Academic literature on the topic 'Head impact kinematics'
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Journal articles on the topic "Head impact kinematics"
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Patton, Declan A., Colin M. Huber, Susan S. Margulies, Christina L. Master, and Kristy B. Arbogast. "NON-HEADER IMPACT EXPOSURE AND KINEMATICS OF MALE YOUTH SOCCER PLAYERS." Biomedical Sciences Instrumentation 57, no. 2 (April 1, 2021): 106–13. http://dx.doi.org/10.34107/yhpn9422.04106.
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Previous studies have investigated the head impact kinematics of purposeful heading in youth soccer; however, less than a third of all head injuries in youth soccer have been found to involve ball contact. The aim of the current study was to identify the head impact kinematics and exposure not associated with purposeful heading of the ball in male youth soccer. Headband-mounted sensors were used to monitor the head kinematics of male junior varsity and middle school teams during games. Video analysis of sensor-recorded events was used to code impact mechanism, surface and site. Junior varsity players had non-header impact rates of 0.28 per athlete-exposure (AE) and 0.37 per player-hour (PH), whereas middle school players had relatively lower non-header impact rates of 0.16 per AE and 0.25 per PH. Such impact rates fell within the large range of values reported by previous studies, which is likely affected by sensor type and recording trigger threshold. The most common non-header impact mechanism in junior varsity soccer was player contact, whereas ball-to-head was the most common non-header impact mechanism in middle school soccer. Non-header impacts for junior varsity players had median peak kinematics of 31.0 g and 17.4 rad/s. Non-header impacts for middle school players had median peak kinematics of 40.6 g and 16.2 rad/s. For non-header impacts, ball impacts to the rear of the head the highest peak kinematics recorded by the sensor. Such data provide targets for future efforts in injury prevention, such as officiating efforts to control player-to-player contact.
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Pritchard, Stewart, Tanner Filben, Sebastian Haja, Logan Miller, Mark Espeland, Joel Stitzel, and Jillian Urban. "Comparison of Head Impact Exposure Across Common Activities in Youth Soccer." Neurology 98, no. 1 Supplement 1 (December 27, 2021): S24.1—S24. http://dx.doi.org/10.1212/01.wnl.0000801964.42946.75.
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ObjectiveThe objective of this study was to compare head impact exposure across common training activities in soccer.BackgroundSoccer is a popular youth sport in the United States, but repetitive head impacts during training may result in neurocognitive deficits. Current research has identified factors associated with increased head impact exposure in soccer, but research has yet to contextualize head impact exposure across soccer activities. Modifying practice structure may be an avenue for reducing head impact exposure and concussion risk in soccer.Design/MethodsEight U15 soccer players participated in this study for 2 soccer seasons. Players wore a custom instrumented mouthpiece sensor during all practices and games. On-field activities were recorded with a time-synchronized camera. Research personnel recorded the duration of all practice (e.g., technical training, team interaction) and game activities performed by each player, and film review was performed to identify all head contact events during each session. Head impact exposure was quantified in terms of peak kinematics and impacts per player per hour. The amount of time an athlete was exposed to an activity was also evaluated. Mixed effects models were used to compare peak kinematics and generalized linear models were used to compare impact rates across activity types.ResultsActivity types were associated with peak kinematics and impact rate. Technical training activities were associated with higher impact rates and lower mean kinematics compared to other activity types. Team interaction activities and game play were associated with the highest rotational kinematics, but the lowest impact rates. A similar number of player-to-player contact events occurred within technical training, team interaction, and game play activities.ConclusionsInterventions designed to reduce head impact frequency in soccer may benefit from targeting technical training activities; whereas, interventions designed to reduce head impact magnitude may benefit from targeting team interaction and game activities.
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Huber, Colin M., Declan A. Patton, Susan S. Margulies, Christina L. Master, and Kristy B. Arbogast. "Quantifying Head Impact Exposure, Mechanisms and Kinematics Using an Instrumented Mouthguard in Female High School Lacrosse." Orthopaedic Journal of Sports Medicine 10, no. 5_suppl2 (May 1, 2022): 2325967121S0040. http://dx.doi.org/10.1177/2325967121s00403.
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Background: There is growing concern for the neurological effects of repetitive head impacts in sports, and girls’ lacrosse represents a popular but understudied sport regarding head impact exposure. Current debate exists over the need for enhanced protective equipment, and it is important to quantify head impact exposure and biomechanics to inform policy discussions and rule changes for improved protection. Purpose: To quantify the head impact biomechanics, by impact mechanism and direction, of female high school lacrosse players during games using an instrumented mouthguard. Methods: A female high school varsity lacrosse team wore the Stanford Instrumented Mouthguard during competitive games for the 2019 season. Video footage was reviewed to confirm head impact events and remove false-positive recordings. For each impact event, the mechanism was coded as stick contact, player contact, fall, or ball contact, and the site was coded as face/jaw, forehead, crown, side, rear or indirect (i.e. body impact with no head contact). Head impact rates were calculated per athlete exposure (AE, defined as a single player participating in a game). Results: Sensor data were recorded for 15 players for 14 games and 97 AEs. During games, 31 sensor-recorded head impacts were video-confirmed resulting in a pooled average head impact rate of 0.32 impacts/AE. The 31 video-confirmed impacts were distributed among stick contacts (17, 54.8%), player contacts (12, 38.7%), and falls (2, 6.5%). There were no ball impacts. The associated peak kinematics are presented in Figure 1.1. The most common impact site was the side (11, 35.5%), followed by face/jaw (8, 25.8%), forehead (2, 6.5%), and crown (2, 6.5%). There were no impacts to the rear of the head and 8 (25.8%) impacts were indirect. The associated peak kinematics are presented in Figure 1.2. Conclusion: Stick impacts were the most common impact mechanism and resulted in the highest peak linear and angular kinematics, which may help explain why they are the most common cause of head injury in female lacrosse. By quantifying the head impact exposure, kinematics and mechanisms in female high school lacrosse, targeted injury preventions can be developed, such as rule changes and protective equipment. [Figure: see text][Figure: see text]
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Bretzin, Abigail C., Jamie L. Mansell, Ryan T. Tierney, and Jane K. McDevitt. "Sex Differences in Anthropometrics and Heading Kinematics Among Division I Soccer Athletes." Sports Health: A Multidisciplinary Approach 9, no. 2 (November 15, 2016): 168–73. http://dx.doi.org/10.1177/1941738116678615.
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Background: Soccer players head the ball repetitively throughout their careers; this is also a potential mechanism for a concussion. Although not all soccer headers result in a concussion, these subconcussive impacts may impart acceleration, deceleration, and rotational forces on the brain, leaving structural and functional deficits. Stronger neck musculature may reduce head-neck segment kinematics. Hypothesis: The relationship between anthropometrics and soccer heading kinematics will not differ between sexes. The relationship between anthropometrics and soccer heading kinematics will not differ between ball speeds. Study Design: Pilot, cross-sectional design. Level of Evidence: Level 3. Methods: Division I soccer athletes (5 male, 8 female) were assessed for head-neck anthropometric and neck strength measurements in 6 directions (ie, flexion, extension, right and left lateral flexions and rotations). Participants headed the ball 10 times (25 or 40 mph) while wearing an accelerometer secured to their head. Kinematic measurements (ie, linear acceleration and rotational velocity) were recorded at 2 ball speeds. Results: Sex differences were observed in neck girth ( t = 5.09, P < 0.001), flexor and left lateral flexor strength ( t = 3.006, P = 0.012 and t = 4.182, P = 0.002, respectively), and rotational velocity at both speeds ( t = −2.628, P = 0.024 and t = −2.227, P = 0.048). Neck girth had negative correlations with both linear acceleration ( r = −0.599, P = 0.031) and rotational velocity at both speeds ( r = −0.551, P = 0.012 and r = −0.652, P = 0.016). Also, stronger muscle groups had lower linear accelerations at both speeds ( P < 0.05). Conclusion: There was a significant relationship between anthropometrics and soccer heading kinematics for sex and ball speeds. Clinical Relevance: Neck girth and neck strength are factors that may limit head impact kinematics.
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Filben, Tanner M., Nicholas S. Pritchard, Logan E. Miller, Sarah K. Woods, Megan E. Hayden, Christopher M. Miles, Jillian E. Urban, and Joel D. Stitzel. "Characterization of Head Impact Exposure in Women’s Collegiate Soccer." Journal of Applied Biomechanics 38, no. 1 (February 1, 2022): 2–11. http://dx.doi.org/10.1123/jab.2020-0304.
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Soccer players are regularly exposed to head impacts by intentionally heading the ball. Evidence suggests repetitive subconcussive head impacts may affect the brain, and females may be more vulnerable to brain injury than males. This study aimed to characterize head impact exposure among National Collegiate Athletic Association women’s soccer players using a previously validated mouthpiece-based sensor. Sixteen players were instrumented during 72 practices and 24 games. Head impact rate and rate of risk-weighted cumulative exposure were compared across session type and player position. Head kinematics were compared across session type, impact type, player position, impact location, and ball delivery method. Players experienced a mean (95% confidence interval) head impact rate of 0.468 (0.289 to 0.647) head impacts per hour, and exposure rates varied by session type and player position. Headers accounted for 89% of head impacts and were associated with higher linear accelerations and rotational accelerations than nonheader impacts. Headers in which the ball was delivered by a long kick had greater peak kinematics (all P < .001) than headers in which the ball was delivered by any other method. Results provide increased understanding of head impact frequency and magnitude in women’s collegiate soccer and may help inform efforts to prevent brain injury.
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Huber, Colin M., Declan A. Patton, Susan Margulies, Christina Master, and Kristy Arbogast. "Head Impact Exposure and Mechanisms in Female High School Lacrosse via an Instrumented Mouthguard." Neurology 98, no. 1 Supplement 1 (December 27, 2021): S13.2—S14. http://dx.doi.org/10.1212/01.wnl.0000801856.45976.d2.
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ObjectiveTo quantify the head impact biomechanics, by impact mechanism, of female high school lacrosse players during games using an instrumented mouthguard.BackgroundThere is growing concern for the neurologic effects of repetitive head impacts in sports, which have been linked with several short-term neurophysiologic deficits. Girls' lacrosse represents a popular but understudied sport with regard to head impact exposure and current debate exists as to the need for enhanced protective equipment.Design/MethodsA female high school varsity lacrosse team wore the Stanford Instrumented Mouthguard during competitive games for the 2019 season. Video footage was reviewed to confirm head impact events and remove false-positive recordings. For each impact event, the mechanism was coded as stick contact, player contact, fall, or ball contact. Head impact rates were calculated per athlete exposure (AE, defined as a single player participating in a single game).ResultsSensor data were recorded for 15 female varsity lacrosse players for 14 games and 97 AEs. During games, 31 sensor-recorded head impacts were video-confirmed resulting in a pooled average head impact rate of 0.32 impacts/AE. The video-confirmed impacts were distributed between stick contact (17, 54.8%), player contact (12, 38.7%), and falls (2, 6.5%). There were no ball impacts. Overall peak kinematics were 34.0 ± 26.6 g, 12.0 ± 9.1 rad/s, and 3,666.5 ± 2,987.6 rad/s2. Stick contacts had the highest peak linear acceleration (42.7 ± 32.2 g), angular velocity (14.5 ± 11.1 rad/s), and angular acceleration (4,242.4 ± 3,634.9 rad/s2).ConclusionsStick impacts were the most common impact mechanism and resulted in the highest peak linear and angular kinematics, which may help explain why they are the most common cause of head injury in female lacrosse. By quantifying the head impact exposure, kinematics and mechanisms in female high school lacrosse, targeted injury preventions can be developed, such as rule changes and protective equipment.
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Viano, David C., Hans von Holst, and Per Lovsund. "Simulation of brain kinematics in closed head impact." International Journal of Crashworthiness 1, no. 4 (January 1996): 413–28. http://dx.doi.org/10.1533/cras.1996.0030.
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Swenson, Abigail, Logan Miller, Jillian Urban, and Joel Stitzel. "Head Kinematics by Contact Scenarios in Youth Ice Hockey." Neurology 95, no. 20 Supplement 1 (November 16, 2020): S1.1—S1. http://dx.doi.org/10.1212/wnl.0000000000011045.
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ObjectiveThe objective of this pilot study was to characterize head impact exposure in a sample of youth boys' ice hockey using a novel instrumented mouthpiece, improving accuracy.BackgroundFrom 2010 to 2018 youth ice hockey saw a 15% increase in participation, despite growing concerns for concussion risk in contact sports. While contact sports with similar rates of concussion have been subjected to rigorous study, head impact exposure in youth ice hockey has been largely underexplored. Existing youth studies have utilized helmet-mounted sensors, which are associated with error due to poor coupling with the skull.Design/MethodsCustom mouthpieces containing a tri-axial accelerometer and gyroscope were fit to seven enrolled athletes, and monitored during practices and games throughout the season. Linear acceleration and rotational velocity of the head were recorded for 60 ms when 5 g was exceeded on any axis for at least 3 ms. Time-synchronized film was reviewed to identify the contact scenario and head contact. Summary statistics of kinematics were calculated by scenario and presence of head contact.ResultsA total of 465 events were recorded over 25 weeks. Of these events 25% involved head contact; 92% of all contact scenarios were board checks, falls, or ice checks. Events involving head contact (i.e., head impacts) had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 8.1 [30.9] g, 7.9 [20.2] rad/s, and 614 [2673] rad/s2, respectively. Events not involving head contact had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 6.6 [43.8] g, 6.5 [17.5] rad/s, and 455 [4115] rad/s2, respectively.ConclusionsThe majority of the recorded events could be classified as board checks, falls, or ice checks. Median peak kinematics were higher for head impacts than non-head impact events. In contrast, 95th percentile linear and angular accelerations were greater for impacts not involving head contact.
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DiFabio, M. S., and T. A. Buckley. "Relationships between Head Impacts, Competitive Aggression, and Risk-taking Behavior in Collegiate Ice Hockey Players." Archives of Clinical Neuropsychology 34, no. 5 (July 2019): 780. http://dx.doi.org/10.1093/arclin/acz026.50.
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Abstract Purpose To examine relationships between head impact kinematics sustained over a season and competitive aggression and self-reported risk-taking behavior in collegiate club ice-hockey athletes. Methods Twenty male ice-hockey players (19.9±1.2 y.o, 1.8±0.06 m, 78.5±5.7 kg) completed the Competitive Anger and Aggression Scale (CAAS, Range:0-84) and the Brief Sensation Seeking Scale (BSSS, Range:8-40) during the preseason as measures of competitive aggression and risk-taking behavior with higher/lower reflecting higher/lower aggression and risk taking. Penalty minutes (PM) and games played (GP) were taken from official game records. Head impact kinematics (number of impacts, linear mean, peak, cumulative acceleration) were recorded by tri-axial accelerometers worn during games/practices. Spearman correlation was performed to examine relationships between variables. Results The mean number of impacts was 76.6±54.9 (range: 6–171); mean and cumulative acceleration were 36.3±4.2g (range:27.8–42.2g) and 2829.4±2024.9g (range:198.4–6527.2g), respectively. Neither CAAS (mean: 48.7±10.9, range: 24–64) nor BSSS scores (mean: 25.3±4.4, range:15–32) were significantly related to impact kinematics. GP was significantly correlated with number of impacts (r=.63, p=.003) and cumulative linear acceleration (r=.61, p=.004). PM was significantly correlated with number of impacts (r=.52, p=.20) and cumulative linear acceleration (r=.55, p=.13). Conclusion There were no relationships between the head impact kinematics and self-reported aggressiveness or risk taking behavior, but more PM was strongly related to higher head impact loads. Considering PM may be useful in aiding to identify athletes who may sustain higher head impact loads, however, self-reports of behavior may not be.
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Pritchard, N. Stewart, and Jillian E. Urban. "AN ANALYSIS OF HEAD KINEMATICS IN WOMEN'S ARTISTIC GYMNASTICS." Science of Gymnastics Journal 12, no. 3 (November 3, 2022): 229–42. http://dx.doi.org/10.52165/sgj.12.3.229-242.
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Concussions in gymnastics have scarcely been researched; however, current evidence suggests that concussion rates may be higher than previously reported due to underreporting among coaches, athletes, and parents. The purpose of this study was to outline a method for collecting head impact data in gymnastics, and to provide the first measurements of head impact exposure within gymnastics. Three optional level women’s artistic gymnasts (ages 11-16) were instrumented with a mouthpiece sensor that measured linear acceleration, rotational velocity, and rotational acceleration of the head during contact and aerial phases of skills performed during practice. Peak linear acceleration, peakrotational velocity, peak rotational acceleration, duration, and time to peak linearacceleration were calculated from sensor data. Kinematic data was time-synchronized to videoand then sensor data was segmented into contact scenarios and skills characterized by theevent rotation, apparatus, landing mat type, skill type, skill phase, landing stability, andbody region contacted. The instrumented gymnasts were exposed to 1,394 contact scenarios(41 per gymnast per session), of which 114 (3.9 per gymnast per session) contained headcontact. Peak kinematics varied across skill type, apparatuses, and landing mats. The medianduration of impacts with head contact (177 ms) was longer than measured impacts in youth andcollegiate level soccer. Results from this study help provide a foundation for future researchthat may seek to examine head impact exposure within gymnastics to better informconcussion prevention and post-concussion return to play protocols within the sport.
Dissertations / Theses on the topic "Head impact kinematics"
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Bland, Megan Lindsay. "Assessing the Efficacy of Bicycle Helmets in Reducing Risk of Head Injury." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89478.
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Although cycling offers many health and environmental benefits, it is not an activity free of injury risk. Increases in cycling popularity in the United States over the past 15 years have been paralleled by a 120% growth in cycling-related hospital admissions, with injuries to the head among the most common and debilitating injuries. Bicycle helmets can reduce head injury risk and are presently required to meet safety standard certification criteria specifying a minimal level of acceptable impact protection. However, the conditions surrounding cyclist head impacts are thought to be much more complex than the test conditions prescribed in standards and have important implications related to mechanisms of injury. The overarching aim of this dissertation was thus to investigate the protective capabilities of bicycle helmets in the context of real-world impact conditions and relevant head injury mechanisms. This aim was achieved through a series of studies, the objectives of which were to: compare helmet impact performance across standards impact testing and more realistic, oblique impact testing; to probe how changing boundary conditions of oblique impact testing may influence helmet test outcomes; to use this knowledge to inform the development of an objective helmet evaluation protocol reflective of realistic impact conditions and related head injury risks; and finally, to enhance the body of knowledge pertaining to cyclist head impact conditions via advanced helmet damage reconstruction techniques. The compilation of results across these studies serves to enhance cyclist safety by stimulating improved helmet evaluation and design while simultaneously providing objective, biomechanical data to consumers, enabling them to make safety-based purchasing decisions.Doctor of Philosophy
Although cycling offers many health and environmental benefits and is increasing in popularity in the United States, it is not always a perfectly safe activity. The number of cycling-related hospital admissions in the US has been increasing over the past 15 years. Cyclists often sustain head injuries from crashes, which can be particularly debilitating. Fortunately, wearing a helmet can protect against head injuries during a crash. Bicycle helmets are presently designed around safety standards that drop a helmeted dummy head onto a horizontal anvil and require the helmet to limit the force on the head to acceptable levels. However, standards tests overly simplify how cyclists actually hit their head during a crash and are consequently unable to assess how well helmets protect against common brain injuries like concussion. The overarching goal of this research was to evaluate how effectively bicycle helmets protect cyclists from concussion in realistic impact scenarios. Several studies were conducted to achieve this goal. Their individual objectives were to: compare how bicycle helmets reduce impact forces associated with standards tests versus more realistic, angled impact tests; to understand how changing constraints of an angled impact setup influences helmet effectiveness; to develop an unbiased evaluation protocol for bicycle helmets based on realistic cyclist crash scenarios and concussion risk assessment; and finally, to further explore how cyclists impact their head in real-world crashes using advanced techniques for reconstructing bicycle helmet damage from actual accidents. All of these studies lead to improved cyclist safety by stimulating improved helmet evaluation and design, while also providing consumers with information on how protective their helmets are.
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Kieffer, Emily Elana. "Sex-Specific Head Impact Exposure in Rugby: Measurement Considerations and Relationships to Clinical Outcomes." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103203.
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Concussions are diffuse injuries that affect areas of the brain responsible for a person's physical, cognitive, and emotional health. Although concussions were once thought only to present transient symptoms, mounting evidence suggests potential for long-term neurological impairments. The deleterious effects of concussion can be from a single, high severity impact event or the accumulation of lower severity impacts. Clinical changes that can result from concussion include an elevated symptom presentation and changes in gait, or an individual's walking pattern. It is not well understood if similar deficits result after an accumulation of subconcussive impacts. The majority of research on human tolerance to head injury has been based on American football, using helmet-mounted sensors in male athletes. Limited studies have attempted to quantify biomechanical tolerance in women, despite the sex-specific nature of presentation and outcome of concussion. Biomechanical, physiologic, and psychosocial factors differ between males and females, likely contributing to this difference.
The research presented in this dissertation was aimed at describing sex-specific outcomes of subconcussion in a matched cohort of male and female athletes to gain a better sense of unhelmeted, sex-specific tolerance to head impacts. On-field data were collected from collegiate rugby players using instrumented mouthguards. Rugby involves high energy, frequent head impacts, does not require protective headgear, and is played the same for both men and women. The females in our study sustained fewer impacts per session than the males, but their impacts had similar linear acceleration magnitudes. The kinematics of the concussive male impacts were higher than the kinematics of the concussive female impacts. Both sexes reported concussion-like symptoms in the absence of diagnosed concussion during a season. Females reported more symptoms with a higher severity in-season compared to males after subconcussive and concussive impacts. Female athletes saw deficits in cadence, double support time, gait speed, and stride length post-concussion. The majority of athletes improved in their dual-task gait assessment by the end of the season, suggesting there may not be a negative effect on gait after an accumulation of subconcussive impacts. This work assessed the biomechanics of head impacts and concussions of this population, and evaluated changes in symptom presentation through weekly graded symptom surveys and dual-task gait assessments both after a concussion and as an effect of subconcussive impacts. Understanding the sex-specific clinical effects of head impacts is critical, and can provide insight into concussion diagnostic, management, and prevention tools that are appropriate and effective.Doctor of Philosophy
Concussions are injuries that affect many areas of the brain, including those responsible for a person's physical, cognitive, and emotional health. Although concussions were once thought only to present transient symptoms, mounting evidence suggests potential for long-term neurological impairments. The harmful effects of concussion can be from a single, high intensity impact event or the build-up of lower intensity impacts. Clinical changes that can result from concussion include an elevated symptom presentation and changes in gait, or an individual's walking pattern. It is not well understood if similar side effects result after an accumulation of subconcussive impacts. The majority of research on human tolerance to head injury has been based on American football, using helmet-mounted sensors in male athletes. Limited studies have attempted to quantify concussion tolerance in women, despite the differences in men and women's symptoms and recovery time after a concussion. Female's neck strength, hormones, and increased honesty in reporting concussion differ from males, likely contributing to this difference. The research presented in this dissertation was aimed at describing how sex affects the results of subconcussion in a group of male and female athletes to gain a better sense of unhelmeted, sex-specific tolerance to head impacts. On-field data were collected from collegiate rugby players using sensor-embedded mouthguards. Rugby involves high energy, frequent head impacts, does not require protective headgear, and is played the same by both men and women. The females in our study sustained fewer impacts per session than the males, but their impacts were similar in magnitude. The impact energies of the concussive male impacts were higher than those of the concussive female impacts. Both sexes reported concussion-like symptoms in the absence of diagnosed concussion during a season. Females reported more symptoms with a higher severity in-season compared to males after subconcussive and concussive impacts. Female athletes had a slower walking pace and walking speed, a shorter stride length, and spent more time with both feet on the ground post-concussion. The majority of athletes improved in their dual-task gait assessment by the end of the season, suggesting there may not be a negative effect on gait after an accumulation of subconcussive impacts. This work assessed the biomechanics of head impacts and concussions of this population, and evaluated changes in symptom presentation through weekly graded symptom surveys and dual-task gait assessments both after a concussion and as an effect of subconcussive impacts. Understanding the sex-specific clinical effects of head impacts is critical, and can provide insight into concussion diagnostic, management, and prevention tools that are appropriate and effective.
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Kang, Yun Seok. "Evaluation of Biofidelity of Anthropomorphic Test Devices and Investigation of Cervical Spine Injury in Rear Impacts: Head-Neck Kinematics and Kinetics of Post Mortem Human Subjects." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313554843.
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Dall'Acqua, Nicolo. "Analysis and reconstruction of head kinematics during accidents in fast alpine skiing disciplines : Experimental research about the accuracy and drawbacks associated with a video analysis tool." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302561.
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Head injuries caused by impacts are among the most critical and dangerous types of accidents that can occur while practising sports. Alpine skiing is one of the activities with the highest incidence of head injuries. Over the years, specific regulations have been introduced to protect athletes where possible, but the perception is that the level of protection needed to manage the forces to which they are exposed has yet to be achieved. This thesis project aims to examine video sequences of accidents in alpine ski competitions (Giant Slalom, Super-G, Downhill, Ski Cross) to better understand the translational violence exerted on the head during impacts. After an in-depth analysis, it was shown that, in at least 41% of the videos investigated, the translational impact speeds exceeded the standards adopted in helmet certifications by 44.3% and 52.2%, respectively. Besides, in 60% of these accidents, the blow was located on the upper semicircle of the helmet, which is believed to be due to the ever-increasing use of airbags for the torso.Huvudskador orsakade av slag är bland den alvarligaste typen av olyckor som kan inträffa vid utövande av idrott. Alpin skidåkning är en av de sporter med den högsta förekomsten av skador på huvudet. Under årens lopp har särskilda regler införts för att skydda atleterna där så är möjligt, men uppfattningen är att den skyddsnivå som krävs för att hantera de krafter åkarna utsätts för ännu inte har uppnåtts. Detta examensarbete syftar göra videoanalys på olyckor vid alpina skidtävlingar (Storslalom, Super-G, Störtlopp, Ski Cross) för att bättre förstå translationsvåldet mot huvudet vid olyckor. Efter en djupgående analys visades att i minst 41% av de undersökta fallen översteg translationshastigheten de hastigheter som används vid hjälmcertifieringar med 44.3% respektive 52.2%. För 60% av olyckorna skedde slaget högt upp på bakre delen av hjälmen, något som tros bero på den ökande användningen av krockkuddar för torso.
Book chapters on the topic "Head impact kinematics"
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Kobayashi, Shiro, Soo-Ik Oh, and Taylan Altan. "Metal-Forming Processes." In Metal Forming and the Finite-Element Method. Oxford University Press, 1989. http://dx.doi.org/10.1093/oso/9780195044027.003.0005.
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In metal forming, an initially simple part—a billet or sheet blank, for example—is plastically deformed between tools (or dies) to obtain the desired final configuration. Thus, a simple part geometry is transformed into a complex one, in a process whereby the tools “store” the desired geometry and impart pressure on the deforming material through the tool-material interface. The physical phenomena constituting a forming operation are difficult to express with quantitative relationships. The metal flow, the friction at the tool-material interface, the heat generation and transfer during plastic flow, and the relationships between microstructure/properties and process conditions are difficult to predict and analyze. Often, in producing discrete parts, several forming operations (preforming) are required to transform the initial “simple” geometry into a “complex” geometry, without causing material failure or degrading material properties. Consequently, the most significant objective of any method of analysis is to assist the forming engineer in the design of forming and/or preforming sequences. For a given operation (preforming or finish-forming), such design essentially consists of (1) establishing the kinematic relationships (shape, velocities, strain-rates, strains) between the deformed and undeformed part, i.e., predicting metal flow; (2) establishing the limits of formability or producibility, i.e., determining whether it is possible to form the part without surface or internal defects; and (3) predicting the forces and stresses necessary to execute the forming operation so that tooling and equipment can be designed or selected. For the understanding and quantitative design and optimization of metal-forming operations it is useful (a) to consider a metal forming process as a system and (b) to classify these processes in a systematic way. A metal-forming system comprises all the input variables relating the billet or blank (geometry and material), the tooling (geometry and material), the conditions at the tool-material interface, the mechanics of plastic deformation, the equipment used, the characteristics of the final product, and finally the plant environment in which the process is being conducted. Such a system is illustrated in Fig. 2.1, using impression die forging as an example.
Conference papers on the topic "Head impact kinematics"
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Zhang, Jiangyue, Narayan Yoganandan, and Frank A. Pintar. "Translational and Rotational Head Kinematics in Side Impact." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206140.
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Regulatory tests use translational head accelerations and its derived variable HIC (head injury criterion) as the criteria for automotive vehicle crashworthiness evaluation. The FMVSS standard sets HIC36 of 1000 as the threshold for frontal impact protection. On the other hand, rotational head kinematics, such as rotational accelerations and velocities, has been attributed to brain injury in the motor vehicle environment for more than six decades [1–5]. As documented in recent real-world case studies, severe brain injuries without skull fracture, such as diffuse axonal injury, can result from rotational head motions in side impacts even at low change in impact velocity [6, 7]. Because the HIC only accounts for the translational head accelerations, there is no clear evidence showing there is a direct correlation between translational and rotational head acceleration. Therefore, it is important to quantify the correlation between head translational and rotational accelerations and HIC, in side impacts. Consequently, the current research was designed with this purpose.
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Hernandez, Fidel, Pete B. Shull, Bruce Cam, Lyndia Wu, Rebecca Shultz, Dan Garza, and David B. Camarillo. "Comparing In Vivo Head Impact Kinematics From American Football With Laboratory Drop and Linear Impactors." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14680.
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Roughly 5% of all collegiate and high school American football players suffer a concussion each season [1]. Concussions and repetitive sub-concussive trauma can have measurable effects on brain function and neurophysiological changes [2]. Several studies have suggested that a combination of linear and angular kinematic measures may be predictive of concussion [3, 4]. Presently, laboratory testing and analysis of purely linear kinematics is used to design and assess the safety of protective headgear. However, it is not known how well existing laboratory tests recapitulate angular kinematics. In this study, we analyze combinations of linear and angular head kinematics experienced by players on the field. This study sought to answer the question: how well do the twin-wire drop test apparatus and a spring-driven linear impactor reproduce the combination of linear and angular head impact kinematics experienced in vivo by players of American football?
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Pal, Chinmoy, Shigeru Hirayama, Pratap Naidu Vallabhaneni, Kulothungan Vimalathithan, and Jeyabharath Manoharan. "Comparison of Head Kinematics of Bicyclist in Car-to-Bicycle Impact." In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2020. http://dx.doi.org/10.4271/2020-01-0932.
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Stemper, Brian D., Narayan Yoganandan, and Frank A. Pintar. "Segmental Cervical Spine Kinematics Due to Posteroanterior Impact Acceleration." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32630.
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An experimental investigation was performed to determine the segmental cervical spine kinematics in rear impact acceleration. Segmental motions were analyzed at the time of maximum S-curve for 10 isolated head-neck specimens (5 male, 5 female). Females experienced greater segmental angles at each level of the spine for all input velocities. Statistically significant gender differences were obtained for levels C2-C3, C5-C6, and C6-C7. Motions were statistically dependent upon input velocity for C4 to C7 segments. Results of this study provide a biomechanical basis for the differing rates of reported whiplash injuries between males and females.
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Meyer, Andrew, Jessica M. Fritz, and Gerald F. Harris. "TRID Cranial Analysis During Rear Impact Simulation With MADYMO." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206165.
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Early studies of cranial kinematics were primarily limited to sagittal plane assessments of motion secondary to impact in volunteers, models, anthropometric dummies and human specimens [1]. With advances in instrumentation and imaging technology, more relevant studies of three dimensional (3-D) motion began to emerge. More complex 3-D head kinematics were first quantified with arrays of precisely positioned multi-axis accelerometers [1]. This evolution in quantitative ability has continued to the present time with the application of high speed motion capture systems and more sophisticated mathematical models.
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Mkandawire, Chimba, Eric S. Winkel, Nicholas A. White, and Edward Schatz. "FOCUS Headform Testing Used to Evaluate Head Injury Risk for Ejected Riders of Personal Watercraft." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72676.
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Operators of personal watercraft (PWC) can perform maneuvers that may result in riders separating from the moving watercraft; the tested hypothesis was whether substantial brain injury concurrent with substantial facial and skull fractures can occur from contact with the PWC during a fall. The present study reports the potential for AIS2+ facial/skull fractures and AIS2+ traumatic brain injury (TBI) during a generic fall from the PWC in the absence of wave-jumping or other aggressive maneuvers. While it is well known that PWC can be used for wave-jumping which can result in more severe impacts, such impacts are beyond the scope of the present study because of the wide variability in occupant and PWC kinematics and possible impact velocities and orientations. Passenger separation and fall kinematics from both seated and standing positions were analyzed to estimate head impact velocities and possible impact locations on the PWC. A special purpose headform, known as the Facial and Ocular CountermeasUre Safety (FOCUS) device was used to evaluate the potential for facial fractures, skull fractures and TBI. Impacts between the FOCUS headform and the PWC were performed at velocities of 8, 10, and 12 miles per hour at 5 locations near the stern of a PWC. This study reports impact forces for various facial areas, linear and angular head accelerations, and Head Injury Criteria (HIC). The risk for facial fracture and TBI are reported herein. The results of this study indicate that concurrent AIS2 facial fractures, AIS2+ skull fractures, and AIS2+ TBI do not occur during a simple fall from a PWC.
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Tan, X. Gary, and Amit Bagchi. "Computational Analysis of Combat Helmet Protection Against Blunt Impact to Head." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-10903.
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Abstract Computational modeling provides significant benefits in assessing the helmet performance and identifying promising helmet designs. We develop multi-fidelity computational tools, representative virtual human head and helmet system models to help the design of next generation combat helmet with improved protection against blunt impact. By integrating the fast-running articulated human with personal protective equipment (PPE) biodynamics model with the high-fidelity human head with combat helmet finite element (FE) model, the multi-fidelity approach can be used to efficiently investigate impact-related traumatic brain injury (TBI) in the real-world scenario. The FE model is used to capture the dynamics of the composite helmet shell, foam pad suspension, retention strap and head while the biodynamics model provides the proper kinematics and boundary conditions for the FE model. An orthotropic elasto-plastic material with damage model is employed for the helmet shell. Enhanced tetrahedral elements are used to model the nearly-incompressible tissues. The head with helmet and without helmet under a severe impact due to a fall caused by blast loading are simulated and compared. The resulting biomechanical responses of head acceleration, shear stresses and strains in brain and mechanical injury criterion as well as helmet energy absorption are used to characterize the performance of helmet system.
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Stemper, Brian D., Narayan Yoganandan, and Frank A. Pintar. "Effects of Thoracic Ramping on Whiplash Kinematics." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59447.
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Whiplash injuries result from differential motion between the head and thorax. Experimental investigations using human volunteers and full body cadavers have described thoracic ramping due to interaction with the seatback and straightening of the thoracic spine. The effect of this motion on cervical kinematics has not been investigated. A head-neck computer model was used to determine the effects of thoracic ramping on whiplash kinematics. The model consisted of skull, cervical spine, first thoracic vertebra, intervertebral discs, spinal ligaments, facet joints, and passive musculature, and was subjected to 2.7 m/sec rear impact velocity. Vertical acceleration of T1 was prescribed according to literature. Segmental angulations and region dependent facet joint capsular ligament distractions were obtained from levels C2-C3 through C7-T1 during the time of cervical S-curvature. Maximum capsular ligament distractions during this time occurred in the dorsal region at the C2-C3 level and in the lateral region at the C3-C4 through C7-T1 levels. Increasing magnitudes of T1 ramping decreased segmental angulations and ligament distractions by less than 20% in most cases. Results of the present investigation demonstrated that thoracic ramping may play a secondary role in whiplash kinematics.
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Tan, X. Gary, and Amit Bagchi. "Modeling and Reconstruction of Multi-Fidelity Traumatic Head Injury due to Blunt Impact." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70610.
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Traumatic brain injury (TBI) is one of the most common injuries to service members in recent conflicts. Computational models can offer insights in understanding the underlying mechanism of brain injury, which lead to the crucial development of effective personal protective equipment designed to prevent or mitigate the TBI. Historically many computational models were developed for the brain injury study. However, these models use relatively coarse mesh with a less detailed head anatomy. Many models consider the head only and thus cannot properly model the real scenario, i.e., accidental fall, blunt impact or blast loading. A whole-body finite element model can represent the real scenario but is very expensive to use. By combining the high-fidelity human head model with an articulated human body model, we developed the computational multi-fidelity human models to investigate the blunt- and blast-related TBI efficiently. A high-fidelity computational head model was generated from the high resolution image data to accurately reproduce the complex musculoskeletal and tissue structure of the head. The fast-running articulated human body model is based on the multi-body dynamics and was used to reconstruct the accidental falls. By utilizing the kinematics and force and moment at the joint of the articulated human body model, we can realistically simulate the blunt impact and assess the brain injury using the high-fidelity head model.
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Roberts, J. C., T. P. Harrigan, E. E. Ward, D. Nicolella, L. Francis, T. Eliason, and A. C. Merkle. "The Influence of Neck Kinematics on Brain Pressures and Strains Under Blast Loading." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64821.
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Strains and pressures in the brain are known to be influenced by rotation of the head in response to loading. This brain rotation is governed by the motion of the head, as permitted by the neck, due to loading conditions. In order to better understand the effect neck characteristics have on pressures and strains in the brain, a human head finite element model (HHFEM) was attached to two neck FEMs: a standard, well characterized Hybrid III Anthropometric Test Device neck FEM; and a high fidelity parametric probabilistic human FEM neck that has been hierarchically validated. The Hybrid III neck is well-established in automotive injury prevention studies, but is known to be much stiffer than in vivo human necks. The parametric FEM is based on CT scans and anatomic data, and the components of the model are validated against biomechanical tests at the component and system level. Both integrated head-neck models were loaded using pressure histories based on shock tube exposures. The shock tube loading applied to these head models were obtained using a computational fluid dynamics (CFD) model of the HHFEM surface in front of a 6 inch diameter shock tube. The calculated pressure-time histories were then applied to the head-neck models. The global head rotations, pressures, brain displacements, and brain strains of both head-neck models were compared for shock tube driver pressures from 517 to 862 kPa. The intracranial pressure response occurred in the first 1 to 5 msec, after blast impact, prior to a significant kinematic response, and was very similar between the two models. The global head rotations and the strains in the brain occurred at 20 to 100 msec after blast impact, and both were approximately two times higher in the model using the head parametric probabilistic neck FEM (H2PN), as compared to the model using the head Hybrid III neck FEM (H3N). It was also discovered that the H2PN exhibited an initial backward and small downward motion in the first 10 ms not seen in the H3N. The increased displacements and strains were the primary difference between the two combined models, indicating that neck constraints are a significant factor in the strains induced by blast loading to the head. Therefore neck constraints should be carefully controlled in studies of brain strain due to blast, but neck constraints are less important if pressure response is the only response parameter of primary interest.
Reports on the topic "Head impact kinematics"
1
Selvaraju, Ragul, Hari Shankar, and Hariharan Sankarasubramanian. Metamodel Generation for Frontal Crash Scenario of a Passenger Car. SAE International, September 2020. http://dx.doi.org/10.4271/2020-28-0504.
Full textAbstract:
A frontal impact scenario was simulated using a Finite Element Model of a Hybrid III 50th percentile male (LSTC, Livermore CA) along with seatbelt, steering system and driver airbags. The boundary conditions included acceleration pulse to the seat and the outputs including injury measures in terms of Head Injury Criterion (HIC), Normalized Neck Injury Criterion (NIJ) and Chest Severity Index (CSI) were extracted from the simulations. The kinematics of the Hybrid III were validated against the kinematics of post mortem human surrogates (PMHS) available in the literature. Using the validated setup, metamodels were generated by creating a design of varying different parameters and recording the responses for each design. First, the X and Z translation of dummy along the seat is provided as input for which there was no variation in the head injury criterion (HIC). Next, the input pulse to the seat is parameterized along with the seatbelt loading and the results are obtained respectively. The outputs, in terms of injury measures, are generated in the form of metamodels as a function of the parameters. The occupant model used for the frontal crash scenario in LS-Dyna is validated against the previously available crash experimental data. A total of 100 design points was generated with a varying combination of parameters. An increase in various injury measures was observed with an increase in the scale factor of the acceleration pulse. Also, it was found that chest severity index increased with an increase in the scale factor of the seat belt loading force.
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Selvaraju, Ragul, Hari Shankar, and Hariharan Sankarasubramanian. Metamodel Generation for Frontal Crash Scenario of a Passenger Car. SAE International, September 2020. http://dx.doi.org/10.4271/2020-28-0504.
Full textAbstract:
A frontal impact scenario was simulated using a Finite Element Model of a Hybrid III 50th percentile male (LSTC, Livermore CA) along with seatbelt, steering system and driver airbags. The boundary conditions included acceleration pulse to the seat and the outputs including injury measures in terms of Head Injury Criterion (HIC), Normalized Neck Injury Criterion (NIJ) and Chest Severity Index (CSI) were extracted from the simulations. The kinematics of the Hybrid III were validated against the kinematics of post mortem human surrogates (PMHS) available in the literature. Using the validated setup, metamodels were generated by creating a design of varying different parameters and recording the responses for each design. First, the X and Z translation of dummy along the seat is provided as input for which there was no variation in the head injury criterion (HIC). Next, the input pulse to the seat is parameterized along with the seatbelt loading and the results are obtained respectively. The outputs, in terms of injury measures, are generated in the form of metamodels as a function of the parameters. The occupant model used for the frontal crash scenario in LS-Dyna is validated against the previously available crash experimental data. A total of 100 design points was generated with a varying combination of parameters. An increase in various injury measures was observed with an increase in the scale factor of the acceleration pulse. Also, it was found that chest severity index increased with an increase in the scale factor of the seat belt loading force.