scholarly journals Head Impact Exposure in Junior and Adult Australian Football Players

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mark Hecimovich ◽  
Doug King ◽  
Alasdair Dempsey ◽  
Myles Murphy
Keyword(s):  
Head Impact ◽  
Football Players ◽  
Prevention Strategies ◽  
Comparable Amount ◽  
Head Impacts ◽  
Australian Football ◽  
Collection Period ◽  
The Impact ◽  
Player Positions ◽  
Frequency Magnitude

This study measured and compared the frequency, magnitude, and distribution of head impacts sustained by junior and adult Australian football players, respectively, and between player positions over a season of games. Twelve junior and twelve adult players were tracked using a skin-mounted impact sensor. Head impact exposure, including frequency, magnitude, and location of impacts, was quantified using previously established methods. Over the collection period, there were no significant differences in the impact frequency between junior and adult players. However, there was a significant increase in the frequency of head impacts for midfielders in both grades once we accounted for player position. A comparable amount of head impacts in both junior and adult players has implications for Australian football regarding player safety and medical coverage as younger players sustained similar impact levels as adult players. The other implication of a higher impact profile within midfielders is that, by targeting education and prevention strategies, a decrease in the incidence of sports-related concussion may result.

scholarly journals Similar head impact acceleration measured using instrumented ear patches in a junior rugby union team during matches in comparison with other sports

2016 ◽  
Vol 18 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Doug A. King ◽  
Patria A. Hume ◽  
Conor Gissane ◽  
Trevor N. Clark
Keyword(s):  
Injury Risk ◽  
Linear Acceleration ◽  
Rugby Union ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Head Impacts ◽  
Impact Acceleration ◽  
The Impact ◽  
Rugby Players

OBJECTIVE Direct impact with the head and the inertial loading of the head have been postulated as major mechanisms of head-related injuries, such as concussion. METHODS This descriptive observational study was conducted to quantify the head impact acceleration characteristics in under-9-year-old junior rugby union players in New Zealand. The impact magnitude, frequency, and location were collected with a wireless head impact sensor that was worn by 14 junior rugby players who participated in 4 matches. RESULTS A total of 721 impacts > 10g were recorded. The median (interquartile range [IQR]) number of impacts per player was 46 (IQR 37–58), resulting in 10 (IQR 4–18) impacts to the head per player per match. The median impact magnitudes recorded were 15g (IQR 12g–21g) for linear acceleration and 2296 rad/sec2 (IQR 1352–4152 rad/sec2) for rotational acceleration. CONCLUSIONS There were 121 impacts (16.8%) above the rotational injury risk limit and 1 (0.1%) impact above the linear injury risk limit. The acceleration magnitude and number of head impacts in junior rugby union players were higher than those previously reported in similar age-group sports participants. The median linear acceleration for the under-9-year-old rugby players were similar to 7- to 8-year-old American football players, but lower than 9- to 12-year-old youth American football players. The median rotational accelerations measured were higher than the median and 95th percentiles in youth, high school, and collegiate American football players.

scholarly journals High-magnitude head impact exposure in youth football

2017 ◽  
Vol 20 (6) ◽  
pp. 604-612 ◽  
Author(s):  
Eamon T. Campolettano ◽  
Ryan A. Gellner ◽  
Steven Rowson
Keyword(s):  
Open Field ◽  
Body Mass ◽  
Head Impact ◽  
Football Players ◽  
Head Impacts ◽  
Video Recordings ◽  
Youth Football ◽  
High Magnitude ◽  
Or Practice ◽  
The Impact

OBJECTIVEEven in the absence of a clinically diagnosed concussion, research suggests that neurocognitive changes may develop in football players as a result of frequent head impacts that occur during football games and practices. The objectives of this study were to determine the specific situations in which high-magnitude impacts (accelerations exceeding 40g) occur in youth football games and practices and to assess how representative practice activities are of games with regard to high-magnitude head impact exposure.METHODSA total of 45 players (mean age 10.7 ± 1.1 years) on 2 youth teams (Juniors [mean age 9.9 ± 0.6 years; mean body mass 38.9 ± 9.9 kg] and Seniors [mean age 11.9 ± 0.6 years; mean body mass 51.4 ± 11.8 kg]) wore helmets instrumented with accelerometer arrays to record head impact accelerations for all practices and games. Video recordings from practices and games were used to verify all high-magnitude head impacts, identify specific impact characteristics, and determine the amount of time spent in each activity.RESULTSA total of 7590 impacts were recorded, of which 571 resulted in high-magnitude head impact accelerations exceeding 40g (8%). Impacts were characterized based on the position played by the team member who received the impact, the part of the field where the impact occurred, whether the impact occurred during a game or practice play, and the cause of the impact. High-magnitude impacts occurred most frequently in the open field in both games (59.4%) and practices (67.5%). “Back” position players experienced a greater proportion of high-magnitude head impacts than players at other positions. The 2 teams in this study structured their practice sessions similarly with respect to time spent in each drill, but impact rates differed for each drill between the teams.CONCLUSIONSHigh-magnitude head impact exposure in games and practice drills was quantified and used as the basis for comparison of exposure in the 2 settings. In this cohort, game impact rates exceeded those for practice. Back players, who were often positioned in the open field, were shown to experience elevated levels of head impact exposure relative to players at other positions. The analysis also suggests that practice intensity, which may be influenced by coaching style, may also affect high-magnitude head impact exposure. Future studies should investigate this aspect as a factor affecting head impact exposure.

Influence of Neuromuscular Fatigue on Accelerometer Load in Elite Australian Football Players

2013 ◽  
Vol 8 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Stuart J. Cormack ◽  
Mitchell G. Mooney ◽  
Will Morgan ◽  
Michael R. McGuigan
Keyword(s):  
High Speed ◽  
Neuromuscular Fatigue ◽  
Football Players ◽  
Countermovement Jump ◽  
Baseline Measure ◽  
Running Activity ◽  
Australian Football ◽  
Percent Contribution ◽  
Playing Time ◽  
The Impact

Purpose:To determine the impact of neuromuscular fatigue (NMF) assessed from variables obtained during a countermovement jump on exercise intensity measured with triaxial accelerometers (load per minute [LPM]) and the association between LPM and measures of running activity in elite Australian Football.Methods:Seventeen elite Australian Football players performed the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and provided a baseline measure of NMF (flight time:contraction time [FT:CT]) from a countermovement jump before the season. Weekly samples of FT:CT, coaches’ rating of performance (votes), LPM, and percent contribution of the 3 vectors from the accelerometers in addition to high-speed-running meters per minute at >15 km/h and total distance relative to playing time (m/min) from matches were collected. Samples were divided into fatigued and nonfatigued groups based on reductions in FT:CT. Percent contributions of vectors to LPM were assessed to determine the likelihood of a meaningful difference between fatigued and nonfatigued groups. Pearson correlations were calculated to determine relationships between accelerometer vectors and running variables, votes, and Yo-Yo IR2 score.Results:Fatigue reduced the contribution of the vertical vector by (mean ± 90% CI) –5.8% ± 6.1% (86% likely) and the number of practically important correlations.Conclusions:NMF affects the contribution of individual vectors to total LPM, with a likely tendency toward more running at low speed and less acceleration. Fatigue appears to limit the influence of the aerobic and anaerobic qualities assessed via the Yo-Yo IR2 test on LPM and seems implicated in pacing.

Association Between Antemortem FLAIR White Matter Hyperintensities and Neuropathology in Brain Donors Exposed to Repetitive Head Impacts

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000013012
Author(s):  
Madeline Uretsky ◽  
Sylvain Bouix ◽  
Ronald J. Killiany ◽  
Yorghos Tripodis ◽  
Brett Martin ◽  
...  
Keyword(s):  
White Matter ◽  
White Matter Hyperintensities ◽  
Microvascular Disease ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Head Impacts ◽  
Repetitive Head Impacts ◽  
Pathological Correlation ◽  
Daily Function

Background and Objectives:Late neuropathologies of repetitive head impacts from contact sports can include chronic traumatic encephalopathy (CTE) and white matter degeneration. White matter hyperintensities (WMH) on fluid attenuated inversion recovery (FLAIR) MRI scans are often viewed as microvascular disease from vascular risk, but might have unique underlying pathologies and risk factors in the setting of repetitive head impacts. We investigated the neuropathological correlates of antemortem WMH in brain donors exposed to repetitive head impacts. The association between WMH, and repetitive head impact exposure and informant-reported cognitive and daily function were tested.Methods:This imaging-pathological correlation study included symptomatic deceased men exposed to repetitive head impacts. Donors had antemortem FLAIR scans from medical records and were without evidence of CNS neoplasm, large vessel infarcts, hemorrhage, and/or encephalomalacia. WMH were quantified using log-transformed values for total lesion volume (TLV), calculated using the lesion prediction algorithm from the Lesion Segmentation Toolbox. Neuropathological assessments included semi-quantitative ratings of white matter rarefaction, cerebrovascular disease, p-tau severity (CTE stage, dorsolateral frontal cortex), and Aβ. Among football players, years of play was a proxy for repetitive head impact exposure. Retrospective informant-reported cognitive and daily function were assessed using the Cognitive Difficulties Scale (CDS) and Functional Activities Questionnaire (FAQ). Regression models controlled for demographics, diabetes, hypertension, and MRI resolution. Statistical significance was defined as p<0.05.Results:The sample included 75 donors: 67 football players and 8 non-football contact sport athletes and/or military veterans. Dementia was the most common MRI indication (64%). Fifty-three (70.7%) had CTE at autopsy. Log-TLV was associated with white matter rarefaction (OR=2.32, 95% CI=1.03,5.24, p=0.04), arteriolosclerosis (OR=2.38, 95% CI=1.02,5.52, p=0.04), CTE stage (OR=2.58, 95% CI=1.17,5.71, p=0.02), and dorsolateral frontal p-tau severity (OR=3.03, 95% CI=1.32,6.97, p=0.01). There was no association with Aβ. More years of football play was associated with log-TLV (b=0.04, 95% CI=0.01,0.06, p=0.01). Greater log-TLV correlated with higher FAQ (unstandardized beta=4.94, 95% CI=0.42,8.57, p=0.03) and CDS scores (unstandardized beta=15.35, 95% CI=-0.27,30.97, p=0.05).Discussion:WMH might capture long-term white matter pathologies from repetitive head impacts, including those from white matter rarefaction and p-tau, in addition to microvascular disease. Prospective imaging-pathological correlation studies are needed.Classification of Evidence:This study provides Class IV evidence of associations between FLAIR white matter hyperintensities, and neuropathological changes (white matter rarefaction, arteriolosclerosis, p-tau accumulation), years of American football play, and reported cognitive symptoms in symptomatic brain donors exposed to repetitive head impacts.

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 In-season variations in head impact exposure among youth football players

Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S1.3-S2
Author(s):  
Jillian Urban ◽  
Mirellie Kelley ◽  
Mark Espeland ◽  
Elizabeth Davenport ◽  
Christopher T. Whitlow ◽  
...  
Keyword(s):  
Head Impact ◽  
Cumulative Exposure ◽  
Football Players ◽  
Sample Mean ◽  
Head Impacts ◽  
Youth Football ◽  
Single Number ◽  
Practice Time ◽  
Time Frames ◽  
Season Variations

Sport-related head impacts are of increasing concern as early evidence has demonstrated a relationship between subconcussive head impact exposure (HIE) experienced in contact sports, such as football, and changes in pre-to post-season imaging and cognitive measures. Cumulative HIE is often measured with a single number that amounts to the total exposure measured over the season and does not give any indication as to how the exposure was accumulated, nor how it varies during the season. Therefore, the objective of this study was to compare HIE during preseason, the first and second halves of the regular season, and playoffs in a sample of youth football players (n = 119, ages 9–13). Athletes were divided into 1 of 4 exposure groups based on quartiles computed from the distribution of risk-weighted cumulative exposure (RWECP). The mean 95th percentile linear and rotational accelerations and impacts per session in practices and games were compared across 4 exposure groups and time frames using mixed effects models. Within games, the sample mean 95th percentile linear and rotational accelerations ranged from 47.2 g and 2,331.3 rad/s2 during preseason to 52.1 g and 2,533.4 rad/s2 during the second half of regular season. Mean impacts per practice increased from preseason to the second half of regular season and declined into playoffs among all exposure groups; however, the variation between time frames was not greater than 2 impacts per practice. Time of season had a significant effect on mean 95th percentile linear and rotational acceleration in games (both p = 0.01) but not on practice accelerations or impacts/session. Mean 95th percentile accelerations for games showed significant interaction effects between exposure group and season segment (linear p = 0.05 and rotational p = 0.04). The results of this study improve our understanding of in-season variations in youth football HIE and may inform important opportunities for future interventions.

scholarly journals Do American Youth Football Players Intentionally Use Their Heads for High-Magnitude Impacts?

2019 ◽  
Vol 47 (14) ◽  
pp. 3498-3504 ◽  
Author(s):  
Jaclyn Alois ◽  
Srinidhi Bellamkonda ◽  
Eamon T. Campolettano ◽  
Ryan A. Gellner ◽  
Amaris Genemaras ◽  
...  
Keyword(s):  
Head Injuries ◽  
Cross Sectional Study ◽  
Head Impact ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Impact Mechanism ◽  
Head Impacts ◽  
Youth Football ◽  
High Magnitude ◽  
The Impact

Background: Concern for head injuries is widespread and has been reported by the media to be the number one cause of decreased participation in football among the American youth population. Identifying player mechanisms associated with intentional, or purposeful, head impacts should provide critical data for rule modifications, educational programs, and equipment design. Purpose: To investigate the frequency of intentional and unintentional head impacts and to examine the player mechanisms associated with intentional high-magnitude head impacts by comparing the impact mechanism distributions among session type, player position, and ball possession. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Head impact sensors and video footage of 68 players were used to analyze and classify 1319 high-magnitude impacts recorded over 1 season of youth football. Results: In total, 80% of the high-magnitude head impacts were classified as being caused by intentional use of the head. Head-to-head impact was the primary impact mechanism (n = 868; 82.7%) within the 1050 intentional high-magnitude impacts, with classifiable mechanisms, followed by head-to-body (n = 139; 13.2%), head-to-ground (n = 34; 3.2%), and head-to-equipment (n = 9; 0.9%). Head-to-head impacts also accounted for a greater proportion of impacts during practices (n = 625; 88.9%) than games, for linemen (n = 585; 90.3%) than perimeters and backs, and for ball carriers (n = 72; 79.1%) than tacklers. Conclusion: Overall, the majority of high-magnitude head impacts were intentional and resulted from head-to-head contact. The proportion of head-to-head contact was significantly higher for practices than games, linemen than backs and perimeter players, and ball carriers than tacklers.

scholarly journals Measurement of the head impacts in a sub-elite Australian Rules football team with an instrumented patch: An exploratory analysis

2017 ◽  
Vol 12 (3) ◽  
pp. 359-370 ◽  
Author(s):  
D King ◽  
M Hecimovich ◽  
T Clark ◽  
C Gissane
Keyword(s):  
Cohort Analysis ◽  
Medical Personnel ◽  
Magnitude Distribution ◽  
Head Impacts ◽  
Australian Football League ◽  
Football Team ◽  
Australian Rules Football ◽  
Australian Football ◽  
Frequency Magnitude Distribution ◽  
Frequency Magnitude

An investigation was made of the frequency, magnitude, and distribution of head impacts in Australian Football League players over a season of matches. In a prospective cohort analysis of impact magnitude, frequency, and distribution on data collected with a wireless head impact sensor worn behind the ear of 23 players, a total of 4903 impacts were recorded. Players experienced on average 407 ± 143 impacts over the duration of the study resulting in 30 ± 38 impacts per-player per-match. Linear accelerations ranged from 10  g to 153  g with a mean, median, and 95th percentile value of 17  g, 13  g, and 40  g, respectively. Rotational accelerations ranged from 130 rad/s2 to 21,890 rad/s2 with a mean, median, and 95th percentile value of 2426 rad/s2, 1556 rad/s2, and 7571 rad/s2, respectively. This study obtained initial measurements on the frequency, magnitude, distribution, and risk weighted exposure of head impacts in Australia Rules Football in order to better inform medical personnel in the identification and evaluation of at-risk players for concussion. The location of impacts varied considerably with the back of the head recording more total impacts than the front, side, and top. Midfielders sustained more impacts per-player, per-match, and had higher median resultant linear accelerations than forwards and defenders. The results of this study, in which most impacts were within the low severity limit for linear, rotational, HITSP, and RWECP, indicate that Australian Rules football needs to include more encompassing methods of examination of player exposure.

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.

scholarly journals Frequency and Location of Head Impact Exposures in Individual Collegiate Football Players

2010 ◽  
Vol 45 (6) ◽  
pp. 549-559 ◽  
Author(s):  
Joseph J. Crisco ◽  
Russell Fiore ◽  
Jonathan G. Beckwith ◽  
Jeffrey J. Chu ◽  
Per Gunnar Brolinson ◽  
...  
Keyword(s):  
National Collegiate Athletic Association ◽  
Median Number ◽  
Head Impact ◽  
Clinical Aspects ◽  
Brain Concussion ◽  
Head Impacts ◽  
Session Type ◽  
Subconcussive Impacts ◽  
Player Positions ◽  
Collegiate Football

Abstract Context: Measuring head impact exposure is a critical step toward understanding the mechanism and prevention of sport-related mild traumatic brain (concussion) injury, as well as the possible effects of repeated subconcussive impacts. Objective: To quantify the frequency and location of head impacts that individual players received in 1 season among 3 collegiate teams, between practice and game sessions, and among player positions. Design: Cohort study. Setting: Collegiate football field. Patients or Other Participants: One hundred eighty-eight players from 3 National Collegiate Athletic Association football teams. Intervention(s): Participants wore football helmets instrumented with an accelerometer-based system during the 2007 fall season. Main Outcome Measure(s): The number of head impacts greater than 10g and location of the impacts on the player's helmet were recorded and analyzed for trends and interactions among teams (A, B, or C), session types, and player positions using Kaplan-Meier survival curves. Results: The total number of impacts players received was nonnormally distributed and varied by team, session type, and player position. The maximum number of head impacts for a single player on each team was 1022 (team A), 1412 (team B), and 1444 (team C). The median number of head impacts on each team was 4.8 (team A), 7.5 (team B), and 6.6 (team C) impacts per practice and 12.1 (team A), 14.6 (team B), and 16.3 (team C) impacts per game. Linemen and linebackers had the largest number of impacts per practice and per game. Offensive linemen had a higher percentage of impacts to the front than to the back of the helmet, whereas quarterbacks had a higher percentage to the back than to the front of the helmet. Conclusions: The frequency of head impacts and the location on the helmet where the impacts occur are functions of player position and session type. These data provide a basis for quantifying specific head impact exposure for studies related to understanding the biomechanics and clinical aspects of concussion injury, as well as the possible effects of repeated subconcussive impacts in football.

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