Objectives Motorcycle helmet laws vary by state, with Kentucky requiring helmets only for younger riders. We hypothesized that motorcyclists injured in Kentucky and seen at a Tennessee trauma center would be more likely to be unhelmeted, have more severe head injuries, and sustain more fatal injuries than those injured in Tennessee or Virginia. Methods A Trauma Registry review of 729 injured motorcyclists from January 2005 through June 2015 examined state location of crash, demographics, helmet use, and clinical outcomes. Multivariate logistic regression analysis evaluated predictors for head injury severity and death. Results Unhelmeted motorcycle rider status predicted more severe head injuries (relative risk 15.3, P < 0.001) and death (relative risk 4.2, P < 0.001). Motorcyclists injured in the state of Kentucky were more likely to be unhelmeted, require an operative procedure, have more severe head injuries, have longer lengths of stay, and sustain more fatal injuries (all with < 0.001) than motorcyclists injured in Tennessee or Virginia. Conclusions This study lends support for maintaining and enforcing current universal motorcycle helmet laws for all ages in states where they are in effect and for upgrading helmet laws that apply only to some riders.

No description available.

Background: Unhelmeted motorcyclists injured in states with lax or poorly enforced helmet safety laws are frequently seen in rural trauma centers. A trauma surgeon started a comprehensive injury prevention and research fund with outreach to a three-state trauma center catchment area promoting injury prevention at area high schools and local communities. We hypothesized that unhelmeted riders would have more severe head injuries and fatalities than helmeted riders. Methods: A trauma registry review of 708 injured motorcycle riders over an 11-year period examined demographics, helmet use, and clinical outcomes of helmeted and unhelmeted riders. A full-time injury prevention coordinator collaborating with law enforcement provided electronic and mechanical simulations with discussions regarding helmet use, alcohol avoidance, and responsible motorcycle riding for area high school students. This program coincided with the second half of our 11-year study. Multiple regression analysis evaluated predictors for head injury and death. Results: Unhelmeted motorcyclists suffered worse head injuries, (OR 8.8, CI 1.6-2.4, P <.001), more severe overall injury (OR 10, CI 12.7-18.6, P <.001), and higher mortality (OR 2.7, CI.02-.15, P <.001). Local motorcycle-related trauma center admissions and deaths have stabilized in recent years while statewide motorcycle crashes have increased (P <.05). Discussion: Unhelmeted motorcyclists suffer worse head injuries and mortality rates. Physician-led outreach efforts for injury prevention may be effective. Trauma surgeons have ongoing opportunities to promote responsible motorcycle riding for schools and local communities.

The purpose of this research was to identify the design characteristics and attitudes that impact the use of snowboarding helmets and to test statistically a proposed conceptual framework for identifying perceived importance of functional, expressive, aesthetic, and regulatory (FEAR) needs of snowboarding helmets for current snowboarders. Data for this study was collected online. The final sample was composed of 391 participants, which represented a 13.67% response rate. Multiple comparisons were used to examine mean differences among the FEAR variables, as well as attitudes toward helmet use. A multiple linear regression was used to test four proposed hypotheses. The results of hypotheses revealed that there was an impact between attitudes toward helmet use and perceived importance of functional needs, but this relationship depended on the level of expressive needs, aesthetic needs, and helmet usage. The typical impact of functional needs on attitudes toward helmet use was positive (slope = .013) when all variables were at their respective means (Hypothesis 1). Hypothesis 2 tested to see if there was an impact between attitudes toward helmet use and perceived importance of expressive needs, but again, this relationship depended on the level of functional needs and helmet usage. The typical impact of expressive needs on attitudes toward helmet use was positive (slope = .014) when all variables were at their respective means. Similarly, the impact between attitudes toward helmet use and the perceived importance of aesthetic needs was dependent on the level of functional needs and helmet usage. The impact of aesthetic needs on attitudes toward helmet use was typically negative (slope = -.012) when all variables were at their respective means (Hypothesis 3). Finally, Hypothesis 4 looked at the impact between attitudes toward helmet use and the perceived importance of regulatory needs. Unlike the other three hypotheses, this relationship did not depend on any other variables. The impact of regulatory needs on attitudes toward helmet use was positive, and the strength of association was .010. Although hypothesis 1-3 were substantially supported, and hypothesis 4 was fully supported, from a statistical point of view, the interaction effects between the independent variables (i.e., FEA needs) and the covariate (i.e., helmet usage) limit the findings, so we can not really state that the hypotheses were supported. However, based on information obtained from the respondents in this study, the application of a FEAR needs assessment of snowboarding helmets could help to enhance the overall performance of snowboarders. In other words, the improvement of helmet functionality, expressive qualities, aesthetic attributes and regulatory needs would provide a more enjoyable snow activity to participants. Thus, the conceptual framework of the perceived importance of FEAR needs would be acceptable to understand the attitudes toward helmet use among snowboarders. / Ph. D.

Cycling is an increasingly popular mode of transportation and a preferred form of exercise worldwide. From 1990 to 2015, commuting via bicycle increased as much as four-fold in cities across North America and Europe. However, this increase in cycling is associated with an increase in cycling related fatalities and head injuries. The best way to prevent severe head injury while cycling is to wear a bike helmet. Bike helmets are designed to decrease the linear acceleration of the head, decreasing the rider's risk of severe head injuries, such as skull fracture. In order to sell a bike helmet, it must meet a minimum standard of protection based on linear acceleration of the head upon impact. However, bike helmet impacts are not completely linear in nature and experience a tangential component through angled impacts of the helmet, resulting in rotational accelerations and shear-strain at the skull-brain interface. This strain cause brain injuries such as concussion. Therefore, recent helmet advancements have aimed to decrease rotational acceleration of the head. To continue the advancement of helmet technology and the subsequent decrease of brain injury risk to riders, investigating the impact conditions of real-world impacts is pertinent. This thesis aimed to increase the current body of knowledge of cycling related head impacts. The first aim was to quantify real-world impact locations and analyze how impact location may influence helmet performance. The second aim of this thesis was to investigate the impact velocities and resulting kinematics of real-world crashes based on the magnitude of corresponding damage conditions. Additionally, this aim analyzed the impact conditions from cases which resulted in concussion. Together these studies aim to provide valuable real-world data to be used for the advancement of helmet technologies and design. / Master of Science / Cycling is an increasingly popular mode of transportation and a preferred form of exercise worldwide. From 1990 to 2015, commuting via bicycle increased as much as four-fold in cities across North America and Europe. However, this increase in cycling is associated with an increase in cycling related fatalities and head injuries. The best way to prevent severe head injury while cycling is to wear a bike helmet. Bike helmets are designed to decrease the linear acceleration of the head, decreasing the rider's risk of severe head injuries, such as skull fracture. In order to sell a bike helmet, it must meet a minimum standard of protection based on linear acceleration of the head upon impact. However, bike helmet impacts are not completely linear in nature and experience a tangential component through angled impacts of the helmet, resulting in rotational accelerations and shear-strain at the skull-brain interface. This strain cause brain injuries such as concussion. Therefore, recent helmet advancements have aimed to decrease rotational acceleration of the head. To continue the advancement of helmet technology and the subsequent decrease of brain injury risk to riders, investigating the impact conditions of real-world impacts is pertinent. This thesis aimed to increase the current body of knowledge of cycling related head impacts. The first aim was to quantify real-world impact locations and analyze how impact location may influence helmet performance. The second aim of this thesis was to investigate the impact velocities and resulting kinematics of real-world crashes based on the magnitude of corresponding damage conditions. Additionally, this aim analyzed the impact conditions from cases which resulted in concussion. Together these studies aim to provide valuable real-world data to be used for the advancement of helmet technologies and design.

The studies presented in this dissertation investigated biomechanical factors associated with sports-related brain injuries on the field and in the laboratory. In the first study, head impact exposure in youth football was observed using a helmet mounted accelerometer system to measure head kinematics. The results suggest that restriction on contact in practice at the youth level can translate into reduced head impact exposure over the course of a season. A second study investigated the effect of measurement error in the head impact kinematic data collected by the helmet mounted system have on subsequent analyses. The objective of this study was to characterize the propagation of random measurement error through data analyses by quantifying descriptive statistic uncertainties and biases for biomechanical datasets with random measurement error. For distribution analyses, uncertainties tend to decrease as sample sizes grow such that for a typical player, the uncertainties would be around 5% for peak linear acceleration and 10% for peak angular (rotational) acceleration. The third and fourth studies looked at comparisons between two headforms commonly used in athletic helmet testing, the Hybrid III and NOCSAE headforms. One study compared the headform shape, particularly looking at regions that are likely to affect helmet fit. Major differences were found at the nape of the neck and in the check/jaw regions that may contribute to difficulty with fitting a helmet to the Hybrid III headform. For the final study, the impact responses of the two headforms were compared. Both headforms were mounted on a Hybrid III neck and impacted at various magnitudes and locations that are representative of impacts observed on the football field. Some condition-specific differences in kinematic parameters were found between the two headforms though they tended to be small. Both headforms showed reasonable repeatability. / Ph. D.

The research presented in this thesis aims to improve the knowledge of head impact biomechanics in youth football players by analyzing head impact exposure of youth football players and the performance of youth football helmets. The results of the studies presented provide a foundation for researchers, football leagues, and helmet manufactures to implement changes and modifications that aim to reduce concussion risk in youth athletes. The first study presented in this thesis aims to quantify the head impact exposure of 7 to 8 year old football players and determine the cause of variation in player exposure. To conduct this study, 19 players were instrumented with helmet mounted accelerometers that measured real-time acceleration data on the field. This data was analyzed to determine the magnitude, frequency, and location of each impact sustained by players in the 2011 and 2012 football season. From these data, it was determined that the average 7 to 8 year old player experienced 161 impacts per season, 60% of which were in practice and 40% were in games. The median impact for 7 to 8 year old players was 16 g and 686 rad/s². The magnitude of the 95th percentile impact was 38 g and 2052 rad/s². A total of 125 impacts above 40 g were recorded, 67% of which occurred in practices and 33% occurred in games. It was determined that returning players experienced significantly more impacts per season than first time players and practices had significantly higher magnitude impacts than games. These data can be used to further develop practice modifications that aim to reduce total impacts and high magnitude impacts experienced by youth football players. The second study presented in this thesis aims to quantify differences in youth football helmet performance before and after a football season. Currently, the only requirement regarding helmet recertification and reconditioning states that no helmet older than 10 years will be recertified or reconditioned. Quantitative data is needed to either support or refute this guideline and provide data describing how often youth football helmets should be recertified and reconditioned. To conduct this study, 6 youth Riddell Revolution football helmets, 3 that were new and 3 that had been used for one season, were tested on a drop tower from various heights and impact locations before and after the 2013 football season. It was determined that there was no significant difference in helmet performance before and after a season for new helmets or helmets that had been used for one season. In addition, there was no significant correlation between the frequency of impacts, the 95th percentile impact magnitude, or the product of the frequency and 95th percentile impact magnitude with the change in helmet performance. Future studies should be conducted that analyze the performance of youth football helmets over the course of multiple seasons. / Master of Science

Youth and varsity football helmets are currently designed similarly and tested to the same impact standards from the National Operating Committee on Standards for Athletic Equipment (NOCSAE). Youth players have differences in anthropometry, physiology, impact exposure, and potentially injury tolerance that should be considered in future youth-specific helmets and standards. This thesis begins by investigating the current standards and relating them to on-field data. The standard drop tests represented the most severe on-field impacts, and the performance of the youth and varsity helmet did not differ. There likely is not a need for a youth-specific standard as the current standard has essentially eliminated the catastrophic head injuries it tests for. As more is known about concussion, standards specific to the youth population can be developed. The second portion of this thesis compares the impact performance between 8 matched youth and varsity helmet models, using linear acceleration, rotational acceleration, and concussion correlate. It was found that helmet performance did not differ between the youth and varsity helmets, likely attributed to testing to the same standard. The final portion of this feature is aimed at advancing STAR for youth and varsity football helmets by including linear and rotational head kinematics. For varsity helmets, an adult surrogate is used for impact tests which are weighted based on on-field data collected from collegiate football players. For youth helmets, a youth surrogate is used and tests are weighted based on data collected from youth players. / Master of Science

When football originated in the 1800s, players wore no protective equipment. Between 1869 and 1905, there were 18 deaths and 159 serious injuries attributed to the sport. Following this, players began to wear protective equipment. The first use of a football helmet was in 1893, made of leather and designed to reduce the risk of skull fracture. Initially, football helmets were intended to protect a player against the most severe hits they would experience on the field. More recently, it has been shown that mild traumatic brain injuries, such as concussions, can induce long-term neurodegenerative processes. Since their introduction, helmets have transformed into plastic shells with padding designed to mitigate accelerations on the brain. With the growing concern for player safety, regulating bodies, like the National Operating Committee on Standards for Athletic Equipment, have implemented standards for protective equipment, including football helmets. On top of these standards, there have been multiple methods developed to assess helmet performance with different testing apparatuses. Manufacturers are interested in how their helmet performs according to multiple testing methods. This could be costly if they do not have the proper testing equipment that a protocol utilizes. This thesis assesses the interchangeability of different test equipment to reproduce a testing protocol. The desire to perform well in testing standards has driven the improvement of helmet performance and continued design innovation. The second aim of this thesis is to evaluate helmet performance and its relationship with design changes in football helmets manufactured between 1980 and 2018. / Master of Science / When football originated in the 1800s, players wore no protective equipment. Between 1869 and 1905, there were 18 deaths and 159 serious injuries attributed to the sport. Following this, players began to wear protective equipment. The first use of a football helmet was in 1893, made of leather and designed to reduce the risk of skull fracture. Initially, football helmets were intended to protect a player against the most severe hits they would experience on the field. More recently, it has been shown that mild traumatic brain injuries, such as concussions, can induce long-term neurodegenerative processes. Since their introduction, helmets have transformed into plastic shells with padding designed to mitigate accelerations on the brain. With the growing concern for player safety, regulating bodies, like the National Operating Committee on Standards for Athletic Equipment, have implemented standards for protective equipment, including football helmets. On top of these standards, there have been multiple methods developed to assess helmet performance with different testing apparatuses. Manufacturers are interested in how their helmet performs according to multiple testing methods. This could be costly if they do not have the proper testing equipment that a protocol utilizes. This thesis assesses the interchangeability of different test equipment to reproduce a testing protocol. The desire to perform well in testing standards has driven the improvement of helmet performance and continued design innovation. Another aim of this thesis is to evaluate helmet performance and its relationship with design changes in football helmets manufactured between 1980 and 2018.

The research presented in the thesis explores the biomechanics of the head and neck during impacts in football. The research related to the head is geared towards advancing the current understanding of the mechanisms of mild traumatic brain injury, specifically by investigating head accelerations experienced by football players during impacts. To do this, a six degree of freedom sensor that could be integrated into existing football helmets and is capable of measuring linear and angular acceleration about each axis of the head was developed and validated. This sensor was then installed in the helmets of 10 Virginia Tech football players and data was recorded for every game and practice during the 2007 football season. A total 1712 impacts were recorded, creating a large and unbiased dataset. No instrumented player sustained a concussion during the 2007 season. From 2007 head acceleration dataset, 24 of the most severe impacts were modeled using a finite element head model, SIMon (Simulated Injury Monitor). Besides looking at head acceleration, the force transmitted to the mandible by chin straps in football helmets was investigated through impact testing. Little research has been conducted looking at the mandible-chin strap interface in the helmet, and this may be an area of helmet design that can be improved. The research presented in this thesis related to the neck is based on stingers. Football players wear neck collars to prevent stingers; however, their designs are largely based on empirical data, with little biomechanical testing. The load limiting capabilities of various neck collars were investigated through dynamic impact testing with anthropomorphic test devices. It was found that reductions in loads correlate with the degree to which each collar restricted motion of the head and neck. To investigate the differences in results that using different anthropomorphic test devices may present, the matched neck collar tests were performed with the Hybrid III and THOR-NT 50th percentile male dummies. The dummies exhibited the same trends, in that either a load was reduced or increased; however, each load was affected to a different degree. / Master of Science