Behavioral Tackling Interventions Decrease Head Impact Frequency in American Football Players: A Critically Appraised Topic

2020 ◽  
pp. 1-7
Author(s):  
Ashley E. Evans ◽  
Madeline Curtis ◽  
Marguerite (Meg) Montjoy ◽  
Erica Beidler
Keyword(s):  
High School ◽  
Injury Prevention ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Clinical Question ◽  
Impact Frequency ◽  
Bottom Line ◽  
Head Impacts ◽  
Different Types

Context: The rate of sport-related concussion diagnosis has significantly increased in recent years, which has created a need for injury prevention initiatives. There have been efforts put forth by researchers and American football organizations to teach athletes how to tackle properly in order to decrease the number of subconcussive head impacts and concussions. Clinical Question: Does the implementation of a behavioral tackling intervention decrease the head impact frequency in American football players? Clinical Bottom Line: There is moderate SORT Level B evidence to support the use of behavioral tackling interventions as a means for reducing head impact frequency in football athletes. All four included studies found a significant reduction in head impacts following a behavioral tackling intervention with study findings ranging from a 26–33% reduction in impact frequency. These findings were consistent in youth, high school, and college football players and for different types of behavioral tackling interventions. Therefore, these results indicate that behavioral tackling interventions have the potential to reduce the number of head impacts sustained by American football players, which may ultimately lead to a reduction in concussion occurrence as well.

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.

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 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 Association of physiological variables with football subconcussive head impacts: Why measure?

2018 ◽  
Author(s):  
Megan E. Huibregtse ◽  
Steven W. Zonner ◽  
Keisuke Ejima ◽  
Zachary W. Bevilacqua ◽  
Sharlene Newman ◽  
...  
Keyword(s):  
High School ◽  
Skeletal Muscle ◽  
Heart Rate ◽  
Muscle Damage ◽  
Physical Exertion ◽  
Head Impact ◽  
American Football ◽  
Physiological Factors ◽  
Head Impacts ◽  
Skeletal Muscle Damage

AbstractSubconcussive head impacts, defined as impacts to the cranium that do not result in clinical symptoms of concussion, are gaining traction as a major public health concern. Researchers begin to suggest subconcussive impact-dependent changes in various neurological measures. However, a contribution of physiological factors such as physical exertion and muscle damage has never been accounted. We conducted a prospective longitudinal study during a high school American football season to examine the association between physiological factors and subconcussive head impact kinematics. Fifteen high-school American football players volunteered in the study. A sensor-installed mouthguard recorded the number of head impacts, peak linear (PLA: g) and peak rotational (PRA: rad/s2) head accelerations from every practice and game. Serum samples were collected at 12 time points (pre-season baseline, five in-season pre-post games, and post-season) and assessed for the creatine kinase skeletal muscle-specific isoenzyme (CK-MM), as a surrogate for skeletal muscle damage. Physical exertion was estimated in the form of excess post-exercise oxygen consumption (EPOC) from heart rate data captured during five games via a wireless heart rate monitor. A total of 9,700 hits, 214,492 g, and 19,885,037 rad/s2 were recorded from 15 players across the study period. Mixed-effect regression models indicated that head impact kinematics (frequency, PLA, and PRA) were significantly and positively associated with CK-MM increase, but not with EPOC. There was a significant and positive association between CK-MM and EPOC. These data suggest that skeletal muscle damage effects should be considered when using outcome measures that may have an interaction with muscle damage, including inflammatory biomarkers and vestibular/balance tests.

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 BIOMECHANIC DATA-DRIVEN BEHAVIOR MODIFICATION TO REDUCE CONCUSSION RISK IN HIGH SCHOOL FOOTBALL ATHLETES

2019 ◽  
Vol 7 (3_suppl) ◽  
pp. 2325967119S0010 ◽  
Author(s):  
Patricia R. Combs ◽  
Cassie B. Ford ◽  
Maryalice Nocera ◽  
Kody R. Campbell ◽  
Stephen W. Marshall ◽  
...  
Keyword(s):  
High School ◽  
High Risk ◽  
Intervention Program ◽  
Head Impact ◽  
Impact Frequency ◽  
High School Football ◽  
Post Intervention ◽  
Head Impacts ◽  
High Magnitude ◽  
Impact Data

Background: Each year, between 1.1 and 1.9 million sports and recreation-related concussions occur annually in US children aged =18 years. Football has a high concussion incidence relative to other youth sports. This is particularly concerning given recent evidence suggesting sport-related concussions are associated with late-life cognitive and psychological dysfunction in former athletes. Unfortunately, there are currently few proven interventions to prevent concussion in football. The purpose of this study was to evaluate a mentored intervention program designed to teach safe play techniques and thereby reduce head impact frequency and severity in high school football players. Methods: In a clustered quasi-experimental study design, the player education intervention program was provided to two out of three teams in year one, two out of four teams in year two, and all four teams in year three. Head impacts were measured using in-helmet accelerometers worn by all players. Head impact data and game video were used to identify “high risk” players on intervention teams to receive individualized mentoring. Players were identified as candidates for intervention based on three criteria: 1) greater than 20% of head impacts sustained to the top of the head, 2) greater than 7% of impacts exceeded 60 g in peak linear acceleration, and 3) player sustained a concussion. High-risk players attended 3 individual or small-group education sessions over 3 weeks with a mentor who analyzed game film to teach safer playing techniques. Intervention effects were evaluated by comparing post-intervention to pre-intervention head impact data. Coach and player satisfaction were assessed to evaluate the program’s acceptability and impact. Results: 220 athletes (143 intervention; 77 control) participated. Of these, 32 (14%) were classified “high risk” with playing techniques amenable to intervention. Overall, 21 (66%) of mentored athletes demonstrated a reduction in top-of-head impacts (considered a high-risk impact zone) and 17 (53%) of mentored athletes demonstrated a reduction in high magnitude (>60 g) hits. On average, the proportion of top-of-head impacts dropped 2.75% in mentored players, and 2.04% in non-mentored players. The proportion of head impacts classified as high-magnitude (>60 g) dropped 1.07% from pre- to post-intervention in mentored players. There was minimal (<1%) change in high magnitude impacts in non-mentored players. In post-season exit surveys, most mentored players “agreed” (n=18, 69%) that his playing behaviors improved because of the study. Most intervention team coaches thought the study was “effective” (n=31, 97%). Conclusions/Significance: Mentoring effects were modest; however, athletes and coaches viewed the program as effective. Behavioral interventions have potential to reduce head impact frequency and severity in football but may require more intensive mentoring than the 3-session model tested in this study. Tables/Figures: [Table: see text][Table: see text]

Comparing In Vivo Head Impact Kinematics From American Football With Laboratory Drop and Linear Impactors

2013 ◽  
Author(s):  
Fidel Hernandez ◽  
Pete B. Shull ◽  
Bruce Cam ◽  
Lyndia Wu ◽  
Rebecca Shultz ◽  
...  
Keyword(s):  
High School ◽  
Brain Function ◽  
Laboratory Testing ◽  
Laboratory Tests ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Test Apparatus ◽  
Kinematic Measures

Roughly 5% of all collegiate and high school American football players suffer a concussion each season [1]. Concussions and repetitive sub-concussive trauma can have measurable effects on brain function and neurophysiological changes [2]. Several studies have suggested that a combination of linear and angular kinematic measures may be predictive of concussion [3, 4]. Presently, laboratory testing and analysis of purely linear kinematics is used to design and assess the safety of protective headgear. However, it is not known how well existing laboratory tests recapitulate angular kinematics. In this study, we analyze combinations of linear and angular head kinematics experienced by players on the field. This study sought to answer the question: how well do the twin-wire drop test apparatus and a spring-driven linear impactor reproduce the combination of linear and angular head impact kinematics experienced in vivo by players of American football?

scholarly journals Association of physiological variables with subconcussive head impacts in high school American football

Neurology ◽  
2019 ◽  
Vol 93 (14 Supplement 1) ◽  
pp. S28.2-S28
Author(s):  
Megan E. Huibregtse ◽  
Steven W. Zonner ◽  
Keisuke Ejima ◽  
Zachary W. Bevilacqua ◽  
Sharlene D. Newman ◽  
...  
Keyword(s):  
High School ◽  
Heart Rate ◽  
Muscle Damage ◽  
Physical Exertion ◽  
Head Impact ◽  
American Football ◽  
Health Concern ◽  
Mixed Effect ◽  
Head Impacts ◽  
Physiological Variables

ObjectiveThe purpose of this investigation was to examine the relationships between subconcussive head impact frequency and magnitude and measures of physical exertion and muscle damage.BackgroundSubconcussive head impacts, or impacts that do not present with concussion symptoms, are gaining traction as a major public health concern. However, there is a gap in knowledge about the contribution of physiological variables, such as muscle damage and physical exertion, to neurological measures used to assess subconcussive impact-dependent changes. The unknown contribution of physical exertion and strenuous exercise is often listed as a limitation in field studies of subconcussive head impacts.Design/MethodsFifteen high school football players wore mouthguards installed with triaxial accelerometers and gyroscopes in order to quantify the linear and rotational accelerations of every head impact sustained throughout one season (practices and games). Additionally, serum samples were collected at twelve time points (pre-season, pre- and post-competition for five in-season games, and post-season) and assayed for CK-MM, the skeletal muscle-specific isoenzyme of creatine kinase. Subjects wore heart rate monitors during the five games, and heart rate data were used to estimate physical exertion in terms of excess post-exercise oxygen consumption (EPOC).ResultsMixed-effect regression modeling (MRM) showed significant and positive associations between CK-MM and subconcussive head impact kinematic variables, in addition to a significant and positive association between CK-MM and EPOC. The models were adjusted for cumulative head impact exposures up to each game and the pre-season serum CK-MM levels, when applicable.ConclusionsWhen investigating subconcussive head impacts, the effects of muscle damage should be considered when using correlated outcome measures, such as inflammatory biomarkers and vestibular assessments.

scholarly journals Comparison of video-based and sensor-based head impact exposure

2017 ◽  
Author(s):  
Calvin Kuo ◽  
Lyndia Wu ◽  
Jesus Loza ◽  
Daniel Senif ◽  
Scott C. Anderson ◽  
...  
Keyword(s):  
Angular Position ◽  
Head Impact ◽  
American Football ◽  
Rear Side ◽  
Football Players ◽  
Head Impacts ◽  
Video Assessment ◽  
Impact Location ◽  
Video Observations ◽  
Time Stamps

AbstractPrevious research has sought to quantify head impact exposure using wearable kinematic sensors. However, many sensors suffer from poor accuracy in estimating impact kinematics and count, motivating the need for additional independent impact exposure quantification for comparison. Here, we equipped seven collegiate American football players with instrumented mouthguards, and video recorded practices and games to compare video-based and sensor-based exposure rates and impact location distributions. Over 50 player-hours, we identified 271 helmet contact periods in video, while the instrumented mouthguard sensor recorded 2,032 discrete head impacts. Matching video and mouthguard real-time stamps yielded 193 video-identified helmet contact periods and 217 sensor-recorded impacts. To compare impact locations, we binned matched impacts into frontal, rear, side, oblique, and top locations based on video observations and sensor kinematics. While both video-based and sensor-based methods found similar location distributions, our best method utilizing integrated linear and angular position only correctly predicted 81 of 217 impacts. Finally, based on the activity timeline from video assessment, we also developed a new exposure metric unique to American football quantifying number of cross-verified sensor impacts per player-play. We found significantly higher exposure during games (0.35, 95% CI: 0.29-0.42) than practices (0.20, 95% CI: 0.17-0.23) (p<0.05). In the traditional impacts per player-hour metric, we observed higher exposure during practices (4.7) than games (3.7) due to increased player activity in practices. Thus, our exposure metric accounts for variability in on-field participation. While both video-based and sensor-based exposure datasets have limitations, they can complement one another to provide more confidence in exposure statistics.

scholarly journals Disparate Associations of Years of Football Participation and a Metric of Head Impact Exposure with Neurobehavioral Outcomes in Former Collegiate Football Players

2021 ◽  
pp. 1-13
Author(s):  
Benjamin L. Brett ◽  
Amy M. Nader ◽  
Zachary Y. Kerr ◽  
Avinash Chandran ◽  
Samuel R. Walton ◽  
...  
Keyword(s):  
Sport Participation ◽  
Verbal Learning ◽  
Brief Symptom Inventory ◽  
Head Impact ◽  
American Football ◽  
Football Players ◽  
Structured Interviews ◽  
Head Impacts ◽  
Exposure Estimate ◽  
Neurobehavioral Outcomes

Abstract Objectives: Years of sport participation (YoP) is conventionally used to estimate cumulative repetitive head impacts (RHI) experienced by contact sport athletes. The relationship of this measure to other estimates of head impact exposure and the potential associations of these measures with neurobehavioral functioning are unknown. We investigated the association between YoP and the Head Impact Exposure Estimate (HIEE), and whether associations between the two estimates of exposure and neurobehavioral functioning varied. Methods: Former American football players (N = 58; age = 37.9 ± 1.5 years) completed in-person evaluations approximately 15 years following sport discontinuation. Assessments consisted of neuropsychological assessment and structured interviews of head impact history (i.e., HIEE). General linear models were fit to test the association between YoP and the HIEE, and their associations with neurobehavioral outcomes. Results: YoP was weakly correlated with the HIEE, p = .005, R 2 = .13. Higher YoP was associated with worse performance on the Symbol Digit Modalities Test, p = .004, R 2 = .14, and Trail Making Test-B, p = .001, R 2 = .18. The HIEE was associated with worse performance on the Delayed Recall trial of the Hopkins Verbal Learning Test-Revised, p = .020, R 2 = .09, self-reported cognitive difficulties (Neuro-QoL Cognitive Function), p = .011, R 2 = .10, psychological distress (Brief Symptom Inventory-18), p = .018, R 2 = .10, and behavioral regulation (Behavior Rating Inventory of Executive Function for Adults), p = .017, R 2 = .10. Conclusions: YoP was marginally associated with the HIEE, a comprehensive estimate of head impacts sustained over a career. Associations between each exposure estimate and neurobehavioral functioning outcomes differed. Findings have meaningful implications for efforts to accurately quantify the risk of adverse long-term neurobehavioral outcomes potentially associated with RHI.

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