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 In-Season Variations in Head Impact Exposure among Youth Football Players

2019 ◽  
Vol 36 (2) ◽  
pp. 275-281 ◽  
Author(s):  
Jillian E. Urban ◽  
Mireille E. Kelley ◽  
Mark A. Espeland ◽  
Elizabeth M. Davenport ◽  
Christopher T. Whitlow ◽  
...  
Keyword(s):  
Head Impact ◽  
Football Players ◽  
Youth Football ◽  
Season Variations

Head Impact Exposure in Youth Football: Middle School Ages 12–14 Years

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Ray W. Daniel ◽  
Steven Rowson ◽  
Stefan M. Duma
Keyword(s):  
High School ◽  
Middle School ◽  
Head Impact ◽  
Football Players ◽  
Head Acceleration ◽  
Limited Data ◽  
Head Impacts ◽  
Football Helmet ◽  
Injury Criteria ◽  
Youth Football

The head impact exposure experienced by football players at the college and high school levels has been well documented; however, there are limited data regarding youth football despite its dramatically larger population. The objective of this study was to investigate head impact exposure in middle school football. Impacts were monitored using a commercially available accelerometer array installed inside the helmets of 17 players aged 12–14 years. A total of 4678 impacts were measured, with an average (±standard deviation) of 275 ± 190 impacts per player. The average of impact distributions for each player had a median impact of 22 ± 2 g and 954 ± 122 rad/s2, and a 95th percentile impact of 54 ± 9 g and 2525 ± 450 rad/s2. Similar to the head impact exposure experienced by high school and collegiate players, these data show that middle school football players experience a greater number of head impacts during games than practices. There were no significant differences between median and 95th percentile head acceleration magnitudes experienced during games and practices; however, a larger number of impacts greater than 80 g occurred during games than during practices. Impacts to the front and back of the helmet were most common. Overall, these data are similar to high school and college data that have been collected using similar methods. These data have applications toward youth football helmet design, the development of strategies designed to limit head impact exposure, and child-specific brain injury criteria.

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.

scholarly journals Drill-specific head impact exposure in youth football practice

2016 ◽  
Vol 18 (5) ◽  
pp. 536-541 ◽  
Author(s):  
Eamon T. Campolettano ◽  
Steven Rowson ◽  
Stefan M. Duma
Keyword(s):  
United States ◽  
The United States ◽  
High Impact ◽  
Head Impact ◽  
Football Players ◽  
Head Impacts ◽  
Youth Football ◽  
Impact Rate ◽  
High Magnitude ◽  
Specific Activities

OBJECTIVE Although 70% of football players in the United States are youth players (6–14 years old), most research on head impacts in football has focused on high school, collegiate, or professional populations. The objective of this study was to identify the specific activities associated with high-magnitude (acceleration > 40g) head impacts in youth football practices. METHODS A total of 34 players (mean age 9.9 ± 0.6 years) on 2 youth teams were equipped with helmet-mounted accelerometer arrays that recorded head accelerations associated with impacts in practices and games. Videos of practices and games were used to verify all head impacts and identify specific drills associated with each head impact. RESULTS A total of 6813 impacts were recorded, of which 408 had accelerations exceeding 40g (6.0%). For each type of practice drill, impact rates were computed that accounted for the length of time that teams spent on each drill. The tackling drill King of the Circle had the highest impact rate (95% CI 25.6–68.3 impacts/hr). Impact rates for tackling drills (those conducted without a blocker [95% CI 14.7–21.9 impacts/hr] and those with a blocker [95% CI 10.5–23.1 impacts/hr]) did not differ from game impact rates (95% CI 14.2–21.6 impacts/hr). Tackling drills were observed to have a greater proportion (between 40% and 50%) of impacts exceeding 60g than games (25%). The teams in this study participated in tackling or blocking drills for only 22% of their overall practice times, but these drills were responsible for 86% of all practice impacts exceeding 40g. CONCLUSIONS In youth football, high-magnitude impacts occur more often in practices than games, and some practice drills are associated with higher impact rates and accelerations than others. To mitigate high-magnitude head impact exposure in youth football, practices should be modified to decrease the time spent in drills with high impact rates, potentially eliminating a drill such as King of the Circle altogether.

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 Analysis of longitudinal head impact exposure and white matter integrity in returning youth football players

2021 ◽  
pp. 1-10
Author(s):  
Mireille E. Kelley ◽  
Jillian E. Urban ◽  
Derek A. Jones ◽  
Elizabeth M. Davenport ◽  
Logan E. Miller ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Head Impact ◽  
Cumulative Exposure ◽  
Control Group ◽  
Football Players ◽  
Imaging Data ◽  
Practice Session ◽  
Youth Football

OBJECTIVE The objective of this study was to characterize changes in head impact exposure (HIE) across multiple football seasons and to determine whether changes in HIE correlate with changes in imaging metrics in youth football players. METHODS On-field head impact data and pre- and postseason imaging data, including those produced by diffusion tensor imaging (DTI), were collected from youth football athletes with at least two consecutive seasons of data. ANCOVA was used to evaluate HIE variations (number of impacts, peak linear and rotational accelerations, and risk-weighted cumulative exposure) by season number. DTI scalar metrics, including fractional anisotropy, mean diffusivity, and linear, planar, and spherical anisotropy coefficients, were evaluated. A control group was used to determine the number of abnormal white matter voxels, which were defined as 2 standard deviations above or below the control group mean. The difference in the number of abnormal voxels between consecutive seasons was computed for each scalar metric and athlete. Linear regression analyses were performed to evaluate relationships between changes in HIE metrics and changes in DTI scalar metrics. RESULTS There were 47 athletes with multiple consecutive seasons of HIE, and corresponding imaging data were available in a subsample (n = 19) of these. Increases and decreases in HIE metrics were observed among individual athletes from one season to the next, and no significant differences (all p > 0.05) in HIE metrics were observed by season number. Changes in the number of practice impacts, 50th percentile impacts per practice session, and 50th percentile impacts per session were significantly positively correlated with changes in abnormal voxels for all DTI metrics. CONCLUSIONS These results demonstrate a significant positive association between changes in HIE metrics and changes in the numbers of abnormal voxels between consecutive seasons of youth football. Reducing the number and frequency of head impacts, especially during practice sessions, may decrease the number of abnormal imaging findings from one season to the next in youth football.

scholarly journals Examining Play Counts and Measurements of Injury Incidence in Youth Football

2017 ◽  
Vol 52 (10) ◽  
pp. 955-965 ◽  
Author(s):  
Zachary Y. Kerr ◽  
Susan W. Yeargin ◽  
Aristarque Djoko ◽  
Sara L. Dalton ◽  
Melissa M. Baker ◽  
...  
Keyword(s):  
Outcome Measure ◽  
Age Groups ◽  
Injury Rate ◽  
Football Players ◽  
Injury Incidence ◽  
Injury Rates ◽  
Head Impacts ◽  
Youth Football ◽  
Rate Ratios ◽  
Age Range

Context: Whereas researchers have provided estimates for the number of head impacts sustained within a youth football season, less is known about the number of plays across which such impact exposure occurs.Objective: To estimate the number of plays in which youth football players participated during the 2013 season and to estimate injury incidence through play-based injury rates.Design: Descriptive epidemiology study.Setting: Youth football.Patients or Other Participants: Youth football players (N = 2098; age range, 5−15 years) from 105 teams in 12 recreational leagues across 6 states.Main Outcome Measure(s): We calculated the average number of athlete-plays per season and per game using independent-samples t tests to compare age groups (5–10 years old versus 11–15 years old) and squad sizes (&lt;20 versus ≥20 players); game injury rates per 1000 athlete-exposures (AEs) and per 10 000 athlete-plays; and injury rate ratios (IRRs) with 95% confidence intervals (CIs) to compare age groups.Results: On average, youth football players participated in 333.9 ± 178.5 plays per season and 43.9 ± 24.0 plays per game. Age groups (5- to 10-year-olds versus 11- to 15-year-olds) did not differ in the average number of plays per season (335.8 versus 332.3, respectively; t2086.4 = 0.45, P = .65) or per game (44.1 versus 43.7, respectively; t2092.3 = 0.38, P = .71). However, players from smaller teams participated in more plays per season (373.7 versus 308.0; t1611.4 = 8.15, P &lt; .001) and per game (47.7 versus 41.4; t1523.5 = 5.67, P &lt; .001). Older players had a greater game injury rate than younger players when injury rates were calculated per 1000 AEs (23.03 versus 17.86/1000 AEs; IRR = 1.29; 95% CI = 1.04, 1.60) or per 10 000 athlete-plays (5.30 versus 4.18/10 000 athlete-plays; IRR = 1.27; 95% CI = 1.02, 1.57).Conclusions: A larger squad size was associated with a lower average number of plays per season and per game. Increasing youth football squad sizes may help reduce head-impact exposure for individual players. The AE-based injury rates yielded effect estimates similar to those of play-based injury rates.

Relationship Between Time-Weighted Head Impact Exposure on Directional Changes in Diffusion Imaging in Youth Football Players

2021 ◽  
Vol 49 (10) ◽  
pp. 2852-2862
Author(s):  
Suraj K. Puvvada ◽  
Elizabeth M. Davenport ◽  
James M. Holcomb ◽  
Logan E. Miller ◽  
Christopher T. Whitlow ◽  
...  
Keyword(s):  
Diffusion Imaging ◽  
Head Impact ◽  
Football Players ◽  
Youth Football

scholarly journals Concussion BASICS II

Neurology ◽  
2018 ◽  
Vol 91 (23) ◽  
pp. e2123-e2132 ◽  
Author(s):  
Breton M. Asken ◽  
Russell M. Bauer ◽  
Steven T. DeKosky ◽  
Zachary M. Houck ◽  
Charles C. Moreno ◽  
...  
Keyword(s):  
Collegiate Athletes ◽  
Head Impact ◽  
Amyloid Peptide ◽  
Serum Biomarker ◽  
Cumulative Exposure ◽  
Head Impacts ◽  
Clinical Assessments ◽  
Recent Exposure ◽  
Impact Index ◽  
Concussion History

ObjectiveTo examine the effect of concussion history and cumulative exposure to collision sports on baseline serum biomarker concentrations, as well as associations between biomarker concentrations and clinical assessments.MethodsIn this observational cohort study, β-amyloid peptide 42 (Aβ42), total tau, S100 calcium binding protein B (S100B), ubiquitin carboxy-terminal hydrolyzing enzyme L1 (UCH-L1), glial fibrillary acidic protein, microtubule associated protein 2, and 2′,3′-cyclic-nucleotide 3′-phosphodiesterase serum concentrations were measured in 415 (61% male, 40% white, aged 19.0 ± 1.2 years) nonconcussed collegiate athletes without recent exposure to head impacts. Regression analyses were used to evaluate the relationship between self-reported history of concussion(s), cumulative years playing collision sports, clinical assessments, and baseline biomarker concentrations. Football-specific analyses were performed using a modified Cumulative Head Impact Index. Clinical assessments included symptom, cognitive, balance, and oculomotor tests.ResultsAthletes with a greater number of concussions had a higher baseline Aβ42 concentration only (ρ = 0.140, p = 0.005, small effect size). No biomarker concentrations correlated with cumulative exposure to collision sports. Race status fully mediated the correlations of S100B, UCH-L1, and Aβ42 with cognitive scores. Football exposure, specifically, was not associated with serum biomarker concentrations or clinical assessment scores based on the modified Cumulative Head Impact Index.ConclusionConcussion-related serum biomarkers showed no consistent association with concussion history, cumulative exposure to collision sports, or clinical assessments in a sample of healthy collegiate athletes. Serum Aβ42 concentrations could increase following multiple previous concussions. Considering race status is essential when investigating links between biomarkers and cognition. The biomarkers studied may not detect residual effects of concussion or repetitive head impact exposure in otherwise asymptomatic collegiate athletes without recent exposure to head impacts. Much more research is needed for identifying reliable and valid blood biomarkers of brain trauma history.

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.

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