Effects of Striker Compliance on Dynamic Response and Brain Tissue Strain for Helmeted Ice Hockey Impacts PDF Download
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Author: Santiago de Grau Amezcua
Publisher:
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Languages : en
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The effect of striking compliance in ice hockey impacts, and its influence on dynamic response and brain tissue strain was investigated in this study. In hockey, players can experience a broad range of striking/surface compliance during a head impact, from the stiff ice surface to highly compliant player collisions. An increase in striking compliance has been shown to extend the duration of an impact that is associated with an increase in risk of sustaining brain injuries. Three striking caps of low, medium, and high compliance were used to impact a helmeted 50th percentile Hybrid III male headform attached to an unbiased neckform. Each level of compliance was used to impact five high risk locations at three different velocities, representative of head impact scenarios in ice hockey. The dependent variables, peak resultant linear accelerations and peak resultant rotational acceleration as well as MPS, were analyzed using a multivariate analysis of variance (MANOVA) to determine if there were significant differences between the three controlled variables. The results demonstrate a significant effect of compliance, over the influence of velocity and acceleration. Conditions of low impact compliance resulted in higher response values compared to impacts of increased compliance. That being said, high compliance conditions remained in the range of concussion risk, even at the lowest velocity. The use of brain tissue modeling, compared to dynamic response alone, demonstrated an elevated risk of brain injury as a result of extended impact durations. Impact compliance in hockey is a factor that has not been considered when designing and testing helmet technology. The results of this study demonstrate that compliance is a determining factor in producing brain injury, and should be incorporated into helmet standard testing to mitigate risk. The results of this study have implications on brain injury risk that extend beyond the impacting scenarios of ice hockey. The results can be extrapolated to any contact sport that includes impacting scenarios against varied impacting compliances such as football and rugby.
Author: Santiago de Grau Amezcua
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The effect of striking compliance in ice hockey impacts, and its influence on dynamic response and brain tissue strain was investigated in this study. In hockey, players can experience a broad range of striking/surface compliance during a head impact, from the stiff ice surface to highly compliant player collisions. An increase in striking compliance has been shown to extend the duration of an impact that is associated with an increase in risk of sustaining brain injuries. Three striking caps of low, medium, and high compliance were used to impact a helmeted 50th percentile Hybrid III male headform attached to an unbiased neckform. Each level of compliance was used to impact five high risk locations at three different velocities, representative of head impact scenarios in ice hockey. The dependent variables, peak resultant linear accelerations and peak resultant rotational acceleration as well as MPS, were analyzed using a multivariate analysis of variance (MANOVA) to determine if there were significant differences between the three controlled variables. The results demonstrate a significant effect of compliance, over the influence of velocity and acceleration. Conditions of low impact compliance resulted in higher response values compared to impacts of increased compliance. That being said, high compliance conditions remained in the range of concussion risk, even at the lowest velocity. The use of brain tissue modeling, compared to dynamic response alone, demonstrated an elevated risk of brain injury as a result of extended impact durations. Impact compliance in hockey is a factor that has not been considered when designing and testing helmet technology. The results of this study demonstrate that compliance is a determining factor in producing brain injury, and should be incorporated into helmet standard testing to mitigate risk. The results of this study have implications on brain injury risk that extend beyond the impacting scenarios of ice hockey. The results can be extrapolated to any contact sport that includes impacting scenarios against varied impacting compliances such as football and rugby.
Author: Andrew Meehan
Publisher:
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Category :
Languages : en
Pages :
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Ice hockey helmets effectively mitigate the risk of skull fractures and focal traumatic brain injuries in professional ice hockey (PIH), but do not manage diffuse brain injuries such as concussion. This is due to current standard tests, which only represent one head impact event (a fall to the ice) and do not measure rotational head kinematics. It is important that helmets are evaluated using impact conditions that represent how players sustain concussions in ice hockey. The objective of this study was to describe the relationship between three ice hockey helmet tests and reconstructions of three concussive injury events in PIH. A flat anvil drop test (representing head-to-ice impacts), angled anvil drop test (representing head-to-boards impacts at 30o and 45o) and pneumatic ram test (representing medium and high compliance shoulder-to-head impacts) were performed using parameters reflecting concussive injuries in PIH. Stepwise regressions identified the dynamic response variables producing the strongest relationships with MPS. For the flat anvil drop test, dominant linear acceleration had the strongest relationship with MPS (R2 = 0.960), while there were no significant predictors of MPS from the PIH head-to-ice reconstructions. Rotational velocity had the strongest relationship for the 30o (R2 = 0.978) and 45o Anvil Drop Tests (R2 = 0.977), while rotational acceleration had the strongest relationship for the PIH head-to-boards reconstructions (R2 = 0.649). Resultant rotational acceleration had the strongest relationship for the medium compliance ram test (R2 = 0.671), the high compliance ram test (R2 = 0.850) and the PIH shoulder-to-head reconstructions (R2 = 0.763). The flat anvil drop test results indicate that falls on a flat, rigid surface induce primarily linear acceleration of the head. Standards should continue using this type of test to ensure helmets prevent skull fracture and focal TBI. Ice hockey helmets should also be evaluated using an angled anvil drop test and a collision ram test, representing two unique head impact events known to cause concussive injuries. The 45o Anvil Drop Test provided a closer representation of concussive head-to-boards impacts in PIH, with rotational velocity producing the strongest relationship with MPS. For collision impacts, the Medium Compliance Ram Test yielded repeatable impact conditions while the High Compliance Ram Test provided a closer representation of real-world concussive shoulder-to-head impacts. For these pneumatic ram tests, rotational acceleration produced the strongest relationship with MPS. The information in this thesis may be used by standards organizations when designing future ice hockey helmet tests.
Author: James Michio Hjalmar Clark
Publisher:
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Category :
Languages : en
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Author: Wesley Chen
Publisher:
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Category :
Languages : en
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There is an increasing concern surrounding brain trauma risks for young athletes participating in contact sports, as brain injuries in youth have detrimental consequences on their cognition, behaviour, and learning abilities (Ayr et al., 2009; Yeates and Taylor, 2005). Given the potential for future neurological and mental health issues, there is further need to quantify brain trauma within youth sport populations (Daneshvar et al., 2011). Ice hockey is a sport with high rates of brain injury in youth, and the shift from Pee Wee (ages 11-12) to Bantam (ages 13-14) hockey is an important transition period in which athletes are introduced to body checking (Black et al., 2017; Marar et al., 2012). The purpose of this study was to compare the brain trauma profiles between Pee Wee and Bantam hockey in terms of the head dynamic response, brain tissue deformation, and frequency of head impact events. Head impact events from 16 Pee Wee and 16 Bantam hockey games were analyzed, and 71 exemplar impact reconstructions were conducted. No differences were found between Pee Wee and Bantam for magnitudes of peak linear acceleration, peak rotational acceleration, or maximum principal strain (MPS). Overall frequency of head impact events was also similar between the two groups. However, chi-squared tests found that the type of head impact event was significantly associated with the age group (X2 (6) = 17.699, p = 0.006, ?c = .347). Ice and boards head impact events were more frequent in Pee Wee, while shoulder and glass head impact events were more frequent in Bantam. There were slightly higher frequencies of events {601}26% MPS reported in Pee Wee. However, events were more frequently within the 17-25.9% MPS range for Bantam and were typically the result of shoulder to head impacts. While head impact events at younger ages are more accidental in nature, deliberate player contact from body checking is associated with greater risks for sustaining brain trauma. Policymakers should consider whether Bantam is the most appropriate age to continue allowing for body checking. Developing age-specific helmet technology may be an effective method for protecting against the unique brain trauma risks which are associated with different levels of youth hockey competition. Understanding the characteristics of how brain trauma occurs within youth hockey can help inform and guide future protective and preventative strategies to keep participation in this sport safe for all athletes.
Author: Gabrielle Kosziwka
Publisher:
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Languages : en
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Head injuries are a major health concern for sport participants as 90% of emergency department visits for sport-related brain injuries are concussion related (Canadian Institute for Health Information, 2016). Recently, reports have shown a higher incidence of sport-related concussion in female athletes compared to males (Agel et al., 2007). Few studies have described the events by which concussions occur in women's hockey (Delaney et al., 2014, Brainard et al., 2012; Wilcox et al., 2014), however a biomechanical analysis of the risk of concussion has not yet been conducted. Therefore, the purpose of this study was to identify the riskiest concussive events in elite women's hockey and characterize these events through reconstructions to identify the associated levels of peak linear and angular acceleration and strain from finite element analysis. 44 head impact events were gathered from elite women's hockey game video and analyzed for impact event, location and velocity. In total, 27 distinct events based on impact event, location and velocity were reconstructed using a hybrid III headform and various testing setups to obtain dynamic response and brain tissue response. A three-way Multivariate Analysis of Variance (MANOVA) was conducted to determine the influence of event, location and velocity. The results of this study show that head-to-ice impacts resulted in significantly higher responses compared to shoulder-to-head collisions and head-to boards impacts however, shoulder and boards impacts were more frequent. All events produced responses comparable to proposed concussion threshold values (Zhang et al., 2004). This research demonstrates the importance of considering the event, the impact characteristics, the magnitude of response, and the frequency of these impacts when attempting to capture the short and long term risks of brain trauma in women's hockey.
Author: Bianca Brigitte Rock
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Languages : en
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The long-term consequences of repetitive mild traumatic brain injuries (mTBIs), or concussions, as well as the immediate acute dangers of head collisions in sport have become of growing concern in the field of medicine, research and athletics. An estimated 3.8 million sports-related concussions occur in the United States annually, with the highest incidence having been documented in football, hockey, soccer, basketball and rugby (Harmon et al., 2013). The incidence of concussion in the National Rugby League (NRL) corresponds to approximately 8.0-17.5 injuries per 1000 playing hours, with tackling having been identified as the most common cause (Gardner et al., 2014; King et al., 2014). The highest incidence of rugby concussive impacts is a result of shoulder-to-head collisions (35%) during tackles and game play (Gardner et al., 2014). Shoulder-to-head concussive events occur primarily on the ball carrier and secondarily on the tacklers (Hendricks et al., 2014; Quarrie & Hopkins, 2008). While some studies report that the ball carrier is at a greater risk of sustaining a concussion (Gardner et al., 2015; King et al., 2010, 2014), others have demonstrated a greater incidence of tacklers being removed from play for sideline concussion evaluation (Gardner et al., 2014). Given this discrepancy, the purpose of this study was to compare dynamic response and brain tissue deformation metrics for ball carriers and defensive tacklers in professional rugby during shoulder-to-head concussive impacts using in-laboratory reconstructions. Ten cases with an injured defensive tackler and ten cases with an injured ball carrier were reconstructed using a pneumatic linear impactor striking a 50th percentile Hybrid III headform to calculate dynamic response and maximum principal strain values. There was no significant difference between the two impact conditions for peak resultant linear and rotational accelerations, as well as brain tissue deformation. Differences between metrics in this research and past research where the impacting system was not reported were discussed. These differences reflect the importance of accounting for impact compliance when describing the risk associated with collisions in professional rugby.
Author: David Bruneau
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages : 159
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Among high school and college athletes, ~50% of American football players report a concussion each year, and at least 30% of players sustain more than one concussion per year, which may be reduced in part through improvements in head protection. Football helmets are commonly assessed experimentally using a linear impactor test, where a helmet is donned on a Hybrid III Anthropometric Testing Device (ATD) head and neck affixed to a sliding carriage, and is struck by a deformable impactor. The biofidelity of the Hybrid III ATD is known to have some limitations: the ATD was developed to predict anterior-posterior response while the current test includes multi-directional loading, and the passive neck structure does not simulate active muscle. Additionally, the linear impactor test does not include the body of the player, which may influence the head response. The current study used an advanced Human Body Model (HBM) combined with a validated finite element model of a modern football helmet to assess the importance of the aforementioned limitations, and was then extended to investigate the response of the brain to impact scenarios. A virtual evaluation tool provides the advantage of assessing changes to current helmet designs, and new helmet designs prior to the construction of a physical prototype. An existing ATD head and neck model validated in the linear impact configuration, and a validated football helmet model previously assessed with 60 impact cases, were used as a baseline for the assessment of head response in football impact scenarios. The Global Human Body Models Consortium (GHBMC) head and neck model (HNM) and Full Human Body Model (FBM) were integrated with the helmet and linear impactor, and assessed using the same boundary conditions as the ATD. The HNM allowed for the investigation of muscle activation, using a muscle activation scheme representing a player braced for impact, and a baseline case with no activation. The models were used in three studies to assess: (1) the kinematic response of the ATD and HNM, (2) the effect of ATD and HNM boundary conditions on brain response, and (3) the role of the whole body mass and inertia on head and brain response. The first study compared the head kinematics of the HNM to those of the ATD simulation using the boundary conditions of the linear impactor test. It was found that the HNM and ATD had similar head acceleration and angular velocity in the primary direction of impact, and exhibited similar responses regardless of muscle activation. Differences between the ATD and HNM were identified in the axial head acceleration, attributed to axial neck stiffness, and longer term metrics measured at the base of the neck differed but did not have a large effect on the short-term head response assessed using existing head response metrics (HIC, BrIC, HIP). In the second study, two boundary conditions were investigated for a head FE model: (1) a commonly-used simplified boundary condition where head model kinematics are prescribed from experimentally measured ATD kinematics and (2) a full simulation of the HNM, helmet and linear impactor. The second approach enables the opportunity to assess the effect of modifications to the helmet. While the lateral and rear impacts exhibited similar levels of Maximum Principal Strain (MPS) in the brain tissue using both the prescribed kinematics and simulated HNM boundary condition, differences were noted in the frontal orientation (MPS varied by
Author: Rachanna Anna Oeur
Publisher:
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Category :
Languages : en
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Falls and collisions are the most common types of events leading to sports-related concussions where impacts to the head play an important role on the onset of traumatic brain injury. Each event can be described by impact parameters that define the loading conditions on the head and brain and are necessary for accurate accident reconstruction employing physical impact tests, anthropometric headforms, and finite element (FE) modelling. It was the purpose of this research to describe the effects and interactions of impact velocity, compliance, mass and impact location on head acceleration and brain tissue strain measures associated with risk of concussions in sports. Impact parameters were varied to capture responses from no-injury up to concussive levels. Study one examined the effect of impact parameters on fall events simulated using a monorail drop tower. Impact mass was varied using three different headforms representing child, adolescent, and adult sizes measuring peak linear and angular acceleration and maximum principal strain. Regression analysis revealed that impact compliance was the most influential on peak linear and angular acceleration measures, meanwhile FE strain was most affected by changes in impact velocity. Smaller headforms tend to produce higher acceleration and strain values, supporting the need for age and size related mechanical definitions of risk. Study two examined the effect of impact parameters for collision events simulated using a multi-mass pendulum to represent common striking masses in sport measuring peak linear and angular acceleration and strain. Study three provided further insight into collision impacts by evaluating the distribution of peak strains in different brain lobes and the volume of the brain experiencing strains passed a critical level. Results show that compliance was similarly the most influential on peak head acceleration whereas peak strain and volume were most affected by impact velocity. Mass-velocity interactions had effects where a 9 kg mass had greater response than 15 kg, but similar to 21 kg. The temporal lobe consistently contained the highest strains with the rear boss non-centric impact location producing the largest values. Interacting impact parameters illustrate the challenges with predicting associated risk of concussion from head collisions in sport and supports the need to identify effective performance ranges of protective materials.
Author: Clara Karton
Publisher:
ISBN:
Category : Biomechanics
Languages : en
Pages :
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The varied impact parameters that characterize an impact to the head have shown to influence the resulting type and severity of outcome injury, both in terms of the dynamic response, and the corresponding deformation of neural tissue. Therefore, when determining head injury risks through event reconstruction, it is important to understand how individual impact characteristics influence these responses. The effect of inbound mass had not yet been documented in the literature. The purpose of this study was to determine the effects of inbound mass on the dynamic impact response and brain tissue deformation. A 50th percentile Hybrid III adult male head form was impacted using a simple pendulum system. Impacts to a centric and a non-centric impact location were performed with six varied inbound masses at a velocity of 4.0 m/s. The peak linear and peak angular accelerations were measured. A finite element model, (UCDBTM) was used to determine brain deformation, namely peak maximum principal strain and peak von Mises stress. Inbound mass produced significant differences for peak linear acceleration for centric (F(5, 24) = 217.55, p=.0005) and non-centric (F(5, 24) = 161.98, p=.0005), and for peak angular acceleration for centric (F(5, 24) = 52.51, p=.0005) and non-centric (F(5, 24) = 4.18, p=.007) impact locations. A change in inbound mass also had a significant effect on peak maximum principal strain for centric (F(5, 24) = 11.04, p=.0005) and non-centric (F(5, 24) = 5.87, p =.001), and for peak von Mises stress for centric (F(5, 24) = 24.01, p=.0005) and non-centric (F(5, 24) = 4.62, p=.004) impact locations. These results indicate the inbound mass of an impact should be of consideration when determining risks and prevention to head and brain injury.
Author: Alan B. Ashare
Publisher: ASTM International
ISBN: 0803124880
Category : Geometry
Languages : en
Pages : 317
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