scholarly journals Impact Performance Comparison of Advanced Snow Sport Helmets with Dedicated Rotation-Damping Systems

2021 ◽  
Author(s):  
Gina DiGiacomo ◽  
Stanley Tsai ◽  
Michael Bottlang
Keyword(s):  
Linear Acceleration ◽  
Performance Comparison ◽  
Rotational Acceleration ◽  
Head Acceleration ◽  
Impact Performance ◽  
Predicted Probability ◽  
Rotational Kinematics ◽  
Hybrid Iii ◽  
The Brain ◽  
Damping Systems

AbstractRotational acceleration of the head is a principal cause of concussion and traumatic brain injury. Several rotation-damping systems for helmets have been introduced to better protect the brain from rotational forces. But these systems have not been evaluated in snow sport helmets. This study investigated two snow sport helmets with different rotation-damping systems, termed MIPS and WaveCel, in comparison to a standard snow sport helmet without a rotation-damping system. Impact performance was evaluated by vertical drops of a helmeted Hybrid III head and neck onto an oblique anvil. Six impact conditions were tested, comprising two impact speeds of 4.8 and 6.2 m/s, and three impact locations. Helmet performance was quantified in terms of the linear and rotational kinematics, and the predicted probability of concussion. Both rotation-damping systems significantly reduced rotational acceleration under all six impact conditions compared to the standard helmet, but their effect on linear acceleration was less consistent. The highest probability of concussion for the standard helmet was 89%, while helmets with MIPS and WaveCel systems exhibited a maximal probability of concussion of 67 and 7%, respectively. In conclusion, rotation-damping systems of advanced snow sport helmets can significantly reduce rotational head acceleration and the associated concussion risk.

The influence of dynamic response and brain deformation metrics on the occurrence of subdural hematoma in different regions of the brain

2014 ◽  
Vol 120 (2) ◽  
pp. 453-461 ◽  
Author(s):  
Andrew Post ◽  
T. Blaine Hoshizaki ◽  
Michael D. Gilchrist ◽  
Susan Brien ◽  
Michael D. Cusimano ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Subdural Hematoma ◽  
Parietal Lobe ◽  
Linear Acceleration ◽  
Occipital Lobe ◽  
Von Mises Stress ◽  
Rotational Acceleration ◽  
Brain Deformation ◽  
Strain And Strain Rate ◽  
The Brain

Object The purpose of this study was to examine how the dynamic response and brain deformation of the head and brain—representing a series of injury reconstructions of which subdural hematoma (SDH) was the outcome—influence the location of the lesion in the lobes of the brain. Methods Sixteen cases of falls in which SDH was the outcome were reconstructed using a monorail drop rig and Hybrid III headform. The location of the SDH in 1 of the 4 lobes of the brain (frontal, parietal, temporal, and occipital) was confirmed by CT/MR scan examined by a neurosurgeon. Results The results indicated that there were minimal differences between locations of the SDH for linear acceleration. The peak resultant rotational acceleration and x-axis component were larger for the parietal lobe than for other lobes. There were also some differences between the parietal lobe and the other lobes in the z-axis component. Maximum principal strain, von Mises stress, shear strain, and product of strain and strain rate all had differences in magnitude depending on the lobe in which SDH was present. The parietal lobe consistently had the largest-magnitude response, followed by the frontal lobe and the occipital lobe. Conclusions The results indicated that there are differences in magnitude for rotational acceleration and brain deformation metrics that may identify the location of SDH in the brain.

scholarly journals Impact Performance Comparison of Advanced Bicycle Helmets with Dedicated Rotation-Damping Systems

2019 ◽  
Vol 48 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Michael Bottlang ◽  
Alexandra Rouhier ◽  
Stanley Tsai ◽  
Jordan Gregoire ◽  
Steven M. Madey
Keyword(s):  
Performance Comparison ◽  
Impact Performance ◽  
Bicycle Helmets ◽  
Damping Systems

Validation of a Noninvasive System for Measuring Head Acceleration for Use during Boxing Competition

2007 ◽  
Vol 23 (3) ◽  
pp. 238-244 ◽  
Author(s):  
Jonathan G. Beckwith ◽  
Jeffrey J. Chu ◽  
Richard M. Greenwald
Keyword(s):  
Severity Index ◽  
Rotational Acceleration ◽  
Head Acceleration ◽  
Measuring Head ◽  
Head Injury Criterion ◽  
Impact Location ◽  
Hybrid Iii ◽  
Biomechanical Factors ◽  
Accuracy And Repeatability ◽  
Impact Events

Although the epidemiology and mechanics of concussion in sports have been investigated for many years, the biomechanical factors that contribute to mild traumatic brain injury remain unclear because of the difficulties in measuring impact events in the field. The purpose of this study was to validate an instrumented boxing headgear (IBH) that can be used to measure impact severity and location during play. The instrumented boxing headgear data were processed to determine linear and rotational acceleration at the head center of gravity, impact location, and impact severity metrics, such as the Head Injury Criterion (HIC) and Gadd Severity Index (GSI). The instrumented boxing headgear was fitted to a Hybrid III (HIII) head form and impacted with a weighted pendulum to characterize accuracy and repeatability. Fifty-six impacts over 3 speeds and 5 locations were used to simulate blows most commonly observed in boxing. A high correlation between the HIII and instrumented boxing headgear was established for peak linear and rotational acceleration (r2= 0.91), HIC (r2= 0.88), and GSI (r2= 0.89). Mean location error was 9.7 ± 5.2°. Based on this study, the IBH is a valid system for measuring head acceleration and impact location that can be integrated into training and competition.

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.

scholarly journals Development of a Concussion Risk Function for a Youth Population Using Head Linear and Rotational Acceleration

2019 ◽  
Vol 48 (1) ◽  
pp. 92-103 ◽  
Author(s):  
Eamon T. Campolettano ◽  
Ryan A. Gellner ◽  
Eric P. Smith ◽  
Srinidhi Bellamkonda ◽  
Casey T. Tierney ◽  
...  
Keyword(s):  
Muscle Development ◽  
Risk Function ◽  
Area Under The Curve ◽  
Linear Acceleration ◽  
Neck Muscle ◽  
Rotational Acceleration ◽  
Head Acceleration ◽  
Age Related ◽  
Acceleration Model ◽  
Youth Population

Abstract Physical differences between youth and adults, which include incomplete myelination, limited neck muscle development, and a higher head-body ratio in the youth population, likely contribute towards the increased susceptibility of youth to concussion. Previous research efforts have considered the biomechanics of concussion for adult populations, but these known age-related differences highlight the necessity of quantifying the risk of concussion for a youth population. This study adapted the previously developed Generalized Acceleration Model for Brian Injury Threshold (GAMBIT) that combines linear and rotational head acceleration to model the risk of concussion for a youth population with the Generalized Acceleration Model for Concussion in Youth (GAM-CY). Survival analysis was used in conjunction with head impact data collected during participation in youth football to model risk between individuals who sustained medically-diagnosed concussions (n = 15). Receiver operator characteristic curves were generated for peak linear acceleration, peak rotational acceleration, and GAM-CY, all of which were observed to be better injury predictors than random guessing. GAM-CY was associated with an area under the curve of 0.89 (95% confidence interval: 0.82–0.95) when all head impacts experienced by the concussed players were considered. Concussion tolerance was observed to be lower for youth athletes, with average peak linear head acceleration of 62.4 ± 29.7 g compared to 102.5 ± 32.7 g for adults and average peak rotational head acceleration of 2609 ± 1591 rad/s2 compared to 4412 ± 2326 rad/s2. These data provide further evidence of age-related differences in concussion tolerance and may be used for the development of youth-specific protective designs.

Laboratory evaluation of a wearable head impact sensor for use in water polo and land sports

2020 ◽  
Vol 234 (2) ◽  
pp. 162-169 ◽  
Author(s):  
Nicholas J Cecchi ◽  
Derek C Monroe ◽  
Theophil J Oros ◽  
Steven L Small ◽  
James W Hicks
Keyword(s):  
Rotational Velocity ◽  
Linear Acceleration ◽  
Head Impact ◽  
Laboratory Evaluation ◽  
Rotational Acceleration ◽  
Similar Performance ◽  
Water Polo ◽  
Impact Location ◽  
Hybrid Iii ◽  
Mode Of Attachment

The SIM-G is a waterproof head impact sensor that has been previously evaluated for use in a headband, but not yet in a mode of attachment suitable for water polo. For this study, a CADEX linear impactor was used to impact a Hybrid III headform while wearing either a headband or modified water polo cap, each housing a SIM-G. In both headgears, the SIM-G consistently underestimated peak linear acceleration ( p < .001) and peak rotational velocity ( p < .001), and consistently overestimated peak rotational acceleration ( p < .001) relative to the headform. These inaccuracies are consistent with previous evaluations of the SIM-G, but notably, impact magnitudes did not differ between the different modes of attachment ( p > .198). The proprietary SIM-G algorithm used for classifying false/true positives performed poorly at the back and crown impact locations in both the water polo cap and headband, but accuracy of this algorithm did not significantly differ between the water polo cap and headband (60.5% vs 49.4%, respectively). The SIM-G’s ability to correctly predict impact location also performed poorly in both headgears when impacts occurred at the crown location, but was significantly better overall in the water polo cap than the headband (80.2% vs 55.6%, respectively). These results demonstrate that the SIM-G exhibits shared limitations and a similar performance overall when placed in either a headband or water polo cap. Potential explanations for the inaccuracies of the SIM-G, as well as methods of optimizing its application in sports, are discussed.

Head Impact Biomechanics in Youth Flag Football: A Prospective Cohort Study

2021 ◽  
pp. 036354652110266
Author(s):  
Landon B. Lempke ◽  
Rachel S. Johnson ◽  
Rachel K. Le ◽  
Melissa N. Anderson ◽  
Julianne D. Schmidt ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Acceleration ◽  
Cross Sectional Study ◽  
Head Impact ◽  
Rotational Acceleration ◽  
Event Type ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Head Impact Biomechanics ◽  
Impact Biomechanics

Background: Youth flag football participation has rapidly grown and is a potentially safer alternative to tackle football. However, limited research has quantitatively assessed youth flag football head impact biomechanics. Purpose: To describe head impact biomechanics outcomes in youth flag football and explore factors associated with head impact magnitudes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We monitored 52 player-seasons among 48 male flag football players (mean ± SD; age, 9.4 ± 1.1 years; height, 138.6 ± 9.5 cm; mass, 34.7 ± 9.2 kg) across 3 seasons using head impact sensors during practices and games. Sensors recorded head impact frequencies, peak linear ( g) and rotational (rad/s2) acceleration, and estimated impact location. Impact rates (IRs) were calculated as 1 impact per 10 player-exposures; IR ratios (IRRs) were used to compare season, event type, and age group IRs; and 95% CIs were calculated for IRs and IRRs. Weekly and seasonal cumulative head impact frequencies and magnitudes were calculated. Mixed-model regression models examined the association between player characteristics, event type, and seasons and peak linear and rotational accelerations. Results: A total of 429 head impacts from 604 exposures occurred across the study period (IR, 7.10; 95% CI, 4.81-10.50). Weekly and seasonal cumulative median head impact frequencies were 1.00 (range, 0-2.63) and 7.50 (range, 0-21.00), respectively. The most frequent estimated head impact locations were the skull base (n = 96; 22.4%), top of the head (n = 74; 17.2%), and back of the head (n = 66; 15.4%). The combined event type IRs differed among the 3 seasons (IRR range, 1.45-2.68). Games produced greater IRs (IRR, 1.24; 95% CI, 1.01-1.53) and peak linear acceleration (mean difference, 5.69 g; P = .008) than did practices. Older players demonstrated greater combined event–type IRs (IRR, 1.46; 95% CI, 1.12-1.90) and increased head impact magnitudes than did younger players, with every 1-year age increase associated with a 3.78 g and 602.81-rad/s2 increase in peak linear and rotational acceleration magnitude, respectively ( P≤ .005). Conclusion: Head IRs and magnitudes varied across seasons, thus highlighting multiple season and cohort data are valuable when providing estimates. Head IRs were relatively low across seasons, while linear and rotational acceleration magnitudes were relatively high.

scholarly journals Football concussion case series using biomechanical and video analysis

Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S2.2-S2
Author(s):  
Mirellie Kelley ◽  
Jillian Urban ◽  
Derek Jones ◽  
Alexander Powers ◽  
Christopher T. Whitlow ◽  
...  
Keyword(s):  
Video Analysis ◽  
Case Series ◽  
Linear Acceleration ◽  
The United States ◽  
Head Impact ◽  
Rotational Acceleration ◽  
Impact Location ◽  
Injury Mechanisms ◽  
The Mean ◽  
Impact Data

Approximately 1.1–1.9 million sport-related concussions among athletes ≤18 years of age occur annually in the United States, but there is limited understanding of the biomechanics and injury mechanisms associated with concussions among lower level football athletes. Therefore, the objective of this study was to combine biomechanical head impact data with video analysis to characterize youth and HS football concussion injury mechanisms. Head impact data were collected from athletes participating on 22 youth and 6 HS football teams between 2012 and 2017. Video was recorded, and head impact data were collected during all practices and games by instrumenting players with the Head Impact Telemetry (HIT) System. For each clinically diagnosed concussion, a video abstraction form was completed, which included questions concerning the context in which the injury occurred. Linear acceleration, rotational acceleration, and impact location were used to characterize the concussive event and each injured athlete's head impact exposure on the day of the concussion. A total of 9 (5 HS and 4 youth) concussions with biomechanics and video of the event were included in this study. The mean [range] linear and rotational acceleration of the concussive impacts were 62.9 [29.3–118.4] g and 3,056.7 [1,046.8–6,954.6] rad/s2, respectively. Concussive impacts were the highest magnitude impacts for 6 players and in the top quartile of impacts for 3 players on the day of injury. Concussions occurred in both practices (N = 4) and games (N = 5). The most common injury contact surface was helmet-to-helmet (N = 5), followed by helmet-to-ground (N = 3) and helmet-to-body (N = 1). All injuries occurred during player-to-player contact scenarios, including tackling (N = 4), blocking (N = 4), and collision with other players (N = 1). The biomechanics and injury mechanisms of concussions varied among athletes in our study; however, concussive impacts were among the highest severity for each player and all concussions occurred as a result of player-to-player contact.

scholarly journals Perception of the dynamic visual vertical during sinusoidal linear motion

2017 ◽  
Vol 118 (4) ◽  
pp. 2499-2506 ◽  
Author(s):  
A. Pomante ◽  
L. P. J. Selen ◽  
W. P. Medendorp
Keyword(s):  
Vestibular System ◽  
Spatial Orientation ◽  
Linear Acceleration ◽  
The Body ◽  
Body Motion ◽  
Whole Body ◽  
Linear Motion ◽  
Modeling Framework ◽  
Visual Vertical ◽  
The Brain

The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical—as a proxy for the tilt percept—during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s2peak acceleration, 80 cm displacement). While subjects ( n=10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model’s prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical.NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the disambiguation of linear acceleration and spatial orientation. We discuss the dynamics of these illusory percepts in terms of a dynamic Bayesian model that combines uncertainty in the vestibular signals with priors based on the natural statistics of head motion.

scholarly journals Forensic Engineering Analysis Of Dot Verses Non-Dot Helmet Performance As A Function Of Velocities Exceeding Standardized Testing As A Function Of Velocities Exceeding Standardized Testing

2012 ◽  
Vol 29 (2) ◽  
Author(s):  
Laura L. Liptai
Keyword(s):  
Standardized Testing ◽  
The United States ◽  
Department Of Transportation ◽  
Impact Performance ◽  
Performance Improvements ◽  
Motorcycle Helmet ◽  
Road Surfaces ◽  
Hybrid Iii ◽  
Forensic Engineering ◽  
Testing Standards

Motorcyclists Suffer Serious Trauma More Often Than Automotive Occupants Tracing To Contact With Non-Yielding Road Surfaces And/Or Direct Impact From Other Vehicles. A Motorcycle Helmet Is The Principal Defense To Head Impact. If A Motorcycle Helmet Passes Dot, Department Of Transportation, Approval, What Performance Improvements Correlate? Dot And Non-Dot Helmets Were Tested To Determine Impact Performance At Velocities Exceeding Standardized Testing Velocities. Three Types Of Dot Approved And Three Types Of Non-Dot Approved Helmets Were Tested At Two Speeds Outside Of The Federal Testing Standards In The United States. The Analysis Was Performed Using An Inverted Pendulum Sub-System Experimental Device With A Hybrid-Iii Anthropometric Dummy Cranium And Neck. Results Quantify The Performance By Category, Model, And Experiment By Test Metric.

Sign in / Sign up

Export Citation Format

Share Document