Athlete ECG T-wave abnormality interpretation patterns by non-experts.

Background: The presence of T-wave abnormalities (TWA) on an athlete's electrocardiogram (ECG) presents as a diagnostic challenge for physicians. Types of TWA patterns classified as abnormal by inexperienced readers have not been systematically analyzed. Methods: ECGs from the 2011-2015 National Football League Scouting Combine (initially interpreted by general cardiologists) were retrospectively reviewed by expert sports cardiologists with strict application of the 2017 International Criteria. Patterns of TWA that were altered from the original interpretation were analyzed. Results: The study included 1643 athletes (mean age 22 years). There was a 67 % reduction in the number of athletes with any TWA (p < 0.001) with 111 ECGs changed to normal. Inferior TWA was the most common interpreted initial ECG abnormality altered followed by anterior and lateral. Discussion: This analysis revealed an initial high rate of TWA by non-expert readers. Tailored education programs to physicians who interpret athlete ECGs should highlight these specific T-wave patterns. We see this as an opportunity to make more clinicians aware of ECG interpretation guidelines as sports trained cardiologists are mostly self-taught.

Prevalence of Inflammatory Heart Disease Among Professional Athletes With Prior COVID-19 Infection Who Received Systematic Return-to-Play Cardiac Screening.

Importance: The major North American professional sports leagues were among the first to return to full-scale sport activity during the coronavirus disease 2019 (COVID-19) pandemic. Given the unknown incidence of adverse cardiac sequelae after COVID-19 infection in athletes, these leagues implemented a conservative return-to-play (RTP) cardiac testing program aligned with American College of Cardiology recommendations for all athletes testing positive for COVID-19. Objective: To assess the prevalence of detectable inflammatory heart disease in professional athletes with prior COVID-19 infection, using current RTP screening recommendations. Design, Setting, and Participants: This cross-sectional study reviewed RTP cardiac testing performed between May and October 2020 on professional athletes who had tested positive for COVID-19. The professional sports leagues (Major League Soccer, Major League Baseball, National Hockey League, National Football League, and the men's and women's National Basketball Association) implemented mandatory cardiac screening requirements for all players who had tested positive for COVID-19 prior to resumption of team-organized sports activities. Exposures: Troponin testing, electrocardiography (ECG), and resting echocardiography were performed after a positive COVID-19 test result. Interleague, deidentified cardiac data were pooled for collective analysis. Those with abnormal screening test results were referred for additional testing, including cardiac magnetic resonance imaging and/or stress echocardiography. Main Outcomes and Measures: The prevalence of abnormal RTP test results potentially representing COVID-19-associated cardiac injury, and results and outcomes of additional testing generated by the initial screening process. Results: The study included 789 professional athletes (mean [SD] age, 25 [3] years; 777 men [98.5%]). A total of 460 athletes (58.3%) had prior symptomatic COVID-19 illness, and 329 (41.7%) were asymptomatic or paucisymptomatic (minimally symptomatic). Testing was performed a mean (SD) of 19 (17) days (range, 3-156 days) after a positive test result. Abnormal screening results were identified in 30 athletes (3.8%; troponin, 6 athletes [0.8%]; ECG, 10 athletes [1.3%]; echocardiography, 20 athletes [2.5%]), necessitating additional testing; 5 athletes (0.6%) ultimately had cardiac magnetic resonance imaging findings suggesting inflammatory heart disease (myocarditis, 3; pericarditis, 2) that resulted in restriction from play. No adverse cardiac events occurred in athletes who underwent cardiac screening and resumed professional sport participation. Conclusions and Relevance: This study provides large-scale data assessing the prevalence of relevant COVID-19-associated cardiac pathology with implementation of current RTP screening recommendations. While long-term follow-up is ongoing, few cases of inflammatory heart disease have been detected, and a safe return to professional sports activity has thus far been achieved.

Arrhythmias and Adaptations of the Cardiac Conduction System in Former National Football League Players.

Background Habitual high-intensity endurance exercise is associated with increased atrial fibrillation (AF) risk and impaired cardiac conduction. It is unknown whether these observations extend to prior strength-type sports exposure. The primary aim of this study was to compare AF prevalence in former National Football League (NFL) athletes to population-based controls. The secondary aim was to characterize other conduction system parameters. Methods and Results This cross-sectional study compared former NFL athletes (n=460, age 56±12 years, black 47%) with population-based controls of similar age and racial composition from the cardiovascular cohort Dallas Heart Study-2 (n=925, age 54±9 years, black 53%). AF was present in 28 individuals (n=23 [5%] in the NFL group; n=5 [0.5%] in the control group). After controlling for other cardiovascular risk factors in multivariable regression analysis, former NFL participation remained associated with a 5.7 (95% CI: 2.1-15.9, P<0.001) higher odds ratio of AF. Older age, higher body mass index, and nonblack race were also independently associated with higher odds ratio of AF, while hypertension and diabetes mellitus were not. AF was previously undiagnosed in 15/23 of the former NFL players. Previously undiagnosed NFL players were rate controlled and asymptomatic, but 80% had a CHA2DS2-VASc score ≥1. Former NFL players also had an 8-fold higher prevalence of paced cardiac rhythms (2.0% versus 0.25%, P<0.01), compared with controls. Furthermore, former athletes had lower resting heart rates (62±11 versus 66±11 beats per minute, P<0.001), and a higher prevalence of first-degree atrioventricular block (18% versus 9%, P<0.001). Conclusions Former NFL participation was associated with an increased AF prevalence and slowed cardiac conduction when compared with a population-based control group. Former NFL athletes who screened positive for AF were generally rate controlled and asymptomatic, but 80% should have been considered for anticoagulation based on their stroke risk.

Risk and Causes of Death among Former National Football League Players (1986-2012).

PURPOSE: Previous research identified decreased overall and cardiovascular mortality for National Football League (NFL) players from the 1959-1988 era. The present study explored the mortality risk among recent NFL players who played in an era of heavier linemen and nearly year-round physical conditioning. METHODS: This cohort study included 9778 former NFL players with at least 1 yr in the NFL whose last season was between 1986 and 2012. Players' pension fund records were matched to the National Death Index to determine vital status, date of death, and cause of death. Standardized mortality ratios (SMR) compared player mortality through 2014 with US men of the same age, race, and calendar year. Cox proportional hazards models assessed the effect of player characteristics on overall and cardiovascular mortality. RESULTS: Two percent (n = 227) of players were deceased, with a median age at death of 38 yr (range, 23-61 yr). The most common major causes of death were diseases of the heart (n = 47; 21%), violence (n = 39; 17%), and transportation injuries (n = 34; 15%). Risk of death was significantly lower than the general population for overall mortality (SMR, 0.46, 95% confidence interval (CI), 0.40-0.52), cardiovascular disease (SMR, 0.65; 95% CI, 0.50-0.84), and other major causes. Players with playing-time body mass index (BMI) of >35 kg·m had significantly higher cardiovascular disease mortality (SMR, 2.20; 95% CI, 1.32-3.44) than did the general population and higher overall mortality risk (standardized rate ratio, 3.84; 95% CI, 2.66-5.54) than did players with a BMI of <30 kg·m. CONCLUSIONS: Consistent with an earlier NFL cohort and other elite athlete populations, the overall and cardiovascular mortality risk of this NFL cohort was significantly lower than that of the general US male population, likely attributable to a healthy worker effect and less smoking.However, players with the highest playing-time BMI exhibited elevated cardiovascular mortality risk.

Ascending Aortic Dimensions in Former National Football League Athletes.

BACKGROUND: Ascending aortic dimensions are slightly larger in young competitive athletes compared with sedentary controls, but rarely >40 mm. Whether this finding translates to aortic enlargement in older, former athletes is unknown. METHODS AND RESULTS: This cross-sectional study involved a sample of 206 former National Football League (NFL) athletes compared with 759 male subjects from the DHS-2 (Dallas Heart Study-2; mean age of 57.1 and 53.6 years, respectively, P<0.0001; body surface area of 2.4 and 2.1 m2, respectively, P<0.0001). Midascending aortic dimensions were obtained from computed tomographic scans performed as part of a NFL screening protocol or as part of the DHS. Compared with a population-based control group, former NFL athletes had significantly larger ascending aortic diameters (38±5 versus 34±4 mm; P<0.0001). A significantly higher proportion of former NFL athletes had an aorta of >40 mm (29.6% versus 8.6%; P<0.0001). After adjusting for age, race, body surface area, systolic blood pressure, history of hypertension, current smoking, diabetes mellitus, and lipid profile, the former NFL athletes still had significantly larger ascending aortas (P<0.0001). Former NFL athletes were twice as likely to have an aorta >40 mm after adjusting for the same parameters. CONCLUSIONS: Ascending aortic dimensions were significantly larger in a sample of former NFL athletes after adjusting for their size, age, race, and cardiac risk factors. Whether this translates to an increased risk is unknown and requires further evaluation.

Sleep-apnea risk and subclinical atherosclerosis in early-middle-aged retired National Football League players.

PURPOSE: Limited data from former National Football League (NFL) players suggest that obstructive sleep apnea (OSA) may be highly prevalent after retirement. It remains unclear whether the high prevalence of OSA in retired players is comparable to nonathletes. This retrospective analysis compared sleep apnea (SA) risk in retired NFL players to a community cohort (CARDIA Sleep study), and examined associations between SA risk and cardiovascular risk factors, including subclinical atherosclerosis. MATERIALS AND METHODS: Retired NFL players (n=122) were matched to CARDIA Sleep participants by age ±2 years (range 37-55 years), body mass index ±2 kg/m2, race, and male sex. Participants underwent electron-beam computed tomography to measure coronary artery calcium (CAC) and completed the Berlin Questionnaire to determine SA risk. The presence of CAC was defined as an Agatston score >0. RESULTS: Retired NFL players had a greater prevalence of high SA risk than the matched CARDIA Sleep participants (27% vs 11.5%, P=0.002). Compared to the CARDIA Sleep participants, retired players were less likely to smoke, and had higher blood pressure, lower fasting glucose levels, and higher cholesterol levels. However, there was no difference in the prevalence of detectable CAC (30% vs 30%, P=1). In both players and the community cohort, SA risk was not significantly associated with CAC after controlling for age, race, and body mass index. CONCLUSION: Retired NFL players have a greater prevalence of high SA risk but similar prevalence of CAC compared with a well-matched community cohort.

Conflicts of Interest in Sports Medicine.

Conflict of interest is common in the practice of medicine, and likely more so in the practice of sports medicine at the highest levels of competition. Two areas where conflict of interest frequently manifest in sports medicine are confidentiality and clinical decision making. Confidentiality can be challenging by the team physician's dual responsibilities to the player-patient and the team. Clinical decision making, traditionally associated with a patient's long term health interests, can be complicated by short term interests rooted in pursuit of winning. These issues are reviewed, hopefully to increase awareness in clinicians who find themselves in these unique situations.

Lack of blood pressure difference by race in professional American football players.

Previous findings suggest that professional American football players have higher blood pressures (BP) and a higher prevalence of pre-hypertension and hypertension than the general population. We sought to determine whether race is associated with differences in BP and prevalence of pre-hypertension and hypertension among a large sample of professional football players. BP was measured at 2009 team mini-camps for 1484 black (n = 1007) and white (n = 477) players from 27 National Football League (NFL) teams. Players were categorized into three position groups based on body mass index (BMI). There was no racial difference in mean systolic or diastolic BP in any of the three position groups. There were no racial differences in prevalence of hypertension (99 [9.8%] black players vs. 39 [8.2%] white players; P = .353) or pre-hypertension (557 [55.3%] black players vs. 264 [55.3%] white players; P = 1.0). Contrary to findings in the general population, BP and prevalence of pre-hypertension/hypertension did not vary with race in a large population of active NFL players.

Association of body mass index and waist circumference with subclinical atherosclerosis in retired NFL players.

OBJECTIVES: It is unknown which measure of adiposity (body mass index [BMI] or waist circumference [WC]) is associated with subclinical atherosclerosis in retired National Football League (NFL) players and whether this relation is attenuated after adjusting for components of the metabolic syndrome (elevated triglycerides, fasting glucose, and low levels of high-density lipoprotein-cholesterol [HDL-C]) that frequently coexist with obesity. METHODS: Coronary artery calcium (CAC) was measured in 926 retired NFL players. BMI was calculated as weight (in kilograms)/height (in meters)(2) and WC was measured in inches. Logistic regression analyses adjusting for age, race, systolic blood pressure, high sensitivity C-reactive protein, triglycerides, HDL-C, and fasting blood glucose were performed to evaluate whether BMI or WC was independently associated with the presence of CAC (CAC score >0). RESULTS: The median age, BMI and WC were 54 years, 31 kg/m(2), and 40 inches, respectively. CAC was present in 61% (n = 562) of retired players. Adjusting for age, race, systolic blood pressure, high sensitivity C-reactive protein, triglycerides, HDL-C, and fasting blood glucose, each standard deviation increase in BMI (4.85 kg/m(2)) was significantly associated with CAC (odds ratio [OR] 1.25, 95% confidence interval [CI] 1.03-1.50), but each standard deviation increase in WC (10.53 inches) was not significantly associated with CAC (OR 1.18, 95% CI 0.96-1.45). There was a significant association for the presence of CAC for highest versus lowest quartiles of both BMI (OR 1.93, 95% CI 1.13-3.28) and WC (OR 1.75, 95% CI 1.05-2.92), although the trend for the presence of CAC was significant only across increasing BMI quartiles, even in models that included WC. CONCLUSIONS: In retired NFL players both BMI and WC were associated with CAC. Higher BMI may be associated with an increasing trend for the presence of CAC independent of WC.

Update on sports concussion.

Over the past 20 years, sports concussion has become one of the most researched topics in sports medicine. Significant resources have been allocated to the study of this issue, with a dramatic increase in information concerning most aspects of this common sports injury. In light of this considerable increase in research, this review is offered to provide clinicians involved in the care of athletes a summary of key features of the evaluation and management of sports concussion with attention to recent contributions to the literature.

Association between traditional cholesterol parameters, lipoprotein particle concentration, novel biomarkers and carotid plaques in retired National Football League players.

OBJECTIVES: We assessed whether low-density lipoprotein particle concentration (LDL-P) and high-sensitivity C-reactive protein [hs-CRP] can identify subclinical atherosclerosis better than traditional cholesterol parameters in retired National Football League (NFL) players. BACKGROUND: It is not known whether LDL-P and the biomarker hs-CRP can identify subclinical atherosclerosis better than low-density lipoprotein cholesterol (LDL-C) or non-high-density-lipoprotein cholesterol (non-HDL-C) in retired NFL players, given high prevalence of metabolic syndrome in these players. METHODS: Carotid artery plaque screening was performed with traditional lipids, LDL-P, and hs-CRP in 996 retired players. Logistic regression analyses comparing highest with the lowest quartile were performed. RESULTS: Carotid artery plaques were seen in 41%. LDL-C (odds ratio [OR] 1.66, 95% confidence interval [CI] 1.06-2.59), non-HDL-C (OR 1.67, 95% CI 1.04-2.67), and LDL-P (OR 2.21, 95% CI 1.35-3.62) were associated with plaques in adjusted models. Among 187 retired players with metabolic syndrome, LDL-C (OR 1.40, 95% CI 0.53-3.72) was not associated with carotid plaques, whereas LDL-P (OR 3.71, 95% CI 1.16-11.84) and non-HDL-C (OR 2.63, 95% CI 0.91-7.63, p=0.07; borderline significant) were associated with carotid plaques. hs-CRP (OR 1.13, 95% CI 0.71-1.79) was not associated with carotid plaques. CONCLUSION: Carotid artery plaques were common in retired NFL players and were strongly associated with LDL-P, especially among those with metabolic syndrome. hs-CRP was not associated with carotid plaques in this cohort.

Sleep-disordered breathing in the National Football League.

STUDY OBJECTIVES: Prior studies have suggested that the prevalence of sleep disordered breathing (SDB) among players in the National Football League (NFL) is disproportionately high. SDB can increase cardiovascular disease risk and is correlated with hypertension. NFL players have a higher prevalence of hypertension, and we sought to determine the prevalence of SDB among players the NFL and the associations of SDB with anthropometric measures and cardiovascular risk factors. DESIGN: Cross-sectional cohort study. SETTING: NFL athletic training facilities from April to July 2007. PARTICIPANTS: A total of 137 active veteran players from 6 NFL teams. MEASUREMENTS: This evaluation of SDB among players in the NFL used a single-channel, home-based, unattended, portable, sleep apnea monitor. Multiple domains of self-reported sleep were assessed. Weight, body mass index, body fat percentage, neck circumference, waist circumference, and waist-to-hip ratio, as well as blood pressure, cholesterol, and fasting glucose concentrations were measured. RESULTS: The mean respiratory disturbance index was 4.7 (+/- 12), with a median (interquartile range) of 2 (1,4). The prevalence of at least mild SDB (RDI > or = 5) was 19% (95% confidence interval, 12.8%-26.6%). Only 4.4% (95% confidence interval, 1.6%-9.2%) of participants had respiratory disturbance index of 15 or greater. Linemen and non-linemen were not different in their prevalence or severity of SDB. No single anthropometric measure was highly associated with SDB, and SDB was not well correlated with cardiovascular risk factors. CONCLUSIONS: The prevalence of SDB in active NFL players was modest, predominately mild, and positively associated with several measures of adiposity. SDB did not account for excess cardiovascular risk factors.

Body size, body composition, and cardiovascular disease risk factors in NFL players.

AIMS: We characterized the size of active National Football League (NFL) players by multiple criteria and analyzed their relation to traditional cardiovascular disease (CVD) risk factors with the objective of further clarifying the occurrence of cardiovascular risk factors in different player positions. METHODS: This cross-sectional study was conducted in professional athletic training facilities. The participants were 504 active veteran players from a convenience sample of 12 NFL teams, grouped as interior linemen (IL) or all others (AO). Comparisons were made between the NFL groups and an age-equivalent general population database. RESULTS: The IL group was significantly larger than AO by all size measures. Both groups were significantly larger than the Coronary Artery Risk Development in Young Adults (CARDIA) group. Mean percent body fat measurements in AO (mean, 13.4%; 95% confidence interval [CI], 12.9%-14%) and IL (mean, 25.2%; 95% CI, 24.4%-26%) groups were lower than estimates for the general population. Systolic blood pressure (BP) was higher in IL (mean, 131 mm Hg; 95% CI, 129-133 mm Hg) than AO (mean, 126 mm Hg; 95% CI, 125-127 mm Hg) and greater in both groups compared with the CARDIA group (mean, 112 mm Hg; 95% CI, 111-112 mm Hg). Mean low-density lipoprotein cholesterol and high-density lipoprotein cholesterol (HDL-C), total cholesterol, triglycerides, and glucose were within the normal range for both IL and AO. Interior linemen had significantly lower HDL-C than AO and the CARDIA group. Both NFL groups had significantly lower fasting glucose than CARDIA. CONCLUSION: Body fat in active NFL players was lower than predicted by standard measures of obesity. Although the players were large, they were in the normal range for most CVD risk factors. Mean BP in the prehypertensive range was found in both NFL position groups, but was significantly higher in IL than in AO. Prehypertension in these athletes warrants vigilance.

Prevalence of cardiovascular disease risk factors among National Football League players.

CONTEXT: Concern exists about the cardiovascular health implications of large size among professional football players and those players who aspire to professional status. OBJECTIVES: To assess cardiovascular disease (CVD) risk factors in active National Football League (NFL) players and to compare these findings with data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study of 504 active, veteran football players from a convenience sample of 12 NFL teams at professional athletic training facilities between April and July 2007. Data were compared with men of the same age in the general US population (CARDIA study, a population-based observational study of 1959 participants aged 23 to 35 years recruited in 1985-1986). MAIN OUTCOME MEASURES: Prevalence of CVD risk factors (hypertension, dyslipidemia, glucose intolerance, and smoking). RESULTS: The NFL players were less likely to smoke when compared with the CARDIA group (0.1% [n = 1]; 95% confidence interval [CI], 0%-1.4%; vs 30.5% [n = 597]; 95% CI, 28.5%-32.5%; P < .001). Despite being taller and heavier, NFL players had significantly lower prevalence of impaired fasting glucose (6.7% [n = 24]; 95% CI, 4.6%-8.7%; vs 15.5% [n = 267]; 95% CI, 13.8%-17.3%; P < .001). The groups did not differ in prevalence of high total cholesterol and low-density lipoprotein cholesterol (LDL-C), low high-density lipoprotein cholesterol (HDL-C), or high triglycerides. Hypertension (13.8% [n = 67]; 95% CI, 11.0%-16.7%; vs 5.5% [n = 108]; 95% CI, 4.6%-6.6%) and prehypertension (64.5% [n = 310]; 95% CI, 58.3%-70.7%; vs 24.2% [n = 473]; 95% CI, 22.3%-26.1%) were significantly more common in NFL players than in the CARDIA group (both P < .001). Large size measured by body mass index (BMI) was associated with increased blood pressure, LDL-C, triglycerides, and fasting glucose, and decreased HDL-C. CONCLUSIONS: Compared with a sample of healthy young-adult men, a sample of substantially larger NFL players had a lower prevalence of impaired fasting glucose, less reported smoking, a similar prevalence of dyslipidemia, and a higher prevalence of hypertension. Increased size measured by BMI was associated with increased CVD risk factors in this combined population.

Concussion in professional football: neuropsychological testing--part 6.

OBJECTIVE: The National Football League (NFL) neuropsychological testing program is reviewed, and neuropsychological test data are presented on various samples of NFL athletes who sustained concussion (mild traumatic brain injury, MTBI). METHODS: This study evaluated post-MTBI neuropsychological testing of NFL players from 1996 to 2001. All athletes completed a standardized battery of neuropsychological tests and underwent postinjury neuropsychological testing within a few days after concussion. Test scores were compared with baselines using analysis of variance for athletes having on-field memory dysfunction, three or more concussions, or 7+ days out from practice and play. RESULTS: The MTBI group did not display significant neuropsychological dysfunction relative to baseline scores within a few days of injury. However, a subsample of the injured athletes who displayed on-field memory dysfunction performed significantly more poorly on two of the memory tests. The neuropsychological test results of a group of athletes with a history of three or more MTBIs did not differ significantly compared with a group who had fewer than three concussions or compared with league-wide normative data. The neuropsychological performance of athletes who were out from full participation 7+ days was not significantly different from the group who returned to play within 7 days or the norms. CONCLUSION: Neuropsychological testing is used within the overall medical evaluation and care of NFL athletes. Players who experience MTBI generally demonstrate rapid recovery of neuropsychological performance, although poorer neuropsychological test results were related to on-field memory dysfunction. NFL players did not demonstrate evidence of neurocognitive decline after multiple (three or more) MTBIs or in those players out 7+ days. The data show that MTBI in this population is characterized by a rapid return of neuropsychological function in the days after injury.

Concussion in professional football: repeat injuries--part 4.

OBJECTIVE: A 6-year study was conducted to determine the signs, symptoms, and management of repeat concussion in National Football League players. METHODS: From 1996 to 2001, concussions were reported by 30 National Football League teams using a standardized reporting form filled out by team physicians with input from athletic trainers. Signs and symptoms were grouped by general symptoms, somatic complaints, cranial nerve effects, cognition problems, memory problems, and unconsciousness. Medical actions taken and management were recorded. RESULTS: Data were captured for 887 concussions in practices and games involving 650 players. A total of 160 players experienced repeat injury, with 51 having three or more concussions during the study period. The median time between injuries was 374.5 days, with only six concussions occurring within 2 weeks of the initial injury. Repeat concussions were more prevalent in the secondary (16.9%), the kick unit on special teams (16.3%), and wide receivers (12.5%). The ball return carrier on special teams (odds ratio [OR] = 2.08, P = not significant) and quarterbacks (OR = 1.92, P < 0.1) had elevated odds for repeat injury, followed by the tight end (OR = 1.24, P = not significant) and linebackers (OR = 1.22, P = not significant). There were similar signs and symptoms with single and repeat concussion, except for a higher prevalence of somatic complaints in players on their repeat concussions compared with their first concussion (27.5% versus 18.8%, P < 0.05). More than 90% of players were managed by rest, and 57.5% of those with second injuries returned to play within a day. Players with three or more concussions had signs, symptoms, and treatment similar to those with only a single injury. CONCLUSION: The most vulnerable players for repeat concussion in professional football are the ball return carrier on special teams and quarterbacks. Single and repeat concussions are managed conservatively with rest, and most players return quickly to play.

Ethics and the professional team physician.

The professional team physician may face ethical questions that are unique to the practice of sports medicine. There are numerous pressures that potentially may affect or interfere with ethical medical decision-making. The purpose of this article is to highlight some of these issues and to increase awareness of them for the practicing team physician and trainers and others involved in professional sports.

Concussion in professional football: epidemiological features of game injuries and review of the literature--part 3.

OBJECTIVE: A 6-year study was performed to determine the circumstances, causes, and outcomes of concussions in the National Football League. METHODS: Between 1996 and 2001, the epidemiological features of concussions were recorded by National Football League teams with a standardized reporting form. Symptoms were reported and grouped as general symptoms, cranial nerve symptoms, memory or cognitive problems, somatic complaints, and loss of consciousness. The medical actions taken were recorded. In total, 787 game-related cases were reported, with information on the players involved, type of helmet impact, symptoms, medical actions, and days lost. Concussion risks were calculated according to player game positions. RESULTS: There were 0.41 concussions per National Football League game. The relative risk was highest for quarterbacks (1.62 concussions/100 game-positions), followed by wide receivers (1.23 concussions/100 game-positions), tight ends (0.94 concussion/100 game-positions), and defensive secondaries (0.93 concussion/100 game-positions). The majority of concussions (67.7%) involved impact by another player's helmet. The remainder involved impact by other body regions of the striking player (20.9%) or ground contact (11.4%). The three most common symptoms of mild traumatic brain injury were headaches (55.0%), dizziness (41.8%), and blurred vision (16.3%). The most common signs noted in physical examinations were problems with immediate recall (25.5%), retrograde amnesia (18.0%), and information-processing problems (17.5%). In 58 of the reported cases (9.3%), the players lost consciousness; 19 players (2.4%) were hospitalized. A total of 92% of concussed players returned to practice in less than 7 days, but that value decreased to 69% with unconsciousness. CONCLUSION: The professional football players most vulnerable to concussions are quarterbacks, wide receivers, and defensive secondaries. Concussions involved 2.74 symptoms/injury, and players were generally removed from the game. More than one-half of the players returned to play within 1 day, and symptoms resolved in a short time in the vast majority of cases.

Concussion in professional football: location and direction of helmet impacts-Part 2.

OBJECTIVE: National Football League game video was analyzed for the typical locations of severe helmet impacts in professional football. By use of selected cases that were reconstructed in laboratory tests and reported previously, the magnitude and direction of force causing concussion was determined for these locations. METHODS: Multiple video views were obtained for 182 severe helmet impacts that occurred between 1996 and 2001. From a top view, the helmet was divided into 45-degree quadrants with 0 degrees eyes forward. From a side view, it was divided into seven equal levels, four (+Q1 to +Q4) above the head center of gravity and three below (-Q1 to -Q3). The initial helmet contact was located in these regions. Thirty-one impacts were reconstructed with helmeted Hybrid III dummies involving 25 concussions. Measurement of head translational and rotational acceleration was used to determine the average and +/-1 standard deviation in responses, with impacts reflected to the right side. RESULTS: From video, the majority (71%) of impact is to the helmet shell primarily from a striking player's helmet, arm, or shoulder pad to the side (45-135 degrees) or from ground contact to the back (135-180 degrees). Most impacts were high on the helmet at +Q2 to +Q4. The remainder (29%) were primarily from helmet contact on the facemask at an oblique frontal angle (0-45 degrees) and -Q3 to +Q1 height. From reconstructions, concussion occurred with the lowest peak head acceleration in facemask impacts at 78 +/- 18 g versus an average 107 to 117 g for impacts on other quadrants (t = 2.90, P < 0.005). There was a significantly higher head acceleration for concussed versus nonconcussed players (t = 2.85, P < 0.05). The vector of peak force was essentially horizontal for facemask impacts and downward at 12 to 27 degrees for impacts to the helmet side and back. Concussion in professional football involves four typical conditions, as follows: A, 0- to 45-degree quadrant, -Q3 to +Q3 level, peak force 49 +/- 18 degrees from front and horizontal; B, 45- to 90-degree quadrant, -Q2 to +Q3 level, peak force 73 +/- 12 degrees and horizontal; C, 90- to 135-degree quadrant, +Q1 to +Q4 level, peak force 97 +/- 9 degrees and 12 degrees downward; and D, 135- to 180-degree quadrant, +Q1 to +Q4 level, peak force 157 +/- 1 degrees and 27 degrees downward. Concussed players averaged 3.6 +/- 2.7 initial signs and symptoms. The most common were headaches, dizziness, immediate recall problems, and difficulty with information processing. CONCLUSION: The location, direction, and severity of helmet impacts causing concussion in the National Football League have been defined from analysis of game video and laboratory reconstruction. These conditions define the circumstances in which helmets need to reduce head injury risks in professional football.