The Effect of Shoulder Pad Design on Reducing Peak Resultant Linear and Rotational Acceleration in Shoulder-to-Head Impacts

2014 ◽  
pp. 142-152 ◽  
Author(s):  
Marshall Kendall ◽  
Andrew Post ◽  
Philippe Rousseau ◽  
T. Blaine Hoshizaki
Keyword(s):  
Rotational Acceleration ◽  
Head Impacts

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.

Incidence and Force Application of Head Impacts in Men’s Lacrosse: A Pilot Study

2019 ◽  
Vol 24 (5) ◽  
pp. 213-216 ◽  
Author(s):  
John M. Rosene ◽  
Christian Merritt ◽  
Nick R. Wirth ◽  
Daniel Nguyen
Keyword(s):  
Pilot Study ◽  
Rotational Velocity ◽  
Linear Acceleration ◽  
Ncaa Division Iii ◽  
Rotational Acceleration ◽  
Division Iii ◽  
Head Impacts ◽  
Repetitive Nature ◽  
Significant Difference ◽  
Frequency Magnitude

Subconcussive head impacts in sport may have a greater impact on neurological degradation versus concussive hits given the repetitive nature of these head impacts. The purpose of this investigation was to quantify the frequency, magnitude, and location of head impacts in an NCAA Division III men’s lacrosse team. There was no significant difference (p ≤ .05) in peak linear acceleration, peak rotational acceleration, and peak rotational velocity between games and practices. There was no significant difference (p ≤ .05) for PLA among player position and location of head impact. The quantity and intensity of subconcussive head impacts between practices and games were similar. These multiple subconcussive head impacts have the potential to lead to future neurological impairments.

scholarly journals Magnitude of Head Impact Exposures in Individual Collegiate Football Players

2012 ◽  
Vol 28 (2) ◽  
pp. 174-183 ◽  
Author(s):  
Joseph J. Crisco ◽  
Bethany J. Wilcox ◽  
Jason T. Machan ◽  
Thomas W. McAllister ◽  
Ann-Christine Duhaime ◽  
...  
Keyword(s):  
Cognitive Deficits ◽  
Linear Acceleration ◽  
Head Impact ◽  
Football Players ◽  
Rotational Acceleration ◽  
Head Impacts ◽  
Factors Associated ◽  
Impact Location ◽  
Collegiate Football

The purpose of this study was to quantify the severity of head impacts sustained by individual collegiate football players and to investigate differences between impacts sustained during practice and game sessions, as well as by player position and impact location. Head impacts (N = 184,358) were analyzed for 254 collegiate players at three collegiate institutions. In practice, the 50th and 95th percentile values for individual players were 20.0 g and 49.5 g for peak linear acceleration, 1187 rad/s2 and 3147 rad/s2 for peak rotational acceleration, and 13.4 and 29.9 for HITsp, respectively. Only the 95th percentile HITsp increased significantly in games compared with practices (8.4%, p = .0002). Player position and impact location were the largest factors associated with differences in head impacts. Running backs consistently sustained the greatest impact magnitudes. Peak linear accelerations were greatest for impacts to the top of the helmet, whereas rotational accelerations were greatest for impacts to the front and back. The findings of this study provide essential data for future investigations that aim to establish the correlations between head impact exposure, acute brain injury, and long-term cognitive deficits.

scholarly journals THE EFFECT OF A BODY CHECKING RULE CHANGE ON HEAD IMPACT BIOMECHANICS IN BANTAM ICE HOCKEY ATHLETES

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0021
Author(s):  
Patricia R. Combs ◽  
Cassie B. Ford ◽  
Elizabeth F. Teel ◽  
Erin B. Wasserman ◽  
Michael J. Cools ◽  
...  
Keyword(s):  
Injury Risk ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Rotational Acceleration ◽  
Body Checking ◽  
Head Impacts ◽  
Head Impact Biomechanics ◽  
Impact Biomechanics ◽  
Hockey Players

Background: Body checking is the most common injury mechanism in ice hockey. Rule changes have sought to mitigate body checking exposure among youth players. In 2011, USA Hockey changed the legal body checking age from Pee Wee (11/12-year-olds) to Bantam (13/14-year-olds). Interestingly, Bantam players with checking experience during Pee Wee had a lower concussion risk relative to Bantam players without checking experience in a sample of Canadian youth hockey players. Understanding the head impact biomechanics underlying these findings could further elucidate the consequences of this rule change. Purpose: To determine the association between Pee Wee checking exposure and head impact biomechanics in a cohort of Bantam players. Methods: We prospectively collected data on Bantam ice hockey players during the 2006/07-2009/10 seasons and the 2012-2013 season. The 2006/07-2009/10 cohort (n= 61, age=13.9±0.5 years, height=168.2±8.7 cm, mass=59.9±10.4 kg) was allowed to body check (BC) as a Pee Wee player. The 2012-2013 cohort (n=15, age=13.3±0.4 years, height=167.5±7.4 cm, mass=57.5±8.6 kg) was not permitted to body check (NBC) as a Pee Wee player. Over the course of each season, head impacts were measured using in-helmet accelerometers. Only head impacts with linear acceleration ≥10 g were included in our analysis. Main outcome measures were mean linear acceleration (g) and rotational acceleration (rad/s2). Levene’s tests assessed equality of variance between groups. We employed mixed effects models to assess group differences in mean linear and rotational acceleration between BC and NBC groups. Results: The BC and NBC groups did not differ in height (t74=0.28, p=0.78) or mass (t74=0.84, p=0.40). When assessing group differences in head impact biomechanics, the NBC experienced significantly greater linear acceleration (F1,74=4.36, p=0.04) and greater rotational acceleration (F1,74=21.2, p<0.001) relative to the BC group. On average, the NBC group experienced 23.1 ± 0.87 g linear acceleration and 1993.5 ± 68.4 rad/s2 rotational acceleration compared to the BC group, which experienced 21.2 ± 0.30 g linear acceleration and 1615.9 ± 45.2 rad/s2 rotational acceleration. Conclusions: Bantam ice hockey players without body checking experience during their Pee Wee years experienced greater average linear and rotational acceleration relative to players with Pee Wee body checking experience. While removing body checking from Pee Wee ice hockey may reduce short-term injury risk, these athletes may demonstrate more high-risk head impact biomechanics when legally allowed to body check. Future research should continue to examine the influence of policy changes on head impact biomechanics and injury risk in youth ice hockey. [Figure: see text]

scholarly journals COMPARISON OF HEAD IMPACT BIOMECHANICS BETWEEN TACKLE AND FLAG YOUTH FOOTBALL

2019 ◽  
Vol 7 (3_suppl) ◽  
pp. 2325967119S0000
Author(s):  
Landon B. Lempke ◽  
A. Faith Bartello ◽  
Melissa N. Anderson ◽  
Rachel S. Johnson ◽  
Julianne D. Schmidt ◽  
...  
Keyword(s):  
Linear Acceleration ◽  
Head Impact ◽  
Football Players ◽  
Rotational Acceleration ◽  
Head Impacts ◽  
Head Impact Biomechanics ◽  
Impact Rate ◽  
High Magnitude ◽  
Impact Biomechanics

Background: There is growing fear among healthcare professionals and parents regarding youth tackle football, likely due to highly publicized concerns about potential long-term physical and cognitive health of professional football players. Parents and advocacy groups are pushing for state legislation to ban youth tackle football in favor of flag football to avoid repetitive head impacts that are potentially associated with late-life cognitive deficits. Although the head impact burden experienced during flag football is likely lower than tackle, no research has compared head impact exposure between youth tackle and flag football. Therefore, our purpose was to examine head impact exposure and magnitudes between youth tackle and flag football players. Methods: Twenty-seven tackle (age=11.0±1.5y, height=145.8±11.9 cm, mass=45.0±14.9 kg) and 29 flag football players (age=8.6±1.1y, height=133.9±8.4 cm, mass=33.9±9.5 kg) were enrolled in this prospective cohort study. Participants were fitted with head impact sensors (Triax Sim-G) worn throughout the entire 2017 season that recorded impact frequency and magnitude (linear [g] and rotational acceleration [rad/s2]). Athlete exposure was defined as one player participating in one session. Impact rates (IR) were calculated as impacts per one athlete exposure. Game, practice, and combined IR were compared between groups using impact rate ratios (IRR). IRR with 95% confidence intervals (CI) not containing 1.0 were considered statistically significant. Acceleration values were binned into low- and high-magnitude categories (linear split at 40 g, rotational split at 4,600rad/s2). Magnitude category frequencies were compared between groups using Chi-square test of association (p<0.05), and 90th percentile acceleration values are presented. Results: One-thousand nine-hundred and eight tackle (735 game, 1173 practice; 70.66 impacts/player) and 169 flag (101 game, 68 practice; 5.83 impacts/player) football head impacts were recorded. Tackle players experienced a higher impact rate during games versus practices (IRR=1.41; 95%CI:1.29 -1.55) while flag players experienced a lower impact rate (IRR=0.60; 95%CI:0.44-0.81). Practice and game head impacts combined resulted in tackle players (IR=3.06) accruing 4.61 times the impact rate (95%CI:3.94-5.40) of flag players (IR=0.66). Tackle players sustained a significantly greater head impact rate than flag players during games (tackle IR=3.83, flag IR=0.55; IRR=6.90; 95%CI:5.60-8.49) and practices (tackle IR=2.72, flag IR=0.93; IRR=2.91; 95%CI:2.28-3.72). Tackle 90th percentile linear acceleration was 53.32 g (median=32.50 g) and flag was 53.32 g (median=32.65 g). Tackle 90th percentile rotational acceleration was 7,000 rad/s2 (median=3,200rad/s2) while flag was 8,300 rad/s2 (median=4,100rad/s2). Tackle experienced a significantly higher frequency of low-magnitude rotational acceleration impacts (71.6% vs. 57.4%) and lower frequency of high-magnitude impacts than flag (28.4% vs 42.6%;?2=15.15, p<0.001). There were no significant associations for linear acceleration (p=0.75). Conclusions/Significance: Our results indicate youth flag football head impact rates are 82%-88% lower compared to tackle. Contrary to general belief, youth flag football players experienced numerous head impacts with a greater tendency for high-magnitude rotational acceleration head impacts. Although fewer head impacts occur during youth flag football, parents and coaches should be aware that head impacts do occur during practices and games. Whether high-magnitude or high-frequency head impacts influence long-term health remains unknown. Our findings provide novel evidence into the head impact exposure occurring during youth tackle and flag football. Longitudinal studies examining head impact biomechanics and advanced neuroimaging in youth tackle and flag football players nationwide is warranted to ensure long term cognitive health.

scholarly journals Laboratory Validation of Instrumented Mouthguard for Use in Sport

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6028
Author(s):  
Danyon Stitt ◽  
Nick Draper ◽  
Keith Alexander ◽  
Natalia Kabaliuk
Keyword(s):  
Linear Acceleration ◽  
Systematic Bias ◽  
Strongly Correlated ◽  
Rotational Acceleration ◽  
Sports Performance ◽  
Kinematic Parameters ◽  
Measuring Head ◽  
Head Impacts ◽  
Inherent Risk ◽  
Measurement Devices

Concussion is an inherent risk of participating in contact, combat, or collision sports, within which head impacts are numerous. Kinematic parameters such as peak linear and rotational acceleration represent primary measures of concussive head impacts. The ability to accurately measure and categorise such impact parameters in real time is important in health and sports performance contexts. The purpose of this study was to assess the accuracy of the latest HitIQ Nexus A9 instrumented mouthguard (HitIQ Pty. Ltd. Melbourne Australia) against reference sensors in an aluminium headform. The headform underwent drop testing at various impact intensities across the NOCSAE-defined impact locations, comparing the peak linear and rotational acceleration (PLA and PRA) as well as the shapes of the acceleration time-series traces for each impact. Mouthguard PLA and PRA measurements strongly correlated with (R2 = 0.996 and 0.994 respectively), and strongly agreed with (LCCC = 0.997) the reference sensors. The root mean square error between the measurement devices was 1 ± 0.6g for linear acceleration and 47.4 ± 35 rad/s2 for rotational acceleration. A Bland–Altman analysis found a systematic bias of 1% for PRA, with no significant bias for PLA. The instrumented mouthguard displayed high accuracy when measuring head impact kinematics in a laboratory setting.

scholarly journals Practice type effects on head impact in collegiate football

2016 ◽  
Vol 124 (2) ◽  
pp. 501-510 ◽  
Author(s):  
Bryson B. Reynolds ◽  
James Patrie ◽  
Erich J. Henry ◽  
Howard P. Goodkin ◽  
Donna K. Broshek ◽  
...  
Keyword(s):  
National Collegiate Athletic Association ◽  
Collegiate Athletes ◽  
Head Impact ◽  
Football Players ◽  
Rotational Acceleration ◽  
Event Type ◽  
Cumulative Impact ◽  
Head Impacts ◽  
Average Impact ◽  
Collegiate Football

OBJECT This study directly compares the number and severity of subconcussive head impacts sustained during helmet-only practices, shell practices, full-pad practices, and competitive games in a National Collegiate Athletic Association (NCAA) Division I-A football team. The goal of the study was to determine whether subconcussive head impact in collegiate athletes varies with practice type, which is currently unregulated by the NCAA. METHODS Over an entire season, a cohort of 20 collegiate football players wore impact-sensing mastoid patches that measured the linear and rotational acceleration of all head impacts during a total of 890 athletic exposures. Data were analyzed to compare the number of head impacts, head impact burden, and average impact severity during helmet-only, shell, and full-pad practices, and games. RESULTS Helmet-only, shell, and full-pad practices and games all significantly differed from each other (p ≤ 0.05) in the mean number of impacts for each event, with the number of impacts being greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. The cumulative distributions for both linear and rotational acceleration differed between all event types (p < 0.01), with the acceleration distribution being similarly greatest for games, then full-pad practices, then shell practices, and then helmet-only practices. For both linear and rotational acceleration, helmet-only practices had a lower average impact severity when compared with other event types (p < 0.001). However, the average impact severity did not differ between any comparisons of shell and full-pad practices, and games. CONCLUSIONS Helmet-only, shell, and full-pad practices, and games result in distinct head impact profiles per event, with each succeeding event type receiving more impacts than the one before. Both the number of head impacts and cumulative impact burden during practice are categorically less than in games. In practice events, the number and cumulative burden of head impacts per event increases with the amount of equipment worn. The average severity of individual impacts is relatively consistent across event types, with the exception of helmet-only practices. The number of hits experienced during each event type is the main driver of event type differences in impact burden per athletic exposure, rather than the average severity of impacts that occur during the event. These findings suggest that regulation of practice equipment could be a fair and effective way to substantially reduce subconcussive head impact in thousands of collegiate football players.

The Effect of Player Contact Characteristics on Head Impact Exposure in Youth Football Games

2020 ◽  
pp. 1-11
Author(s):  
Daniella M. DiGuglielmo ◽  
Mireille E. Kelley ◽  
Mark A. Espeland ◽  
Zachary A. Gregory ◽  
Tanner D. Payne ◽  
...  
Keyword(s):  
Injury Risk ◽  
Body Position ◽  
Mixed Effects ◽  
Head Impact ◽  
Mixed Effects Models ◽  
Rotational Acceleration ◽  
Head Impacts ◽  
Factors Influencing ◽  
Youth Football ◽  
Impact Data

To reduce head impact exposure (HIE) in youth football, further understanding of the context in which head impacts occur and the associated biomechanics is needed. The objective of this study was to evaluate the effect of contact characteristics on HIE during player versus player contact scenarios in youth football. Head impact data and time-synchronized video were collected from 4 youth football games over 2 seasons in which opposing teams were instrumented with the Head Impact Telemetry (HIT) System. Coded contact characteristics included the player’s role in the contact, player speed and body position, contact height, type, and direction, and head contact surface. Head accelerations were compared among the contact characteristics using mixed-effects models. Among 72 instrumented athletes, 446 contact scenarios (n = 557 impacts) with visible opposing instrumented players were identified. When at least one player had a recorded impact, players who were struck tended to have higher rotational acceleration than players in striking positions. When both players had a recorded impact, lighter players and taller players experienced higher mean head accelerations compared with heavier players and shorter players. Understanding the factors influencing HIE during contact events in football may help inform methods to reduce head injury risk.

scholarly journals Head Impacts During High School Football: A Biomechanical Assessment

2009 ◽  
Vol 44 (4) ◽  
pp. 342-349 ◽  
Author(s):  
Steven P. Broglio ◽  
Jacob J. Sosnoff ◽  
SungHoon Shin ◽  
Xuming He ◽  
Christopher Alcaraz ◽  
...  
Keyword(s):  
High School ◽  
Linear Acceleration ◽  
Rotational Acceleration ◽  
High School Football ◽  
Head Impacts ◽  
Biomechanical Assessment ◽  
Football Team ◽  
Impact Biomechanics ◽  
Session Type ◽  
The Impact

Abstract Little is known about the impact biomechanics sustained by players during interscholastic football.Context: To characterize the location and magnitude of impacts sustained by players during an interscholastic football season.Objective: Observational design.Design: On the field.Setting: High school varsity football team (n  =  35; age  =  16.85 ± 0.75 years, height  =  183.49 ± 5.31 cm, mass  =  89.42 ± 12.88 kg).Patients or Other Participants: Biomechanical variables (linear acceleration, rotational acceleration, jerk, force, impulse, and impact duration) related to head impacts were categorized by session type, player position, and helmet impact location.Main Outcome Measure(s): Differences in grouping variables were found for each impact descriptor. Impacts occurred more frequently and with greater intensity during games. Linear acceleration was greatest in defensive linemen and offensive skill players and when the impact occurred at the top of the helmet. The largest rotational acceleration occurred in defensive linemen and with impacts to the front of the helmet. Impacts with the highest-magnitude jerk, force, and impulse and shortest duration occurred in the offensive skill, defensive line, offensive line, and defensive skill players, respectively. Top-of-the-helmet impacts yielded the greatest magnitude for the same variables.Results: We are the first to provide a biomechanical characterization of head impacts in an interscholastic football team across a season of play. The intensity of game play manifested with more frequent and intense impacts. The highest-magnitude variables were distributed across all player groups, but impacts to the top of the helmet yielded the highest values. These high school football athletes appeared to sustain greater accelerations after impact than their older counterparts did. How this finding relates to concussion occurrence has yet to be elucidated.Conclusions:

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