth Population Using Head Linear and Rotational Acceleration.

Physical differences between youth and adults, which include incomplete myelination, limited neck muscle development, and a higher head-body ratio in the youth population, likely contribute towards the increased susceptibility of youth to concussion. Previous research efforts have considered the biomechanics of concussion for adult populations, but these known age-related differences highlight the necessity of quantifying the risk of concussion for a youth population. This study adapted the previously developed Generalized Acceleration Model for Brian Injury Threshold (GAMBIT) that combines linear and rotational head acceleration to model the risk of concussion for a youth population with the Generalized Acceleration Model for Concussion in Youth (GAM-CY).

Relationship between Impact Velocity and Resulting Head Accelerations during Head Impacts in Youth Football.

Football helmet testing standards for youth players make use of the same testing protocol for adult helmets despite research showing differences in head impact exposure between these populations. The objective of this study was to pair estimated impact velocities with linear acceleration data collected from on-field head impacts in youth football to inform youth-specific helmet testing methods. A total of 49 youth football players received helmets instrumented with accelerometer arrays to measure head acceleration throughout the season.

Accounting for Variance in Concussion Tolerance Between Individuals: Comparing Head Accelerations Between Concussed and Physically Matched Control Subjects.

Researchers have been collecting head impact data from instrumented football players to characterize the biomechanics of concussion for the past 15 years, yet the link between biomechanical input and clinical outcome is still not well understood. We have previously shown that even though concussive biomechanics might be unremarkable in large datasets of head impacts, the impacts causing injury are of high magnitude for the concussed individuals relative to their impact history. This finding suggests a need to account for differences in tolerance at the individual level.

Factors Affecting Head Impact Exposure in College Football Practices: A Multi-Institutional Study.

Biomechanical data collected from head impacts in football have been used to characterize exposure and predict injury risk. This study sought to specifically quantify the factors that contribute towards player head impact exposure in college football practices. All players included in this study were outfitted with football helmets instrumented with accelerometer arrays (Head Impact Telemetry System).

Are specific players more likely to be involved in high-magnitude head impacts in youth football?

Objective: Youth football attracts approximately 3.5 million participants every year, but concern has recently arisen about the long-term effects of experiencing repetitive head accelerations from a young age due to participation in football. The objective of this study was to quantify total involvement in high-magnitude impacts among individual players in youth football practices.

THE EFFECT OF COACHING AND PLAYER POSITION ON HEAD IMPACT EXPOSURE IN YOUTH FOOTBALL PLAYERS.

Youth football players comprise almost 70% of the football playing population, and the ongoing development of these athletes makes the understanding of concussions and repetitive head impact exposure in this population of particular concern. The objective of this study was to determine how player position and coaching influence head impact exposure in youth football players while controlling for player age. This analysis focused on a cohort of 45 youth football players between the ages of 9 and 14 that had helmets instrumented with accelerometer arrays for at least two seasons.

Head Impact Exposure in Practices Correlates With Exposure in Games for Youth Football Players.

This study aimed to compare head impact exposures between practices and games in football players ages 9 to 14 years, who account for approximately 70% of all football players in the United States. Over a period of 2 seasons, 136 players were enrolled from 3 youth programs, and 49,847 head impacts were recorded from 345 practices and 137 games. During the study, individual players sustained a median of 211 impacts per season, with a maximum of 1226 impacts.

ASSOCIATION BETWEEN TACKLING TECHNIQUE AND HEAD ACCELERATION MAGNITUDE IN YOUTH FOOTBALL PLAYERS.

In order to address concerns about head injury in youth sports, a number of youth football organizations have developed rules and recommendations surrounding the tackling form which should be used in order to reduce unnecessary head impact exposure. Reduction in injury has been suggested with these programs, but association between tackling form and head acceleration magnitude has not been studied previously. To address this knowledge gap, grading criteria were developed from multiple youth organizations' recommendations for a collision.

ASSESSING STATIC AND DYNAMIC POSTURAL CONTROL IN A HEALTHY POPULATION.

Static postural control testing is often conducted by clinicians and athletic trainers for use with athletes who have sustained a concussion. Dynamic postural control involves the body's response to perturbation of the center of mass and may offer additional insight that static testing cannot capture. The objective of this study was to assess the reliability and feasibility of a balance protocol consisting of both static and dynamic postural control assessments with a healthy, adult population.

EFFECTS OF A SEASON OF YOUTH FOOTBALL ON STATIC POSTURAL CONTROL.

Concussions occur in youth football with lower frequency than observed at higher levels of play, though the effect of repetitive subconcussive head impacts resulting from participation in youth football is unknown at this point. One measure shown to be affected by concussions is athlete postural control. The objective of this study was to compare performance on the Balance Error Scoring System (BESS) and a force plate protocol at two time points within a cohort of healthy youth football players and healthy non-contact youth track or baseball athletes.

Football helmet impact standards in relation to on-field impacts.

Youth football helmets currently undergo the same impact testing and must satisfy the same criteria as varsity helmets, although youth football players differ from their adult counterparts in anthropometry, physiology, and impact exposure. This study aimed to relate football helmet standards testing to on-field head impact magnitudes for youth and varsity football helmets. Head impact data, filtered to include only impacts to locations in the current National Operating Committee on Standards for Athletic Equipment standard, were collected for 48 collegiate players (ages 18-23 years) and 25 youth players (ages 9-11 years) using helmet-mounted accelerometer arrays.

Postural Control and Head Impact Exposure in Youth Football Players: Comparison of the Balance Error Scoring System and a Force Plate Protocol.

Postural control testing is often used by clinicians and athletic trainers to assess the health of athletes during recovery from a concussion. Characterization of postural control as a clinical tool for use with youth athletes is limited though. The objective of this study was to compare performance on the Balance Error Scoring System (BESS) and a force plate protocol at the beginning and end of a season of football within a cohort of 34 healthy youth football players (average age of 9.

High-magnitude head impact exposure in youth football.

OBJECTIVE Even in the absence of a clinically diagnosed concussion, research suggests that neurocognitive changes may develop in football players as a result of frequent head impacts that occur during football games and practices. The objectives of this study were to determine the specific situations in which high-magnitude impacts (accelerations exceeding 40 g) occur in youth football games and practices and to assess how representative practice activities are of games with regard to high-magnitude head impact exposure. METHODS A total of 45 players (mean age 10.

Ranges of Injury Risk Associated with Impact from Unmanned Aircraft Systems.

Regulations have allowed for increased unmanned aircraft systems (UAS) operations over the last decade, yet operations over people are still not permitted. The objective of this study was to estimate the range of injury risks to humans due to UAS impact. Three commercially-available UAS models that varied in mass (1.