Interaction of Surface Type, Temperature, and Week of Season on Concussion Risk in the National Football League: A Bayesian Analysis.

BACKGROUND: Artificial turf fields and environmental conditions may influence sports concussion risk, but existing research is limited by uncontrolled confounding factors, limited sample size, and the assumption that risk factors are independent of one another. The purpose of this study was to examine how playing surface, time of season, and game temperature relate to diagnosed concussion risk in the National Football League (NFL). METHODS: This retrospective cohort study examined data from the 2012 to the 2019 NFL regular season. We fit Bayesian negative binomial regression models to relate how playing surface, game temperature, and week of the season independently related to diagnosed concussion risk and any interactions among these factors. RESULTS: We identified 1096 diagnosed concussions in 1830 games. There was a >99% probability that concussion risk was reduced on grass surface (median incidence rate ratio [IRR] = 0.78 [95% credible interval: 0.68, 0.89]), >99% probability that concussion risk was lower at higher temperatures (IRR = 0.85 [0.76,0.95] for each 7.9 °C), and >91% probability that concussion risk increased with each week of the season (IRR = 1.02 [1.00,1.04]). There was an >84% probability for a surface × temperature interaction (IRR = 1.01 [0.96, 1.28]) and >75% probability for a surface × week interaction (IRR = 1.02 [0.99, 1.05]). CONCLUSIONS: Diagnosed concussion risk is increased on artificial turf compared with natural grass, and this is exacerbated in cold weather and, independently, later in the season. The complex interplay between these factors necessitates accounting for multiple factors and their interactions when investigating sports injury risk factors and devising mitigation methods.

Mpox and Monkeypox Virus: Special Considerations for Athletes in Contact Sports.

Monkeypox virus infections (mpox) in humans have become increasingly common since the virus was first identified in 1970. Coverage of the ongoing mpox outbreak has emphasized the role of skin-to-skin contact in monkeypox virus transmission and has focused on the community of men who have sex with men. While close contact from sexual activity is currently the main mechanism of monkeypox virus transmission, the potential for contact sports to exacerbate the 2022 outbreak has largely been overlooked. Infectious diseases rapidly spread in sports with significant skin-to-skin contact (i.e., wrestling and other combat sports, American football, and rugby). Mpox has not yet reached the athletic community, but once it does, it may follow a similar pattern of other infectious skin diseases in sports. Thus, it is critical to initiate a discussion of the risk of mpox and potential preventive measures within a sports context. This Current Opinion aims to provide stakeholders within the sports community with a brief review of infectious skin diseases in athletes, an overview of mpox and why it is relevant to athletes, and recommendations to reduce the risk of monkeypox virus transmission within sports settings. Guidelines for sports participation in athletes exposed to mpox and those with suspected, probable, and confirmed cases of monkeypox are provided.

Premature Death in Bodybuilders: What Do We Know?

Premature deaths in bodybuilders regularly make headlines and are cited as evidence that bodybuilding is a dangerous activity. A wealth of research has revealed elite athletes typically enjoy lower mortality rates than non-athletes, but research on bodybuilder lifespan is surprisingly limited. Anabolic androgenic steroid (AAS) use is commonly cited as a key contributor to morbidity and premature mortality in bodybuilders, but this area of research is highly nuanced and influenced by numerous confounders unique to bodybuilding. It is quite possible that bodybuilders are at elevated risk and that AAS use is the primary reason for this, but there remains much unknown in this realm. As global participation in bodybuilding increases, and healthcare providers play a more active role in monitoring bodybuilder health, there is a need to identify how numerous factors associated with bodybuilding ultimately influence short- and long-term health and mortality rate. In this Current Opinion, we discuss what is currently known about the bodybuilder lifespan, identify the nuances of the literature regarding bodybuilder health and AAS use, and provide recommendations for future research on this topic.

Kids on the Run-Is Marathon Running Safe for Children?

This Viewpoint examines youth marathon participation through the collective perspectives of clinicians and researchers invested in optimizing health, safety, and performance in young runners.

Bad Altitude: Categorizing Elevation Produces Spurious Association With Concussions in the National Football League (NFL).

OBJECTIVE: To assess whether prior analyses, where there was a relationship between altitude and concussion rates in American football, would replicate using a larger data set and altitude as a continuous variable. DESIGN: Cohort study replication. METHODS: We analyzed data from all NFL regular season games from 2012-2019. Concussions were identified from public databases and NFL injury reports. The altitude of each stadium was identified using mapping software. Concussion rates were calculated for each stadium and plotted against continuous altitude. We calculated crude rate ratios for several categorical cut points and used logistic and Poisson regression models to assess associations with continuous altitudes. RESULTS: We identified 867 players (1103 player seasons) who sustained 1159 concussions during the time period 2012-2019. All continuous plots and models showed no evidence of any association between concussions and altitude. A Poisson model found an IRR of 1.00 (95% CI, 0.99-1.01) for every 100-ft increase in altitude. A 644-ft cut point (used in previous studies) produced a significant difference (incidence rate ratio [IRR], 0.71; 95% CI, 0.54-0.94) in 2012-2013, but this did not replicate in 2014-2019 (IRR, 0.99; 95% CI, 0.84-1.14). CONCLUSION: We found no association between altitude and concussion rates in the NFL when altitude was analyzed continuously rather than inappropriately categorized. Our findings should increase skepticism of any effect of altitude on concussions at the elevations at which most American football is played, as well as clinical interventions based on that theory. It also underscores the importance of keeping continuous variables continuous wherever possible. J Orthop Sports Phys Ther 2022;52(10):694-701. Epub: 27 July 2022. doi:10.2519/jospt.2022.11220.

Giving science the finger-is the second-to-fourth digit ratio (2D:4D) a biomarker of good luck? A cross sectional study.

OBJECTIVES: To explore whether random chance, weak research methodology, or inappropriate reporting can lead to claims of statistically significant (yet, biologically meaningless) biomarker associations, using as a model the relation between a common surrogate of prenatal testosterone exposure, second-to-fourth digit ratio (2D:4D), and a random indicator of good luck. DESIGN: Cross sectional study. SETTING: University sports performance laboratory in the United States. Data were collected from May 2015 to February 2017. PARTICIPANTS: 176 adults (74 women, 102 men), including university students, faculty, and staff with no history of injuries, disease, or medical conditions that would affect digit length. MAIN OUTCOME MEASURES: 2D:4D, body composition parameters potentially influenced by androgens (bone mineral content, bone mineral density, body fat percentage), and good luck (using poker hands from randomly selected playing cards as a surrogate). RESULTS: 2D:4D significantly correlated with select body composition parameters (Spearman's r s range -0.26 to 0.23; P<0.05), but the correlations varied by sex, participant hand measured, and the method of measuring 2D:4D (by photocopy or radiography). However, the strongest correlation observed was between right hand 2D:4D in men measured by radiograph and poker hand rank (r s=0.28, P=0.004). CONCLUSIONS: Greater prenatal exposure to testosterone, as estimated by a lower 2D:4D, significantly increases good luck in adulthood, and also modulates body composition (albeit to a lesser degree). While these findings are consistent with a wealth of research reporting that 2D:4D is related to many seemingly disparate outcomes, they are not meant to provide confirmatory evidence that 2D:4D is a universal biomarker of nearly everything. Instead, the associations between 2D:4D and good luck are simply due to chance, and provide a "handy" example of the reproducibility crisis within medical and scientific research. Biologically sound hypotheses, pre-registration of trials, strong methodological and statistical analyses, transparent reporting of negative results, and unbiased interpretation of data are all necessary for biomarker studies and other areas of clinical research.

Comprehensive Return to Competitive Distance Running: A Clinical Commentary.

Running injuries are very common, and there are well-established protocols for clinicians to manage specific musculoskeletal conditions in runners. However, competitive and elite runners may experience different injuries than the average recreational runner, due to differences in training load, biomechanics, and running experience. Additionally, injury-specific rehabilitation protocols do not consider the broader goal of return to competitive running, including the unique psychosocial and cardiorespiratory fitness needs of elite athletes. This review aims to suggest a guideline for running-specific progression as part of a comprehensive rehabilitation program for injured competitive runners. Tools to evaluate an athlete's psychosocial preparedness to return to competition are presented. Recommendations are also provided for monitoring cardiorespiratory fitness of injured runners, including the nuances of interpreting these data. Finally, a six-phase training paradigm is proposed to guide clinicians as they help competitive runners transition from the early stages of injury through a full return to competition.

Most ankle sprain research is either false or clinically unimportant: A 30-year audit of randomized controlled trials.

BACKGROUND: Lateral ankle sprain is the most common musculoskeletal injury. Although clinical research in this field is growing, there is a broader concern that clinical trial outcomes are often false and fail to translate into patient benefits. METHODS: We audited 30 years of experimental research related to lateral ankle sprain management (n = 74 randomized controlled trials) to determine if reports of treatment effectiveness could be validated beyond statistical certainty. RESULTS: A total of 77% of trials reported positive treatment effects, but there was a high risk of false discovery. Most trials were unregistered and relied solely on statistical significance, or lack of statistical significance, rather than on interpreting key measures of minimum clinical importance (e.g., minimal detectable change, minimal clinically important difference). CONCLUSION: Future clinical trials must adopt higher standards of reporting and data interpretation. This includes consideration of the ethical responsibility to preregister their research and interpretation of clinical outcomes beyond statistical significance.

Optimizing Intersession Reliability of Heart Rate Variability-The Effects of Artifact Correction and Breathing Type.

Gisselman, AS, D'Amico, M, and Smoliga, JM. Optimizing intersession reliability of heart rate variability-the effects of artifact correction and breathing type. J Strength Cond Res 34(11): 3199-3207, 2020-This study aimed to comprehensively investigate the reliability of multiple heart rate variability (HRV) parameters and to explore the influence of artifact removal and breathing condition on HRV reliability. Resting HRV was collected using Polar Team monitors on 41 participants (age: 19.9 ± 1.2 years; 28 females and 13 males) during 2 separate days. Within each session, participants performed 10 minutes each of spontaneous and controlled breathing (randomized order). Kubios HRV analysis software was used to analyze 180-second data epochs using "low" or "strong" artifact removal. Relative reliability was assessed using intraclass correlation coefficient (ICC2,1), and absolute reliability was quantified using mean-normalized SEM%. Time-domain and nonlinear parameters produced poor to good intersession agreement (ICC = 0.34-0.68; SEM% = 11.0-39.0) with "low" artifact removal, regardless of breathing condition. Frequency-domain parameters demonstrated fair intersession agreement during controlled breathing (ICC = 0.40-0.45; SEM% = 26.0-70.0) but poor agreement during spontaneous breathing (ICC = 0.07-0.13; SEM% = 32.0-81.0). Minimal differences in ICCs were observed between "low" and "strong" artifact removal. Thus, this study provides 3 practical applications: (a) HRV monitoring is most reliable when using time-domain and nonlinear parameters, regardless of breathing or filtering condition, but no single parameter is especially reliable. The large variation and poor intersession reliability of frequency indices during spontaneous breathing are improved by controlling breathing rate; (b) "Low" artifact removal seems superior to more aggressive artifact removal; and (c) intersession differences in HRV measurements <30% may be indicative of normal daily variation rather than true physiologic changes.

Modelling the maximal active consumption rate and its plasticity in humans-perspectives from hot dog eating competitions.

Gut capacity and plasticity have been examined across multiple species, but are not typically explored in the context of extreme human performance. Here, I estimate the theoretical maximal active consumption rate (ACR) in humans, using 39 years of historical data from the annual Nathan's Famous Hot Dog Eating Contest. Through nonlinear modelling and generalized extreme value analysis, I show that humans are theoretically capable of achieving an ACR of approximately 832 g min-1 fresh matter over 10 min duration. Modelling individual performances across 5 years reveals that maximal ACR significantly increases over time in 'elite' competitive eaters, likely owing to training effects. Extreme digestive plasticity suggests that eating competition records are quite biologically impressive, especially in the context of carnivorous species and other human athletic competitions.

Many High-Quality Randomized Controlled Trials in Sports Physical Therapy Are Making False-Positive Claims of Treatment Effect: A Systematic Survey.

OBJECTIVE: To examine the risk of false-positive reporting within high-quality randomized controlled trials (RCTs) in the sports physical therapy field. DESIGN: Cross-sectional. METHODS: We searched the Physiotherapy Evidence Database for parallel-design, 2-arm RCTs reporting positive treatment effects, based on null-hypothesis significance testing, and scoring greater than 6/10 on the Physiotherapy Evidence Database scale. No restrictions were made on pathology, intervention, or outcome variables. Sixty-two of 212 RCTs reported positive effects in at least 1 outcome variable. We estimated false-positive risk (FPR) with an online calculator, based on number of participants, P value, and effect size. For each study, FPR was estimated using a range of prior probability assumptions: 0.2 (skeptical hypothesis), 0.5, and 0.8 (optimistic hypothesis). RESULTS: We calculated the FPR associated with 189 statistically significant findings (P<.05) reported across 44 trials. The median FPR was 9% (25th-75th percentile, 2%-24%). Sixty-three percent of statistically significant results (119/189) had an FPR greater than 5%, and 18% (35/189) had an FPR greater than 50%. Changing the prior probability from skeptical to optimistic reduced the median FPR from 29% (25th-75th percentile, 9%-56%) to 2% (25th-75th percentile, 0.6%-7.0%). CONCLUSION: High-quality RCTs using null-hypothesis significance testing often overestimated treatment effects. The median FPR was 9%: in 1 in 10 trials, the researchers falsely concluded that there was a treatment effect. Future RCTs in sports physical therapy should be informed by prestudy odds and a minimum FPR estimation. J Orthop Sports Phys Ther 2020;50(2):104-109. doi:10.2519/jospt.2020.9264.

Physical therapy musculoskeletal imaging authority: A survey of the World Confederation for Physical Therapy Nations.

OBJECTIVES: Medical evidence largely supports PTs in expanded roles, however, healthcare policy within the United States (USA) typically restricts PTs from ordering musculoskeletal (MSK) imaging. It is unknown how MSK imaging policy in the USA compares to other World Confederation for Physical Therapy (WCPT) member nations. The primary objective of our study was to investigate the authority of PTs to order MSK imaging. A secondary objective was to identify factors associated with the authority for PTs to order MSK imaging. METHODS: 111 WCPT member nations were surveyed over a 2-month period on the authority of PTs ordering MSK imaging within their nation. A secondary analysis utilizing a step-wise binary regression compared member nation demographic statistics to MSK imaging authority. RESULTS: 81 member nations responded to the survey. 31 (38.3%) of member nations reported having some level of PT MSK imaging authority while 50 (61.7%) did not. Member nations with lower per capita healthcare costs were significantly more likely to allow PTs to order MSK imaging (p = 0.02). Those with direct access authority were 7.4 times more likely to authorize PTs to order MSK imaging (p < 0.01). Entry-level clinical degree and years of entry-level collegiate credit were not associated with imaging authority. CONCLUSION: This is the first study to report MSK imaging policy within the WCPT member nations. While many nations within the WCPT allow PTs to order MSK imaging, the majority of nations still restrict PTs from such practice. Lower per capita healthcare costs and direct access authority were significant predictors of MSK imaging authority, however, causation cannot be established within the confines of this study. Future studies should consider issues such as restrictive policy origin (i.e. governmental vs. institutional), insurance reimbursement (i.e. private vs. public sector policy), and limitations on imaging modality.

Physical Activity Intolerance and Cardiorespiratory Dysfunction in Patients with Moderate-to-Severe Traumatic Brain Injury.

Moderate-to-severe traumatic brain injury (TBI) is a chronic health condition with multi-systemic effects. Survivors face significant long-term functional limitations, including physical activity intolerance and disordered sleep. Persistent cardiorespiratory dysfunction is a potentially modifiable yet often overlooked major contributor to the alarmingly high long-term morbidity and mortality rates in these patients. This narrative review was developed through systematic and non-systematic searches for research relating cardiorespiratory function to moderate-to-severe TBI. The literature reveals patients who have survived moderate-to-severe TBI have ~ 25-35% reduction in maximal aerobic capacity 6-18 months post-injury, resting pulmonary capacity parameters that are reduced 25-40% for weeks to years post-injury, increased sedentary behavior, and elevated risk of cardiorespiratory-related morbidity and mortality. Synthesis of data from other patient populations reveals that cardiorespiratory dysfunction is likely a consequence of ventilator-induced diaphragmatic dysfunction (VIDD), which is not currently addressed in TBI management. Thus, cardiopulmonary exercise testing should be routinely performed in this patient population and those with cardiorespiratory deficits should be further evaluated for diaphragmatic dysfunction. Lack of targeted treatment for underlying cardiorespiratory dysfunction, including VIDD, likely contributes to physical activity intolerance and poor functional outcomes in these patients. Interventional studies have demonstrated that short-term exercise training programs are effective in patients with moderate-to-severe TBI, though improvement is variable. Inspiratory muscle training is beneficial in other patient populations with diaphragmatic dysfunction, and may be valuable for patients with TBI who have been mechanically ventilated. Thus, clinicians with expertise in cardiorespiratory fitness assessment and exercise training interventions should be included in patient management for individuals with moderate-to-severe TBI.

The absorptive effects of orobuccal non-liposomal nano-sized glutathione on blood glutathione parameters in healthy individuals: A pilot study.

BACKGROUND: Glutathione is an endogenous antioxidant found in oxidized (GSSG) and reduced (GSH) forms. Glutathione depletion is indicative of oxidative stress and occurs in various pathological conditions and following extreme exercise activity. Raising blood glutathione concentration has potential to attenuate and prevent chronic disease and also to improve recovery from exercise. There are a number of challenges to achieving this through traditional dietary supplements, and thus there is a need to develop optimized delivery methods to improve blood glutathione status. This study evaluated the effect of a novel glutathione formulation on blood glutathione parameters in healthy individuals. METHODS: 15 (8 male) healthy individuals (25±5y old, 78.0±14.6kg) participated in a single-blinded randomized placebo-controlled crossover study, with a minimum one-week washout period between treatments. Participants were overnight fasted and administered 1mL of a non-liposomal nano-size glutathione solution (NLNG) containing 200mg of glutathione or 1mL of placebo lacking glutathione. The solution was held in the mouth for 90 seconds before the remainder was swallowed. Blood was collected at baseline, 5, 10, 30, 60 and 120 minutes post-treatment. Protein-bound plasma and erythrocyte lysate concentrations of GSH and GSSG were measured at all time points using previously validated procedures. Linear mixed effects models were used to compare differences between baseline and post-treatment glutathione concentrations between NLNG and placebo for each parameter. RESULTS: There was a significant main effect for treatment type, such that increases in GSH concentration in erythrocyte lysate were greater following NLNG than placebo (p = 0.001). Similar significant main effects for treatment were also found for total (protein bound + erythrocyte lysate) GSH (p = 0.015) and GSSG (p = 0.037) concentration, as well as total blood glutathione pool (GSH+GSSG, p = 0.006). DISCUSSION: NLNG increased multiple blood glutathione parameters compared to placebo. Future research should examine whether NLNG can attenuate oxidative stress.

Thermal profiles over the Achilles tendon in a cohort of non-injured collegiate athletes over the course of a cross country season.

OBJECTIVES: To determine normal temperatures over the Achilles tendon over nine weeks. DESIGN: A prospective cohort study with nine weeks of observation. SETTING: University's Human Biomechanics and Physiology Laboratory. PARTICIPANTS: Male or female competitive runners running at least 25 miles per week who did not report pain in the region of the Achilles over 9 weeks of data collection. MAIN OUTCOME MEASURE: Thermal images taken at the same time and day of the week, were used to measure the temperature of the skin over the Achilles tendon. RESULTS: Seventeen athletes were eligible for analysis. The Achilles tendon temperatures were right 28.7 °C ±â€¯1.3 °C, left 28.8 °C ±â€¯1.3 °C. ICC demonstrated a very high consistency and minimal variations in temperatures (right 0.86 (95% CI = 0.58, 0.98), left 0.79 (95% CI = 0.38, 0.97). The mean difference between sides over the season was 0.50 °C ±â€¯0.43 °C (p = 0.681). A decreasing trend in the Achilles tendon temperatures as the season progressed was observed. CONCLUSION: This is the first report of normal thermal profiles over an extended period. Variations in Achilles temperatures left to right, and over time were not significant. The decreasing temperature trend over the season warrants further investigation.