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The rate of concussion in women’s lacrosse is alarmingly high despite the sport being non-contact. Conflicting opinions on the potential effectiveness of helmet use in the sport led to the development of an ASTM standard in 2015 for optional headgear. These headgears are unique to most other head protection in that they do not have a hard outer shell because it could endanger players that choose not to wear the optional headgear. Because these headgears are so new and have unique design constraints, there is still much to learn about their ability to protect the players wearing them. The purpose of this research was to determine the impact mitigation properties of two commercially available women’s lacrosse headgears (the Cascade LX and the Hummingbird v2) across a variety of impact types and severities and to incorporate rotational velocity kinematic concussion metrics in impact analysis because of their correlation to brain strains. Because polymers that are commonly used in sports headgears have been shown to exhibit cold temperature hardening, the influence of cold temperatures on the ability of the headgears to mitigate impacts was also studied. Linear impactor and ball impact testing was performed on ambient and cold conditioned headgears. The kinematic concussion metrics peak linear acceleration (PLA), peak rotational acceleration (PRA), peak rotational velocity (PRV), head injury criterion (HIC15), and brain injury criterion (BrIC) were calculated for each impact. Results showed that both headgears were able to significantly reduce all five metrics, but that this reduction was much more subtle for the two rotational velocity metrics (PRV and BrIC). Cold conditioning did not have significant effects on the headgears’ ability to mitigate impacts. Materials that were used in the headgears were then tested in compression at various strain rates and at ambient and cold temperatures to acquire their mechanical characterizations. These characterizations can be used in future finite element analysis studies to more accurately investigate how the headgears are able to protect against concussions through brain strain analysis and to study how much they may endanger other players that are not wearing headgear.

The Mouthguard pilot program is unique because it aims to: (1) provide health education regarding sports dental injury and discuss behaviors to increase wear; (2) how to properly wear and care for their mouth guards; and (3) provide free custom mouthguards to high school athletes who participate in high impact sports ranging from ages 12-19 to prevent facial sports injury. Mouthguard pilot program participants (N= 100) are recruited through relationships with athletic directors within Flint Area Schools.

This dissertation applies tools from health services research to the college sports medicine context. The first two papers analyze a sample survey of college football players, asking questions about individual-level risk perceptions and injury reporting. The third paper evaluates a novel combined data set and evaluates institutional-level modifiers of athlete injury outcomes. Together these papers provide important evidence about individual, institutional, and ethical considerations of risk in college sport. Chapter one describes features of athletes’ concussion and injury reporting tendencies. Using original survey data from a cohort of college football players, we evaluate two assumptions of the current literature on concussion reporting. First, we assess whether athletes make reasoned deliberative decisions about whether to report their concussion or other injury. Second, we investigate whether the probability of reporting a concussion or injury is independent of where it occurs in the sequence of injuries experienced. Descriptively, we find that athletes are much less likely to report a concussion to a medical professional than they are to report another injury. We also find a much lower rate of concussion reporting in this study compared to the previous literature. There is no association between concussion or injury reporting behaviors and one measure of athletes’ ability to switch between fast reactive thinking to reasoned deliberative thinking. We do find significant variation in athletes’ injury and concussion reporting over the sequence of injuries. While the likelihood to report decreases for both injury and concussion, there is a notable decrease in the probability of reporting around four concussions, a cutoff that sports medicine clinicians may use as an occasion to discuss curtailing sports participation. Sports medicine clinicians may need to consider athlete injury history as a risk factor for concussion under-reporting. Chapter two compares athletes’ perceptions of the risks of sports participation to an estimate of their actual risk. Using primary survey data of a cohort of football players from the most competitive sub-division of college football, we model athletes’ single-season risk of injury and of concussion and compare these to their perceptions of these risks. Across many measures, we find a significant proportion of athletes underestimate their risk of concussion specifically and injury overall. In the context of the modern debate around the risks of football, this has significant implications for advocates of an informed-consent approach to participation. Chapter three describes the relationship between access to clinicians and injury outcomes in the context of college athletics. Using a novel combined dataset including injury and exposure data from the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP), sports medicine staffing data from NCAA Research, and athletic department characteristics from the United States Department of Education Equity in Athletics data, we evaluate whether the average number of clinicians per athlete at a college, is associated with rates of injury, reinjury, time loss to injury, and concussion. We also evaluate whether schools that voluntarily contribute data to the NCAA ISP differ from non-contributing schools in observable ways. We find a significant inverse relationship between number of clinicians per athlete and rates of injury, rates of reinjury, and rates of concussion, with schools one standard deviation above average in their number of clinicians per athlete having 9.5%, 2.7%, and 6.7%, fewer injuries respectively. We find a significant positive correlation between clinicians per athlete and time loss to injury, with schools one standard deviation above average in their number of clinicians per athlete having 16% greater time loss on average. Although these reductions in injury rates are relatively modest, the large number of college athletes means that the absolute reduction in injury that could be achieved is meaningful. For example, a 9.5% reduction in injury extrapolated to the NCAA context more broadly would equate to 3,165 fewer athlete injuries occurring annually. Schools that contribute data to the NCAA ISP tend to have more athletes, more clinicians per athlete, greater athletic department revenues and are more skewed toward Division I than non-contributing schools, reducing generalizability of these and other NCAA ISP findings. This study supports the idea that improving staffing in college sports medicine departments would improve athlete health and wellbeing by reducing rates of injury.

Abstract: Psychological factors have been shown to play a role in the frequency and severity of injury among athletes. The Behaviour Assessment System for Children Second Edition (BASC-II) was utilized to measure sixteen psychological factors and determine whether these factors predicted rate and severity of total injury and concussion versus musculoskeletal (MSK) injuries. Participants included male Bantam and Midget level ice hockey players (n=524). Participants completed the BASC-II at baseline and post injury. Injury records were completed by team designates during the hockey season during a period of six months. The five main factors included in the regression model were sensation seeking, locus of control, anxiety, depression and attention problems. The result suggested that together the five main factors could explain 10.7% of total injury occurrence and 12.0% of MSK injury occurrence. The five main factors did not significantly predict concussion occurrence or injury severity. Attention problems alone significantly predicted total injury and concussion occurrence and injury severity. Locus of control and depression significantly predicted MSK injuries. Knowledge of these psychological risk factors should guide psychosocial risk assessment and subsequent interventions.

Background: Season-ending injuries, particularly those to the anterior cruciate ligament (ACL), continue at a high-rate in many sports, particularly ski racing. Although many factors are thought to contribute to this injury rate in both genders, no study has looked at possible psychological influences. Hypothesis: There is a form of post-traumatic stress disorder (PTSD) that affects athletes after seeing someone in their own sport sustain a serious injury. The result could be a decrease in performance both on and off the mountain. In the worst-case scenario, this change in tactics could result in injury to themselves, representing an "injury contagion". Study Design: Case-control study; Level of evidence, 3. Methods: Students at four Eastern ski academies were studied for 3 consecutive years (2002-2005). The subjects ranged in age from 13-19 and consisted of 277 men (60.3%) and 182 women (39.7% ). When a subject sustained a season-ending injury, a peer group of that subject was tested for both psychological and performance effects. The results of this testing was compared to previous baseline testing and a similarly constructed control group from an academy without such an injury. Results: There were twelve season-ending injuries sustained over the three-year period. Significant data results were obtained from one aspect of the psychological testing of the peer group. There was a trend toward a possible "injury contagion" i.e. injury to a member of the peer group soon after injury to a teammate. Conclusions: Although the results of this study were inconclusive in establishing the existence of an "injury contagion", there were data to establish a psychological affect on some athletes after injury to one of their teammates. Clinical Relevance: Although a teammate's injury did not measurably effect performance and only showed mild evidence of a possible injury contagion, there were significant psychological affects noted in female subjects. School personnel should be trained in basic counseling techniques specific to this problem.

Previous laboratory style research has shown that fatigue worsens postural control and proprioception at the ankle. The purpose of this research was to test the effect of fatigue due to a game of Australian Rules football has on postural control, and therefore the relevance of previous research to a sporting environment. The method of analysis was a uni-lateral standing balance test. The frequency of toe touches and therefore loss of balance over a 30 second period were calculated before and after a game. The dominant leg increased significantly from 2.65 to 4.03 toe touches, whilst the non-dominant leg recorded a non-significant increase from 3.06 to 3.19 toe touches. A significant difference in the change from pre-to post game was also noted between dominant and non-dominant legs. Effect size data supported these findings. This research demonstrates that a player becomes significantly fatigued on the dominant leg during a game of football. This may indicate an increased risk of injury on the dominant side as a player becomes fatigued during the game. This minor thesis was written by a post-graduate student as part of the requirements of the Master of Health Science (Osteopathy) program.

The aim of this paper is to examine injury patterns in elite female field hockey players, and to identify the injury rates of different playing positions so that preventative measures can be implemented. Based on available research it was hypothesised that goalkeepers and midfielders will have the highest rate of injury. However, after the injury data was collected from the team's physiotherapist, post 2003 hockey season, it was found that within the distribution of injuries by position, forwards had the greatest percentage (44%), followed by those positioned in the midfield (23%), goals (18%), and back (15%). The most common type of injury was categorised as bruising or inflammation (27%), predominantly occurring in the lower limb with most of these cases reported as shin splints. Other prevalent types of injury included joint sprains (119%) and muscle hypertonicity (19%) occurring in the ankle and thigh areas. A greater percentage of injuries occurred to the lower limb in this study, when compared to others. This may be due to the use of elite hockey players. Leading to more advanced stick control and accurate hitting, combined with the flatter surface of artificial turf - which all play and training was executed on. If accurate and comprehensible injury data on injury patterns for particular positions were available, more attention could be made to tailoring training and rehabilitation programs for positions susceptible to specific injuries. Theoretically, this should eventually lead to minimising the prevalence and severity of injury. This minor thesis was written by a post-graduate student as part of the requirements of the Master of Health Science (Osteopathy) program.