Validation of a Custom Instrumented Retainer Form Factor for Measuring Linear and Angular Head Impact Kinematics

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Logan E. Miller ◽  
Calvin Kuo ◽  
Lyndia C. Wu ◽  
Jillian E. Urban ◽  
David B. Camarillo ◽  
...  
Keyword(s):  
Form Factor ◽  
Degrees Of Freedom ◽  
Rotational Velocity ◽  
Linear Acceleration ◽  
Head Impact ◽  
Contact Sports ◽  
Head Impacts ◽  
Sensing Technology ◽  
The One ◽  
Impact Data

Head impact exposure in popular contact sports is not well understood, especially in the youth population, despite recent advances in impact-sensing technology which has allowed widespread collection of real-time head impact data. Previous studies indicate that a custom-instrumented mouthpiece is a superior method for collecting accurate head acceleration data. The objective of this study was to evaluate the efficacy of mounting a sensor device inside an acrylic retainer form factor to measure six-degrees-of-freedom (6DOF) head kinematic response. This study compares 6DOF mouthpiece kinematics at the head center of gravity (CG) to kinematics measured by an anthropomorphic test device (ATD). This study found that when instrumentation is mounted in the rigid retainer form factor, there is good coupling with the upper dentition and highly accurate kinematic results compared to the ATD. Peak head kinematics were correlated with r2 > 0.98 for both rotational velocity and linear acceleration and r2 = 0.93 for rotational acceleration. These results indicate that a rigid retainer-based form factor is an accurate and promising method of collecting head impact data. This device can be used to study head impacts in helmeted contact sports such as football, hockey, and lacrosse as well as nonhelmeted sports such as soccer and basketball. Understanding the magnitude and frequency of impacts sustained in various sports using an accurate head impact sensor, such as the one presented in this study, will improve our understanding of head impact exposure and sports-related concussion.

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.

scholarly journals Game-Related Impacts in High School Boys’ Lacrosse

2019 ◽  
Vol 7 (4) ◽  
pp. 232596711983558 ◽  
Author(s):  
Shane V. Caswell ◽  
Patricia Kelshaw ◽  
Andrew E. Lincoln ◽  
Lisa Hepburn ◽  
Reginald Dunn ◽  
...  
Keyword(s):  
High School ◽  
Rotational Velocity ◽  
Linear Acceleration ◽  
The United States ◽  
Head Impact ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Head Impacts ◽  
Direct Head ◽  
The Impact

Background: The rate of concussions in boys’ lacrosse is reported to be the third highest among high school sports in the United States, but no studies have described game-related impacts among boys’ lacrosse players. Purpose: To characterize verified game-related impacts, both overall and those directly to the head, in boys’ varsity high school lacrosse. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 77 male participants (mean age, 16.6 ± 1.2 years; mean height, 1.77 ± 0.05 m; mean weight, 73.4 ± 12.2 kg) were instrumented with sensors and were videotaped during 39 games. All verified game-related impacts ≥20 g were summarized in terms of frequency, peak linear acceleration (PLA), and peak rotational velocity (PRV). Descriptive statistics and impact rates per player-game (PG) with corresponding 95% CIs were calculated. Results: Overall, 1100 verified game-related impacts were recorded (PLA: median, 33.5 g [interquartile range (IQR), 25.7-51.2]; PRV: median, 1135.5 deg/s [IQR, 790.0-1613.8]) during 795 PGs. The rate for all verified game-related impacts was 1.38 impacts per PG (95% CI, 1.30-1.47). Of these, 680 (61.8%) impacts (PLA: median, 35.9 g [IQR, 26.7-55.5]; PRV: 1170.5 deg/s [IQR, 803.2-1672.8]) were directly to the head (impact rate, 0.86 impacts/PG [95% CI, 0.79-0.92]). Overall, midfielders (n = 514; 46.7%) sustained the most impacts, followed by attackers (n = 332; 30.2%), defenders (n = 233; 21.2%), and goalies (n = 21; 1.9%). The most common mechanisms for overall impacts and direct head impacts were contact with player (overall: n = 706 [64.2%]; head: n = 397 [58.4%]) and stick (overall: n = 303 [27.5%]; head: n = 239 [35.1%]), followed by ground (overall: n = 73 [6.6%]; head: n = 26 [3.8%]) and ball (overall: n = 15 [1.4%]; head: n = 15 [2.2%]). Direct head impacts were associated with a helmet-to-helmet collision 31.2% of the time, and they were frequently (53.7%) sustained by the players delivering the impact. Nearly half (48.8%) of players delivering contact used their helmets to initiate contact that resulted in a helmet-to-helmet impact. Players receiving a head impact from player contact were most often unprepared (75.9%) for the collision. Conclusion: The helmet is commonly used to initiate contact in boys’ high school lacrosse, often targeting defenseless opponents. Interventions to reduce head impacts should address rules and coaching messages to discourage intentional use of the helmet and encourage protection of defenseless opponents.

scholarly journals Biomechanical head impact characteristics during sparring practice sessions in high school taekwondo athletes

2017 ◽  
Vol 19 (6) ◽  
pp. 662-667 ◽  
Author(s):  
David M. O'Sullivan ◽  
Gabriel P. Fife
Keyword(s):  
High School ◽  
Rotational Velocity ◽  
Linear Acceleration ◽  
Head Impact ◽  
Rotational Acceleration ◽  
Head Impacts ◽  
Head Injury Criterion ◽  
Impact Location ◽  
Male High School ◽  
Impact Characteristics

OBJECTIVEThe purpose of this study was to monitor head impact magnitude and characteristics, such as impact location and frequency, at high school taekwondo sparring sessions.METHODSEight male high school taekwondo athletes participated in this study. The head impact characteristics were recorded by X-Patch, a wireless accelerometer and gyroscope, during 6 taekwondo sparring sessions. The outcome measures were the peak linear acceleration (g = 9.81 msec2), peak rotational acceleration, rotational velocity, and Head Injury Criterion.RESULTSA total of 689 impacts occurred over 6 sessions involving the 8 athletes. There was an average of 24 impacts per 100 minutes, and there were significant differences in the frequency of impacts among both the sessions and individual athletes. In order of frequency, the most commonly hit locations were the side (38.2%), back (35.7%), and front (23.8%) of the head.CONCLUSIONSThe data indicate that there is a relatively high number of head impacts experienced by taekwondo athletes during sparring practice. According to the rotational acceleration predicting impact severity published in previous research, 17.1% of the impacts were deemed to be a moderate and 15.5% were deemed to be severe.

scholarly journals Subconcussive head impact exposure differences between drill intensities in U.S. high school football

2020 ◽  
Author(s):  
Kyle Kercher ◽  
Jesse A. Steinfeldt ◽  
Jonathan T. Macy ◽  
Keisuke Ejima ◽  
Keisuke Kawata
Keyword(s):  
High School ◽  
Linear Acceleration ◽  
Head Impact ◽  
Football Players ◽  
Impact Frequency ◽  
High School Football ◽  
Head Impacts ◽  
Air Bags ◽  
Frequency Peak ◽  
Impact Data

ABSTRACTPurposeUSA Football established five levels of contact (LOC) to guide the intensity of high school football practices. However, it remains unclear whether head impact exposure differs by LOC. The purpose of this study was to examine head impact frequency and magnitude by LOC in the overall sample and three position groups.MethodsThis longitudinal observational study included 24 high school football players during all practices and games in the 2019 season. Players wore a sensor-installed mouthguard that monitored head impact frequency, peak linear acceleration (PLA), and rotational head acceleration (PRA). Practice/game drills were filmed and categorized into 5 LOCs (air, bags, control, thud, live), and head impact data were assigned into 5 LOCs. Player position was categorized into linemen, hybrid, and skill.ResultsA total of 6016 head impacts were recorded during 5 LOCs throughout the season. In the overall sample, total number of impacts, sum of PLA, and PRA per player increased in an incremental manner (air<bags<control<thud<live), with the most head impacts in live (113.7±17.8 hits/player) and the least head impacts in air (7.7±1.9 hits/player). The linemen and hybrid groups had consistently higher impact exposure than the skill group. Average head impact magnitudes by position group were higher during live drills (PLA (41.0-45.9g) and PRA (3.3-4.6 krad/s2) per head impact), whereas other LOCs had lower magnitudes (PLA (18.2-23.2g) and PRA (1.6-2.3krad/s2) per impact).ConclusionOur data suggest that LOC may influence cumulative head impact exposure in high school football, with players incurring frequent head impacts during live, thud, and control. The data indicate the importance of considering LOCs to refine practice guidelines and policies to minimize head impact burden in high school football athletes.

Video Analysis Verification of Head Impact Events Measured by Wearable Sensors

2017 ◽  
Vol 45 (10) ◽  
pp. 2379-2387 ◽  
Author(s):  
Nelson Cortes ◽  
Andrew E. Lincoln ◽  
Gregory D. Myer ◽  
Lisa Hepburn ◽  
Michael Higgins ◽  
...  
Keyword(s):  
Video Analysis ◽  
Rotational Velocity ◽  
Wearable Sensors ◽  
Linear Acceleration ◽  
Current Data ◽  
Head Impact ◽  
Accelerometer Data ◽  
Level Of Evidence ◽  
Head Impacts ◽  
Impact Events

Background: Wearable sensors are increasingly used to quantify the frequency and magnitude of head impact events in multiple sports. There is a paucity of evidence that verifies head impact events recorded by wearable sensors. Purpose: To utilize video analysis to verify head impact events recorded by wearable sensors and describe the respective frequency and magnitude. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Thirty male (mean age, 16.6 ± 1.2 years; mean height, 1.77 ± 0.06 m; mean weight, 73.4 ± 12.2 kg) and 35 female (mean age, 16.2 ± 1.3 years; mean height, 1.66 ± 0.05 m; mean weight, 61.2 ± 6.4 kg) players volunteered to participate in this study during the 2014 and 2015 lacrosse seasons. Participants were instrumented with GForceTracker (GFT; boys) and X-Patch sensors (girls). Simultaneous game video was recorded by a trained videographer using a single camera located at the highest midfield location. One-third of the field was framed and panned to follow the ball during games. Videographic and accelerometer data were time synchronized. Head impact counts were compared with video recordings and were deemed valid if (1) the linear acceleration was ≥20 g, (2) the player was identified on the field, (3) the player was in camera view, and (4) the head impact mechanism could be clearly identified. Descriptive statistics of peak linear acceleration (PLA) and peak rotational velocity (PRV) for all verified head impacts ≥20 g were calculated. Results: For the boys, a total recorded 1063 impacts (2014: n = 545; 2015: n = 518) were logged by the GFT between game start and end times (mean PLA, 46 ± 31 g; mean PRV, 1093 ± 661 deg/s) during 368 player-games. Of these impacts, 690 were verified via video analysis (65%; mean PLA, 48 ± 34 g; mean PRV, 1242 ± 617 deg/s). The X-Patch sensors, worn by the girls, recorded a total 180 impacts during the course of the games, and 58 (2014: n = 33; 2015: n = 25) were verified via video analysis (32%; mean PLA, 39 ± 21 g; mean PRV, 1664 ± 619 rad/s). Conclusion: The current data indicate that existing wearable sensor technologies may substantially overestimate head impact events. Further, while the wearable sensors always estimated a head impact location, only 48% of the impacts were a result of direct contact to the head as characterized on video. Using wearable sensors and video to verify head impacts may decrease the inclusion of false-positive impacts during game activity in the analysis.

scholarly journals Comparison of head impact exposure in practice drills among multiple youth football teams

2019 ◽  
Vol 23 (3) ◽  
pp. 381-389 ◽  
Author(s):  
Mireille E. Kelley ◽  
Mark A. Espeland ◽  
William C. Flood ◽  
Alexander K. Powers ◽  
Christopher T. Whitlow ◽  
...  
Keyword(s):  
Open Field ◽  
Linear Models ◽  
Linear Acceleration ◽  
Head Impact ◽  
Head Acceleration ◽  
Head Impacts ◽  
Youth Football ◽  
Impact Rate ◽  
Full Speed ◽  
Impact Data

OBJECTIVELimiting contact in football practice can reduce the number of head impacts a player receives, but further research is needed to inform the modification of optimal drills that mitigate head impact exposure (HIE) while the player develops the skills needed to safely play the game. This study aimed to compare HIE in practice drills among 6 youth football teams and to evaluate the effect of a team on HIE.METHODSOn-field head impact data were collected from athletes (ages 10–13 years) playing on 6 local youth football teams (teams A–F) during all practices using the Head Impact Telemetry System. Video was recorded and analyzed to verify and assign impacts to a specific drill. Drills were identified as follows: dummy/sled tackling, half install, install, install walk through, multiplayer tackle, Oklahoma, one-on-one, open field tackling, other, passing, position skill work, scrimmage, special teams, tackling drill stations, and technique. HIE was quantified in terms of impacts per player per minute (ppm) and peak linear and rotational head acceleration. Generalized linear models were used to assess differences in head impact magnitude and frequency among drills as well as among teams within the most common drills.RESULTSAmong 67 athlete-seasons, a total of 14,718 impacts during contact practices were collected and evaluated in this study. Among all 6 teams, the mean linear (p < 0.0001) and rotational (p < 0.0001) acceleration varied significantly among all drills. Open field tackling had significantly (p < 0.001) higher mean linear acceleration than all other drills. Multiplayer tackle had the highest mean impact rate (0.35 ppm). Significant variations in linear acceleration and impact rate were observed among teams within specific drills. Team A had the highest mean linear acceleration in install, one-on-one, and open field tackling and the highest mean impact rate in Oklahoma and position skill work. Although team A spent the greatest proportion of their practice on minimal- or no-player versus player contact drills (27%) compared to other teams, they had the highest median (20.2g) and 95th percentile (56.4g) linear acceleration in practice.CONCLUSIONSFull-speed tackling and blocking drills resulted in the highest HIE. Reducing time spent on contact drills relative to minimal or no contact drills may not lower overall HIE. Instead, interventions such as reducing the speed of players engaged in contact, correcting tackling technique, and progressing to contact may reduce HIE more effectively.

scholarly journals Head Impact Exposure in Practices Correlates With Exposure in Games for Youth Football Players

2018 ◽  
Vol 34 (5) ◽  
pp. 354-360 ◽  
Author(s):  
Srinidhi Bellamkonda ◽  
Samantha J. Woodward ◽  
Eamon Campolettano ◽  
Ryan Gellner ◽  
Mireille E. Kelley ◽  
...  
Keyword(s):  
Linear Acceleration ◽  
The United States ◽  
Head Impact ◽  
Football Players ◽  
Valuable Insight ◽  
Head Impacts ◽  
Youth Football ◽  
Exposure Profile ◽  
Impact Data ◽  
Insight Into

This study aimed to compare head impact exposures between practices and games in football players ages 9 to 14 years, who account for approximately 70% of all football players in the United States. Over a period of 2 seasons, 136 players were enrolled from 3 youth programs, and 49,847 head impacts were recorded from 345 practices and 137 games. During the study, individual players sustained a median of 211 impacts per season, with a maximum of 1226 impacts. Players sustained 50th (95th) percentile peak linear acceleration of 18.3 (46.9) g, peak rotational acceleration of 1305.4 (3316.6) rad·s−2, and Head Impact Technology Severity Profile of 13.7 (24.3), respectively. Overall, players with a higher frequency of head impacts at practices recorded a higher frequency of head impacts at games (P < .001,r2 = .52), and players who sustained a greater average magnitude of head impacts during practice also recorded a greater average magnitude of head impacts during games (P < .001). The youth football head impact data quantified in this study provide valuable insight into the player exposure profile, which should serve as a key baseline in efforts to reduce injury.

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 Can helmet design reduce the risk of concussion in football?

2014 ◽  
Vol 120 (4) ◽  
pp. 919-922 ◽  
Author(s):  
Steven Rowson ◽  
Stefan M. Duma ◽  
Richard M. Greenwald ◽  
Jonathan G. Beckwith ◽  
Jeffrey J. Chu ◽  
...  
Keyword(s):  
Head Impact ◽  
Dartmouth College ◽  
University Of Minnesota ◽  
Head Impacts ◽  
University Of Oklahoma ◽  
Significant Difference ◽  
Rule Changes ◽  
Impact Data ◽  
Collegiate Football ◽  
Helmet Design

Of all sports, football accounts for the highest incidence of concussion in the US due to the large number of athletes participating and the nature of the sport. While there is general agreement that concussion incidence can be reduced through rule changes and teaching proper tackling technique, there remains debate as to whether helmet design may also reduce the incidence of concussion. A retrospective analysis was performed of head impact data collected from 1833 collegiate football players who were instrumented with helmet-mounted accelerometer arrays for games and practices. Data were collected between 2005 and 2010 from 8 collegiate football teams: Virginia Tech, University of North Carolina, University of Oklahoma, Dartmouth College, Brown University, University of Minnesota, Indiana University, and University of Illinois. Concussion rates were compared between players wearing Riddell VSR4 and Riddell Revolution helmets while controlling for the head impact exposure of each player. A total of 1,281,444 head impacts were recorded, from which 64 concussions were diagnosed. The relative risk of sustaining a concussion in a Revolution helmet compared with a VSR4 helmet was 46.1% (95% CI 28.1%–75.8%). When controlling for each player's exposure to head impact, a significant difference was found between concussion rates for players in VSR4 and Revolution helmets (χ2 = 4.68, p = 0.0305). This study illustrates that differences in the ability to reduce concussion risk exist between helmet models in football. Although helmet design may never prevent all concussions from occurring in football, evidence illustrates that it can reduce the incidence of this injury.

Laboratory and field evaluation of a small form factor head impact sensor in un-helmeted play

2017 ◽  
Vol 232 (3) ◽  
pp. 242-254 ◽  
Author(s):  
Derek Nevins ◽  
Kasee Hildenbrand ◽  
Jeff Kensrud ◽  
Anita Vasavada ◽  
Lloyd Smith
Keyword(s):  
Form Factor ◽  
Center Of Mass ◽  
False Negative ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Field Evaluation ◽  
Head Impact ◽  
Sensor Data ◽  
Small Form ◽  
Small Form Factor

Head impact sensors are increasingly used to quantify the frequency and magnitude of head impacts in sports. A dearth of information exists regarding head impact in un-helmeted sport, despite the substantial number of concussions experienced in these sports. This study evaluated the performance of one small form factor head impact sensor in both laboratory and field environments. In laboratory tests, sensor performance was assessed using a Hybrid III headform and neck. The headform assembly was mounted on a low-friction sled and impacted with three sports balls over a range of velocities (10–31 m/s) at two locations and from three directions. Measures of linear and angular acceleration obtained from the small form factor wireless sensor were compared to measures of linear and angular acceleration obtained by wired sensors mounted at the headform center of mass. Accuracy of the sensor varied inversely with impact magnitude, with relative differences across test conditions ranging from 0.1% to 266.0% for peak linear acceleration and 4.7% to 94.6% for peak angular acceleration when compared to a wired reference system. In the field evaluation, eight male high school soccer players were instrumented with the head impact sensor in seven games. Video of the games was synchronized with sensor data and reviewed to determine the number of false positive and false negative head acceleration event classifications. Of the 98 events classified as valid by the sensor, 20.5% (20 impacts) did not result from contact with the ball, another player, the ground or player motion and were therefore considered false positives. Video review of events classified as invalid or spurious by the sensor found 77.8% (14 of 18 impacts) to be due to contact with the ball, another player or player motion and were considered false negatives.

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