Does tackling form affect head acceleration in youth football players?

2020 ◽  
Vol 234 (3) ◽  
pp. 257-267 ◽  
Author(s):  
Ryan A Gellner ◽  
Eamon T Campolettano ◽  
Steven Rowson
Keyword(s):  
Football Players ◽  
Head Acceleration ◽  
Head Impacts ◽  
Youth Football ◽  
High Magnitude ◽  
Close Range ◽  
Agreement Coefficient ◽  
Reduce Risk ◽  
Effectiveness Of Training ◽  
Age Range

To reduce head impact exposure, a number of youth football organizations have begun teaching tackling technique. This study sought to develop and utilize a set of tackling form grading criteria for both tacklers and ball carriers as well as to relate tackling form to head acceleration outcome. It was hypothesized that players exhibiting better form would experience lower head accelerations in individual tackles. Three teams consisting of 67 players (20, 29, and 18 players per team; age 12.7 ± 0.95, age range 11–14 years, body mass 55.1 ± 16.2 kg) were instrumented with helmet-mounted accelerometer arrays for one season. Videos of close-range tackling drills were used to develop tackling form criteria. Two raters used these criteria to each score 105 impacts. Six of the seven categories were found to have good inter-rater reliability metrics (total percent agreement ≥ 79%, agreement coefficient ≥ 0.65). Bending at both the hips and knees, leading with the shoulder or arm, and initiating contact were found to reduce risk of high-magnitude (>40 g) head impacts in tacklers. Keeping the eyes up and avoiding dropping the head reduced the risk of high-magnitude head impacts in ball carriers. This study shows the potential effectiveness of training both tacklers and ball carriers in proper technique for collisions in youth football to minimize head impacts.

Are specific players more likely to be involved in high-magnitude head impacts in youth football?

2019 ◽  
Vol 24 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Ryan A. Gellner ◽  
Eamon T. Campolettano ◽  
Eric P. Smith ◽  
Steven Rowson
Keyword(s):  
Data Driven ◽  
Small Subset ◽  
Football Players ◽  
Head Acceleration ◽  
Long Term Effects ◽  
Head Impacts ◽  
Youth Football ◽  
High Magnitude ◽  
The Relationship

OBJECTIVEYouth football attracts approximately 3.5 million participants every year, but concern has recently arisen about the long-term effects of experiencing repetitive head accelerations from a young age due to participation in football. The objective of this study was to quantify total involvement in high-magnitude impacts among individual players in youth football practices. The authors explored the relationship between the total number of high-magnitude accelerations in which players were involved (experienced either by themselves or by other players) during practices and the number of high-magnitude accelerations players experienced.METHODSA local cohort of 94 youth football players (mean age 11.9 ± 1.5, mean body mass 50.3 ± 16.4 kg) from 4 different teams were recruited and outfitted with helmet-mounted accelerometer arrays. The teams were followed for one season each for a total of 128 sessions (practices, games, and scrimmages). All players involved in high-magnitude (greater than 40g) head accelerations were subsequently identified through analysis of practice film.RESULTSPlayers who experienced more high-magnitude accelerations were more likely to be involved in impacts associated with high-magnitude accelerations in other players. A small subset of 6 players (6%) were collectively involved in 230 (53%) high-magnitude impacts during practice, were involved in but did not experience a high-magnitude acceleration 78 times (21% of the 370 one-sided high-magnitude impacts), and experienced 152 (30%) of the 502 high-magnitude accelerations measured. Quarterbacks/running backs/linebackers were involved in the greatest number of high-magnitude impacts in practice and experienced the greatest number of high-magnitude accelerations. Which team a player was on was an important factor, as one team showed much greater head impact exposure than all others.CONCLUSIONSThis study showed that targeting the most impact-prone players for individualized interventions could reduce high-magnitude acceleration exposure for entire teams. These data will help to further quantify elevated head acceleration exposure and enable data-driven interventions that modify exposure for individual players and entire teams.

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 (<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 < .001) and per game (47.7 versus 41.4; t1523.5 = 5.67, P < .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.

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 Relating on-field youth football head impacts to pneumatic ram laboratory testing procedures

2020 ◽  
pp. 175433712094906
Author(s):  
Eamon T Campolettano ◽  
Steven Rowson
Keyword(s):  
Severity Index ◽  
Football Players ◽  
Head Acceleration ◽  
Head Impacts ◽  
Testing Procedures ◽  
Youth Athletes ◽  
Football Helmet ◽  
Youth Football ◽  
Impact Data ◽  
Athletic Equipment

A youth-specific football helmet testing standard has been proposed to address the physical and biomechanical differences between adult and youth football players. This study sought to relate the proposed youth standard-defined laboratory impacts to on-field head impacts collected from youth football players. Head impact data from 112 youth football players (ages 9–14) were collected through the use of helmet-mounted accelerometer arrays. These head impacts were filtered to only include those that resided in corridors near prescribed National Operating Committee on Standards for Athletic Equipment (NOCSAE) impact locations. Peak linear head acceleration and peak rotational head acceleration magnitudes collected from pneumatic ram impactor tests as specified by the proposed NOCSAE youth standard were compared to the distribution of on-field head impacts. All laboratory impact tests were among the top 10% in terms of magnitude for Severity Index and peak rotational acceleration of matched location head impacts experienced by youth football players. As concussive head impacts are among the most severe impacts experienced on the field, a safety standard geared toward mitigating concussion should assess the most severe on-field head impacts. This proposed testing standard may be refined as more becomes known regarding the biomechanics of concussion among youth athletes.

Differences in Head Impact Exposures Between Youth Tackle and Flag Football Games and Practices: Potential Implications for Prevention Strategies

2021 ◽  
pp. 036354652110117
Author(s):  
Kelly Sarmiento ◽  
Dana Waltzman ◽  
Owen Devine ◽  
Xinjian Zhang ◽  
Lara DePadilla ◽  
...  
Keyword(s):  
Large Population ◽  
Head Impact ◽  
Level Of Evidence ◽  
Head Impacts ◽  
Youth Football ◽  
High Magnitude ◽  
Average Impact ◽  
Tackle Football ◽  
Impact Data ◽  
Age Range

Background: Interventions designed to reduce the risk for head impacts and concussion in youth football have increased over the past decade; however, understanding of the role of regular game play on head impact exposure among youth tackle and flag football athletes is currently limited. Purpose: To explore head impact exposure among youth tackle and flag football athletes (age range, 6-14 years) during both practices and games. Study Design: Cohort study; Level of evidence, 2. Methods: Using the Vector MouthGuard sensor, the authors collected head impact data from 524 tackle and flag youth football athletes over the course of a football season. Quantities of interest were estimated from regression models using Bayesian methods. Results: For impacts ≥10 g, a tackle football athlete had an estimated 17.55 (95% CI, 10.78-28.96) times more head impacts per practice compared with a flag football athlete (6.85 [95% CI, 6.05-7.76] and 0.39 [95% CI, 0.24-0.62] head impacts, respectively). Additionally, a tackle football athlete had an estimated 19.48 (95% CI, 12.74-29.98) times more head impacts per game compared with a flag football athlete (13.59 [95% CI, 11.97-15.41] and 0.70 [95% CI, 0.46-1.05] head impacts, respectively). Among tackle football athletes, the estimated average impact rate was 6.51 (95% CI, 5.75-7.37) head impacts during a practice and 12.97 (95% CI, 11.36-14.73) impacts during a game, resulting in 2.00 (95% CI, 1.74-2.29) times more ≥10 g head impacts in games versus practices. Tackle football athletes had 2.06 (95% CI, 1.80-2.34) times more high-magnitude head impacts (≥40 g) during a game than during a practice. On average, flag football athletes experienced an estimated 0.37 (95% CI, 0.20-0.60) head impacts during a practice and 0.77 (95% CI, 0.53-1.06) impacts during a game, resulting in 2.06 (95% CI, 1.29-3.58) times more ≥10 g head impacts in games versus practices. Because of model instability caused by a large number of zero impacts for flag football athletes, a comparison of high-magnitude head impacts is not reported for practices or games. Conclusion: This study provides a characterization of the head impact exposure of practices and games among a large population of youth tackle and flag football athletes aged 6 to 14 years. These findings suggest that a greater focus on game-based interventions, such as fair play interventions and strict officiating, may be beneficial to reduce head impact exposures for youth football athletes.

scholarly journals Origins of Relative Age Effects in Youth Football—A Nationwide Analysis

2020 ◽  
Vol 2 ◽  
Author(s):  
Michael Romann ◽  
Eva Rüeger ◽  
Mirjam Hintermann ◽  
Raphael Kern ◽  
Oliver Faude
Keyword(s):  
Sport Participation ◽  
Waiting Lists ◽  
Age Effects ◽  
Football Players ◽  
Relative Age ◽  
Youth Football ◽  
Grassroots Level ◽  
Age Range ◽  
First Time ◽  
Age Category

Introduction: Relative age effects (RAEs) refer to the overrepresentation of players born earlier in the selection year compared to late-born players within the same age category. To date, the origins and mechanisms of RAEs are still unclear. To evaluate the development of RAEs in terms of age group and selection level, we analyzed data of all registered child and adolescent football players in Switzerland.Methods: Age category, selection level, and birthdate from all licensed 101,991 Swiss child and youth football players assigned to a specific team [9,149 girls (9.0%) and 92,842 boys (91.0%); age range: 4.6–19.6 years] were analyzed. Additionally, out of 1,128 clubs, 54 clubs provided their documented waiting lists (1,224 players). Birthdate distributions were split by age category, sex, and birth quarter (Q1 = January to March, Q4 = October to December). RAEs were calculated using odds ratios (Q1 vs. Q4) with 95% confidence intervals (95% CI).Results: We found small RAEs among U8 players (OR 1.44 [95% CI 1.31, 1.59]) and U10 (OR 1.24 [95% CI 1.16, 1.32]). The RAE was negligible in all other age categories, independent of gender. In children's football, 5,584 (71.3%) teams performed selections. In teams without selection, there were no obvious RAEs. However, teams with selections for the same age category showed small RAEs with an overrepresentation of Q1 athletes in the first team (OR = 1.29 [95% CI 1.24, 1.35]) and inverse RAEs with an underrepresentation of Q1 athletes in the last team (OR = 0.85 [95% CI 0.82, 0.89]). Only small RAEs were observed on the waiting lists for the U8 (OR = 1.48 [1.13, 1.95]).Discussion and Conclusion: RAEs have a small, but consistent effect on participation in Swiss children's football at the grassroots level. Contrary to expectations, no inverse RAEs were found on the waiting lists. Nonetheless, first time coach selections seem to be the origin of RAEs. To protect young athletes from discrimination, RAE biases should be analyzed and eliminated at all stages of sport participation, selection, and dropout situations. Modifications to the organizational structure of sport and athlete development systems are recommended to prevent RAE-related discrimination in youth sports.

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.

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