Head Kinematics in Mini-Sled Tests of Foam Padding: Relevance of Linear Responses From Free Motion Headform (FMH) Testing to Head Angular Responses

2003 ◽  
Vol 125 (4) ◽  
pp. 523-532 ◽  
Author(s):  
J. Ivarsson ◽  
D. C. Viano ◽  
P. Lo¨vsund ◽  
Y. Parnaik
Keyword(s):  
Angular Velocity ◽  
Brain Injuries ◽  
Motor Vehicle ◽  
Sagittal Plane ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Free Motion ◽  
Constant Thickness ◽  
Head Impacts ◽  
Hybrid Iii

The revised Federal Motor Vehicle Safety Standard (FMVSS) No. 201 specifies that the safety performance of vehicle upper interiors is determined from the resultant linear acceleration response of a free motion headform (FMH) impacting the interior at 6.7 m/s. This study addresses whether linear output data from the FMH test can be used to select an upper interior padding that decreases the likelihood of rotationally induced brain injuries. Using an experimental setup consisting of a Hybrid III head-neck structure mounted on a mini-sled platform, sagittal plane linear and angular head accelerations were measured in frontal head impacts into foam samples of various stiffness and density with a constant thickness (51 mm) at low (∼5.0 m/s), intermediate (∼7.0 m/s), and high (∼9.6 m/s) impact speeds. Provided that the foam samples did not bottom out, recorded peak values of angular acceleration and change in angular velocity increased approximately linearly with increasing peak resultant linear acceleration and value of the Head Injury Criterion HIC36. The results indicate that the padding that produces the lowest possible peak angular acceleration and peak change in angular velocity without causing high peak forces is the one that produces the lowest possible HIC36 without bottoming out in the FMH test.

Laboratory Validation of a Wearable Sensor for the Measurement of Head Acceleration in Men's and Women's Lacrosse

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Jessica M. Buice ◽  
Amanda O. Esquivel ◽  
Christopher J. Andrecovich
Keyword(s):  
Angular Velocity ◽  
Brain Injuries ◽  
Wearable Sensors ◽  
Linear Acceleration ◽  
Wearable Sensor ◽  
Head Acceleration ◽  
Impact Location ◽  
Acceleration Data ◽  
Hybrid Iii ◽  
Correction Equations

Mild traumatic brain injuries, or concussions, can result from head acceleration during sports. Wearable sensors like the GForceTrackerTM (GFT) can monitor an athlete's head acceleration during play. The purpose of this study was to evaluate the accuracy of the GFT for use in boys' and girls' lacrosse. The GFT was mounted to either a strap connected to lacrosse goggles (helmetless) or a helmet. The assembly was fit to a Hybrid III (HIII) headform instrumented with sensors and impacted multiple times at different velocities and locations. Measurements of peak linear acceleration and angular velocity were obtained from both systems and compared. It was found that a large percent error between the GFT and headform system existed for linear acceleration (29% for helmetless and 123% for helmet) and angular velocity (48% for helmetless and 17% for helmet). Linear acceleration data transformed to the center of gravity (CG) of the head still produced errors (47% for helmetless and 76% for helmet). This error was substantially reduced when correction equations were applied based on impact location (3–22% for helmetless and 3–12% for helmet impacts at the GFT location and transformed to the CG of the head). Our study has shown that the GFT does not accurately calculate linear acceleration or angular velocity at the CG of the head; however, reasonable error can be achieved by correcting data based on impact location.

Protective Capabilities of a Watersports Helmet for Boom-to-Head Impacts During Sailing

2010 ◽  
Author(s):  
Lenka L. Stepan ◽  
Irving S. Scher ◽  
Reed Thomas
Keyword(s):  
United States ◽  
Head Injury ◽  
Angular Velocity ◽  
The United States ◽  
Testing Device ◽  
Laboratory Setting ◽  
Head Impacts ◽  
Hybrid Iii ◽  
Angular Velocities ◽  
Highly Correlated

In sailing, the boom comes across the boat during tacks and jibes and has potential to impact a participant’s head and cause injury. To our knowledge, there are no sailing specific helmets on the market in the United States. To determine the effectiveness of a wakeboarding helmet to mitigate the risk of head injury, we measured the boom angular velocity on a 24-foot keel sailboat during controlled jibes. The boom motion was recreated in a laboratory setting and positioned to contact the occiput of the instrumented head of a Hybrid III 50th percentile male anthropometric testing device (ATD). Tests were conducted with an unhelmeted ATD and with an ATD wearing a wakeboarding helmet. Boom angular velocities and head accelerations for unhelmeted impacts were highly correlated (R2 = 0.996). The watersports helmet reduced head accelerations by 52 ± 4% when compared to accelerations from unhelmeted impacts.

scholarly journals Brain injury in sports

2016 ◽  
Vol 124 (3) ◽  
pp. 667-674 ◽  
Author(s):  
John Lloyd ◽  
Frank Conidi
Keyword(s):  
Brain Injuries ◽  
Scientific Evidence ◽  
Head Injuries ◽  
Skull Fracture ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Impact Testing ◽  
Common Belief ◽  
Percentage Reduction ◽  
Football Helmets

OBJECT Helmets are used for sports, military, and transportation to protect against impact forces and associated injuries. The common belief among end users is that the helmet protects the whole head, including the brain. However, current consensus among biomechanists and sports neurologists indicates that helmets do not provide significant protection against concussion and brain injuries. In this paper the authors present existing scientific evidence on the mechanisms underlying traumatic head and brain injuries, along with a biomechanical evaluation of 21 current and retired football helmets. METHODS The National Operating Committee on Standards for Athletic Equipment (NOCSAE) standard test apparatus was modified and validated for impact testing of protective headwear to include the measurement of both linear and angular kinematics. From a drop height of 2.0 m onto a flat steel anvil, each football helmet was impacted 5 times in the occipital area. RESULTS Skull fracture risk was determined for each of the current varsity football helmets by calculating the percentage reduction in linear acceleration relative to a 140-g skull fracture threshold. Risk of subdural hematoma was determined by calculating the percentage reduction in angular acceleration relative to the bridging vein failure threshold, computed as a function of impact duration. Ranking the helmets according to their performance under these criteria, the authors determined that the Schutt Vengeance performed the best overall. CONCLUSIONS The study findings demonstrated that not all football helmets provide equal or adequate protection against either focal head injuries or traumatic brain injuries. In fact, some of the most popular helmets on the field ranked among the worst. While protection is improving, none of the current or retired varsity football helmets can provide absolute protection against brain injuries, including concussions and subdural hematomas. To maximize protection against head and brain injuries for football players of all ages, the authors propose thresholds for all sports helmets based on a peak linear acceleration no greater than 90 g and a peak angular acceleration not exceeding 1700 rad/sec2.

Head Kinematics by Contact Scenarios in Youth Ice Hockey

Neurology ◽  
2020 ◽  
Vol 95 (20 Supplement 1) ◽  
pp. S1.1-S1
Author(s):  
Abigail Swenson ◽  
Logan Miller ◽  
Jillian Urban ◽  
Joel Stitzel
Keyword(s):  
Rotational Velocity ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Contact Sports ◽  
Head Impacts ◽  
Rigorous Study ◽  
Improving Accuracy ◽  
Impact Events

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.

An Automated Kinematic Measurement System for Sagittal Plane Murine Head Impacts

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Kurt A. McInnes ◽  
Zelalem A. Abebe ◽  
Thomas Whyte ◽  
Asma Bashir ◽  
Carlos Barron ◽  
...  
Keyword(s):  
High Speed ◽  
Brain Injuries ◽  
Sagittal Plane ◽  
Tracking System ◽  
Head Impact ◽  
Percentage Error ◽  
Head Tracking ◽  
Rigid Fixation ◽  
Head Impacts ◽  
The Brain

Abstract Mild traumatic brain injuries are typically caused by nonpenetrating head impacts that accelerate the skull and result in deformation of the brain within the skull. The shear and compressive strains caused by these deformations damage neural and vascular structures and impair their function. Accurate head acceleration measurements are necessary to define the nature of the insult to the brain. A novel murine head tracking system was developed to improve the accuracy and efficiency of kinematic measurements obtained with high-speed videography. A three-dimensional (3D)-printed marker carrier was designed for rigid fixation to the upper jaw and incisors with an elastic strap around the snout. The system was evaluated by impacting cadaveric mice with the closed head impact model of engineered rotational acceleration (CHIMERA) system using an energy of 0.7 J (5.29 m/s). We compared the performance of the head-marker system to the previously used skin-tracking method and documented significant improvements in measurement repeatability (aggregate coefficient of variation (CV) within raters from 15.8 to 1.5 and between raters from 15.5 to 1.5), agreement (aggregate percentage error from 24.9 to 8.7), and temporal response (aggregate temporal curve agreement from 0.668 to 0.941). Additionally, the new system allows for automated software tracking, which dramatically decreases the analysis time required (74% reduction). This novel head tracking system for mice offers an efficient, reliable, and real-time method to measure head kinematics during high-speed impacts using CHIMERA or other rodent or small mammal head impact models.

scholarly journals Development of a Methodology for Simulating Complex Head Impacts With the Advanced Combat Helmet

2019 ◽  
Vol 184 (Supplement_1) ◽  
pp. 237-244
Author(s):  
Mark Begonia ◽  
Tyler Rooks ◽  
Frank A Pintar ◽  
Narayan Yoganandan
Keyword(s):  
Brain Injuries ◽  
Complex Loading ◽  
Free Fall ◽  
Head Motion ◽  
Computational Results ◽  
Head Impacts ◽  
Blunt Impact ◽  
Hybrid Iii ◽  
Athletic Equipment ◽  
Diffuse Brain

Abstract Blunt impact assessment of the Advanced Combat Helmet (ACH) is currently based on the linear head response. The current study presents a methodology for testing the ACH under complex loading that generates linear and rotational head motion. Experiments were performed on a guided, free-fall drop tower using an instrumented National Operating Committee for Standards on Athletic Equipment (NOCSAE) head attached to a Hybrid III (HIII) or EuroSID-2 (ES-2) dummy neck and carriage. Rear and lateral impacts occurred at 3.0 m/s with peak linear accelerations (PLA) and peak rotational accelerations (PRA) measured at the NOCSAE head center-of-gravity. Experimental data served as inputs for the Simulated Injury Monitor (SIMon) computational model to estimate brain strain. Rear ACH impacts had 22% and 7% higher PLA and PRA when using the HIII neck versus the ES-2 neck. Lateral ACH impacts had 33% and 35% lower PLA and PRA when using HIII neck versus the ES-2 neck. Computational results showed that total estimated brain strain increased by 25% and 76% under rear and lateral ACH impacts when using the ES-2 neck. This methodology was developed to simulate complex ACH impacts involving the rotational head motion associated with diffuse brain injuries, including concussion, in military environments.

The influence of deflection and neck compliance on the impact dynamics of a Hybrid III headform

2009 ◽  
Vol 223 (3) ◽  
pp. 89-97 ◽  
Author(s):  
P Rousseau ◽  
T B Hoshizaki
Keyword(s):  
Angular Acceleration ◽  
Linear Acceleration ◽  
Severity Index ◽  
Impact Dynamics ◽  
Risk Of Injury ◽  
Lateral Translation ◽  
Hybrid Iii ◽  
Front Impact ◽  
The Impact

The objective of this study was to determine the influence of impact deflection and neck compliance on the Gadd severity index (GSI), peak linear acceleration, and peak angular acceleration during a front impact to a Hybrid III head using a pneumatic linear impactor. Impact deflection was performed by translating the headform laterally and was shown to be effective at reducing the linear and angular accelerations as well as the GSI. Neck compliance was altered using one Hybrid III 50th percentile neck and two modified Hybrid III necks. A less compliant neck increased linear acceleration but decreased angular acceleration and GSI. When compared with estimated injury thresholds, the results demonstrated that an increase in the lateral translation or a decrease in the neck compliance resulted in a significant decrease in the risk of injury as reflected by peak linear and angular accelerations and the GSI.

Rotational Acceleration Duration Affects Brain Strains in Lateral Impact

2007 ◽  
Author(s):  
Jianrong Li ◽  
Jiangyue Zhang ◽  
Narayan Yoganandan ◽  
Frank A. Pintar ◽  
Thomas A. Gennarelli
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Brain Injuries ◽  
Motor Vehicle ◽  
Angular Acceleration ◽  
The United States ◽  
Physical Models ◽  
Lateral Impact ◽  
Diffuse Brain Injury ◽  
Diffuse Brain

Traumatic brain injury is a leading cause of disability and fatality in the United States. Approximately two million traumatic brain injury cases occur every year [1]. Motor vehicle crashes are a primary source [2]. Both clinical and laboratory studies have been conducted to understand injury mechanisms and establish injury thresholds [3, 4]. Physical models have also been used to investigate injury biomechanics [5, 6]. Angular acceleration is considered as a major cause of diffuse brain injuries (DBI) [7, 8], while the angular velocity is chosen as a suitable load descriptor for a diffuse brain injury criterion [4]. The present study is focused on the effect of angular acceleration duration on brain strains due to lateral impact.

scholarly journals Concussion and the severity of head impacts in mixed martial arts

2020 ◽  
Vol 234 (12) ◽  
pp. 1472-1483 ◽  
Author(s):  
Stephen Tiernan ◽  
Aidan Meagher ◽  
David O’Sullivan ◽  
Eoin O’Keeffe ◽  
Eoin Kelly ◽  
...  
Keyword(s):  
Martial Arts ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Head Impact ◽  
Sensor Technology ◽  
Mixed Martial Arts ◽  
Head Impacts ◽  
Impact Power ◽  
Average Maximum ◽  
The Impact

Concern about the consequences of head impacts in US football has motivated researchers to investigate and develop instrumentation to measure the severity of these impacts. However, the severity of head impacts in unhelmeted sports is largely unknown as miniaturised sensor technology has only recently made it possible to measure these impacts in vivo. The objective of this study was to measure the linear and angular head accelerations in impacts in mixed martial arts, and correlate these with concussive injuries. Thirteen mixed martial arts fighters were fitted with the Stanford instrumented mouthguard (MiG2.0) participated in this study. The mouthguard recorded linear acceleration and angular velocity in 6 degrees of freedom. Angular acceleration was calculated by differentiation. All events were video recorded, time stamped and reported impacts confirmed. A total of 451 verified head impacts above 10g were recorded during 19 sparring events (n = 298) and 11 competitive events (n = 153). The average resultant linear acceleration was 38.0624.3g while the average resultant angular acceleration was 256761739 rad/s2. The competitive bouts resulted in five concussions being diagnosed by a medical doctor. The average resultant acceleration (of the impact with the highest angular acceleration) in these bouts was 86.7618.7g and 756163438 rad/s2. The average maximum Head Impact Power was 20.6kW in the case of concussion and 7.15kW for the uninjured athletes. In conclusion, the study recorded novel data for sub-concussive and concussive impacts. Events that resulted in a concussion had an average maximum angular acceleration that was 24.7% higher and an average maximum Head Impact Power that was 189% higher than events where there was no injury. The findings are significant in understanding the human tolerance to short-duration, high linear and angular accelerations.

scholarly journals Research on Kinematic Parameters of Multiple Gait Pattern Transitions

2021 ◽  
Vol 11 (15) ◽  
pp. 6911
Author(s):  
Chaoyue Guo ◽  
Yali Liu ◽  
Qiuzhi Song ◽  
Shuting Liu
Keyword(s):  
Angular Velocity ◽  
Sagittal Plane ◽  
Gait Recognition ◽  
Angular Acceleration ◽  
Gait Pattern ◽  
Kinematic Parameters ◽  
Gait Patterns ◽  
Time Points ◽  
Axis Direction ◽  
Significant Difference

Gait recognition technology is the key technology in the field of exoskeletons. In the current research of gait recognition technology, there is less focus on the recognition of the transition between gait patterns. This study aims to determine which kinematic parameters have significant differences in the transitions (between level and stair walking and between level and ramp walking) of different gait patterns, to determine whether these parameters change differently in different gait pattern transitions, and the order the significant differences occur through a comparative analysis of various kinematic parameters between the transition stride and the before stride in the former pattern. We analyzed 18 parameters concerning both lower limbs and trunk. We compared each time point of the transition strides to the corresponding time points of the before stride using a series of two-sample t-tests, and we then evaluated the difference between the transition stride and the before stride based upon the number of time points within the gait cycle that were statistically different. We found that the sagittal plane angular velocity and the angular acceleration of all joints and the resultant velocity of the thigh and shank of the leading limb had significant differences in the process of transition; the sagittal plane angular velocity of all joints of the trailing limb and the velocity of the trunk in the coronary axis direction also showed a significant difference. The angular acceleration of all joints, the sagittal plane angular velocity of the ankle joint of the leading limb, and the acceleration of the trunk in the coronal axis direction showed a difference in the early stage of the transition. In general, the leading limb had a significant difference earlier than the trailing limb, and the acceleration parameters changed earlier than the velocity parameters. These parameters showed different combinations of changes in the transition of different gait patterns, and the changes in these parameters reflected different gait pattern transitions. Therefore, we believe that the results of this study can provide a reference for the gait pattern transition recognition of wearable exoskeletons.

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