Collegiate American Football Players Research Articles

Impact of fish oil supplementation on plasma levels of highly unsaturated fatty acid-containing lipid classes and molecular species in American football athletes

BackgroundPrevious studies have linked sports-related concussions and repeated subconcussive head impacts in contact sport athletes to elevated brain injury biomarkers. Docosahexaenoic acid (DHA), the primary omega-3 (n-3) highly unsaturated fatty acid (HUFA) in the brain, has shown neuroprotective effects in animal models after brain injury, but clinical research has shown mixed results.MethodsWe conducted a randomized, double-blind, placebo-controlled study on 29 Division 1 collegiate American football players, exploring the impact of DHA (2.5 g) and eicosapentaenoic acid (EPA) (1.0 g) supplied as ethyl esters, on levels of plasma lipids shown to cross the blood-brain barrier. Dietary intake data was collected using food frequency questionnaires (FFQ). Complex lipids and unesterified fatty acids were isolated from plasma, separated via reversed-phase liquid chromatography and analyzed by targeted lipidomics analysis.ResultsFFQ results indicated that participants had low dietary n-3 HUFA intake and high omega-6 (n-6):n-3 polyunsaturated fatty acids (PUFA) and HUFA ratios at baseline. After DHA + EPA supplementation, plasma lysophosphatidylcholine (LPC) containing DHA and EPA significantly increased at all timepoints (weeks 17, 21, and 26; p < 0.0001), surpassing placebo at Weeks 17 (p < 0.05) and 21 (p < 0.05). Phosphatidylcholine (PC) molecular species containing DHA or EPA, PC38:6 PC36:6, PC38:7, PC40:6, and PC40:8, increased significantly in the DHA + EPA treatment group at Weeks 17 (and 21. Plasma concentrations of non-esterified DHA and EPA rose post-supplementation in Weeks 17 and 21.ConclusionsThis study demonstrates that n-3 HUFA supplementation, in the form of ethyl esters, increased the DHA and EPA containing plasma lipid pools the have the capacity to enrich brain lipids and the potential to mitigate the effects of sports-related concussions and repeated subconcussive head impacts.Trial RegistrationAll deidentified data are available at ClinicalTrials.gov #NCT0479207.

Impact of fish oil supplementation on plasma levels of highly unsaturated fatty acid-containing lipid classes and molecular species in American football athletes

BackgroundPrevious studies have linked sports-related concussions and repeated subconcussive head impacts in contact sport athletes to elevated brain injury biomarkers. Docosahexaenoic acid (DHA), the primary omega-3 (n-3) highly unsaturated fatty acid (HUFA) in the brain, has shown neuroprotective effects in animal models after brain injury, but clinical research has shown mixed results.MethodsWe conducted a randomized, double-blind, placebo-controlled study on 29 Division 1 collegiate American football players, exploring the impact of DHA (2.5 g) and eicosapentaenoic acid (EPA) (1.0 g) supplied as ethyl esters, on levels of plasma lipids shown to cross the blood-brain barrier. Dietary intake data was collected using food frequency questionnaires (FFQ). Complex lipids and unesterified fatty acids were isolated from plasma, separated via reversed-phase liquid chromatography and analyzed by targeted lipidomics analysis.ResultsFFQ results indicated that participants had low dietary n-3 HUFA intake and high omega-6 (n-6):n-3 polyunsaturated fatty acids (PUFA) and HUFA ratios at baseline. After DHA + EPA supplementation, plasma lysophosphatidylcholine (LPC) containing DHA and EPA significantly increased at all timepoints (weeks 17, 21, and 26; p < 0.0001), surpassing placebo at Weeks 17 (p < 0.05) and 21 (p < 0.05). Phosphatidylcholine (PC) molecular species containing DHA or EPA, PC38:6 PC36:6, PC38:7, PC40:6, and PC40:8, increased significantly in the DHA + EPA treatment group at Weeks 17 (and 21. Plasma concentrations of non-esterified DHA and EPA rose post-supplementation in Weeks 17 and 21.ConclusionsThis study demonstrates that n-3 HUFA supplementation, in the form of ethyl esters, increased the DHA and EPA containing plasma lipid pools the have the capacity to enrich brain lipids and the potential to mitigate the effects of sports-related concussions and repeated subconcussive head impacts.Trial RegistrationAll deidentified data are available at ClinicalTrials.gov #NCT0479207.

Effect of Extreme Volume-Load Differences for a Single Unilateral Exercise During In-Season Resistance Training on Measures of Bilateral Strength, Power, and Speed in Collegiate American Football Players.

Crawley, K, Adams, KJ, DeBeliso, M, and Lawrence, MM. Effect of Extreme Volume-Load Differences for a Single Unilateral Exercise During In-Season Resistance Training on Measures of Bilateral Strength, Power, and Speed in Collegiate American Football Players. J Strength Cond Res XX(X): 000-000, 2023-This study examined the impact extreme volume-load differences for a single weekly exercise, when all other exercises' volume loads were similar, would have on American football performance variables after in-season resistance training (RT). Twenty male National Collegiate Athletic Association (NCAA) American footballers (18-23 years, 98.4 ± 19.3 kg) were randomly assigned to an extreme high-volume low-intensity (EHVLI; n = 11) group or a low-volume high-intensity (LVHI; n = 9) group. Subjects performed the same evidence-based RT exercises and volume loads for 8 weeks thrice weekly, with the only differences being once weekly unilateral reverse dumbbell lunge (EHVLI) or unilateral Hatfield safety bar back squat (LVHI) exercises performed with different volume loads. Performance variables were assessed 1 week before (PRE) and after (POST) 8 weeks of RT. A 2-way analysis of variance with repeated measures and the Sidak post hoc test were used (p < 0.05). Extreme high-volume low-intensity had no significant (p > 0.05) PRE-to-POST RT changes in muscular strength in 1 repetition maximum (251.8 ± 48.7 to 274.6 ± 61.3 kg) or power in vertical jump (79.2 ± 8.8 to 78.2 ± 10.8 cm). Conversely, LVHI had significant (p < 0.05) PRE-to-POST RT improvements in strength (249.2 ± 54.4 to 284.1 ± 55.0 kg) and power (72.8 ± 11.4 to 76.3 ± 10.0 cm). Furthermore, LVHI vs. EHVLI displayed significantly greater percentage difference increases from PRE values in muscular power (6.7% ± 7.2 vs. -1.3% ± 6.0, respectively), with no significant differences between groups (LVHI vs. EHVLI) in muscular strength (8.8% ± 3.1 vs. 6.7% ± 8.0, respectively) and 10-yard acceleration (2.2% ± 5.6 vs. 3.2% ± 5.6, respectively). For in-season RT of strength and power in collegiate American football players, all exercises performed should use evidence-based volume loads to optimize adaptations because a single exercise performed with extreme volume load may limit muscular strength and power development.

Strength and Power Thresholds to Identify High and Low Linear Sprint Speed Performers in Collegiate American Football Players.

Philipp, NM, Crawford, DA, Cabarkapa, D, and Fry, AC. Strength and power thresholds to identify high and low linear sprint speed performers in collegiate American football players. J Strength Cond Res XX(X): 000-000, 2023-Lower-body strength and power are commonly measured performance qualities across a number of sports. In recent years, more attention has been given to relationships, primarily between lower-body strength and linear speed performance. While still limited, evidence is in agreement that lower-body strength positively contributes to linear speed performance. However, what is less well understood is if there comes a point in an athlete's development, at which, further working on increasing maximal strength may not fully compliment additional gains in speed performance. Within this study, authors aimed to provide practitioners with lower-body strength and power thresholds that can discriminate between slow and fast performers, within a group of collegiate American football players. The sample was further divided into a high-body and low-body weight group, and authors hypothesized that by using logistic regression, supplemented with receiver operator curve analyses, optimal cut-off points (i.e., relative lower-body strength thresholds) that are able to significantly discriminate between slow and fast linear speed performers may be identified. Findings indicate that optimal cut-off scores differed between the groups of athletes, as well as the lower body strength and power tests. All models were able to significantly distinguish between slower and faster performers, and area under the curve values ranged from 0.695 to 0.903. Although thresholds will likely vary based on factors such as sex, training age, and sport, findings from this investigation may be used to benchmark athletes and to further individualize training aimed at improving linear speed performance.

Longitudinal cardiac remodeling in collegiate American football players as assessed by echocardiography during their collegiate career.

Studies on the longitudinal effects of intense physical training on cardiac remodeling are limited, especially in American collegiate football players. College-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. We 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. Mean 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. American football players college-level training was associated with increases in left and right ventricular chamber sizes, left atrial size, and aortic root diameter.

Effect of repeated head impacts on amount of cervical vertebral translation among collegiate American football players

Effect of repeated head impacts on amount of cervical vertebral translation among collegiate American football players

Annual Changes in the Physical Characteristics of Japanese Division I Collegiate American Football Players

We aimed to examine the annual changes in various physical characteristics of Japanese Division I (D1) Collegiate American footballers according to their positional groups. We measured body mass, and assessed performance in three gym tests (bench press, back squat, and power clean) and three field tests (40-yard dash, pro-agility shuttle, and broad jump) at each pre-season from 2014 to 2016 for players from a Japanese D1 university. Data from 55 players who completed ≥ 50% (three out of six) of the performance measurements in consecutive years were used in this analysis. Performance data across the two positional groups (skill players and linemen) were analyzed using pairwise t-tests to determine annual changes. The skill players’ body mass increased from their freshman to sophomore years (p &lt; 0.05, Cohen’s d &gt; 0.8), but not from their sophomore to junior or junior to senior years. The skill players’ 40-yard sprint time was shorter between all the annual comparisons (p &lt; 0.05, d &gt; 0.8). The linemen’s body mass increased from their freshman to sophomore years, and maintained from their sophomore to junior years and junior to senior years. There were significant improvements in strength and power outputs, but limited improvements in the pro-agility run and broad jump among most of the annual class comparisons for each positional group. These results indicate that annual improvements in the physical characteristics occur nonlinearly for Japanese D1 footballers. They will benefit from targeted strength and conditioning programs. However, the improvements of jumping and agility performances may be limited.

The Trainability of Explosive Power Features and Their Negative Correlation with Body Fatness in Collegiate American Football Players

Both sports education and training interventions create a dose-response relationship in the body which change the body composition. The aim of this study is to investigate the relationship between pre-season body composition and physical performance parameters of collegiate American football players. 23 American football players (age: 22.3±3.1 years, height: 180.6±5.6 cm, weight: 94.2±16.9 kg) voluntarily participated in the study. The body compositions of players were determined via Dual-Energy X-ray Absorptiometry (DEXA) device and countermovement jump (CMJ), 10 and 40-yard sprinting and pro-agility tests were applied to evaluate physical performance. Pearson Correlation analysis was used to determine whether there was a relationship between body composition parameters and field tests. As a result, a statistically significant negative correlation (p &lt; 0.05) was found between body fat percentage (r = -.736; p &lt; .001) and body fat mass (r = -.717; p &lt; .001) with CMJ. A statistically significant relationship (p&lt;0.05) was found between body fat percentage (r = .622; p &lt; .002; r = -.759; p &lt; .001) and body fat mass (r = .595; p &lt; .003; r = -.736; p &lt; .001) with 10 and 40-yard sprints respectively. Body fat percentage (r = .659; p &lt; .001) and body fat mass (r = .638; p &lt; .001) also correlated with pro-agility. Our results support earlier research by showing a direct correlation between body composition and power attributes and performance in American football. Coaches were advised to pay attention to body adiposity in terms of a decline in physical performance for this reason.

Associations of lifetime concussion history and repetitive head impact exposure with resting-state functional connectivity in former collegiate American football players: An NCAA 15-year follow-up study.

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.

Salivary immunity of elite collegiate American football players infected with SARS-CoV-2 normalizes following isolation

The impact of COVID-19 on systemic immunity in the general population has been well characterized, however the short-term effects of COVID-19 infection on innate salivary immunity in elite-level athletes are unknown. Therefore, this study aimed to determine whether elite college football athletes had altered salivary immunity following the CDC-recommended isolation post-SARS-CoV-2 infection. Salivary samples were obtained from fourteen elite football players who tested positive for SARS-CoV-2 (n = 14), immediately after CDC-recommended isolation (average days = 14 ± 2 days) and fifteen controls who remained uninfected with SARS-CoV-2. Biomarkers of innate salivary immunity (sIgA and alpha-amylase), antimicrobial proteins (AMPs, i.e., HNP1-3, lactoferrin, LL-37) and lung inflammation (SPA, SPLI, and Neutrophil Elastase-alpha-1-antitrypsin complex) were measured. Independent student t-tests were used to determine changes in biomarkers between groups. Although all AMP levels were within normal range, Human Neutrophil Defensin 1–3 concentrations and secretion rates were higher in SARS-CoV-2+ compared to SARS-CoV-2–. This suggests that the CDC-recommended isolation period is sufficient to ensure that athletes’ salivary immunity is not compromised upon return to sports, and athletes post-COVID-19 infection do not appear to be at greater risk for secondary infection than those with no history of COVID-19.

The impact of different playing surfaces on physiological parameters in collegiate DI American football athletes

Heat conditioning aids in acclimatization to support health and performance, yet heat safety is an important factor. This quasi-experimental pilot study investigated differences in micro-environmental conditions and physiological outcomes in n = 5 Division I collegiate American football players over different playing surfaces during summertime in the southwest U.S. Participants performed three practice sessions on hot days (∼33°C): outdoors on artificial turf (AT) and natural grass (NG); and an indoor dome (ID). Microclimate parameters, including net radiative fluxes, and physiological markers (core temperature (Tc), skin temperature (Tsk), heart rate, and hydration) were continuously and simultaneously monitored. Microclimate conditions varied across the three environments. Outdoors, the largest differences were observed in surface temperatures between AT and NG (67.0°C and 32.8°C, respectively), resulting in higher emitted longwave radiation (infrared heat), slightly increasing air temperatures. Indoors, the lack of radiation lessened the overall heat load, yet higher humidity and lower airflow were observed. Physiologically, similar baseline Tc and Tsk and self-reported heat stress levels were recorded. During exercise, a significantly higher Tsk value was found on the AT (higher heat load), followed by the NG (moderate) and ID (lowest). The same pattern was reflected in Tc, RPE, and self-reported heat stress, even with lower solar radiation on AT. No differences between environments were reported for estimated energy expenditure, pre/post-body weight, bodyweight loss, fluid intake, or sweat rate. Small changes in microclimates affect overall heat loads and measured and perceived heat stress, which coaches can use in decision-making for session type, heat safety, and/or acclimatization goals.

A Total Score of Athleticism to Estimate the Amount of Variance Explained in On-Field Performance Within Collegiate American Football Players

The identification of sport and position-specific key performance indicators has been of increased interest to practitioners working within high performance sport settings. The aim of this study was to create statistical models, across a spectrum of position groups, that explain the largest amount of variance in on-field performance over four collegiate American football seasons. A total of four position groups were analyzed, including Wide Receiver/Tight End (n = 29), Running Backs (n = 8), Linebacker/Defensive Line (n =41), Defensive Backs (n = 28). Different tests of physical performance (back squat, bench press, hang clean, 40-yard dash, pro-agility, L-drill, vertical jump, and broad jump) were set as the independent variables, while a Total Score of On-Field Performance, consisting of position-specific game statistics was set as the dependent variable. Linear mixed models, using backwards model selection were used to identify models that best fit the position-specific data. Results revealed that models consisted of at least three different physical performance test, were position-specific, and explained the variance in on-field performance to different degrees. Significant correlations were found between physical performance models and on-field performance. Results from our study may be of interest to practitioners working within American football that are interested in maximizing success through and individual approach towards the implementation of training.

Physical and performance characteristics related to starter status, position, and division in Japanese collegiate American-football players

BACKGROUND: Few studies have investigated the variations in body composition and performance in Japanese collegiate American-football players. OBJECTIVE: To clarify what characterizes competitors at the highest levels – in the top division or on the starting lineup – we compared players’ body compositions and performance test results. METHODS: This study included 172 players. Each player’s body composition and performance (one-repetition maximum bench press, one-repetition maximum back squat, and vertical jump height) were measured; power was estimated from vertical jump height and body weight. Players were compared according to status (starter vs. non-starter), position (skill vs. linemen), and division (1 vs. 2). Regression analysis was performed to determine characteristics for being a starter. RESULTS: Players in higher divisions and who were starters were stronger and had more power, greater body size, and better performance test results. Players in skill positions were relatively stronger than those in linemen positions. Vertical jump height was a significant predictor of being a starter in Division 1. CONCLUSION: Power and vertical jump may be a deciding factor for playing as a starter or in a higher division.

Momentum, Rather Than Velocity, Is a More Effective Measure of Improvements in Division IA Football Player Performance.

Mann, JB, Mayhew, JL, Dos Santos, ML, Dawes, JJ, and Signorile, JF. Momentum, rather than velocity, is a more effective measure of improvements in Division IA football player performance. J Strength Cond Res 36(2): 551-557, 2022-Speed, or the time to complete straight runs or agility drills, is commonly used to assess performance in collegiate American football players. However, it is common for players' speeds to plateau by the second year of eligibility, whereas their body masses continue to increase. The purpose of this study was to track change in speed, body mass, and momentum (body mass · velocity), across Division 1 football players' 4-year careers (n = 512). Complete data were derived for the 40-yd sprint (n = 82), the proagility shuttle (n = 73), and the L drill (n = 73) from the same NCAA Division 1 team over a 15-year period. Significant changes were seen for velocity between year 1 and the next 3 playing years (p < 0.05), with no differences between years 2 and 4, whereas body mass increased significantly across all playing years (p < 0.05). Further momentum increased across all years for all tests (p < 0.0001). These results indicate the importance of including changes in body mass when evaluating performances during sprints and change of direction drills. Our results also suggest that using sprint or agility drill times to evaluate playing potential across football players' collegiate careers may be ineffective and can provide players with a false and disheartening picture of their improvements across their careers. Momentum, which incorporates training-induced increases in both speed and body mass, would be a more relevant and supportive measure of players' improvements. In addition, the simple computation of this variable, using existing speed and body mass data, may be an important addition to the National Football League combine as a measure of playing potential in the professional game.

Associations of lifetime concussion history and repetitive head impact exposure with resting-state functional connectivity in former collegiate American football players: An NCAA 15-year follow-up study

Associations of lifetime concussion history and repetitive head impact exposure with resting-state functional connectivity in former collegiate American football players: An NCAA 15-year follow-up study

Perceptual-Motor Efficiency and Concussion History Are Prospectively Associated With Injury Occurrences Among High School and Collegiate American Football Players.

Background:After a sport-related concussion (SRC), the risk for lower extremity injury is approximately 2 times greater, and the risk for another SRC may be as much as 3 to 5 times greater.Purpose:To assess the predictive validity of screening methods for identification of individual athletes who possess an elevated risk of SRC.Study Design:Case-control study; Level of evidence, 3.Methods:Metrics derived from a smartphone flanker test software application and self-ratings of both musculoskeletal function and overall wellness were acquired from American high school and college football players before study participation. Occurrences of core or lower extremity injury (CLEI) and SRC were documented for all practice sessions and games for 1 season. Receiver operating characteristic and logistic regression analyses were used to identify variables that provided the greatest predictive accuracy for CLEI or SRC occurrence.Results:Overall, there were 87 high school and 74 American college football players included in this study. At least 1 CLEI was sustained by 45% (39/87) of high school players and 55% (41/74) of college players. Predictors of CLEI included the flanker test conflict effect ≥69 milliseconds (odds ratio [OR], 2.12; 90% CI, 1.24-3.62) and a self-reported lifetime history of SRC (OR, 1.70; 90% CI, 0.90-3.23). Of players with neither risk factor, only 38% (29/77) sustained CLEI compared with 61% (51/84) of players with 1 or both of the risk factors (OR, 2.56; 90% CI, 1.50-4.36). SRC was sustained by 7 high school players and 3 college players. Predictors of SRC included the Overall Wellness Index score ≤78 (OR, 9.83; 90% CI, 3.17-30.50), number of postconcussion symptoms ≥4 (OR, 8.35; 90% CI, 2.71-25.72), the Sport Fitness Index score ≤78 (OR, 5.16; 90% CI, 1.70-15.65), history of SRC (OR, 4.03; 90% CI, 1.35-12.03), and the flanker test inverse efficiency ratio ≥1.7 (OR, 3.19; 90% CI, 1.08-9.47).Conclusion:Survey responses and smartphone flanker test metrics predicted greater injury incidence among individual football players classified as high-risk compared with that for players with a low-risk profile.

Offseason Body Composition Changes Detected by Dual-Energy X-ray Absorptiometry versus Multifrequency Bioelectrical Impedance Analysis in Collegiate American Football Athletes.

Tracking changes in body composition may provide key information about the effectiveness of training programs for athletes. This study reports on the agreement between bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) for tracking body composition changes during a seven-week offseason training program in 29 NCAA collegiate American football players. Body composition in subjects (mean ± SD; age: 19.7 ± 1.5 y; height: 179.8 ± 6.6 cm; body mass (BM: 96.1 ± 12.6 kg; DXA body fat: 20.9 ± 4.4%) was estimated using BIA (InBody 770) and DXA (Hologic Horizon) before and after the training intervention. Repeated measures ANOVA and post hoc comparisons were performed. Longitudinal agreement between methods was also examined by concordance correlation coefficient (CCC) and Bland–Altman analysis alongside linear regression to identify bias. Significant method by time interactions were observed for BM (DXA: 1.1 ± 2.4 kg; BIA: 1.4 ± 2.5 kg; p < 0.03), arms fat-free mass (FFM) (DXA: 0.4 ± 0.5 kg; BIA: 0.2 ± 0.4 kg; p < 0.03), and legs FFM (DXA: 0.6 ± 1.1 kg; BIA: 0.1 ± 0.6 kg; p < 0.01). Post hoc comparisons indicated that DXA—but not BIA—detected increases in FFM of the arms and legs. Time main effects, but no method by time interactions, were observed for total FFM (DXA: 1.6 ± 1.9 kg; BIA: 1.2 ± 2.1 kg; p = 0.004) and trunk FFM (DXA: 0.7 ± 1.3 kg; BIA: 0.5 ± 1.0 kg; p = 0.02). Changes in total BM (CCC = 0.96), FFM (CCC = 0.49), and fat mass (CCC = 0.50) were significantly correlated between BIA and DXA. DXA and BIA may similarly track increases in whole-body FFM in American collegiate football players; however, BIA may possess less sensitivity in detecting segmental FFM increases, particularly in the appendages.

Integrating multi-omics with neuroimaging and behavior: A preliminary model of dysfunction in football athletes

Contact sports affect measures at multiple scales such as transcriptomics, metabolomics, brain function, and behavior, but studies have not yet studied the statistical structure of how they are integrated. This preliminary study, examining collegiate American football players, integrated across-season changes (Δ) from transcriptomic and metabolomic variables (neuroinflammatory miRNAs and metabolites), neuroimaging (resting-state fMRI network fingerprint similarity), and virtual reality (VR)-based motor control. These findings were then assessed against head acceleration events (HAE). Using permutation-based moderation analysis (all pFperm,pβ3perm≤0.05), we observed that (1) Δtridecenedioate, a mono-unsaturated fatty acid, interacted with ΔmiR-505 to predict default mode network (DMN) fingerprint similarity, meaning the interaction between two molecular biology measures predicted a neuroimaging measure. Further, (2) Δtridecenedioate and DMN fingerprint similarity interacted to predict motor control, indicating the interaction of a molecular and a neuroimaging measure predicted behavior. ΔmiR-505 was positively related to HAE and DMN fingerprint similarity was negatively related to HAE and reduced relative to non-athlete subjects. These multi-scale, moderating relationships between a potential ROS scavenger, neuroinflammatory miRNA, reduced brain connectivity, and diminished motor control argue that seemingly healthy athletes with frequent HAE may experience chronic neuroinflammation. This imaging-omics framework using permutation-based mediation/moderation analysis has general applicability for human-animal translational studies.

Hip Arthroscopy Outcomes in NFL and Collegiate American Football Players: Single Surgeon Experience with Return to Play, Sustained Return to Play, and Attrition Analysis

Objectives:There has been substantial literature regarding return to play after hip arthroscopy for professional athletes. There is less data with regards to both NFL and Collegiate football players and differences in outcomes between these athletic populations. Our hypothesis was that an arthroscopic FAI corrective procedure in NFL and Collegiate football players would result in improved PROM’s, predictable return to play rates, with higher return to play rates in NFL players vs Collegiate players.Methods:Between 2011 – 2019, 76 hips (65 players) in NFL and Collegiate American football players underwent hip arthroscopy and FAI correction by a single surgeon. An arthroscopic FAI correction procedure was performed for all athletes as previously described by the senior author. All athletes were prospectively followed preoperatively and postoperatively with HOS ADL, HOS Sports, modified Harris Hip, SF-12, VR-12 Physical, VR-12 Mental, and VAS patient related outcomes measures (PROMs). Plain radiographs were evaluated preoperatively and postoperatively with regards to Pincer-type FAI (LCE angle, Cross-over sign (COS), Cam-type FAI (alpha angle on AP and 45 degree modified Dunn radiographs), and Tonnis arthritis grade. Return to play on the roster, return to a game, number of seasons played, and number of games played were retrospectively evaluated via internet search of their respective teams, discussions with team ATC’s, Team Physicians, and Players themselves. Reasons for not returning or no longer playing were also searched and inquired. Players were followed until retirement from the NFL, graduation from collegiate football, or until they no longer were able to play because of injury, by choice, or were cut / released by the club.Results:There were 12 hips in NFL football players and 64 hips in Collegiate American football players. Of the Collegiate players, 31 hips played Division 1, 16 hips played Division 2, and 18 hips played Division 3 level football. The most common positions in this cohort were Linemen (27.7%) and Defensive backs (33.8%). The mean follow-up for all players was 33.4 months. There was a significant improvement for all players for PROMs (Pre to Post, mHHS 70.3 to 95, HOS Sports 52.6 to 92.8, HOS ADL 74.8 to 98.4, SF-12 83.2 to 91.4, VAS 5.2 to 0.9) at mean latest F/U (p<0.01 for each). The rate of return to football for all players was 77.6%. The rate of Return for NFL players was 90%, as compared to 75% for collegiate players (72% D1, 83% D2, 73% D3) (p=.062). The mean number of seasons played after arthroscopy was 2.1 for NFL players (range, 1-5) and 1.74 (range, 1-3) for collegiate athletes. The mean number of games played after arthroscopy was 34.7 games (range, 17-100) for NFL and 17.1 games (range, 0-33) for collegiate players. Six of 12 (50%) NFL players remain active in the NFL and of the 5 not active, 1 was drafted in the 4th round, and 4 were undrafted free agents. All 4 NFL players drafted in the first round remain active in the NFL although one is currently a free agent. An additional 4 collegiate players (5 hips, All D1 athletes) went on to play in the NFL. Only 9.2% (6 players, 7 hips) of players cited continued hip pain as a reason for attrition and all were collegiate players. No NFL players cited persistent hip issues as a reason for attrition. Other reasons for attrition included graduation from college (4 hips, 5.3%), other non-hip related injuries (1 hip, 1.3%), being cut or waived by the club (4 hips, 5.3%), and choosing not return to football (non-injury related) (6 hips, 7.9%).Conclusions:Hip arthroscopy led to a predictable improvement in patient related outcomes measures at a mean 33 months follow-up for NFL and collegiate American football players. NFL players were more likely to return to play than collegiate athletes (90% vs 75%, although non-significant with the numbers available), and higher round draft picks had greater sustained return to play compared to lower round / undrafted free agents. Attrition was rarely the result of persistent hip related pain and was multifactorial in nature in particular for collegiate athletes.

Repetitive head impacts in a collegiate football season: Exposure and effects

This study describes exposure to repetitive head impacts (RHI) by player position and activity during a collegiate football season, and investigates the relationship between RHI and acute (i.e., daily and weekly) and short-term (i.e., pre- to post-season) changes in balance, reaction time, symptoms, and cognition. We recorded RHI exposure in twenty Division I collegiate American football players during a single season using the Riddell InSite system. Participants sustained 4,586 impacts (4.20% high impact, i.e., &gt;63 g; 95.79% low impact, i.e., 20–63 g). Greatest exposure to RHI was observed in running backs and defensive ends during games, and tight ends and defensive ends during practices. Running plays and team drills placed players at greatest risk for exposure during practice. Cumulative RHI exposure across the season was associated with short-term declines in reaction time (p = 0.045), but not balance or cognition. Acute decline in balance was associated with the number of impacts sustained in the past week (p &lt; 0.05), but not the past 24 hours (p &gt; 0.05). Acute increase in total symptom score was also associated with the number of impacts sustained in the past week (p &lt; 0.01), but not the past 24 hours (p &gt; 0.05). Reaction time did not decline based on impact exposure in the past 24 hours or week. This study identifies activities and positions that may put players at risk for RHI exposure, and demonstrates that RHI sustained during the course of typical American football play by non-concussed individuals may result in small changes in balance, reaction time, and symptoms, but not cognition.