Head Impact Exposure in Youth and Collegiate American Football.
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ABSTRACT:
SUBMITTER: Choi GB
PROVIDER: S-EPMC10081156 | biostudies-literature | 2022 Nov
REPOSITORIES: biostudies-literature
Publications
Head Impact Exposure in Youth and Collegiate American Football.
Choi Grace B GB Smith Eric P EP Duma Stefan M SM Rowson Steven S Campolettano Eamon E Kelley Mireille E ME Jones Derek A DA Stitzel Joel D JD Urban Jillian E JE Genemaras Amaris A Beckwith Jonathan G JG Greenwald Richard M RM Maerlender Arthur A Crisco Joseph J JJ
Annals of biomedical engineering 20220504 11
The relationship between head impact and subsequent brain injury for American football players is not well-defined, especially for youth. The objective of this study is to quantify and assess Head Impact Exposure (HIE) metrics among youth and collegiate football players. This multi-season study enrolled 639 unique athletes (354 collegiate; 285 youth, ages 9-14), recording 476,209 head impacts (367,337 collegiate; 108,872 youth) over 971 sessions (480 collegiate; 491 youth). Youth players experie ...[more]
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Project description:BackgroundPromoted as a safer alternative to tackle football, there has been an increase in flag football participation in recent years. However, examinations of head impact exposure in flag football as compared with tackle football are currently limited.HypothesisTackle football athletes will have a greater number and magnitude of head impacts compared with flag football athletes.Study designCohort study.Level of evidenceLevel 4.MethodsUsing mouthguard sensors, this observational, prospective cohort study captured data on the number and magnitude of head impacts among 524 male tackle and flag football athletes (6-14 years old) over the course of a single football season. Estimates of interest based on regression models used Bayesian methods to estimate differences between tackle and flag athletes.ResultsThere were 186,239 head impacts recorded during the study. Tackle football athletes sustained 14.67 (95% CI 9.75-21.95) times more head impacts during an athletic exposure (game or practice) compared with flag football athletes. Magnitude of impact for the 50th and 95th percentile was 18.15g (17.95-18.34) and 52.55g (51.06-54.09) for a tackle football athlete and 16.84g (15.57-18.21) and 33.51g (28.23-39.08) for a flag football athlete, respectively. A tackle football athlete sustained 23.00 (13.59-39.55) times more high-magnitude impacts (≥40g) per athletic exposure compared with a flag football athlete.ConclusionThis study demonstrates that youth athletes who play tackle football are more likely to experience a greater number of head impacts and are at a markedly increased risk for high-magnitude impacts compared with flag football athletes.Clinical relevanceThese results suggest that flag football has fewer head impact exposures, which potentially minimizes concussion risk, making it a safer alternative for 6- to 14-year-old youth football athletes.
| S-EPMC8404728 | biostudies-literature
Project description:UnlabelledOBJECT IVE: 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.MethodsOver 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.ResultsHelmet-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.ConclusionsHelmet-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.
| S-EPMC6155991 | biostudies-literature
Project description:ObjectiveLimiting contact in football practice can reduce the number of head impacts a player receives, but further research is needed to inform the modification of optimal drills that mitigate head impact exposure (HIE) while the player develops the skills needed to safely play the game. This study aimed to compare HIE in practice drills among 6 youth football teams and to evaluate the effect of a team on HIE.MethodsOn-field head impact data were collected from athletes (ages 10–13 years) playing on 6 local youth football teams (teams A–F) during all practices using the Head Impact Telemetry System. Video was recorded and analyzed to verify and assign impacts to a specific drill. Drills were identified as follows: dummy/sled tackling, half install, install, install walk through, multiplayer tackle, Oklahoma, one-on-one, open field tackling, other, passing, position skill work, scrimmage, special teams, tackling drill stations, and technique. HIE was quantified in terms of impacts per player per minute (ppm) and peak linear and rotational head acceleration. Generalized linear models were used to assess differences in head impact magnitude and frequency among drills as well as among teams within the most common drills.ResultsAmong 67 athlete-seasons, a total of 14,718 impacts during contact practices were collected and evaluated in this study. Among all 6 teams, the mean linear (p < 0.0001) and rotational (p < 0.0001) acceleration varied significantly among all drills. Open field tackling had significantly (p < 0.001) higher mean linear acceleration than all other drills. Multiplayer tackle had the highest mean impact rate (0.35 ppm). Significant variations in linear acceleration and impact rate were observed among teams within specific drills. Team A had the highest mean linear acceleration in install, one-on-one, and open field tackling and the highest mean impact rate in Oklahoma and position skill work. Although team A spent the greatest proportion of their practice on minimal- or no-player versus player contact drills (27%) compared to other teams, they had the highest median (20.2g) and 95th percentile (56.4g) linear acceleration in practice.ConclusionsFull-speed tackling and blocking drills resulted in the highest HIE. Reducing time spent on contact drills relative to minimal or no contact drills may not lower overall HIE. Instead, interventions such as reducing the speed of players engaged in contact, correcting tackling technique, and progressing to contact may reduce HIE more effectively.
| S-EPMC11233417 | biostudies-literature
Project description:The objective of this study was to examine associations of lifetime concussion history (CHx) and an advanced metric of lifetime repetitive head impact exposure with resting-state functional connectivity (rsFC) across the whole-brain and among large-scale functional networks (Default Mode; Dorsal Attention; and Frontoparietal Control) in former collegiate football players. Individuals who completed at least one year of varsity collegiate football were eligible to participate in this observational cohort study (n = 48; aged 36-41 years; 79.2% white/Caucasian; 12.5±4.4 years of football played; all men). Individuals were excluded if they reported history/suspicion of psychotic disorder with active symptoms, contraindications to participation in study procedures (e.g., MRI safety concern), or inability to travel. Each participant provided concussion and football playing histories. Self-reported concussion history was analyzed in two different ways based on prior research: dichotomous "High" (≥3 concussions; n = 28) versus "Low" (<3 concussions; n = 20); and four ordinal categories (0-1 concussion [n = 19]; 2-4 concussions [n = 8]; 5-7 concussions [n = 9]; and ≥8 concussions [n = 12]). The Head Impact Exposure Estimate (HIEE) was calculated from football playing history captured via structured interview. Resting-state fMRI and T1-weighted MRI were acquired and preprocessed using established pipelines. Next, rsFC was calculated using the Seitzman et al., (2020) 300-ROI functional atlas. Whole-brain, within-network, and between-network rsFC were calculated using all ROIs and network-specific ROIs, respectively. Effects of CHx and HIEE on rsFC values were examined using separate multivariable linear regression models, with a-priori α set to 0.05. We observed no statistically significant associations between rsFC outcomes and either CHx or HIEE (ps ≥ .12). Neither CHx nor HIEE were associated with neural signatures that have been observed in studies of typical and pathological aging. While CHx and repetitive head impacts have been associated with changes in brain health in older former athletes, our preliminary results suggest that associations with rsFC may not be present in early midlife former football players.
| S-EPMC9462826 | biostudies-literature
Project description:This study evaluated head impact exposure (HIE) metrics in relation to individual-level determinants of HIE. Youth (n = 13) and high school (n = 21) football players were instrumented with the Head Impact Telemetry (HIT) system during one season. Players completed the Trait-Robustness of Self-Confidence Inventory (TROSCI), Sports Climate Questionnaire (SCQ), and Competitive Aggressiveness and Anger Scale (CAAS), measuring self-confidence, perceived coach support, and competitive aggressiveness, respectively. Relationships between HIE metrics (number of impacts, median and 95th percentile accelerations, and risk-weighted exposure (RWE)) and survey scores were evaluated using linear regression analysis. For middle school athletes, TROSCI scores were significantly negatively associated with the number of competition impacts and the mean number of impacts per player per competition. SCQ scores were significantly positively associated with median linear acceleration during practice. CAAS scores were not significantly associated with biomechanical metrics at either level of play. Perceived coach support and self-confidence might influence HIE among middle school football players. Football athletes' competitive aggressiveness may have less influence their HIE than other factors.
| S-EPMC9412463 | biostudies-literature
Project description:Background Ventricular-arterial (VA) coupling is defined as the ratio between arterial elastance (EA) and left ventricular elastance (ELV). VA uncoupling, as occurs in hypertensive heart disease, is associated with adverse outcomes. This study sought to determine the relationship between American football (AF)-associated hypertension and VA uncoupling. Methods and Results This was a multicenter, longitudinal, and repeated measures observational study of collegiate AF athletes across 3 years of AF participation. Of 200 freshman athletes initially enrolled, 142 (67 Black [47%]/75 White [53%], 58 linemen [41%]/84 nonlinemen [59%]) were prospectively studied with echocardiography and applanation tonometry. Primary echocardiographic VA coupling outcome measures were EA/ELV and ΔEA/ELV, with increased EA/ELV indicating VA uncoupling. Adjusting for race and player position, AF athletes demonstrated increased EA/ELV (mean [95% CI]Δ, 0.10 [0.04-0.15]; P=0.001) and systolic blood pressure (SBP) (mean [95% CI]Δ, 11.4 [8.3-14.5] mm Hg, P<0.001) over their collegiate AF careers. In combination with longitudinal VA uncoupling, hypertension prevalence (including both stage 1 and 2) increased from 54% at baseline to 77% (44% stage 2) at the end of the study period (P<0.001). In multivariable mixed-effects linear regression analysis, higher SBP (β=0.021, P=0.02), lower E' (β=-0.010, P=0.03), and worse global longitudinal strain (β=0.036, P<0.001) were associated with higher EA/ELV. Increased SBP (ΔSBP, β=0.029, P=0.02) and worsened global longitudinal strain (Δglobal longitudinal strain, β=0.045, P<0.001) also predicted increased ΔEA/ELV. Conclusions VA uncoupling is associated with pathologically increased SBP and subclinical impairments in left ventricular systolic function in collegiate AF athletes, indicating a key mechanism underlying maladaptive cardiovascular phenotypes observed in this population. Future studies analyzing whether targeted clinical interventions improve VA coupling and health outcomes are warranted.
| S-EPMC9075286 | biostudies-literature
Project description:Background and objectivesThe objective of this study was to examine head-impact exposure by intensity level and position group, and to test the hypothesis that there would be an increase in cumulative head-impact exposure between drill intensities after controlling for duration in each level with air recording the lowest frequency and magnitude and live recording the highest: air < bags < control < thud < live.MethodsWe conducted a prospective, multisite study in 1 season with players from 3 high school football teams (n = 74). Each player wore a sensor-installed mouthguard, which monitored head-impact frequency, peak linear acceleration (PLA), and peak rotational acceleration (PRA). Practice drills and games were categorized by level of contact.ResultsA total of 7312 impacts were recorded with a median of 67 (interquartile range:128) impacts per player. After controlling for duration, increases in head-impact outcomes by level of contact were observed (air < bags = control < thud = live). Live drills had higher cumulative head-impact frequency (45.4 ± 53.0 hits) and magnitude (PLA: 766.3 ± 932.9 g; PRA: 48.9 ± 61.3 kilorad/s2) per player than other levels (P < .0001). In comparison, air drills had the lowest cumulative frequency (4.2 ± 6.9 hits) and magnitude (PLA: 68.0 ± 121.6 g; PRA: 6.4 ± 13.2 kilorad/s2).ConclusionsThese data support the levels-of-contact system as a practical approach to limiting head-impact exposure in tackle football. Our findings are clinically important, because data have begun to suggest the relationship between chronic head-impact exposure and decline in brain health. Since head-impact exposure was influenced by levels of contact, regulation of the duration of certain drill intensities (eg, thud, live) may associate with reduced head-impact exposure in high school football.
| S-EPMC9675985 | biostudies-literature
Project description:BackgroundStudies on the longitudinal effects of intense physical training on cardiac remodeling are limited, especially in American collegiate football players.HypothesisCollege-level American football training will result in remodeling in a pattern consistent of a sport with moderate static and dynamic demands with increases in both wall and chamber sizes.MethodsWe studied 85 American collegiate football players who underwent transthoracic echocardiogram (TTE) for asymptomatic or mild COVID-19-related illness and compared the changes in echo dimensions to their preparticipation screening TTE. Pre- and posttraining variables were compared using a paired t-test for normally distributed variables.ResultsMean age was 19 years ± 1 and 61% of athletes were Black. Mean follow-up between TTEs was 21 ± 13 months. There was an increase in left atrial volume index (26.4 ± 5.5 to 32.8 ± 8.4 mL/m2 , p < .001), LV end diastolic diameter (5.13 ± 0.4 to 5.27 ± 0.4 cm, p = .003), basal RV diameter (3.28 ± 0.7 to 3.83 ± 0.5 cm, p = <.001), LV mass index (86.7 ± 15.3 to 90.1 ± 15.3, p = .015), and aortic root diameter (3.1 ± 0.4 to 3.2 ± 0.3 cm, p = .03) from pre- to posttraining, with a slightly greater magnitude in athletes with >2 years of training. Presence of left atrial enlargement (≥35 mL/m2 ) increased from 2.9% to 29% pre- to postparticipation in athletes with >2 years training. No significant changes in wall thickness, diastolic function, or right ventricular systolic function were observed.ConclusionAmerican football players college-level training was associated with increases in left and right ventricular chamber sizes, left atrial size, and aortic root diameter.
| S-EPMC10540003 | biostudies-literature
Project description:USA Football established five levels-of-contact to guide the intensity of high school football practices. The objective of this study was to examine head impact frequency and magnitude by levels-of-contact to determine which drills had the greatest head impact exposure. Our primary hypothesis was that there would be an incremental increase in season-long head impact exposure between levels-of-contact: air<bags<control<thud<live. This observational study included 24 high-school football players during all 46 practices, 1 scrimmage, 9 junior varsity and 10 varsity games in the 2019 season. Players wore a sensor-installed mouthguard that monitored head impact frequency, peak linear acceleration (PLA), and rotational acceleration (PRA). Practice/game drills were filmed and categorized into five levels-of-contact (air, bags, control, thud, live), and head impact data were assigned into one of five levels-of-contact. Player position was categorized into lineman, hybrid, and skill. A total of 6016 head impacts were recorded during 5 levels-of-contact throughout the season. In the overall sample, total number of impacts, sum of PLA, and PRA per player increased in a near incremental manner (air<bags<control = thud<live), where live drills had significantly higher cumulative frequency (113.7±17.8 hits/player) and magnitude [2,657.6±432.0 g (PLA), and 233.9 ± 40.1 krad/s2 (PRA)] than any other levels-of-contact, whereas air drills showed the lowest cumulative frequency (7.7±1.9 hits/player) and magnitude [176.9±42.5 g (PLA), PRA 16.7±4.2 krad/s2 (PRA)]. There was no significant position group difference in cumulative head impact frequency and magnitude in a season. Although there was no difference in average head impact magnitude across five levels-of-contact and by position group PLA (18.2-23.2g) and PRA (1.6-2.3krad/s2) per impact], high magnitude (60-100g and >100g) head impacts were more frequently observed during live and thud drills. Level-of-contact influences cumulative head impact frequency and magnitude in high-school football, with players incurring frequent, high magnitude head impacts during live, thud, and control. It is important to consider level-of-contact to refine clinical exposure guidelines to minimize head impact burden in high-school football.
| S-EPMC7428124 | biostudies-literature
Project description:ImportanceRepetitive head impacts have been posited to contribute to neurocognitive and behavioral difficulties in contact sport athletes.ObjectiveTo identify associations between cognitive and behavioral outcomes and head impacts measured in youth tackle football players over 4 seasons of play.Design, setting, and participantsThis prospective cohort study was conducted from July 2016 through January 2020, spanning 4 football seasons. The setting was a youth tackle football program and outpatient medical clinic. Players were recruited from 4 football teams composed of fifth and sixth graders, and all interested players who volunteered to participate were enrolled. Data analysis was performed from March 2020 to June 2021.ExposuresImpacts were measured using helmet-based sensors during practices and games throughout 4 consecutive seasons of play. Impacts were summed to yield cumulative head impact gravitational force equivalents per season.Main outcomes and measuresTen cognitive and behavioral measures were completed before and after each football season.ResultsThere were 70 male participants aged 9 to 12 years (mean [SD] age, 10.6 [0.64] years), with 18 completing all 4 years of the study. At the post-season 1 time point, higher cumulative impacts were associated with lower self-reported symptom burden (β = -0.6; 95% CI, -1.0 to -0.2; P = .004). After correcting for multiple comparisons, no other associations were found between impacts and outcome measures. At multiple times throughout the study, premorbid attention-deficit/hyperactivity disorder, anxiety, and depression were associated with worse cognitive or behavioral scores, whereas a premorbid headache disorder or history of concussion was less often associated with outcomes.Conclusions and relevanceIn this cohort of youth tackle football players, premorbid conditions, including attention-deficit/hyperactivity disorder, anxiety, and depression, were associated with cognitive and behavioral outcomes more often than cumulative impact.
| S-EPMC8719231 | biostudies-literature