Effect of Stress-Related Neural Pathways on the Cardiovascular Benefit of Physical Activity.

BACKGROUND: The mechanisms underlying the psychological and cardiovascular disease (CVD) benefits of physical activity (PA) are not fully understood. OBJECTIVES: This study tested whether PA: 1) attenuates stress-related neural activity, which is known to potentiate CVD and for its role in anxiety/depression; 2) decreases CVD in part through this neural effect; and 3) has a greater impact on CVD risk among individuals with depression. METHODS: Participants from the Mass General Brigham Biobank who completed a PA survey were studied. A subset underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomographic imaging. Stress-related neural activity was measured as the ratio of resting amygdalar-to-cortical activity (AmygAC). CVD events were ascertained from electronic health records. RESULTS: A total of 50,359 adults were included (median age 60 years [Q1-Q3: 45-70 years]; 40.1% male). Greater PA was associated with both lower AmygAC (standardized ß: -0.245; 95% CI: -0.444 to -0.046; P = 0.016) and CVD events (HR: 0.802; 95% CI: 0.719-0.896; P < 0.001) in multivariable models. AmygAC reductions partially mediated PA's CVD benefit (OR: 0.96; 95% CI: 0.92-0.99; P < 0.05). Moreover, PA's benefit on incident CVD events was greater among those with (vs without) preexisting depression (HR: 0.860; 95% CI: 0.810-0.915; vs HR: 0.929; 95% CI: 0.910-0.949; P interaction = 0.011). Additionally, PA above guideline recommendations further reduced CVD events, but only among those with preexisting depression (P interaction = 0.023). CONCLUSIONS: PA appears to reduce CVD risk in part by acting through the brain's stress-related activity; this may explain the novel observation that PA reduces CVD risk to a greater extent among individuals with depression.

Mitral regurgitation in heart failure with preserved ejection fraction: The interplay of valve, ventricle, and atrium.

Mitral regurgitation (MR) is highly prevalent among patients with heart failure and preserved ejection fraction (HFpEF). Despite this combination being closely associated with unfavourable outcomes, it remains relatively understudied. This is partly due to the inherent heterogeneity of patients with HFpEF. To address this gap, dissecting HFpEF into mechanism-based phenotypes may offer a promising avenue for advancing our comprehension of these complex intertwined conditions. This review employs the validated CircAdapt model to explore the haemodynamic implications of moderate to severe MR across a well-defined spectrum of myocardial disease, characterized by impaired relaxation and reduced myocardial compliance. Both heart failure and mitral valve disease share overlapping symptomatology, primarily attributed to elevated pulmonary pressures. The intricate mechanisms contributing to these elevated pressures are multifaceted, potentially influenced by diastolic dysfunction, left atrial myopathy, and MR. Accurate evaluation of the haemodynamic and clinical impact of MR necessitates a comprehensive approach, taking into account the characteristics of both the left atrium and left ventricle, as well as their intricate interactions, which may currently be underemphasized in diagnostic practice. This holistic assessment is imperative for enhancing our understanding and refining therapeutic strategies within this patient cohort.

The International Criteria for Electrocardiogram Interpretation in Athletes: Common Pitfalls and Future Directions.

Preparticipation cardiovascular screening (PPCS) in young athletes is performed to detect conditions associated with sudden cardiac death. Many medical societies and sports governing bodies support the addition of a 12-lead electrocardiogram (ECG) to the history and physical to improve PPCS sensitivity. The current standard for ECG interpretation in athletes, the International Criteria, was developed to distinguish physiologic from pathologic ECG findings in athletes. Although application of the International Criteria has reduced the PPCS false-positive rate, interpretative challenges and potential areas of improvement remain. This review provides an overview of common pitfalls and future directions for ECG interpretation in athletes.

Sudden Cardiac Death in National Collegiate Athletic Association Athletes: A 20-Year Study.

BACKGROUND: Understanding the incidence, causes, and trends of sudden cardiac death (SCD) among young competitive athletes is critical to inform preventive policies. METHODS: This study included National Collegiate Athletic Association athlete deaths during a 20-year time frame (July 1, 2002, through June 30, 2022). Athlete deaths were identified through 4 separate independent databases and search strategies (National Collegiate Athletic Association resolutions list, Parent Heart Watch database and media reports, National Center for Catastrophic Sports Injury Research database, and insurance claims). Autopsy reports and medical history were reviewed by an expert panel to adjudicate causes of SCD. RESULTS: A total of 143 SCD cases in National Collegiate Athletic Association athletes were identified from 1102 total deaths. The National Collegiate Athletic Association resolutions list identified 117 of 143 (82%), the Parent Heart Watch database or media reports identified 89 of 143 (62%), the National Center for Catastrophic Sports Injury Research database identified 63 of 143 (44%), and insurance claims identified 27 of 143 (19%) SCD cases. The overall incidence of SCD was 1:63 682 athlete-years (95% CI, 1:54 065-1:75 010). Incidence was higher in male athletes than in female athletes (1:43 348 [95% CI, 1:36 228-1:51 867] versus 1:164 504 [95% CI, 1:110 552-1:244 787] athlete-years, respectively) and Black athletes compared with White athletes (1:26 704 [1:20 417-1:34 925] versus 1:74 581 [1:60 247-1:92 326] athlete-years, respectively). The highest incidence of SCD was among Division I male basketball players (1:8188 [White, 1:5848; Black, 1:7696 athlete-years]). The incidence rate for SCD decreased over the study period (5-year incidence rate ratio, 0.71 [95% CI, 0.61-0.82]), whereas the rate of noncardiovascular deaths remained stable (5-year incidence rate ratio, 0.98 [95% CI, 0.94-1.04]). Autopsy-negative sudden unexplained death (19.5%) was the most common postmortem examination finding, followed by idiopathic left ventricular hypertrophy or possible cardiomyopathy (16.9%) and hypertrophic cardiomyopathy (12.7%), in cases with enough information for adjudication (118 of 143). Eight cases of death were attributable to myocarditis over the study period (1 case from January 1, 2020, through June 30, 2022), with none attributed to COVID-19 infection. SCD events were exertional in 50% of cases. Exertional SCD was more common among those with coronary artery anomalies (100%) and arrhythmogenic cardiomyopathy (83%). CONCLUSIONS: The incidence of SCD in college athletes has decreased. Male sex, Black race, and basketball are associated with a higher incidence of SCD.

Deep learned representations of the resting 12-lead electrocardiogram to predict at peak exercise.

AIMS: To leverage deep learning on the resting 12-lead electrocardiogram (ECG) to estimate peak oxygen consumption (V˙O2peak) without cardiopulmonary exercise testing (CPET). METHODS AND RESULTS: V ˙ O 2 peak estimation models were developed in 1891 individuals undergoing CPET at Massachusetts General Hospital (age 45 ± 19 years, 38% female) and validated in a separate test set (MGH Test, n = 448) and external sample (BWH Test, n = 1076). Three penalized linear models were compared: (i) age, sex, and body mass index ('Basic'), (ii) Basic plus standard ECG measurements ('Basic + ECG Parameters'), and (iii) basic plus 320 deep learning-derived ECG variables instead of ECG measurements ('Deep ECG-V˙O2'). Associations between estimated V˙O2peak and incident disease were assessed using proportional hazards models within 84 718 primary care patients without CPET. Inference ECGs preceded CPET by 7 days (median, interquartile range 27-0 days). Among models, Deep ECG-V˙O2 was most accurate in MGH Test [r = 0.845, 95% confidence interval (CI) 0.817-0.870; mean absolute error (MAE) 5.84, 95% CI 5.39-6.29] and BWH Test (r = 0.552, 95% CI 0.509-0.592, MAE 6.49, 95% CI 6.21-6.67). Deep ECG-V˙O2 also outperformed the Wasserman, Jones, and FRIEND reference equations (P < 0.01 for comparisons of correlation). Performance was higher in BWH Test when individuals with heart failure (HF) were excluded (r = 0.628, 95% CI 0.567-0.682; MAE 5.97, 95% CI 5.57-6.37). Deep ECG-V˙O2 estimated V˙O2peak <14 mL/kg/min was associated with increased risks of incident atrial fibrillation [hazard ratio 1.36 (95% CI 1.21-1.54)], myocardial infarction [1.21 (1.02-1.45)], HF [1.67 (1.49-1.88)], and death [1.84 (1.68-2.03)]. CONCLUSION: Deep learning-enabled analysis of the resting 12-lead ECG can estimate exercise capacity (V˙O2peak) at scale to enable efficient cardiovascular risk stratification.

Researchers here present data describing a method of estimating exercise capacity from the resting electrocardiogram. Electrocardiogram estimation of exercise capacity was accurate and was found to predict the onset of the wide range of cardiovascular diseases including heart attacks, heart failure, arrhythmia, and death.This approach offers the ability to estimate exercise capacity without dedicated exercise testing and may enable efficient risk stratification of cardiac patients at scale.

Combined Value of Dimensionless Index and Transvalvular Flow Rate in Risk Stratification of Aortic Stenosis.

Aortic stenosis (AS) is difficult to phenotype. The metrics of severity are frequently discordant, making prognostication challenging. Flow state is central to accurately determining severity. We sought to evaluate the prognostic value of dimensionless index (DI) and transvalvular flow rate (Q) in AS. We evaluated 2 independent, longitudinal registries of ≥ moderate severity AS (aortic valve area ≤1.5 cm2 or mean gradient ≥20 mm Hg) with complete data follow-up. In the primary cohort (n = 1,104, 77 ± 11 years, 40% female), the DI and Q category significantly predicted mortality (p <0.001) (Figure 1), with the highest risk being low DI and low Q (DI <0.25, Q ≤210 mL/s). In the validation cohort (n = 939, 70 ± 13 years, 42% female), similar results were seen in Kaplan-Meier (p <0.001) and multivariable Cox model analyses (p <0.01). We advocate for wider combined use of DI and Q in AS assessment to augment current diagnostic and prognostic approaches.

Utility of Left and Right Ventricular Strain in Arrhythmogenic Right Ventricular Cardiomyopathy: A Prospective Multicenter Registry.

BACKGROUND: Imaging evaluation of arrhythmogenic right ventricular cardiomyopathy (ARVC) remains challenging. Myocardial strain assessment by echocardiography is an increasingly utilized technique for detecting subclinical left ventricular (LV) and right ventricular (RV) dysfunction. We aimed to evaluate the diagnostic and prognostic utility of LV and RV strain in ARVC. METHODS: Patients with suspected ARVC (n = 109) from a multicenter registry were clinically phenotyped using the 2010 ARVC Revised Task Force Criteria and underwent baseline strain echocardiography. Diagnostic performance of LV and RV strain was evaluated using the area under the receiver operating characteristic curve analysis against the 2010 ARVC Revised Task Force Criteria, and the prognostic value was assessed using the Kaplan-Meier analysis. RESULTS: Mean age was 45.3±14.7 years, and 48% of patients were female. Estimation of RV strain was feasible in 99/109 (91%), and LV strain was feasible in 85/109 (78%) patients. ARVC prevalence by 2010 ARVC Revised Task Force Criteria is 91/109 (83%) and 83/99 (84%) in those with RV strain measurements. RV global longitudinal strain and RV free wall strain had diagnostic area under the receiver operating characteristic curve of 0.76 and 0.77, respectively (both P<0.001; difference NS). Abnormal RV global longitudinal strain phenotype (RV global longitudinal strain > -17.9%) and RV free wall strain phenotype (RV free wall strain > -21.2%) were identified in 41/69 (59%) and 56/69 (81%) of subjects, respectively, who were not identified by conventional echocardiographic criteria but still met the overall 2010 ARVC Revised Task Force Criteria for ARVC. LV global longitudinal strain did not add diagnostic value but was prognostic for composite end points of death, heart transplantation, or ventricular arrhythmia (log-rank P=0.04). CONCLUSIONS: In a prospective, multicenter registry of ARVC, RV strain assessment added diagnostic value to current echocardiographic criteria by identifying patients who are missed by current echocardiographic criteria yet still fulfill the diagnosis of ARVC. LV strain, by contrast, did not add incremental diagnostic value but was prognostic for identification of high-risk patients.

Accelerometer-Derived "Weekend Warrior" Physical Activity and Incident Cardiovascular Disease.

Importance: Guidelines recommend 150 minutes or more of moderate to vigorous physical activity (MVPA) per week for overall health benefit, but the relative effects of concentrated vs more evenly distributed activity are unclear. Objective: To examine associations between an accelerometer-derived "weekend warrior" pattern (ie, most MVPA achieved over 1-2 days) vs MVPA spread more evenly with risk of incident cardiovascular events. Design, Setting, and Participants: Retrospective analysis of UK Biobank cohort study participants providing a full week of accelerometer-based physical activity data between June 8, 2013, and December 30, 2015. Exposures: Three MVPA patterns were compared: active weekend warrior (active WW, ≥150 minutes with ≥50% of total MVPA achieved in 1-2 days), active regular (≥150 minutes and not meeting active WW status), and inactive (<150 minutes). The same patterns were assessed using the sample median threshold of 230.4 minutes or more of MVPA per week. Main Outcomes and Measures: Associations between activity pattern and incident atrial fibrillation, myocardial infarction, heart failure, and stroke were assessed using Cox proportional hazards regression, adjusted for age, sex, racial and ethnic background, tobacco use, alcohol intake, Townsend Deprivation Index, employment status, self-reported health, and diet quality. Results: A total of 89 573 individuals (mean [SD] age, 62 [7.8] years; 56% women) who underwent accelerometry were included. When stratified at the threshold of 150 minutes or more of MVPA per week, a total of 37 872 were in the active WW group (42.2%), 21 473 were in the active regular group (24.0%), and 30 228 were in the inactive group (33.7%). In multivariable-adjusted models, both activity patterns were associated with similarly lower risks of incident atrial fibrillation (active WW: hazard ratio [HR], 0.78 [95% CI, 0.74-0.83]; active regular: 0.81 [95% CI, 0.74-0.88; inactive: HR, 1.00 [95% CI, 0.94-1.07]), myocardial infarction (active WW: 0.73 [95% CI, 0.67-0.80]; active regular: 0.65 [95% CI, 0.57-0.74]; and inactive: 1.00 [95% CI, 0.91-1.10]), heart failure (active WW: 0.62 [95% CI, 0.56-0.68]; active regular: 0.64 [95% CI, 0.56-0.73]; and inactive: 1.00 [95% CI, 0.92-1.09]), and stroke (active WW: 0.79 [95% CI, 0.71-0.88]; active regular: 0.83 [95% CI, 0.72-0.97]; and inactive: 1.00 [95% CI, 0.90-1.11]). Findings were consistent at the median threshold of 230.4 minutes or more of MVPA per week, although associations with stroke were no longer significant (active WW: 0.89 [95% CI, 0.79-1.02]; active regular: 0.87 [95% CI, 0.74-1.02]; and inactive: 1.00 [95% CI, 0.90-1.11]). Conclusions and Relevance: Physical activity concentrated within 1 to 2 days was associated with similarly lower risk of cardiovascular outcomes to more evenly distributed activity.

Consumer Wearable Health and Fitness Technology in Cardiovascular Medicine: JACC State-of-the-Art Review.

The use of consumer wearable devices (CWDs) to track health and fitness has rapidly expanded over recent years because of advances in technology. The general population now has the capability to continuously track vital signs, exercise output, and advanced health metrics. Although understanding of basic health metrics may be intuitive (eg, peak heart rate), more complex metrics are derived from proprietary algorithms, differ among device manufacturers, and may not historically be common in clinical practice (eg, peak V˙O2, exercise recovery scores). With the massive expansion of data collected at an individual patient level, careful interpretation is imperative. In this review, we critically analyze common health metrics provided by CWDs, describe common pitfalls in CWD interpretation, provide recommendations for the interpretation of abnormal results, present the utility of CWDs in exercise prescription, examine health disparities and inequities in CWD use and development, and present future directions for research and development.

Non-COVID-19 cardiovascular pathology from return-to-play screening in college athletes after COVID-19.

OBJECTIVE: Concerns for cardiac involvement after SARS-CoV-2 infection led to widespread cardiac testing in athletes. We examined incidental non-COVID-19 cardiovascular pathology in college athletes undergoing postinfection return-to-play screening. METHODS: The Outcomes Registry for Cardiac Conditions in Athletes was a nationwide prospective multicentre observational cohort study that captured testing and outcomes data from 45 institutions (September 2020-June 2021). Athletes with an ECG and transthoracic echocardiogram (TTE) and no pre-existing conditions were included. Findings were defined as major (associated with sudden cardiac death or requiring intervention), minor (warrants surveillance), incidental (no follow-up needed) or uncertain significance (abnormal with subsequent normal testing). RESULTS: Athletes with both ECG and TTE (n=2900, mean age 20±1, 32% female, 27% black) were included. 35 (1.2%) had ECG abnormalities. Of these, 2 (5.7%) had TTE abnormalities indicating cardiomyopathy (hypertrophic-1, dilated-1), and 1 with normal TTE had atrial fibrillation. Of 2865 (98.8%) athletes with a normal ECG, 54 (1.9%) had TTE abnormalities: 3 (5.6%) with aortic root dilatation ≥40 mm, 15 (27.8%) with minor abnormalities, 25 (46.3%) with incidental findings and 11 (20.4%) with findings of uncertain significance. Overall, 6 (0.2%) athletes had major conditions; however, coronary anatomy and aortic dimensions were inconsistently reported and pathology may have been missed. CONCLUSION: Major non-COVID-19 cardiovascular pathology was identified in 1/500 college athletes undergoing return-to-play screening. In athletes without ECG abnormalities, TTE's added value was limited to pathological aortic root dilatation in 1/1000 athletes and minor abnormalities warranting surveillance in 1/160 athletes. Two-thirds of findings were incidental or of uncertain significance.

Rationale and Design of the ORCCA (Outcomes Registry for Cardiac Conditions in Athletes) Study.

Background Clinical practice recommendations for participation in sports and exercise among young competitive athletes with cardiovascular conditions at risk for sudden death are based largely on expert consensus with a paucity of prospective outcomes data. Recent guidelines have taken a more permissive approach, using a shared decision-making model. However, the impact and outcomes of this strategy remain unknown. Methods The ORCCA (Outcomes Registry for Cardiac Conditions in Athletes) study is a prospective, multicenter, longitudinal, observational cohort study designed to monitor clinical outcomes in athletes with potentially life-threatening cardiovascular conditions. The study will assess sports eligibility decision-making, exercise habits, psychosocial well-being, and long-term cardiovascular outcomes among young competitive athletes with cardiovascular conditions. Competitive athletes aged 18 to <35 years diagnosed with a confirmed cardiovascular condition or borderline finding with potential increased risk of major adverse cardiovascular events are eligible. Outcomes will be monitored for an initial 5-year follow-up period or until age 35, and metrics of psychosocial well-being and composite adverse cardiovascular events including arrhythmias, sudden cardiac arrest/sudden cardiac death, and evidence of disease progression will be compared among athletes who continue versus discontinue competitive sports participation. Conclusions The ORCCA study aims to assess the process and results of return to sport decision-making and to monitor major adverse cardiovascular events, exercise habits, and the psychosocial well-being among young competitive athletes diagnosed with confirmed cardiovascular conditions or borderline findings with potential increased risk of major adverse cardiovascular events. The results of this work will generate an evidence base to inform future guidelines.

Clinical spectrum of COVID-19 complications in young adults: combined analysis of the American Heart Association COVID-19 Cardiovascular Disease Registry and the Outcomes Registry for Cardiac Conditions in Athletes.

BACKGROUND: While young adults 18-24 years old bear a significant proportion of COVID-19 diagnoses, the risk factors for hospitalisation and severe COVID-19 complications in this population are poorly understood. OBJECTIVE: The objective of this study was to identify risk factors for hospitalisation and other COVID-19 complications across the health spectrum of young adults diagnosed with COVID-19 infection. STUDY DESIGN: Retrospective cohort study. PARTICIPANTS: Young adults (aged 18-24) with confirmed COVID-19 infection from the American Heart Association (AHA) COVID-19 Cardiovascular Disease Registry of hospitalised patients and the Outcomes Registry for Cardiac Conditions in Athletes (ORCCA) study of collegiate athletes. The AHA registry included 636 young adults from 152 hospitals. The ORCCA registry consisted of 3653 competitive college athletes from 42 colleges and universities. INTERVENTION: None (exposure to COVID-19). PRIMARY AND SECONDARY OUTCOME MEASURES: Main outcomes included hospitalisation, death, major adverse cardiovascular events (MACE) and other severe clinical events. RESULTS: In comparison to the ORCCA registry, patients in the AHA registry were more likely to be female (59% vs 33%); had higher average body mass index (BMI) (32.4 vs 25.6); and had increased prevalence of diabetes (10% vs 0.4%), hypertension (7% vs 0.6%), chronic kidney disease (2% vs 0%) and asthma (14% vs 8%), all with p<0.01. There were eight (2%) deaths in the AHA hospitalised registry compared with zero in the ORCCA cohort. BMI was a statistically significant predictor of death in the hospitalised cohort (OR 1.05, 95% CI 1.00, 1.10). No significant predictors of MACE or other severe clinical events were identified. CONCLUSIONS: The risk of cardiac events in young adults aged 18-24 diagnosed with COVID-19 infection is low. Patients who were hospitalised (AHA registry) were more likely to have pre-existing medical comorbidities and higher BMI than healthy collegiate athletes (ORCCA registry). Once hospitalised, elevated BMI is associated with increased mortality although other drivers of MACE and other severe clinical events remain unclear.

Sex Differences in Extensive Mitral Annular Calcification With Associated Mitral Valve Dysfunction.

Mitral annular calcification (MAC)-related mitral valve (MV) dysfunction is an increasingly recognized entity, which confers a high burden of morbidity and mortality. Although more common among women, there is a paucity of data regarding how the phenotype of MAC and the associated adverse clinical implications may differ between women and men. A total of 3,524 patients with extensive MAC and significant MAC-related MV dysfunction (i.e., transmitral gradient ≥3 mm Hg) were retrospectively analyzed from a large institutional database, with the goal of defining gender differences in clinical and echocardiographic characteristics and the prognostic importance of MAC-related MV dysfunction. We stratified patients into low- (3 to 5 mm Hg), moderate- (5 to 10 mm Hg), and high- (≥10 mm Hg) gradient groups and analyzed the gender differences in phenotype and outcome. The primary outcome was all-cause mortality, assessed using adjusted Cox regression models. Women represented the majority (67%) of subjects, were older (79.3 ± 10.4 vs 75.5 ± 10.9 years, p <0.001) and had a lower burden of cardiovascular co-morbidities than men. Women had higher transmitral gradients (5.7 ± 2.7 vs 5.3 ± 2.6 mm Hg, p <0.001), more concentric hypertrophy (49% vs 33%), and more mitral regurgitation. The median survival was 3.4 years (95% confidence interval 3.0 to 3.6) among women and 3.0 years (95% confidence interval 2.6 to 4.5) among men. The adjusted survival was worse among men, and the prognostic impact of the transmitral gradient did not differ overall by gender. In conclusion, we describe important gender differences among patients with MAC-related MV dysfunction and show worse adjusted survival among men; although, the adverse prognostic impact of the transmitral gradient was similar between men and women.

The Cardiac Effects of COVID-19 on Young Competitive Athletes: Results from the Outcomes Registry for Cardiac Conditions in Athletes (ORCCA).

The Outcomes Registry for Cardiac Conditions in Athletes (ORCCA) study is a large-scale prospective investigation evaluating the cardiovascular effects and outcomes of SARS-CoV-2 infection on young competitive athletes. This review provides an overview of the key results from the ORCCA study. Results from the ORCCA study have provided important insights into the clinical impact of SARS-CoV-2 infection on the cardiovascular health of young competitive athletes and informed contemporary screening and return to sport practices. Key results include defining a low prevalence of both cardiac involvement and adverse cardiovascular outcomes after SARS-CoV-2 infection and evaluating the utility of a return-to-play cardiac evaluation. Future aims of the ORCCA study include the longer-term evaluation of cardiovascular outcomes among athletes post-SARS-CoV-2 infection and the transition to investigating outcomes in young athletes with potentially high-risk genetic or structural cardiac diagnoses.

The International Criteria for Electrocardiogram Interpretation in Athletes: Common Pitfalls and Future Directions.

Preparticipation cardiovascular screening (PPCS) in young athletes is performed to detect conditions associated with sudden cardiac death. Many medical societies and sports governing bodies support the addition of a 12-lead electrocardiogram (ECG) to the history and physical to improve PPCS sensitivity. The current standard for ECG interpretation in athletes, the International Criteria, was developed to distinguish physiologic from pathologic ECG findings in athletes. Although application of the International Criteria has reduced the PPCS false-positive rate, interpretative challenges and potential areas of improvement remain. This review provides an overview of common pitfalls and future directions for ECG interpretation in athletes.