Football Players' Head-Impact Exposure After Limiting of Full-Contact Practices

Context: Sporting organizations limit full-contact football practices to reduce concussion risk and based on speculation that repeated head impacts may result in long-term neurodegeneration. Objective: To directly compare head-impact exposure in high school football players before and after a statewide restriction on full-contact practices. Design: Cross-sectional study. Setting: High school football field. Patients or Other Participants: Participants were varsity football athletes from a single high school. Before the rule change, 26 athletes (age = 16.2 ± 0.8 years, height = 179.6 ± 6.4 cm, weight = 81.9 ± 13.1 kg) participated. After the rule change, 24 athletes (age = 15.9 ± 0.8 years, height = 178.3 ± 6.5 cm, weight = 76.2 ± 11.6 kg) participated. Nine athletes participated in both years of the investigation. Main Outcome Measure(s): Head-impact exposure was monitored using the Head Impact Telemetry System while the athletes participated in football games and practices in the seasons before and after the rule change. Head-impact frequency, location, and magnitude (ie, linear acceleration, rotational acceleration, and Head Impact Telemetry severity profile [HITsp], respectively) were measured. Results: A total of 15 398 impacts (592 impacts per player per season) were captured before the rule change and 8269 impacts (345 impacts per player per season) after the change. An average 42% decline in impact exposure occurred across all players, with practice-exposure declines occurring among linemen (46% decline); receivers, cornerbacks, and safeties (41% decline); and tight ends, running backs (including fullbacks), and linebackers (39% decline). Impact magnitudes remained largely unchanged between the years. Conclusions: A rule change limiting full-contact high school football practices appears to have been effective in reducing head-impact exposure across all players, with the largest reduction occurring among linemen. This finding is likely associated with the rule modification, particularly because the coaching staff and offensive scheme remained consistent, yet how this reduction influences concussion risk and long-term cognitive health remains unknown.

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Subconcussive head impact exposure differences between drill intensities in U.S. high school football

10.1101/2020.03.29.20047167 ◽

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.

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Game-Related Impacts in High School Boys’ Lacrosse

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119835587 ◽

2019 ◽

Vol 7 (4) ◽

pp. 232596711983558 ◽

Cited By ~ 2

Author(s):

Shane V. Caswell ◽

Patricia Kelshaw ◽

Andrew E. Lincoln ◽

Lisa Hepburn ◽

Reginald Dunn ◽

...

Keyword(s):

High School ◽

Rotational Velocity ◽

Linear Acceleration ◽

The United States ◽

Head Impact ◽

Level Of Evidence ◽

Cross Sectional ◽

Head Impacts ◽

Direct Head ◽

The Impact

Background: The rate of concussions in boys’ lacrosse is reported to be the third highest among high school sports in the United States, but no studies have described game-related impacts among boys’ lacrosse players. Purpose: To characterize verified game-related impacts, both overall and those directly to the head, in boys’ varsity high school lacrosse. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 77 male participants (mean age, 16.6 ± 1.2 years; mean height, 1.77 ± 0.05 m; mean weight, 73.4 ± 12.2 kg) were instrumented with sensors and were videotaped during 39 games. All verified game-related impacts ≥20 g were summarized in terms of frequency, peak linear acceleration (PLA), and peak rotational velocity (PRV). Descriptive statistics and impact rates per player-game (PG) with corresponding 95% CIs were calculated. Results: Overall, 1100 verified game-related impacts were recorded (PLA: median, 33.5 g [interquartile range (IQR), 25.7-51.2]; PRV: median, 1135.5 deg/s [IQR, 790.0-1613.8]) during 795 PGs. The rate for all verified game-related impacts was 1.38 impacts per PG (95% CI, 1.30-1.47). Of these, 680 (61.8%) impacts (PLA: median, 35.9 g [IQR, 26.7-55.5]; PRV: 1170.5 deg/s [IQR, 803.2-1672.8]) were directly to the head (impact rate, 0.86 impacts/PG [95% CI, 0.79-0.92]). Overall, midfielders (n = 514; 46.7%) sustained the most impacts, followed by attackers (n = 332; 30.2%), defenders (n = 233; 21.2%), and goalies (n = 21; 1.9%). The most common mechanisms for overall impacts and direct head impacts were contact with player (overall: n = 706 [64.2%]; head: n = 397 [58.4%]) and stick (overall: n = 303 [27.5%]; head: n = 239 [35.1%]), followed by ground (overall: n = 73 [6.6%]; head: n = 26 [3.8%]) and ball (overall: n = 15 [1.4%]; head: n = 15 [2.2%]). Direct head impacts were associated with a helmet-to-helmet collision 31.2% of the time, and they were frequently (53.7%) sustained by the players delivering the impact. Nearly half (48.8%) of players delivering contact used their helmets to initiate contact that resulted in a helmet-to-helmet impact. Players receiving a head impact from player contact were most often unprepared (75.9%) for the collision. Conclusion: The helmet is commonly used to initiate contact in boys’ high school lacrosse, often targeting defenseless opponents. Interventions to reduce head impacts should address rules and coaching messages to discourage intentional use of the helmet and encourage protection of defenseless opponents.

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Magnitude of Head Impact Exposures in Individual Collegiate Football Players

Journal of Applied Biomechanics ◽

10.1123/jab.28.2.174 ◽

2012 ◽

Vol 28 (2) ◽

pp. 174-183 ◽

Cited By ~ 68

Author(s):

Joseph J. Crisco ◽

Bethany J. Wilcox ◽

Jason T. Machan ◽

Thomas W. McAllister ◽

Ann-Christine Duhaime ◽

...

Keyword(s):

Cognitive Deficits ◽

Linear Acceleration ◽

Head Impact ◽

Football Players ◽

Rotational Acceleration ◽

Head Impacts ◽

Factors Associated ◽

Impact Location ◽

Collegiate Football

The purpose of this study was to quantify the severity of head impacts sustained by individual collegiate football players and to investigate differences between impacts sustained during practice and game sessions, as well as by player position and impact location. Head impacts (N = 184,358) were analyzed for 254 collegiate players at three collegiate institutions. In practice, the 50th and 95th percentile values for individual players were 20.0 g and 49.5 g for peak linear acceleration, 1187 rad/s2 and 3147 rad/s2 for peak rotational acceleration, and 13.4 and 29.9 for HITsp, respectively. Only the 95th percentile HITsp increased significantly in games compared with practices (8.4%, p = .0002). Player position and impact location were the largest factors associated with differences in head impacts. Running backs consistently sustained the greatest impact magnitudes. Peak linear accelerations were greatest for impacts to the top of the helmet, whereas rotational accelerations were greatest for impacts to the front and back. The findings of this study provide essential data for future investigations that aim to establish the correlations between head impact exposure, acute brain injury, and long-term cognitive deficits.

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Effect of a New Rule Limiting Full Contact Practice on the Incidence of Sport-Related Concussion in High School Football Players

The American Journal of Sports Medicine ◽

10.1177/0363546519860120 ◽

2019 ◽

Vol 47 (10) ◽

pp. 2294-2299 ◽

Cited By ~ 6

Author(s):

Adam Y. Pfaller ◽

M. Alison Brooks ◽

Scott Hetzel ◽

Timothy A. McGuine

Keyword(s):

High School ◽

Chronic Traumatic Encephalopathy ◽

The United States ◽

Interquartile Range ◽

American Football ◽

High School Football ◽

Level Of Evidence ◽

Effective Measure ◽

Full Contact ◽

Rule Change

Background: Sport-related concussion (SRC) has been associated with cognitive impairment, depression, and chronic traumatic encephalopathy. American football is the most popular sport among males in the United States and has one of the highest concussion rates among high school sports. Measured head impacts and concussions are approximately 4 times more common in contact practices compared with noncontact practices. The Wisconsin Interscholastic Athletic Association passed new rules defining and limiting contact during practice before the 2014 football season. Purpose: To determine if the SRC rate is lower after a rule change that limited the amount and duration of full-contact activities during high school football practice sessions. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 2081 high school football athletes enrolled and participated in the study in 2012-2013 (before the rule change), and 945 players participated in the study in 2014 (after the rule change). Players self-reported previous concussion and demographic information. Athletic trainers recorded athlete exposures (AEs), concussion incidence, and days lost for each SRC. Chi-square tests were used to compare the incidence of SRC in prerule 2012-2013 seasons with the incidence in the postrule 2014 season. Wilcoxon rank sum tests were used to determine differences in days lost because of SRC. Results: A total of 67 players (7.1%) sustained 70 SRCs in 2014. The overall rate of SRC per 1000 AEs was 1.28 in 2014 as compared with 1.58 in 2012-2013 ( P = .139). The rate of SRC sustained overall in practice was significantly lower ( P = .003) after the rule change in 2014 (15 SRCs, 0.33 per 1000 AEs) as compared with prerule 2012-2013 (86 SRCs, 0.76 per 1000 AEs). There was no difference ( P = .999) in the rate of SRC sustained in games before (5.81 per 1000 AEs) and after (5.74 per 1000 AEs) the rule change. There was no difference ( P = .967) in days lost from SRC before (13 days lost [interquartile range, 10-18]) and after (14 days lost [interquartile range, 10-16]) the rule change. Conclusion: The rate of SRC sustained in high school football practice decreased by 57% after a rule change limiting the amount and duration of full-contact activities, with no change in competition concussion rate. Limitations on contact during high school football practice may be one effective measure to reduce the incidence of SRC.

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Prevalence of Protein and Pre-Workout Supplement Use among High School Football Players and Potential Product Contamination

Global Pediatric Health ◽

10.1177/2333794x211031202 ◽

2021 ◽

Vol 8 ◽

pp. 2333794X2110312

Author(s):

Tal Shoshan ◽

Eric Post

Keyword(s):

High School ◽

Secondary School ◽

National Sample ◽

Football Players ◽

Questionnaire Data ◽

High School Football ◽

Online Questionnaire ◽

Cross Sectional ◽

Supplement Use ◽

Supplement Usage

The purpose was to determine the prevalence of protein and pre-workout supplement usage in high school football players and how many products contained banned substances or dangerous ingredients. A national sample of 102 high school football players was recruited via Qualtrics Research Panels to complete a cross-sectional online questionnaire. Data were summarized as means with standard deviations (SDs) and frequencies with proportions (%). A majority (59.8%) of high school football players reported currently using a protein supplement. Just under one-third (29.4%) reported currently using pre-workout supplements. Five participants reported using a pre-workout product that contained a known NCAA banned substance. Many of the products used contain banned, regulated elsewhere, or unknown substances. Secondary school ATs must educate athletes regarding the use of nutritional supplements and the potential dangers of ingesting banned or unknown substances.

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COMPARISON OF HEAD IMPACT BIOMECHANICS BETWEEN TACKLE AND FLAG YOUTH FOOTBALL

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00001 ◽

2019 ◽

Vol 7 (3_suppl) ◽

pp. 2325967119S0000

Author(s):

Landon B. Lempke ◽

A. Faith Bartello ◽

Melissa N. Anderson ◽

Rachel S. Johnson ◽

Julianne D. Schmidt ◽

...

Keyword(s):

Linear Acceleration ◽

Head Impact ◽

Football Players ◽

Rotational Acceleration ◽

Head Impacts ◽

Head Impact Biomechanics ◽

Impact Rate ◽

High Magnitude ◽

Impact Biomechanics

Background: There is growing fear among healthcare professionals and parents regarding youth tackle football, likely due to highly publicized concerns about potential long-term physical and cognitive health of professional football players. Parents and advocacy groups are pushing for state legislation to ban youth tackle football in favor of flag football to avoid repetitive head impacts that are potentially associated with late-life cognitive deficits. Although the head impact burden experienced during flag football is likely lower than tackle, no research has compared head impact exposure between youth tackle and flag football. Therefore, our purpose was to examine head impact exposure and magnitudes between youth tackle and flag football players. Methods: Twenty-seven tackle (age=11.0±1.5y, height=145.8±11.9 cm, mass=45.0±14.9 kg) and 29 flag football players (age=8.6±1.1y, height=133.9±8.4 cm, mass=33.9±9.5 kg) were enrolled in this prospective cohort study. Participants were fitted with head impact sensors (Triax Sim-G) worn throughout the entire 2017 season that recorded impact frequency and magnitude (linear [g] and rotational acceleration [rad/s2]). Athlete exposure was defined as one player participating in one session. Impact rates (IR) were calculated as impacts per one athlete exposure. Game, practice, and combined IR were compared between groups using impact rate ratios (IRR). IRR with 95% confidence intervals (CI) not containing 1.0 were considered statistically significant. Acceleration values were binned into low- and high-magnitude categories (linear split at 40 g, rotational split at 4,600rad/s2). Magnitude category frequencies were compared between groups using Chi-square test of association (p<0.05), and 90th percentile acceleration values are presented. Results: One-thousand nine-hundred and eight tackle (735 game, 1173 practice; 70.66 impacts/player) and 169 flag (101 game, 68 practice; 5.83 impacts/player) football head impacts were recorded. Tackle players experienced a higher impact rate during games versus practices (IRR=1.41; 95%CI:1.29 -1.55) while flag players experienced a lower impact rate (IRR=0.60; 95%CI:0.44-0.81). Practice and game head impacts combined resulted in tackle players (IR=3.06) accruing 4.61 times the impact rate (95%CI:3.94-5.40) of flag players (IR=0.66). Tackle players sustained a significantly greater head impact rate than flag players during games (tackle IR=3.83, flag IR=0.55; IRR=6.90; 95%CI:5.60-8.49) and practices (tackle IR=2.72, flag IR=0.93; IRR=2.91; 95%CI:2.28-3.72). Tackle 90th percentile linear acceleration was 53.32 g (median=32.50 g) and flag was 53.32 g (median=32.65 g). Tackle 90th percentile rotational acceleration was 7,000 rad/s2 (median=3,200rad/s2) while flag was 8,300 rad/s2 (median=4,100rad/s2). Tackle experienced a significantly higher frequency of low-magnitude rotational acceleration impacts (71.6% vs. 57.4%) and lower frequency of high-magnitude impacts than flag (28.4% vs 42.6%;?2=15.15, p<0.001). There were no significant associations for linear acceleration (p=0.75). Conclusions/Significance: Our results indicate youth flag football head impact rates are 82%-88% lower compared to tackle. Contrary to general belief, youth flag football players experienced numerous head impacts with a greater tendency for high-magnitude rotational acceleration head impacts. Although fewer head impacts occur during youth flag football, parents and coaches should be aware that head impacts do occur during practices and games. Whether high-magnitude or high-frequency head impacts influence long-term health remains unknown. Our findings provide novel evidence into the head impact exposure occurring during youth tackle and flag football. Longitudinal studies examining head impact biomechanics and advanced neuroimaging in youth tackle and flag football players nationwide is warranted to ensure long term cognitive health.

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Concussion Knowledge in High School Football Players

Journal of Athletic Training ◽

10.4085/1062-6050-49.3.34 ◽

2014 ◽

Vol 49 (5) ◽

pp. 654-658 ◽

Cited By ~ 49

Author(s):

Janie Cournoyer ◽

Brady L. Tripp

Keyword(s):

High School ◽

Formal Education ◽

Cross Sectional Study ◽

Football Players ◽

High School Football ◽

Cross Sectional ◽

Education Legislation ◽

Persistent Headache ◽

Descriptive Survey ◽

Concussion Education

Context: Participating in sports while experiencing symptoms of a concussion can be dangerous. An athlete's lack of knowledge may be one factor influencing his or her decision to report symptoms. In an effort to enhance concussion education among high school athletes, legislation in Florida has attempted to address the issue through parental consent forms. Objective: To survey high school varsity football players to determine their level of knowledge about concussions after the initiation of new concussion-education legislation. Design: Cross-sectional study. Setting: Descriptive survey administered in person during a team meeting. Patients or Other Participants: A total of 334 varsity football players from 11 high schools in Florida. Main Outcome Measure(s): Participants completed a survey and identified the symptoms and consequences of a concussion among distractors. They also indicated whether they had received education about concussions from a parent, formal education, neither, or both. Results: The most correctly identified symptoms were headache (97%), dizziness (93%), and confusion (90%), and the most correctly identified consequence was persistent headache (93%). Participants reported receiving education from their parents (54%) or from a formal source (60%). Twenty-five percent reported never receiving any education regarding concussions. No correlations were found between the method of education and the knowledge of symptoms or consequences of concussion. Conclusions: The high school football players we surveyed did not have appropriate knowledge of the symptoms and consequences of concussions. Nausea or vomiting, neck pain, grogginess, difficulty concentrating, and personality or behavioral changes were often missed by participants, and only a small proportion correctly identified brain hemorrhage, coma, and death as possible consequences of inappropriate care after a concussion. Even with parents or guardians signing a consent form indicating they discussed concussion awareness with their child, 46% of athletes suggested they had not.

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