Protective Capacity of Ice Hockey Helmets against Different Impact Events

Potential of Soft-Shelled Rugby Headgear to Lower Regional Brain Strain Metrics During Standard Drop Tests

BACKGROUND

The growing concern for player safety in rugby has led to an increased focus on head impacts. Previous laboratory studies have shown that rugby headgear significantly reduces peak linear and rotational accelerations compared to no headgear. However, these metrics may have limited relevance in assessing the effectiveness of headgear in preventing strain-based brain injuries like concussions. This study used an instantaneous deep-learning brain injury model to quantify regional brain strain mitigation of rugby headgear during drop tests. Tests were conducted on flat and angled impact surfaces across different heights, using a Hybrid III headform and neck.

RESULTS

Headgear presence generally reduced the peak rotational velocities, with some headgear outperforming others. However, the effect on peak regional brain strains was less consistent. Of the 5 headgear tested, only the newer models that use open cell foams at densities above 45 kg/m3 consistently reduced the peak strain in the cerebrum, corpus callosum, and brainstem. The 3 conventional headgear that use closed cell foams at or below 45 kg/m3 showed no consistent reduction in the peak strain in the cerebrum, corpus callosum, and brainstem.

CONCLUSIONS

The presence of rugby headgear may be able to reduce the severity of head impact exposure during rugby. However, to understand how these findings relate to brain strain mitigation in the field, further investigation into the relationship between the impact conditions in this study and those encountered during actual gameplay is necessary.

Investigation of Head Kinematics and Brain Strain Response During Soccer Heading Using a Custom-Fit Instrumented Mouthguard

Association football, also known as soccer in some regions, is unique in encouraging its participants to intentionally use their head to gain a competitive advantage, including scoring a goal. Repetitive head impacts are now being increasingly linked to an inflated risk of developing long-term neurodegenerative disease. This study investigated the effect of heading passes from different distances, using head acceleration data and finite element modelling to estimate brain injury risk. Seven university-level participants wore a custom-fitted instrumented mouthguard to capture linear and angular acceleration-time data. They performed 10 headers within a laboratory environment, from a combination of short, medium, and long passes. Kinematic data was then used to calculate peak linear acceleration, peak angular velocity, and peak angular acceleration as well as two brain injury metrics: head injury criterion and rotational injury criterion. Six degrees of freedom acceleration-time data were also inputted into a widely accepted finite element brain model to estimate strain-response using mean peak strain and cumulative strain damage measure values. Five headers were considered to have a 25% concussion risk. Mean peak linear acceleration equalled 26 ± 7.9 g, mean peak angular velocity 7.20 ± 2.18 rad/s, mean peak angular acceleration 1730 ± 611 rad/s2, and 95th percentile mean peak strain 0.0962 ± 0.252. Some of these data were similar to brain injury metrics reported from American football, which supports the need for further investigation into soccer heading.

Two Minutes for Roughing: A National Analysis of Ice Hockey Injuries from American Trauma Centers

BACKGROUND

Hockey is a high-impact sport that carries a risk of injury. No national-level studies defining the burden of injury in this sport have yet been performed. This study sought to analyze patient demographics, injury types and severity, and outcomes after trauma sustained while playing hockey.

METHODS

Retrospective analysis of hockey-related injuries was performed using the National Trauma Data Bank (NTDB) (2007-2018). Patients were identified based on ICD-9 and -10 codes without exclusions. Demographics, clinical/injury data, and outcomes were examined using univariate analysis. Subgroup analysis was performed by patient sex.

RESULTS

Hockey injuries (n = 306) comprised <1% of the NTDB. Median age was 15 years [IQR 13-25] (range 5-71). Most patients (n = 279, 91%) were male. Lower extremities were the most frequently injured body region (n = 88, 29%). Head injuries occurred in 19% (n = 57). Facial injuries occurred in 6% (n = 17). Tooth loss was infrequent (n = 2, 1%). One (<1%) death occurred after a hockey-related brain injury. Clinical/injury data between male and female hockey players were comparable apart from a significantly higher rate of upper extremity fractures among the female cohort (22% vs 4%, P < .001).

CONCLUSION

Perceptions that hockey players may frequently sustain head, face, and tooth injuries from collisions, fighting, or stick/puck impacts were not supported by this national-level study, in which lower extremity fractures were the most common injury. While hockey injury prevention equipment has primarily focused on head/face protection (eg, helmets and mouthguards), this analysis suggests increased focus on extremity protective measures is warranted.

A technique for in situ intracranial strain measurement within a helmeted deformable headform

Despite the broad use of helmets, incidence of concussion remains high. Current methods for helmet evaluation focus on the measurement of head kinematics as the primary tool for quantifying risk of brain injury. Though the primary cause of mild Traumatic Brain Injury (mTBI) is thought to be intracranial strain, helmet testing methodologies are not able to directly resolve these parameters. Computational injury models and impact severity measures are currently used to approximate intracranial strains from head kinematics and predict injury outcomes. Advancing new methodologies that enable experimental intracranial strain measurements in a physical model would be useful in the evaluation of helmet performance. This study presents a proof-of-concept head surrogate and novel helmet evaluation platform that allows for the measurement of intracranial strain using high-speed X-ray digital image correlation (XDIC). In the present work, the head surrogate was subjected to a series of bare and helmeted impacts using a pneumatically-driven linear impactor. Impacts were captured at 5,000 fps using a high-speed X-ray cineradiography system, and strain fields were computed using digital image correlation. This test platform, once validated, will open the door to using brain tissue-level measurements to evaluate helmet performance, providing a tool that can be translated to represent mTBI injury mechanisms, benefiting the helmet design processes.

Protective equipment in youth ice hockey: are mouthguards and helmet age relevant to concussion risk?

OBJECTIVES

To compare the incidence rates and odds of concussion between youth ice hockey players based on mouthguard use and helmet age.

MATERIALS AND METHODS

Within a 5-year longitudinal cohort (2013/2014 to 2017/2018) of male and female ice hockey players (ages 11-18; n=3330 players) in Alberta (Canada), we analysed the relationship of equipment and concussion in both a prospective cohort and nested case (concussion) control (acute musculoskeletal injury) approach. The prospective cohort included baseline assessments documenting reported mouthguard use (yes/sometimes, no use), helmet age (newer/<2 years old, older/≥2 years old) and important covariables (weight, level of play, position of play, concussion history, body checking policy), with weekly player participation throughout the season. The nested case-control component used injury reports to document equipment (mouthguard use, helmet age) and other information (eg, mechanism and type of injury) for the injury event. Multivariable mixed effects negative binomial regression (prospective cohort, incidence rate ratios (IRRs)) and multivariable mixed effects logistic regression (nested case-control, odds ratios (OR)) examined the association between equipment and concussion.

RESULTS

Players who reported wearing a mouthguard had a 28% lower concussion rate (IRR=0.72, 95% CI 0.56 to 0.93) and 57% lower odds of concussion (OR=0.43, 95% CI 0.27 to 0.70) compared with non-wearers. There were no associations in the concussion rate (IRR=0.94, 95% CI 0.75 to 1.15) and odds (OR=1.16, 95% CI 0.73 to 1.86) between newer and older helmets.

CONCLUSIONS

Wearing a mouthguard was associated with a lower concussion rate and odds. Policy mandating use should be considered in youth ice hockey. More research is needed to identify other helmet characteristics (eg, quality, fit) that could lower concussion risk.

[Traumatic brain injuries in winter sports : An overview based on the winter sports skiing, snowboarding and ice hockey]

In winter sports, skiers, snowboarders and ice hockey players have the highest risk of traumatic brain injuries (TBI). In skiing/snowboarding severe TBIs are of concern; in ice hockey, repetitive minor TBIs are frequent. The main causes of TBI in recreational skiing are collisions with trees; in professionals falls due to technical or tactical mistakes are the main causes. In ice hockey 10-15% of all injuries are due to a sports-related concussion (SRC), mostly caused by player-opponent contact. The pathomechanism in TBI is a combination of rotational and linear acceleration during head impact, which causes a diffuse axonal injury. Long-term complications such as neurodegenerative diseases and functional deficits are of relevance. Prevention by wearing helmets is effective, but less effective in TBI/SRC than in focal injuries.

Male Youth Ice Hockey Concussion Incidence in a USA Hockey Membership-Adjusted Population: A Peak in 2011 and the Impact of Major Rule Changes

OBJECTIVE

To investigate the incidence of youth ice hockey-related concussions preceding and following the implementation of new body-checking and head contact rules by USA hockey in 2011. We hypothesized a decrease in concussions after the rule change.

DESIGN

Retrospective analysis.

SETTING

United States emergency department (ED) data queried in the National Electronic InjurySurveillance System (NEISS).

PATIENTS

National Electronic Injury Surveillance System reported male youth (≤18 years) ice hockey concussion cases from January 1, 2002, to December 31, 2016. In total, 848 players were diagnosed with concussion, representing a national estimate of 17 374 cases.

INDEPENDENT VARIABLES

Time, specifically years.

MAIN OUTCOME MEASURES

Incidences and incidence rates (measured per 10 000 person-years) of male youth ice hockey concussions. Annual trends were analyzed using descriptive and linear or polynomial regression analysis.

RESULTS

The national estimate of youth ice hockey-related concussions seen in US emergency departments (EDs) increased significantly from 656 in 2007 to 2042 in 2011 (P < 0.01). During the same period, their respective incidence increased significantly from 21.8 to 66.8 per 10 000, before dropping through 2016 (P < 0.05). After 2011, concussions decreased from 1965 in 2012 to 1292 in 2016 (P = 0.055). The gap in concussion incidence between the 11 to 12 and 13 to 14 divisions widened after 2011 (before 2011: 41 vs 49 per 10 000 person-years [P = 0.80]; after 2011: 45 and 89, respectively [P < 0.01]).

CONCLUSIONS

US EDs experienced a significant increase in youth ice hockey concussion visits from 2007 to 2011. After the 2011 rule changes, concussion visits decreased significantly from 2012 to 2016.

Epidemiology of Injuries in National Collegiate Athletic Association Men's Ice Hockey: 2014-2015 Through 2018-2019

CONTEXT

The National Collegiate Athletic Association has supported men's ice hockey, a distinct sport that mandates high-velocity gamesmanship, since 1974.

BACKGROUND

Injury surveillance systems are designed to identify evolving injury trends and their temporal qualities. Continual monitoring of collegiate men's ice hockey athletes remains essential.

METHODS

Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program from 2014-2015 through 2018-2019 were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios (IRR) were used to examine differential injury rates.

RESULTS

The overall injury rate was 7.65 per 1000 athlete-exposures. Injuries from competition occurred at a rate nearly 7 times that from practice injuries (IRR = 6.54, 95% CI = 6.08, 7.04). The most common specific injury diagnoses were concussions (9.6%), acromioclavicular sprains (7.3%), and medial collateral ligament tears (3.7%).

SUMMARY

Injury rates by event type and season segment were higher than previously reported. Contusions accounted for nearly a quarter of all injuries, and acromioclavicular sprain rates increased notably across the study period.

Epidemiology and trends of adult ice hockey injuries presenting to United States emergency departments: A ten-year analysis from 2007-2016

PURPOSE

The adult population is under-represented in existing ice hockey injury studies, despite the number of United States (US) adult ice hockey players increasing from 103,533 in 2007 to 180,400 in 2016 (74%). This study establishes trends in demographics, injury location, and injury type for adult ice hockey players (≥19 years old) in the United States.

METHODS

The National Electronic Injury Surveillance System (NEISS) was queried for all ice hockey injuries from January 1, 2007 to December 31, 2016. Cases under age 19 were excluded. Each injury's narrative text field was reviewed to determine mechanism of injury.

RESULTS

A total of 1,653 patients, representing an estimated 68,786 ice-hockey related injuries, presented to NEISS-participating US EDs. The most commonly injured body parts were the face (n = 12,432, 18.1%), head (n = 10,201, 14.8%), shoulder (n = 9,654, 14.0%) and ankle (n = 5,389, 7.8%). The most common diagnoses made were laceration (n = 18,153, 26.4%), strain/sprain (n = 12,202, 17.7%), fracture (n = 10,079, 14.7%), contusion (n = 9,283, 13.5%) and concussion (n = 4,794, 7.0%). The most common mechanisms of injury were falling (n = 11,786, 18.7%), puck contact (n = 10,544, 15.3%) and player contact (n = 9,449, 13.7%). Concussions increased from 46 in 2007 to 928 in 2016 (R2 = 0.8, β = 0.9, p < 0.001). Females (n = 1,852, 32%) had a higher proportion of head injuries than males (n = 8,349, 13.3%) (IPR = 2.4, p < 0.0001). The 50+ year old cohort showed a significant increase in injuries during the study period (n = 146 vs. 982, R2 = 0.75, β = 0.87, p = 0.001).

CONCLUSIONS

Despite changing trends in age and sex-related demographics, the majority of injuries in this population may be preventable with adequate enforcement of protective gear use. Increased education amongst players, coaches, trainers, orthopaedic surgeons and primary care physicians should be encouraged to minimize injuries.

A comparison of frequency and magnitude of head impacts between Pee Wee And Bantam youth ice hockey

The purpose of this research was to compare the frequency and magnitude of head impact events between Pee Wee and Bantam ice hockey players. Videos of Pee Wee and Bantam boys' ice hockey were analysed to determine the frequency and type of head impact events. The head impact events were then reconstructed in the laboratory using physical and finite element models to determine the magnitude of strain in the brain tissues. The results showed that Pee Wee boys experienced more head impacts from elbows and boards, while Bantam players had more head impacts to the glass. Pee Wee and Bantam players experienced similar frequency and magnitudes of very low, low, and medium and above (med+) levels of strain to the brain. This research suggests to ice hockey leagues and coaches that to reduce the incidence of these levels of brain trauma, consideration must be given to either reducing the level of contact along the boards or the removal of body checking. In addition, companies who innovate in ice hockey should develop protective devices and equipment strategies that aim to reduce the risk of head injury from shoulder and glass impacts for Bantam players.

Could a Compliant Foam Anvil Characterize the Biofidelic Impact Response of Equestrian Helmets?

The performance of equestrian helmets to protect against brain injuries caused by fall impacts against compliant surfaces such as turf has not been studied widely. We characterize the kinematic response of simulated fall impacts to turf through field tests on horse racetracks and laboratory experiments. The kinematic response characteristics and ground stiffness at different going ratings (GRs) (standard measurement of racetrack condition) were obtained from 1 m and 2 m drop tests of an instrumented hemispherical impactor onto a turf racetrack. The "Hard" rating resulted in higher peak linear accelerations and stiffness, and shorter impact durations than the "Soft" and "Heavy" ratings. Insignificant differences were found among the other GRs, but a strong overall relationship was evident between the "going rating" and the kinematic response. This relationship was used to propose a series of three synthetic foam anvils as turf surrogates in equestrian falls corresponding to ranges of GRs of (i) heavy-soft (H-S), (ii) good-firm (G-F), and (iii) firm-hard (F-H). Laboratory experiments consisted of a helmeted headform being dropped onto natural turf and the turf surrogate anvils using a monorail drop rig. These experiments revealed that the magnitudes and durations of the linear and rotational accelerations for helmeted impacts to turf/turf surrogates were similar to those in concussive sports falls and collisions. Since the compliance of an impacted surface influences the dynamic response of a jockey's head during a fall impact against the ground, it is important that this is considered during both accident reconstructions and helmet certification tests.

Equestrian Helmet Standards: Do They Represent Real-World Accident Conditions?

The use of helmets in equestrian sports has reduced the occurrence of traumatic brain injuries although, despite improvements to helmets, concussion remains a common injury. Currently, equestrian helmets are designed to pass certification standards involving a linear drop test to a rigid surface, while most concussions in equestrian sports result from oblique impacts to a compliant surface. The purpose of this study was to: (1) Compare the head kinematics and brain tissue response of the current equestrian helmet standard (EN1) and proposed standard EN13087-11 (EN2) to those associated with reconstructions of real-world equestrian concussion accidents. (2) Design a test protocol that would reflect the real-world conditions associated with concussion in equestrian sports. (3) To assess the protective capacity of an equestrian helmet using the flat turf and 45° turf proposed test protocols. Results for reconstructions of real-world concussions were obtained from a previous study (Clark et al. in J. Sci. Med. Sport 23:222-236, 2020). Using one jockey helmet model, impact tests were conducted according to the EN1 and EN2 protocols. Additionally, helmeted and unhelmeted tests were conducted at 5.9 and 6.0 m/s on to flat turf and 45° turf anvils for front, front-boss and rear-boss impact locations. The results demonstrated EN1 and EN2 both had higher magnitude accelerations and shorter duration impacts than reconstructed real-world concussive impacts. Impacts to turf anvils, on the other hand, produced similar head kinematics compared to the reconstructed real-world concussive impacts. Additionally, this study demonstrated that helmeted impacts significantly decreased rotational kinematics and brain tissue response below what is associated with unhelmeted impacts for oblique falls. However, the head kinematics and brain tissue response associated with these helmeted falls were consistent with concussion, suggesting that scope exists to improve the capacity of equestrian helmets to protect against concussion.

Development of a test method for adult ice hockey helmet evaluation

Ice hockey helmet standards have primarily been developed to reduce risk of traumatic brain injury (TBI). While severe TBI has become a rare event in ice hockey, concussion, a type of mild TBI, remains a common head injury. Concussions, in ice hockey result from a number of head impact events including, collisions, stick impacts, puck impacts, falls into the boards, impacts to the glass, and falls to the ice. Helmet testing methods need to represent the impact events creating concussions in ice hockey. The purpose of this research was to develop a helmet test protocol and performance metric for concussive impacts in ice hockey. A protocol using concussion impact parameters from published literature was created that used monorail and linear impactors to impact a helmeted Hybrid III headform. The linear and rotational acceleration time curves were then used to calculate brain tissue strain using the University College Brain Trauma Model. The proposed test protocols created kinematic responses that were representative of levels associated with concussion in ice hockey. Rotational velocity and rotational acceleration were both identified as useful performance metrics representing levels of risk for concussion.

Impact Mitigation Properties of Women's Lacrosse Headgear

Recently, protective headgear has been released for women's lacrosse despite the fact that contact to the head is illegal. The purposes of this study were to (1) compare the linear and rotational impact attenuation properties of 2 brands of lacrosse headgear at 4 different locations during laboratory pendulum impacts and (2) determine impact dissipation of new and used lacrosse headgear. We measured peak rotational acceleration (PRA; rad/s²) and linear acceleration (PLA; g) at 4 impact locations (side, rear boss non-centric (NC), front boss, and front) in two headgear brands (Cascade LX, Hummingbird). Two headgear service lives (new headgear, used headgear) were included for the second analysis. During the slower speed, there was a significant interaction between impact location and helmet brand (p = 0.002) for PLA. No other findings were significant. While the Hummingbird headgear reduced linear and rotational accelerations of the headform better than the Cascade headgear during slow velocity impacts to the front and front boss locations, it did so due to extreme motion of the helmet upon impact that we believe may compromise protection of the head and face from lacerations and other injuries.

Characterizing Craniomaxillofacial Injuries in American Professional Sports Leagues

PURPOSE

The purpose of this study was to characterize the types of craniomaxillofacial (CMF) injuries that occur in professional sports leagues and the associated recovery times.

MATERIALS AND METHODS

A retrospective cohort study was designed and implemented using the Pro Sports Transaction Archive. The database was queried for all registered CMF injuries in the 4 main men's major professional sports leagues in the United States from 2013 to 2018. The sport, injury location, and season were the predictor variables, and the frequency and length of time on the injured list were the outcome variables. Descriptive statistics were computed, and Fisher's exact tests were used to determine the association between the predictor and outcome variables. Analysis of variance was used to compare the injury frequency and duration.

RESULTS

Of the 198 injuries that met the inclusion criteria, 60 were from Major League Baseball (MLB) (30%), 49 from the National Basketball Association (25%), 8 from the National Football League (4%), and 81 from the National Hockey League (NHL) (41%). Injuries to the midface were most common (mean, 25.2 ± 3.6 injuries per season; P < .001) compared with the upper face (mean, 6.0 ± 2.0 injuries per season) and lower face (mean, 8.4 ± 2.3 injuries per season). The mean time on the injured list after CMF trauma was 8.4 ± 10.4 days, with MLB injuries requiring the shortest duration (mean, 3.9 ± 6.6 days; P = .001). A significant association was found between the injury location and sport (P < .001). However, no statistically significant difference was found in the number of injuries per season from 2013 to 2018 for each league (P = .818).

CONCLUSIONS

Midface trauma was significantly more common than upper or lower face trauma in professional sports leagues during the past 5 seasons. The NHL had the greatest injury rate, even after adjustment for games played.

The influence of impact surface on head kinematics and brain tissue response during impacts with equestrian helmets

Current equestrian standards employ a drop test to a rigid steel anvil. However, falls in equestrian sports often result in impacts with soft ground. The purpose of this study was to compare head kinematics and brain tissue response associated with surfaces impacted during equestrian accidents and corresponding helmet certification tests. A helmeted Hybrid III headform was dropped freely onto three different anvils (steel, turf and sand) at three impact locations. Peak linear acceleration, rotational acceleration and impact duration of the headform were measured. Resulting accelerations served as input into a three-dimensional finite element head model, which calculated Maximum principal strain (MPS) and von Mises stress (VMS) in the cerebrum. The results indicated that impacts to a steel anvil produced peak head kinematics and brain tissue responses that were two to three times greater than impacts against both turf and sand. Steel impacts were less than half the duration of turf and sand impacts. The observed response magnitudes obtained in this study suggest that equestrian helmet design should be improved, not only for impacts to rigid surfaces but also to compliant surfaces as response magnitudes for impacts to soft surfaces were still within the reported range for concussion in the literature.

A review of impact testing methods for headgear in sports: Considerations for improved prevention of head injury through research and standards

Standards for sports headgear were introduced as far back as the 1960s and many have remained substantially unchanged to present day. Since this time, headgear has virtually eliminated catastrophic head injuries such as skull fractures and changed the landscape of head injuries in sports. Mild traumatic brain injury (mTBI) is now a prevalent concern and the effectiveness of headgear in mitigating mTBI is inconclusive for most sports. Given that most current headgear standards are confined to attenuating linear head mechanics and recent brain injury studies have underscored the importance of angular mechanics in the genesis of mTBI, new or expanded standards are needed to foster headgear development and assess headgear performance that addresses all types of sport-related head and brain injuries. The aim of this review is to provide a basis for developing new sports headgear impact tests for standards by summarizing and critiquing: 1) impact testing procedures currently codified in published headgear standards for sports and 2) new or proposed headgear impact test procedures in published literature and/or relevant conferences. Research areas identified as needing further knowledge to support standards test development include defining sports-specific head impact conditions, establishing injury and age appropriate headgear assessment criteria, and the development of headgear specific head and neck surrogates for at-risk populations.

Analysis of different volleyballs' collision mechanics across a range of incident velocities

Volleyball involves low-to-high-velocity collisions between the ball and a player. This research examined the kinematics, energetics and impact forces during collisions of different volleyballs across a range of incident velocities. Seven volleyball types were projected downwards between 8 and 30 m/s, impacting on a force platform. Recorded video was digitised and used to calculate incident and rebound velocities, and kinetic energy lost. Peak impact force was determined from the force platform. All ball types had a linear relation between incident and rebound velocities. Four balls had lower while three balls had higher rebound velocities. The slope of this relation varied across ball types. These data indicate that each volleyball type has unique behaviour during collisions; how a player should interact with a ball will depend on the ball type and the incident velocity. The kinetic energy lost was unrelated to peak impact force; of the two ball types with the highest peak impact force, one had the highest and the other the lowest kinetic energy lost. The varying combinations of kinetic energy lost and peak impact force may be useful to examine the role of each of these variables in collision injuries.

Sport-Related Concussion in Children and Adolescents

Sport-related concussion is an important topic in nearly all sports and at all levels of sport for children and adolescents. Concussion knowledge and approaches to management have progressed since the American Academy of Pediatrics published its first clinical report on the subject in 2010. Concussion's definition, signs, and symptoms must be understood to diagnose it and rule out more severe intracranial injury. Pediatric health care providers should have a good understanding of diagnostic evaluation and initial management strategies. Effective management can aid recovery and potentially reduce the risk of long-term symptoms and complications. Because concussion symptoms often interfere with school, social life, family relationships, and athletics, a concussion may affect the emotional well-being of the injured athlete. Because every concussion has its own unique spectrum and severity of symptoms, individualized management is appropriate. The reduction, not necessarily elimination, of physical and cognitive activity is the mainstay of treatment. A full return to activity and/or sport is accomplished by using a stepwise program while evaluating for a return of symptoms. An understanding of prolonged symptoms and complications will help the pediatric health care provider know when to refer to a specialist. Additional research is needed in nearly all aspects of concussion in the young athlete. This report provides education on the current state of sport-related concussion knowledge, diagnosis, and management in children and adolescents.

Distribution of Brain Strain in the Cerebrum for Ice Hockey Goaltender Impacts

Concussions are among the most common injuries sustained by goaltenders. Concussive injuries are characterized by impairment to neurological function which can affect many different brain regions. Understanding how different impact loading conditions (event type and impact site) affect the brain tissue response may help identify what kind of impacts create a high risk of injury to specific brain regions. The purpose of this study was to examine the influence of different impact conditions on the distribution of brain strain for ice hockey goaltender impacts. An instrumented headform was fitted with an ice hockey goaltender mask and impacted under a protocol which was developed using video analysis of real world ice hockey goaltender concussions for three different impact events (collision, puck, and fall). The resulting kinematic response served as input into the University College Dublin Brain Trauma Model, which calculated maximum principal strain in the cerebrum. Strain subsets were then determined and analyzed. Resulting peak strains (0.124 - 0.328) were found to be within the range for concussion reported in the literature. The results demonstrated that falls and collisions produced larger strain subsets in the cerebrum than puck impacts which is likely a reflection of longer impact duration for falls and collisions than puck impacts. For each impact event, impact site was also found to produce strain subsets of varying size and configuration. The results of this study suggest that the location and number of brain regions which can be damaged depend on the loading conditions of the impact.

Comparison of Ice Hockey Goaltender Helmets for Concussion Type Impacts

Concussions are among the most common injuries sustained by ice hockey goaltenders and can result from collisions, falls and puck impacts. However, ice hockey goaltender helmet certification standards solely involve drop tests to a rigid surface. This study examined how the design characteristics of different ice hockey goaltender helmets affect head kinematics and brain strain for the three most common impact events associated with concussion for goaltenders. A NOCSAE headform was impacted under conditions representing falls, puck impacts and shoulder collisions while wearing three different types of ice hockey goaltender helmet models. Resulting linear and rotational acceleration as well as maximum principal strain were measured for each impact condition. The results indicate that a thick liner and stiff shell material are desirable design characteristics for falls and puck impacts to reduce head kinematic and brain tissue responses. However for collisions, the shoulder being more compliant than the materials of the helmet causes insufficient compression of the helmet materials and minimizing any potential performance differences. This suggests that current ice hockey goaltender helmets can be optimized for protection against falls and puck impacts. However, given collisions are the leading cause of concussion for ice hockey goaltenders and the tested helmets provided little to no protection, a clear opportunity exists to design new goaltender helmets which can better protect ice hockey goaltenders from collisions.

Assessing women's lacrosse head impacts using finite element modelling

Recently studies have assessed the ability of helmets to reduce peak linear and rotational acceleration for women's lacrosse head impacts. However, such measures have had low correlation with injury. Maximum principal strain interprets loading curves which provide better injury prediction than peak linear and rotational acceleration, especially in compliant situations which create low magnitude accelerations but long impact durations. The purpose of this study was to assess head and helmet impacts in women's lacrosse using finite element modelling. Linear and rotational acceleration loading curves from women's lacrosse impacts to a helmeted and an unhelmeted Hybrid III headform were input into the University College Dublin Brain Trauma Model. The finite element model was used to calculate maximum principal strain in the cerebrum. The results demonstrated for unhelmeted impacts, falls and ball impacts produce higher maximum principal strain values than stick and shoulder collisions. The strain values for falls and ball impacts were found to be within the range of concussion and traumatic brain injury. The results also showed that men's lacrosse helmets reduced maximum principal strain for follow-through slashing, falls and ball impacts. These findings are novel and demonstrate that for high risk events, maximum principal strain can be reduced by implementing the use of helmets if the rules of the sport do not effectively manage such situations.

Comparison of Concussion Rates Between NCAA Division I and Division III Men's and Women's Ice Hockey Players

BACKGROUND

Examinations related to divisional differences in the incidence of sports-related concussions (SRC) in collegiate ice hockey are limited.

PURPOSE

To compare the epidemiologic patterns of concussion in National Collegiate Athletic Association (NCAA) ice hockey by sex and division.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

A convenience sample of men's and women's ice hockey teams in Divisions I and III provided SRC data via the NCAA Injury Surveillance Program during the 2009-2010 to 2014-2015 academic years. Concussion counts, rates, and distributions were examined by factors including injury activity and position. Injury rate ratios (IRRs) and injury proportion ratios (IPRs) with 95% confidence intervals (CIs) were used to compare concussion rates and distributions, respectively.

RESULTS

Overall, 415 concussions were reported for men's and women's ice hockey combined. The highest concussion rate was found in Division I men (0.83 per 1000 athlete-exposures [AEs]), followed by Division III women (0.78/1000 AEs), Division I women (0.65/1000 AEs), and Division III men (0.64/1000 AEs). However, the only significant IRR was that the concussion rate was higher in Division I men than Division III men (IRR = 1.29; 95% CI, 1.02-1.65). The proportion of concussions from checking was higher in men than women (28.5% vs 9.4%; IPR = 3.02; 95% CI, 1.63-5.59); however, this proportion was higher in Division I women than Division III women (18.4% vs 1.8%; IPR = 10.47; 95% CI, 1.37-79.75). The proportion of concussions sustained by goalkeepers was higher in women than men (14.2% vs 2.9%; IPR = 4.86; 95% CI, 2.19-10.77), with findings consistent within each division.

CONCLUSION

Concussion rates did not vary by sex but differed by division among men. Checking-related concussions were less common in women than men overall but more common in Division I women than Division III women. Findings highlight the need to better understand the reasons underlying divisional differences within men's and women's ice hockey and the need to develop concussion prevention strategies specific to each athlete population.