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Quantifying head impacts is a vital component to understanding and preventing head trauma in sport. Our objective was to establish the frequency and magnitude of head impact mechanisms in men’s lacrosse athletes. Eleven male lacrosse athletes wore xPatch sensors during activity. Video footage of practices and games was analyzed to verify impacts and code them with impact mechanisms. The authors calculated incidence rates (IRs) per 1000 exposures with corresponding 95% confidence intervals (CIs) and used multivariate analysis of variances to compare the linear (g) and rotational (rad/s2) accelerations between mechanisms. A total of 167 head impacts were successfully verified and coded with a mechanism using video footage during 542 total exposures. The highest IR was head to body (IR = 118.08; 95% CI, 89.15–147.01), and the lowest was head to ball (IR = 3.69; 95% CI, 0–8.80) (incidence rate ratio = 32.00; 95% CI, 67.83–130.73). Analysis indicated that impact mechanism failed to significantly alter the combined dependent variables (multivariate F10,306 = 1.79, P = .06, η2 = .06, 1−β = 0.83). While head to head, body to head, and stick to head mechanisms are penalty-inducing offenses in men’s lacrosse, head to ground, head to ball, and combination impacts have similar head accelerations. If penalties and rules are created to protect players from traumatic head injury, the authors recommend stricter enforcement.

Background Head impacts have been studied extensively in football, but little similar research has been conducted in men's lacrosse. It is important to understand the location and magnitude of head impacts during men's lacrosse to recognize the risk of head injury. Methods Descriptive epidemiology study set on collegiate lacrosse fields. Eleven men's lacrosse players (age=20.9±1.13years, mass=83.91±9.04kg, height=179.88±5.99cm) volunteered to participate. We applied X2 sensors behind the right ear of participants for games and practices. Sensors recorded data on linear and rotational accelerations and the location of head impacts. We calculated incidence rates per 1000 exposures with 95% confidence intervals for impact locations and compared the effect of impact location on linear and rotational accelerations with Kruskal-Wallis tests. Findings We verified 167 head impacts (games=112; practices=55). During games, the incidence rate was 651.16 (95% confidence interval=530.57–771.76). The high and low incidence rates for head impact locations during games were: side=410.7 (95% confidence interval=292.02–529.41) and top=26.79 (95% confidence interval=3.53–57.10). For games and practices combined, the impact locations did not significantly affect linear ( χ 2 3 =6.69, P =0.08) or rotational acceleration ( χ 2 3 =6.34, P =0.10). Interpretation We suggest further research into the location of head impacts during games and practices. We also suggest player and coach education on head impacts as well as behavior modification in men's lacrosse athletes to reduce the incidence of impacts to the side of the head in an effort to reduce potential injury.

The National Operating Committee on Standards for Athletic Equipment (NOCSAE) has developed impact attenuation thresholds that protective helmets worn in sport must meet to be commercially available in an attempt to prevent injury. It remains unknown how normal helmet use in athletic activity alters the force attenuation ability of lacrosse helmets. We tested 3 new and 3 randomly selected used helmets from 2 popular lacrosse models (Cascade Pro7, Cascade CPXR). All used helmets had been worn for 3 collegiate seasons prior to testing and had never been refurbished. Helmets were drop-tested using 3 prescribed impact velocities at 6 locations according to the NOCSAE lacrosse helmet standard, and we compared the Gadd Severity Index (GSI) scores between new and used helmets using a repeated measure ANOVA with location as the repeated variable and data separated by impact velocity. All 12 helmets passed the NOCSAE GSI threshold for all testing conditions; however 1 used helmet shell cracked resulting in a failed test. We found a significant main effect for helmet age at the low (F5,50=2.98, P=.02), medium (F5,50=3.71, P=.006), and high (F5,50=2.70, P=.03) velocities. We suspect that helmet use can degrade materials under some conditions, but improve performance in others due to changes in helmet composition from use. The clinical implications of the differences in GSI scores noted remain unclear. Because one helmet shell cracked resulting in a failed test, used helmets should be regularly inspected for cracks or other signs of mechanical fatigue that may weaken helmet integrity.

Monte-Carlo permutation analysis was used to identify sets of head impacts most predictive of functional magnetic resonance imaging (fMRI) changes in football players. The relative distribution of impact location was found to be more predictive of brain activation changes than the number of impacts, suggesting that fMRI changes are related to systematic playing style.

Magnetic resonance spectroscopy and helmet telemetry were used to monitor the neural metabolic response to repetitive head collisions in 25 high school American football athletes. Specific hit characteristics were determined highly predictive of metabolic alterations, suggesting that sub-concussive blows can produce biochemical changes and potentially lead to neurological problems.

Recent work suggests that repetitive subconcussive head impacts may contribute to long-term neurodegeneration; however, the risk thresholds for subconcussive injury are unknown. It was hypothesized that the number and severity of head impacts could quantify the risk of developing abnormal neurophysiology. Twenty-one high school boys (ages 14 to 18) participating in varsity and junior varsity football were evaluated over the course of 1 football season (13 games) using a combination of the ImPACT, functional magnetic resonance imaging (fMRI), and head impact telemetry. The number and severity of head impacts throughout the football season were subsequently compared with the fraction of players flagged by either the ImPACT or fMRI before, during, and after the competition season. Twelve of 22 (54.5%) in-season tests of asymptomatic participants had a minimum of 1 composite ImPACT score flagged. For the fMRI analysis, 16 (72.7%) of the 22 in-sea son sessions were considered flagged. Seven assessments were flagged by both the ImPACT and fMRI. Larger numbers of hits appeared to correspond with a larger fraction of players being flagged by at least fMRI or the ImPACT. A substantial number of clinically asymptomatic athletes exhibit significant neurophysi ological changes in-season. Furthermore, the number of head impacts is a risk factor for the development of neurophysiological changes. [Athletic Training & Sports Health Care. 2014;6(x):xxxxxx.] [Query #2: Reduce to 150 words.]

Head trauma and concussion in football players have recently received considerable media attention. Postmortem evidence suggests that accrual of damage to the brain may occur with repeated blows to the head, even when the individual blows fail to produce clinical symptoms. There is an urgent need for improved detection and characterization of head trauma to reduce future injury risk and promote development of new therapies. In this study we examined neurological performance and health in the presence of head collision events in high school football players, using longitudinal measures of collision events (the HIT(™) System), neurocognitive testing (ImPACT(™)), and functional magnetic resonance imaging MRI (fMRI). Longitudinal assessment (including baseline) was conducted in 11 young men (ages 15-19 years) participating on the varsity and junior varsity football teams at a single high school. We expected and observed subjects in two previously described categories: (1) no clinically-diagnosed concussion and no changes in neurological behavior, and (2) clinically-diagnosed concussion with changes in neurological behavior. Additionally, we observed players in a previously undiscovered third category, who exhibited no clinically-observed symptoms associated with concussion, but who demonstrated measurable neurocognitive (primarily visual working memory) and neurophysiological (altered activation in the dorsolateral prefrontal cortex [DLPFC]) impairments. This new category was associated with significantly higher numbers of head collision events to the top-front of the head, directly above the DLPFC. The discovery of this new category suggests that more players are suffering neurological injury than are currently being detected using traditional concussion-assessment tools. These individuals are unlikely to undergo clinical evaluation, and thus may continue to participate in football-related activities, even when changes in brain physiology (and potential brain damage) are present, which will increase the risk of future neurological injury.

Although the National Operating Committee on Standards for Athletic Equipment (NOCSAE) standards are similar for football and lacrosse helmets, it remains unknown how helmets for each sport compare on drop tests. Due to the increased concern over head injury in sport and the rapid growth in lacrosse participation, it is useful to compare the performance of various football and lacrosse helmets. Therefore, the goal of this study was to document the impact attenuation properties of football and lacrosse helmets and to identify the relative performance between helmets for the two sports. Six models of football and six models of lacrosse helmets were tested using a drop tower at three prescribed velocities and six locations on the helmets. A repeated measures ANOVA was conducted to determine the effect of sport on Gadd Severity Index (GSI) scores and linear accelerations. The interaction between location and sport was significant at the low (F2.64,89.71=7.68, P

Neurocognitive assessment, functional magnetic resonance imaging, and head impact monitoring were used to evaluate neurological changes in high school football players throughout competitive seasons. A substantial number of asymptomatic athletes exhibited neurophysiological changes that persisted post-season, with abnormal measures significantly more common in athletes receiving 50 or more hits per week during the season.

a Department of Athletic Training, Lynchburg College, Lynchburg, VA 24501, United States b Department of Health and Kinesiology, Purdue University, West Lafayette, IN 47907, United States c School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, United States d Department of Exercise Science and Sport Studies, Springfield College, Springfield, MA 01109, United States e Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, United States f Department of Basic Medical Sciences, Purdue University, West Lafayette, IN 47907, United States