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1.  The impact of repeated marathon running on cardiovascular function in the aging population 
Background
Several studies have correlated elevations in cardiac biomarkers of injury post marathon with transient and reversible right ventricular (RV) systolic dysfunction as assessed by both transthoracic echocardiography (TTE) and cardiovascular magnetic resonance (CMR). Whether or not permanent myocardial injury occurs due to repeated marathon running in the aging population remains controversial.
Objectives
To assess the extent and severity of cardiac dysfunction after the completion of full marathon running in individuals greater than 50 years of age using cardiac biomarkers, TTE, cardiac computed tomography (CCT), and CMR.
Methods
A total of 25 healthy volunteers (21 males, 55 ± 4 years old) from the 2010 and 2011 Manitoba Full Marathons (26.2 miles) were included in the study. Cardiac biomarkers and TTE were performed one week prior to the marathon, immediately after completing the race and at one-week follow-up. CMR was performed at baseline and within 24 hours of completion of the marathon, followed by CCT within 3 months of the marathon.
Results
All participants demonstrated an elevated cTnT post marathon. Right atrial and ventricular volumes increased, while RV systolic function decreased significantly immediately post marathon, returning to baseline values one week later. Of the entire study population, only two individuals demonstrated late gadolinium enhancement of the subendocardium in the anterior wall of the left ventricle, with evidence of stenosis of the left anterior descending artery on CCT.
Conclusions
Marathon running in individuals over the age of 50 is associated with a transient, yet reversible increase in cardiac biomarkers and RV systolic dysfunction. The presence of myocardial fibrosis in older marathon athletes is infrequent, but when present, may be due to underlying occult coronary artery disease.
doi:10.1186/1532-429X-14-58
PMCID: PMC3438060  PMID: 22905796
Marathon running; Cardiac biomarkers; Echocardiography; Cardiac computed tomography; Cardiovascular magnetic resonance
2.  The effects of oral hydrolytic enzymes and flavonoids on inflammatory markers and coagulation after marathon running: study protocol for a randomized, double-blind, placebo-controlled trial 
Background
Regular moderate intensity physical activity positively influences the immune system with a lower incidence of upper respiratory tract infections (URTI) and lower levels of pro-inflammatory markers. However, marathon running due to its strenuous and prolonged nature results in immune perturbations with a major increase in pro-inflammatory markers and subsequent increased incidence of URTI. Furthermore, marathon running results in muscle damage and changes in hemostasis that promote a pro-thrombotic state.
Naturally occurring hydrolytic enzymes and flavonoids have antioxidant, anti-inflammatory and fibrinolytic effects, and may serve as countermeasures to exercise-induced inflammation, immune dysfunction and URTI.
The aim of this study is to determine whether the ingestion of oral hydrolytic enzymes and flavonoids before and after a marathon attenuates post-race muscle damage and inflammation, counters pro-thrombotic changes in hemostasis and decreases URTI incidence.
Methods/design
The Enzy-MagIC-study ( Enzy mes, Ma rathon runnin G , I nflammation, C oagulation) is a randomized, double-blind, placebo-controlled, monocenter phase I trial. 160 healthy males (age 20-65 years) will be randomized to receive either placebo or treatment (Wobenzym, MUCOS Pharma, Berlin, Germany) which contains the hydrolytic enzymes (bromelain, trypsin) and the flavonoid rutoside. One week before the marathon race, participants will begin daily ingestion of the investigational product (3×4 tablets). Intake will be continued for two weeks after the race (3×2 tablets per day). Clinical and laboratory measures will be collected 5-weeks and 1-week before the race, and immediately-, 24-h, 72-h, and 2 weeks after the race. The primary endpoint is the influence of the treatment on the pre-to-post marathon race plasma concentration change of the inflammatory marker interleukin-6 (IL-6). Secondary endpoints include the effect of treatment on salivary IgA concentration and the frequency of upper respiratory tract infections (URTI) for two weeks post-marathon as determined by the Wisconsin Upper Respiratory Symptom Survey (WURSS-24). Furthermore, changes of muscular and rheological parameters will be measured before and after the marathon race.
Discussion
We hypothesize that marathon-induced inflammatory perturbations and the incidence of subsequent URTI, muscular damage, and changes of hemostasis can be positively influenced by the anti-edematous, anti-inflammatory, antioxidant, and fibrinolytic effects of oral hydrolytic enzymes and flavonoids (Wobenzym).
Trial registration
ClinicalTrials.gov Identifier: NCT01916408
doi:10.1186/2052-1847-6-8
PMCID: PMC3945524  PMID: 24559067
Exercise; Inflammation; Upper respiratory tract illness; Oral hydrolytic enzymes; Flavonoids
3.  AQUA© as predictor of allergy in elite marathon runners 
Background
The prevalence of allergy in athletes is increasing, and its risk varies across sports. The risk is dependent mainly on the ventilation rate and environmental factors; however, the prevalence of allergy in elite runners remains unknown. Therefore, the aim of this study was to screen allergy symptoms in elite marathon runners by using a validated questionnaire for screening allergy in athletes.
Methods
Two hundred and one elite marathoners, who participated in the most competitive Brazilian marathons and half-marathons during 2011, were invited to complete a validated self-report Allergy Questionnaire for Athletes (AQUA©), with additional questions pertaining to training history, such as running experience, running distance per week and their best race time in marathon or half-marathon events.
Results
Sixty percent of the assessed athletes reported allergy symptoms as defined by a positive AQUA outcome (score [greater than or equal to] 5). No significant differences (p > 0.05) between groups (AQUA + and AQUA-) were observed for gender, age, running experience, weekly training volume and best performance time in the half-marathon and marathon. The most frequently reported symptoms were related to the respiratory tract and physical effort.
Conclusions
This study demonstrates that AQUA© can be used to predict allergy in elite marathon runners. In addition, these athletes have a higher prevalence of allergy symptoms to elite athletes from other sports.
doi:10.1186/1939-4551-7-7
PMCID: PMC3983857  PMID: 24708728
4.  Does Muscle Mass Affect Running Times in Male Long-distance Master Runners? 
Asian Journal of Sports Medicine  2012;3(4):247-256.
Purpose
The aim of the present study was to investigate associations between skeletal muscle mass, body fat and training characteristics with running times in master athletes (age > 35 years) in half-marathon, marathon and ultra-marathon.
Methods
We compared skeletal muscle mass, body fat and training characteristics in master half-marathoners (n=103), master marathoners (n=91) and master ultra-marathoners (n=155) and investigated associations between body composition and training characteristics with race times using bi- and multi-variate analyses.
Results
After multi-variate analysis, body fat was related to half-marathon (β=0.9, P=0.0003), marathon (β=2.2, P<0.0001), and ultra-marathon (β=10.5, P<0.0001) race times. In master half-marathoners (β=-4.3, P<0.0001) and master marathoners (β=-11.9, P<0.0001), speed during training was related to race times. In master ultra-marathoners, however, weekly running kilometers (β=-1.6, P<0.0001) were related to running times.
Conclusions
To summarize, body fat and training characteristics, not skeletal muscle mass, were associated with running times in master half-marathoners, master marathoners, and master ultra-marathoners. Master half-marathoners and master marathoners rather rely on a high running speed during training whereas master ultra-marathoners rely on a high running volume during training. The common opinion that skeletal muscle mass affects running performance in master runners needs to be questioned.
PMCID: PMC3525821  PMID: 23342223
Body Fat; Skinfold Thickness; Anthropometry; Running; Sports
5.  Increased longitudinal contractility and diastolic function at rest in well-trained amateur Marathon runners: a speckle tracking echocardiography study 
Background
Regular physical activity reduces cardiovascular risk. There is concern that Marathon running might acutely damage the heart. It is unknown to what extent intensive physical endurance activity influences the cardiac mechanics at resting condition.
Methods
Eighty-four amateur marathon runners (43 women and 41 men) from Berlin-Brandenburg area who had completed at least one marathon previously underwent clinical examination and echocardiography at least 10 days before the Berlin Marathon at rest. Standard transthoracic echocardiography and 2D strain and strain rate analysis were performed. The 2D Strain and strain rate values were compared to previous published data of healthy untrained individuals.
Results
The average global longitudinal peak systolic strain of the left ventricle was -23 +/- 2% with peak systolic strain rate -1.39 +/- 0.21/s, early diastolic strain rate 2.0 +/- 0.40/s and late diastolic strain rate 1.21 +/- 0.31/s. These values are significantly higher compared to the previous published values of normal age-adjusted individuals. In addition, no age-related decline of longitudinal contractility in well-trained athletes was observed.
Conclusions
There is increased overall longitudinal myocardial contractility at rest in experienced endurance athletes compared to the published normal values in the literature indicating a preserved and even supra-normal contractility in the athletes. There is no age dependent decline of the longitudinal 2D Strain values. This underlines the beneficial effects of regular physical exercise even in advanced age.
doi:10.1186/1476-7120-12-11
PMCID: PMC3975967  PMID: 24571726
6.  Physiological alterations after a marathon in the first 90-year-old male finisher: case study 
SpringerPlus  2014;3:608.
Introduction
Endurance performance decreases during ageing due to alterations in physiological characteristics, energy stores, and psychological factors. To investigate alterations in physiological characteristics and body composition of elderly master athletes in response to an extreme endurance event, we present the case of the first ninety-year-old official male marathon finisher.
Case description
Before and directly after the marathon, a treadmill incremental test, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, mechanography, and dynamometry measurements were conducted. The athlete finished the marathon in 6 h 48 min 55 s, which corresponds to an average competition speed of 6.19 km h-1.
Discussion and Evaluation
Before the marathon, was 31.5 ml min-1 kg-1 body mass and peak heart rate was 140 beats min-1. Total fat mass increased in the final preparation phase (+3.4%), while leg fat mass and leg lean mass were slightly reduced after the marathon (-3.7 and -1.6%, respectively). Countermovement jump (CMJ) peak power and peak velocity decreased after the marathon (-16.5 and -14.7%, respectively). Total impulse during CMJ and energy cost of running were not altered by the marathon. In the left leg, maximal voluntary ground reaction force (Fm1LH) and maximal isometric voluntary torque (MIVT) were impaired after the marathon (-12.2 and -14.5%, respectively).
Conclusions
Side differences in Fm1LH and MIVT could be attributed to the distinct non-symmetrical running pattern of the athlete. Similarities in alterations in leg composition and CMJ performance existed between the nonagenarian athlete and young marathon runners. In contrast, alterations in total body composition and m1LH performance were markedly different in the nonagenarian athlete when compared to his younger counterparts.
doi:10.1186/2193-1801-3-608
PMCID: PMC4210455  PMID: 25392780
Dual-energy X-ray absorptiometry; Peripheral quantitative computed tomography; Countermovement jump; Multiple one-legged hopping; Impulse
7.  Arterial stiffness is inversely associated with a better running record in a full course marathon race 
[Purpose]
Arterial stiffness is an independent predictor of cardiovascular risk and may contribute to reduced running capacity in humans. This study investigated the relationship between course record and arterial stiffness in marathoners who participated in the Seoul International Marathon in 2012.
[Methods]
A total of 30 amateur marathoners (Males n = 28, Females n = 2, mean age = 51.6 ± 8.3 years) were assessed before and after the marathon race. Brachial-ankle pulse wave velocity (ba-PWV) was assessed by VP-1000 plus (Omron Healthcare Co., Ltd., Kyoto, Japan) before and immediately after the marathon race. Pearson's correlation coefficient was used to determine the relationship between race record and ba-PWV. In addition, Wilcoxon signed rank test was used to determine the difference in ba-PWV between before and after the race.
[Results]
There was no significant change in the ba-PWV of marathoners before and after the race (1271.1 ± 185 vs. 1268.8 ± 200 cm/s, P=0.579). Both the full course record (Pearson's correlation coefficient = 0.416, P = 0.022) and the record of half line (Pearson's correlation coefficient = 0.482, P = 0.007) were positively related with the difference in ba-PWV, suggesting that reduced arterial stiffness is associated with a better running record in the marathon.
[Conclusion]
These results may suggest that good vascular function contributes to a better running record in the marathon race.
doi:10.5717/jenb.2014.18.4.355
PMCID: PMC4322026  PMID: 25671202
brachial-ankle pulse wave velocity (ba-PWV); exercise; full course marathon; arterial compliance
8.  Analysis of performance and age of the fastest 100-mile ultra-marathoners worldwide 
Clinics  2013;68(5):605-611.
OBJECTIVES:
The performance and age of peak ultra-endurance performance have been investigated in single races and single race series but not using worldwide participation data. The purpose of this study was to examine the changes in running performance and the age of peak running performance of the best 100-mile ultra-marathoners worldwide.
METHOD:
The race times and ages of the annual ten fastest women and men were analyzed among a total of 35,956 finishes (6,862 for women and 29,094 for men) competing between 1998 and 2011 in 100-mile ultra-marathons.
RESULTS:
The annual top ten performances improved by 13.7% from 1,132±61.8 min in 1998 to 977.6±77.1 min in 2011 for women and by 14.5% from 959.2±36.4 min in 1998 to 820.6±25.7 min in 2011 for men. The mean ages of the annual top ten fastest runners were 39.2±6.2 years for women and 37.2±6.1 years for men. The age of peak running performance was not different between women and men (p>0.05) and showed no changes across the years.
CONCLUSION:
These findings indicated that the fastest female and male 100-mile ultra-marathoners improved their race time by ∼14% across the 1998–2011 period at an age when they had to be classified as master athletes. Future studies should analyze longer running distances (>200 km) to investigate whether the age of peak performance increases with increased distance in ultra-marathon running.
doi:10.6061/clinics/2013(05)05
PMCID: PMC3654294  PMID: 23778421
Running; Ultra-Endurance; Sex Difference; Athlete
9.  Heart Rate Recovery After Exercise and Neural Regulation of Heart Rate Variability in 30-40 Year Old Female Marathon Runners 
The aim of the present study was to examine the effects of endurance training on heart rate (HR) recovery after exercise and cardiac autonomic nervous system (ANS) modulation in female marathon runners by comparing with untrained controls. Six female marathon runners (M group) aged 32-40 years and eight age-matched untrained females (C group) performed a maximum-effort treadmill running exercise. Maximal oxygen uptake (VO2max) was measured during the exercise with a gas analyzer connected to subjects through a face mask. Heart rate, blood pressure and blood lactate were measured before and after the exercise. Rating of perceived exertion (RPE) to the exercise was obtained immediately after the exercise. Holter ECG was recorded and analyzed with power spectral analysis of heart rate variability (HRV) to investigate the cardiac ANS modulation. The M group had significantly higher VO2max, faster HR recovery after exercise, higher Mean RR, SDRR, HF power and lower LF/HF ratio at rest compared with the C group. The M group also presented greater percent decrease of blood pressure after exercise, although their blood pressure after exercise was higher than the C group. It is suggested that endurance training induced significant alterations in cardiac ANS modulation at rest and significant acceleration of HR recovery after exercise in female marathon runners. Faster HR recovery after exercise in the female marathon runners should result from their higher levels of HRV, higher aerobic capacity and exaggerated blood pressure response to exercise compared with untrained controls.
Key PointsThe effects of endurance training on HR recovery after exercise and cardiac ANS modulation were investigated in female marathon runners by comparing with untrained controls.Time and frequency domain analysis of HRV was used to investigate cardiac ANS modulation.As compared with untrained controls, the female marathon runners showed faster HR recovery after exercise, which should result from their higher levels of HRV, higher aerobic capacity and exaggerated blood pressure response to exercise.
PMCID: PMC3880089  PMID: 24431956
Heart rate recovery; heart rate variability; female marathon runner
10.  Metabolic Factors Limiting Performance in Marathon Runners 
PLoS Computational Biology  2010;6(10):e1000960.
Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as ‘hitting the wall’), and thousands drop out before reaching the finish lines (approximately 1–2% of those who start). Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making ‘hitting the wall’ seem inevitable), or implied that maximal glycogen loading is required in order to complete a marathon without ‘hitting the wall.’ The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity) of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding ‘the wall.’ The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.
Author Summary
Marathon running, historically perceived as testing the physiologic limits of human endurance, has become increasingly popular even among recreational runners. Of those runners who test their endurance by racing the marathon distance, however, more than two in five report ‘hitting the wall,’ the rapid onset of severe fatigue and inability to maintain a high-intensity pace, resulting from the near-complete depletion of carbohydrate stores in the leg muscles and liver. An apparent paradox of long-distance running is that even the leanest athletes store enough fat to power back-to-back marathons, yet small carbohydrate reservoirs can nevertheless catastrophically limit performance in endurance exercise. In this study I develop and validate a mathematical model that facilitates computation of personalized estimates of the distances at which runners will exhaust their carbohydrate stores while running at selected paces. In addition, I provide a systematic approach to estimating personalized maximum speeds at which runners can safely complete a marathon, based on accessible physiologic parameters such as heart rate and running speed. This analysis provides a quantitative basis for improving the safety and optimizing the performance of endurance runners, evaluating midrace fueling requirements, and estimating limits of performance in human endurance running, for elite and recreational runners alike.
doi:10.1371/journal.pcbi.1000960
PMCID: PMC2958805  PMID: 20975938
11.  Prevalence of Hyponatremia, Renal Dysfunction, and Other Electrolyte Abnormalities Among Runners Before and After Completing a Marathon or Half Marathon 
Sports Health  2011;3(2):145-151.
Background:
Prior reports on metabolic derangements observed in distance running frequently have small sample sizes, lack prerace laboratory measures, and report sodium as the sole measure.
Hypothesis:
Metabolic abnormalities—hyponatremia, hypokalemia, renal dysfunction, hemoconcentration—are frequent after completing a full or half marathon. Clinically significant changes occur in these laboratory values after race completion.
Study Design:
Observational, cross-sectional study.
Methods:
Consenting marathon and half marathon racers completed a survey as well as finger stick blood sampling on race day of the National Marathon to Fight Breast Cancer (Jacksonville, Florida, February 2008). Parallel blood measures were obtained before and after race completion (prerace, n = 161; postrace, n = 195).
Results:
The prevalence of prerace and postrace hyponatremia was 8 of 161 (5.0%) and 16 of 195 (8.2%), respectively. Hypokalemia was not present prerace but was present in 1 runner postrace (1 of 195). Renal dysfunction occurred prerace in 14 of 161 (8.7%) and postrace in 83 of 195 (42.6%). Among those with postrace renal dysfunction, 45.8% (38 of 83) were classified as moderate or severe. Hemoconcentration was present in 2 of 161 (1.2%) prerace and 6 of 195 (3.1%) postrace. The mean changes in laboratory values were (postrace minus prerace): sodium, 1.6 mmol/L; potassium, −0.2 mmol/L; blood urea nitrogen, 2.8 mg/dL; creatinine, 0.2 mg/dL; and hemoglobin, 0.3 g/dL for 149 pairs (except blood urea nitrogen, n = 147 pairs). Changes were significant for all comparisons (P < 0.01) except potassium (P = 0.08) and hemoglobin (P = 0.01).
Conclusions:
Metabolic abnormalities are common among endurance racers, and they may be present prerace, including hyponatremia. The clinical significance of these findings is unknown.
Clinical relevance:
It is unclear which runners are at risk for developing clinically important metabolic derangements. Participating in prolonged endurance exercise appears to be safe in the majority of racers.
doi:10.1177/1941738111400561
PMCID: PMC3445140  PMID: 23016001
marathon; hyponatremia; renal dysfunction; running; endurance sports
12.  Reduced Incidence of Cardiac Arrhythmias in Walkers and Runners 
PLoS ONE  2013;8(6):e65302.
Purpose
Walking is purported to reduce the risk of atrial fibrillation by 48%, whereas jogging is purported to increase its risk by 53%, suggesting a strong anti-arrhythmic benefit of walking over running. The purpose of these analyses is to compare incident self-reported physician-diagnosed cardiac arrhythmia to baseline energy expenditure (metabolic equivalent hours per day, METhr/d) from walking, running and other exercise.
Methods
Proportional hazards analysis of 14,734 walkers and 32,073 runners.
Results
There were 1,060 incident cardiac arrhythmias (412 walkers, 648 runners) during 6.2 years of follow-up. The risk for incident cardiac arrhythmias declined 4.4% per baseline METhr/d walked by the walkers, or running in the runners (P = 0.0001). Specifically, the risk declined 14.2% (hazard ratio: 0.858) for 1.8 to 3.6 METhr/d, 26.5% for 3.6 to 5.4 METhr/d, and 31.7% for ≥5.4 METhr/d, relative to <1.8 METhr/d. The risk reduction per METhr/d was significantly greater for walking than running (P<0.01), but only because walkers were at 34% greater risk than runners who fell below contemporary physical activity guideline recommendations; otherwise the walkers and runners had similar risks for cardiac arrhythmias. Cardiac arrhythmias were unrelated to walking and running intensity, and unrelated to marathon participation and performance.
Conclusions
The risk for cardiac arrhythmias was similar in walkers and runners who expended comparable METhr/d during structured exercise. We found no significant risk increase for self-reported cardiac arrhythmias associated with running distance, exercise intensity, or marathon participation. Rhythm abnormalities were based on self-report, precluding definitive categorization of the nature of the rhythm disturbance. However, even if the runners’ arrhythmias include sinus bradycardia due to running itself, there was no increase in arrhythmias with greater running distance.
doi:10.1371/journal.pone.0065302
PMCID: PMC3676466  PMID: 23762337
13.  Risk factors for injuries and other health problems sustained in a marathon 
OBJECTIVES: To identify risk factors for injuries and other health problems occurring during or immediately after participation in a marathon. METHODS: A prospective cohort study was undertaken of participants in the 1993 Auckland Citibank marathon. Demographic data, information on running experience, training and injuries, and information on other lifestyle factors were obtained from participants before the race using an interviewer-administered questionnaire. Information on injuries and other health problems sustained during or immediately after the marathon were obtained by a self administered questionnaire. Logistic regression analyses were undertaken to identify significant risk factors for health problems. RESULTS: This study, one of only a few controlled epidemiological studies that have been undertaken of running injuries, has identified a number of risk factors for injuries and other health problems sustained in a marathon. Men were at increased risk of hamstring and calf problems, whereas women were at increased risk of hip problems. Participation in a marathon for the first time, participation in other sports, illness in the two weeks before the marathon, current use of medication, and drinking alcohol once a month or more, were associated with increased self reported risks of problems. While increased training seemed to increase the risk of front thigh and hamstring problems, it may decrease the risk of knee problems. There are significant but complex relations between age and risk of injury or health problem. CONCLUSIONS: This study has identified certain high risk subjects and risk factors for injuries and other health problems sustained in a marathon. In particular, subjects who have recently been unwell or are taking medication should weigh up carefully the pros and cons of participating. 



PMCID: PMC1756136  PMID: 10027053
14.  Whole blood coagulation and platelet activation in the athlete: A comparison of marathon, triathlon and long distance cycling 
Introduction
Serious thrombembolic events occur in otherwise healthy marathon athletes during competition. We tested the hypothesis that during heavy endurance sports coagulation and platelets are activated depending on the type of endurance sport with respect to its running fraction.
Materials and Methods
68 healthy athletes participating in marathon (MAR, running 42 km, n = 24), triathlon (TRI, swimming 2.5 km + cycling 90 km + running 21 km, n = 22), and long distance cycling (CYC, 151 km, n = 22) were included in the study. Blood samples were taken before and immediately after completion of competition to perform rotational thrombelastometry. We assessed coagulation time (CT), maximum clot firmness (MCF) after intrinsically activation and fibrin polymerization (FIBTEM). Furthermore, platelet aggregation was tested after activation with ADP and thrombin activating peptide 6 (TRAP) by using multiple platelet function analyzer.
Results
Complete data sets were obtained in 58 athletes (MAR: n = 20, TRI: n = 19, CYC: n = 19). CT significantly decreased in all groups (MAR -9.9%, TRI -8.3%, CYC -7.4%) without differences between groups. In parallel, MCF (MAR +7.4%, TRI +6.1%, CYC +8.3%) and fibrin polymerization (MAR +14.7%, TRI +6.1%, CYC +8.3%) were significantly increased in all groups. However, platelets were only activated during MAR and TRI as indicated by increased AUC during TRAP-activation (MAR +15.8%) and increased AUC during ADP-activation in MAR (+50.3%) and TRI (+57.5%).
Discussion
While coagulation is activated during physical activity irrespective of type we observed significant platelet activation only during marathon and to a lesser extent during triathlon. We speculate that prolonged running may increase platelet activity, possibly, due to mechanical alteration. Thus, particularly prolonged running may increase the risk of thrombembolic incidents in running athletes.
doi:10.1186/2047-783X-15-2-59
PMCID: PMC3352046  PMID: 20452885
15.  Troponin release following endurance exercise: is inflammation the cause? a cardiovascular magnetic resonance study 
Background
The aetiology and clinical significance of troponin release following endurance exercise is unclear but may be due to transient myocardial inflammation. Cardiovascular magnetic resonance (CMR) affords us the opportunity to evaluate the presence of myocardial inflammation and focal fibrosis and is the ideal imaging modality to study this hypothesis. We sought to correlate the relationship between acute bouts of ultra endurance exercise leading to cardiac biomarkers elevation and the presence of myocardial inflammation and fibrosis using CMR.
Methods
17 recreation athletes (33.5 +/- 6.5 years) were studied before and after a marathon run with troponin, NTproBNP, and CMR. Specific imaging parameters to look for inflammation included T2 weighted images, and T1 weighted spin-echo images before and after an intravenous gadolinium-DTPA to detect myocardial hyperemia secondary to inflammation. Late gadolinium imaging was performed (LGE) to detect any focal regions of replacement fibrosis.
Results
Eleven of the 17 participant had elevations of TnI above levels of cut off for myocardial infarction 6 hrs after the marathon (0.075 +/- 0.02, p = 0.007). Left ventricular volumes were reduced post marathon and a small increase in ejection fraction was noted (64+/- 1% pre, 67+/- 1.2% post, P = 0.014). Right ventricular volumes, stroke volume, and ejection fraction were unchanged post marathon. No athlete fulfilled criteria for myocardial inflammation based on current criteria. No regions of focal fibrosis were seen in any of the participants.
Conclusion
Exercise induced cardiac biomarker release is not associated with any functional changes by CMR or any detectable myocardial inflammation or fibrosis.
doi:10.1186/1532-429X-12-38
PMCID: PMC2908607  PMID: 20598139
16.  Personal best times in an Olympic distance triathlon and in a marathon predict Ironman race time in recreational male triathletes 
Background
The purpose of this study was to define predictor variables for recreational male Ironman triathletes, using age and basic measurements of anthropometry, training, and previous performance to establish an equation for the prediction of an Ironman race time for future recreational male Ironman triathletes.
Methods
Age and anthropometry, training, and previous experience variables were related to Ironman race time using bivariate and multivariate analysis.
Results
A total of 184 recreational male triathletes, of mean age 40.9 ± 8.4 years, height 1.80 ± 0.06 m, and weight 76.3 ± 8.4 kg completed the Ironman within 691 ± 83 minutes. They spent 13.9 ± 5.0 hours per week in training, covering 6.3 ± 3.1 km of swimming, 194.4 ± 76.6 km of cycling, and 45.0 ± 15.9 km of running. In total, 149 triathletes had completed at least one marathon, and 150 athletes had finished at least one Olympic distance triathlon. They had a personal best time of 130.4 ± 44.2 minutes in an Olympic distance triathlon and of 193.9 ± 31.9 minutes in marathon running. In total, 126 finishers had completed both an Olympic distance triathlon and a marathon. After multivariate analysis, both a personal best time in a marathon (P < 0.0001) and in an Olympic distance triathlon (P < 0.0001) were the best variables related to Ironman race time. Ironman race time (minutes) might be partially predicted by the following equation: (r2 = 0.65, standard error of estimate = 56.8) = 152.1 + 1.332 × (personal best time in a marathon, minutes) + 1.964 × (personal best time in an Olympic distance triathlon, minutes).
Conclusion
These results suggest that, in contrast with anthropometric and training characteristics, both the personal best time in an Olympic distance triathlon and in a marathon predict Ironman race time in recreational male Ironman triathletes.
doi:10.2147/OAJSM.S23229
PMCID: PMC3781890  PMID: 24198578
body fat; swimming; cycling; running; triathlon
17.  Pacemaker safety and long-distance running 
Netherlands Heart Journal  2004;12(10):450-454.
Objective
To prove that long-distance running is safe for athletes with pacemaker devices, pacemaker function was evaluated in nine long-distance runners.
Method
Nine runners participated in a nine-month training programme that involved running for 1000 or 2000 km in preparation for either a full or a half marathon. A professional coach, three cardiologists and a technician — all with running experience — conducted the training and medical checkups. Commercial heart rate monitors were used during training to assess heart rates at rest, and during exercise and long-distance running. Sensing and pacing functions of the pacemaker system were tested during training sessions as well as during the race. In addition, the ChampionChip (a time registration device used in competition) and the Polar heart rate monitor (a widely used self-monitoring device) were tested for possible interference with the pacemaker.
Results
All nine athletes completed the Amsterdam 2001 half or full marathon without any pacemaker dysfunction. A short survey after two years showed no pacemaker dysfunction.
Conclusion
Long-distance running is safe for athletes with pacemaker implants. Overall fitness and sufficient endurance training remain the prerequisites for maintaining the condition necessary for successful completion of a marathon regardless of medical status. In our study, it became clear that for patients who had received a pacemaker because of complete heart block, the upper rate of the pacemaker programme needed to be adjusted to 170 to 180 ppm to insure 1:1 atrio-ventricular synchrony during high atrial rates. It is concluded that there is no a priori reason for cardiologists to advise against long-distance running in athletes with pacemakers. Patients with known or suspected structural heart disease should be screened according the recommendations.
PMCID: PMC2497157
endurance sports; marathon; pacemaker; running; safety
18.  Running a Marathon Induces Changes in Adipokine Levels and in Markers of Cartilage Degradation – Novel Role for Resistin 
PLoS ONE  2014;9(10):e110481.
Running a marathon causes strenuous joint loading and increased energy expenditure. Adipokines regulate energy metabolism, but recent studies have indicated that they also exert a role in cartilage degradation in arthritis. Our aim was to investigate the effects of running a marathon on the levels of adipokines and indices of cartilage metabolism. Blood samples were obtained from 46 male marathoners before and after a marathon run. We measured levels of matrix metalloproteinase-3 (MMP-3), cartilage oligomeric protein (COMP) and chitinase 3-like protein 1 (YKL-40) as biomarkers of cartilage turnover and/or damage and plasma concentrations of adipokines adiponectin, leptin and resistin. Mean marathon time was 3∶30∶46±0∶02∶46 (h:min:sec). The exertion more than doubled MMP-3 levels and this change correlated negatively with the marathon time (r = –0.448, p = 0.002). YKL-40 levels increased by 56% and the effect on COMP release was variable. Running a marathon increased the levels of resistin and adiponectin, while leptin levels remained unchanged. The marathon-induced changes in resistin levels were positively associated with the changes in MMP-3 (r = 0.382, p = 0.009) and YKL-40 (r = 0.588, p<0.001) and the pre-marathon resistin levels correlated positively with the marathon induced change in YKL-40 (r = 0.386, p = 0.008). The present results show the impact of running a marathon, and possible load frequency, on cartilage metabolism: the faster the marathon was run, the greater was the increase in MMP-3 levels. Further, the results introduce pro-inflammatory adipocytokine resistin as a novel factor, which enhances during marathon race and associates with markers of cartilage degradation.
doi:10.1371/journal.pone.0110481
PMCID: PMC4204875  PMID: 25333960
19.  Performance and age of African and non-African runners in half- and full marathons held in Switzerland, 2000–2010 
Background
Endurance running performance of African (AF) and non-African (NAF) athletes is investigated, with better performances seen for Africans. To date, no study has compared the age of peak performance between AF and NAF runners. The present research is an analysis of the age and running performance of top AF and NAF athletes, using the hypothesis that AF athletes were younger and faster than NAF athletes.
Methods
Age and performance of male and female AF and NAF athletes in half-marathons and marathons held in Switzerland in 2000–2010 were investigated using single and multilevel hierarchical regression analyses.
Results
For half-marathons, male NAF runners were older than male AF runners (P = 0.02; NAF, 31.1 years ± 6.4 years versus AF, 26.2 years ± 4.9 years), and their running time was longer (P = 0.02; NAF, 65.3 minutes ± 1.7 minutes versus AF, 64.1 minutes ± 0.9 minutes). In marathons, differences between NAF and AF male runners in age (NAF, 33.0 years ± 4.8 years versus AF, 28.6 years ± 3.8 years; P < 0.01) and running time (NAF, 139.5 minutes ± 5.6 minutes versus AF, 133.3 minutes ± 2.7 minutes; P < 0.01) were more pronounced. There was no difference in age (NAF, 31.0 years ± 7.0 years versus AF, 26.7 years ± 6.0 years; P > 0.05) or running time (NAF, 75.0 minutes ± 3.7 minutes versus AF, 75.6 minutes ± 5.3 minutes; P > 0.05) between NAF and AF female half-marathoners. For marathoners, NAF women were older than AF female runners (P = 0.03; NAF, 31.6 years ± 4.8 years versus AF, 27.8 years ± 5.3 years), but their running times were similar (NAF, 162.4 minutes ± 7.2 minutes versus AF, 163.0 minutes ± 7.0 minutes; P > 0.05).
Conclusion
In Switzerland, the best AF male half-marathoners and marathoners were younger and faster than the NAF counterpart runners. In contrast to the results seen in men, AF and NAF female runners had similar performances. Future studies need to investigate performance and age of AF and NAF marathoners in the World Marathon Majors Series.
doi:10.2147/OAJSM.S45918
PMCID: PMC3871899  PMID: 24379724
endurance; running; ethnicity; road race; gender difference
20.  Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners 
The Scientific World Journal  2012;2012:810859.
Purpose. Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). Methods. We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maximal laboratory test and then during a real marathon race (mean performance: 3 hr 30 min ± 45 min). Results. Our data revealed that HR, SV and CO were all in a high but submaximal steady state during the marathon (87.0 ± 1.6%, 77.2 ± 2.6%, and 68.7 ± 2.8% of maximal values, respectively). Marathon performance was inversely correlated with an upward drift in the CO/speed ratio (mL of CO × m−1) (r = −0.65, P < 0.01) and positively correlated with the runner's ability to complete the race at a high percentage of the speed at maximal SV (r = 0.83, P < 0.0002). Conclusion. Our results showed that marathon performance is inversely correlated with cardiac cost and positively correlated with cardiac endurance. The CO response could be a benchmark for race performance in recreational marathon runners.
doi:10.1100/2012/810859
PMCID: PMC3356747  PMID: 22645458
21.  Marathon performance in relation to body fat percentage and training indices in recreational male runners 
Background
The purpose of this study was to investigate the effect of anthropometric characteristics and training indices on marathon race times in recreational male marathoners.
Methods
Training and anthropometric characteristics were collected for a large cohort of recreational male runners (n = 126) participating in the Basel marathon in Switzerland between 2010 and 2011.
Results
Among the parameters investigated, marathon performance time was found to be affected by mean running speed and the mean weekly distance run during the training period prior to the race and by body fat percentage. The effect of body fat percentage became significant as it exceeded a certain limiting value; for a relatively low body fat percentage, marathon performance time correlated only with training indices.
Conclusion
Marathon race time may be predicted (r = 0.81) for recreational male runners by the following equation: marathon race time (minutes) = 11.03 + 98.46 exp(−0.0053 mean weekly training distance [km/week]) + 0.387 mean training pace (sec/km) + 0.1 exp(0.23 body fat percentage [%]). The marathon race time results were valid over a range of 165–266 minutes.
doi:10.2147/OAJSM.S44945
PMCID: PMC3871414  PMID: 24379719
endurance; exercise; anthropometry
22.  Higher Precision of Heart Rate Compared with VO2 to Predict Exercise Intensity in Endurance-Trained Runners 
The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg) with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s-1 with a 0.56 m·s-1 increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg-1·min-1 and 181 ± 13 beats·min-1. The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99) with small standard errors of regression (i.e. Sy.x < 5% at the velocity associated with the 2 and 4 mmol·L-1 lactate thresholds). The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects’ running economy during training periods.
Key pointsHeart rate is used in the control of exercise intensity in endurance sports.However, few studies have quantified the precision of its relationship with oxygen uptake in highly trained runners.We evaluated twelve elite half-marathon runners during track running at various intensities and established three regressions: oxygen uptake / heart rate; heart rate / running velocity and oxygen uptake / running velocity.The three regressions presented, respectively, imprecision of 4,2%, 2,75% and 4,5% at the velocity associated with the 4 mmol·L-1 threshold.The results of the present study show that, in highly trained runners, it is possible to use heart rate as an accurate index of the external work rate during sub maximal running speeds.
PMCID: PMC3737894  PMID: 24149310
Running velocity; internal load; relationships; standard error
23.  Running Pace Decrease during a Marathon Is Positively Related to Blood Markers of Muscle Damage 
PLoS ONE  2013;8(2):e57602.
Background
Completing a marathon is one of the most challenging sports activities, yet the source of running fatigue during this event is not completely understood. The aim of this investigation was to determine the cause(s) of running fatigue during a marathon in warm weather.
Methodology/Principal Findings
We recruited 40 amateur runners (34 men and 6 women) for the study. Before the race, body core temperature, body mass, leg muscle power output during a countermovement jump, and blood samples were obtained. During the marathon (27 °C; 27% relative humidity) running fatigue was measured as the pace reduction from the first 5-km to the end of the race. Within 3 min after the marathon, the same pre-exercise variables were obtained.
Results
Marathoners reduced their running pace from 3.5 ± 0.4 m/s after 5-km to 2.9 ± 0.6 m/s at the end of the race (P<0.05), although the running fatigue experienced by the marathoners was uneven. Marathoners with greater running fatigue (> 15% pace reduction) had elevated post-race myoglobin (1318 ± 1411 v 623 ± 391 µg L−1; P<0.05), lactate dehydrogenase (687 ± 151 v 583 ± 117 U L−1; P<0.05), and creatine kinase (564 ± 469 v 363 ± 158 U L−1; P = 0.07) in comparison with marathoners that preserved their running pace reasonably well throughout the race. However, they did not differ in their body mass change (−3.1 ± 1.0 v −3.0 ± 1.0%; P = 0.60) or post-race body temperature (38.7 ± 0.7 v 38.9 ± 0.9 °C; P = 0.35).
Conclusions/Significance
Running pace decline during a marathon was positively related with muscle breakdown blood markers. To elucidate if muscle damage during a marathon is related to mechanistic or metabolic factors requires further investigation.
doi:10.1371/journal.pone.0057602
PMCID: PMC3583862  PMID: 23460881
24.  Gender differences in wheelchair marathon performance – Oita International Wheelchair Marathon from 1983 to 2011 
Background
The purpose of the study was (1) to examine the changes in participation and performance of males and females at the Oita International Wheelchair Marathon in Oita, Japan, between 1983 and 2011, and (2) to analyze the gender difference in the age of peak wheelchair marathon performance.
Methods
Age and time performance data for all wheelchair athletes completing the Oita International Wheelchair Marathon from 1983 to 2011 were analyzed.
Results
Mean annual number of finishers was 123 ± 43 for males and 6 ± 3 for females (5.0% ± 2.0% of all finishers), respectively. Mean age of overall finishers was significantly (P = 0.026) greater for males (41.3 ± 1.8 years) compared to females (32.7 ± 1.4 years). In contrast, there was no difference in the mean age of the top three overall finishers between males (35.8 ± 3.2 years) and females (31.6 ± 1.5 years). The race time of the top three overall finishers was significantly lower (P < 0.01) for males (1:34 ± 0:11 hours:minutes) compared to females (1:59 ± 0:20 hours:minutes), but it was not significantly different between male (2:06 ± 0:12 hours:minutes) and female (2:12 ± 0:18 hours:minutes) overall finishers. The mean gender difference in time was 26.1% ± 9.7% for the top three overall finishers.
Conclusion
Further studies are required to investigate the reasons for the low participation of females in wheelchair marathons and why the gender difference in marathon performance is much greater for disabled athletes than for able-bodied athletes.
doi:10.2147/OAJSM.S37819
PMCID: PMC3781911  PMID: 24198599
endurance; sex difference; disabled athlete; spinal cord injury
25.  Effect of BETA 1, 3/1, 6 GLUCAN on Upper Respiratory Tract Infection Symptoms and Mood State in Marathon Athletes 
This was a placebo-controlled, double-blind study designed to evaluate the effect of a commercially available dietary supplement on upper-respiratory tract symptoms (URTI) and mood state. Seventy-five marathon runners (35 men, 40 women) ranging in age from 18-53 years, mean age: 36 ± 9, self-administered placebo, 250 mg or 500 mg of BETA 1,3/1,6 GLUCAN (commercial name Wellmune WGP®) daily during the 4 week post-marathon trial period following the 2007 Carlsbad Marathon. Subjects filled out the profile of mood state (POMS) assessment and a questionnaire style health log measuring health status and URTI symptoms after 2- and 4-week treatment administrations. During the course of the 4-week study, subjects in the treatment groups (250 mg and 500 mg BETA-GLUCAN per day) reported significantly fewer URTI symptoms, better overall health and decreased confusion, fatigue, tension, and anger, and increased vigor based on the POMS survey compared to placebo. BETA-GLUCAN may prevent URTI symptoms, and improve overall health and mood following a competitive marathon.
Key pointsBeta-Glucan supplementation maintains immune function in endurance athletes.Beta-Glucan supplementation reduces post-exercise URTIs in marathon runners.Maintenance of post-exercise immune function is associated with improved mood state, including reduced fatigue and increased vigor in athletes.
PMCID: PMC3761532  PMID: 24149590
Dietary supplements; exercise; beta- Glucans; respiratory tract infections

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