Presença de fatores de risco dependentes ou não de esforço físico em praticantes de corrida de rua

In order to reduce the sedentarism and to improve population's health condition, many physical activity incentive programs have been stimulated. As a result, many people have adhered to street racing, but their health condition is almost always ignored. The aim of this study was to evaluate street racers' health condition, identifying the presence of cardiovascular risk factors as well as problems associated to street racing. The study case was composed by 111 racers from the town of Bauru (94 men and 17 women) aged in average 39±13 years old, who were evaluated in 4 street race competitions. The subjects answered to an anamnesis with questions about their socioeconomic status, medicine use, cardiovascular risk, physical exercise practices, and issues related to racing and injury. Weight (kg) and height (m) were measured to calculate the body mass index (BMI, kg/m²) as well as systolic and diastolic blood pressure (BP), heart rate (HR), abdominal circumference (AC), and flexibility. It could be observed that the majority of racers were Caucasian, married and belonged to social classes over C. The prevalent age was between 18 and 35 years old (42%). Among the participants, 38.7% have already undergone some kind of surgery and 13% declared having some health problem. The questionnaire pointed out that 36% had low and moderate cardiovascular risk. It could be noticed from the AC that 10% of men and 18% of women had high cardiac risk. Among the tested, 43.2% (24.3% altered and 18.9% borderline) showed high BP on the day of the test, but only 2.7% had self-declared hypertensive. In relation to injury, 36% had already had lesions of some kind, 27.5% of which had occurred in the last 8 months. 66.6% had derived from training or racing competitions and the knee was the mostly affected body part. Only 43% had professional orientation by a physical education teacher during their training and the main reasons for them to begin racing practice were...

Plasma zinc and immune markers in runners in response to a moderate increase in training volume

Changes in plasma zinc concentration and markers of immune function were examined in a group of 10 male runners (n = 10) following a moderate increase in training over four weeks. Seven sedentary males acted as controls. Fasting blood samples were taken at rest, before (T0) and after (T4) four weeks of increased (+ 16 %) training and after two weeks of reduced (-31 %) training (T6). Blood was analysed for plasma zinc concentration, differential leucocyte counts, lymphocyte subpopulations and lymphocyte proliferation using incorporation of 3H-thymidine. The runners increased their training volume by 16 % over the four weeks. When compared with the nonathletes, the runners had lower concentrations of plasma zinc (p = 0.012), CD3 + (p = 0.042) and CD19 + lymphocytes (p = 0.010) over the four weeks. Lymphocyte proliferation in response to Concanavalin A stimulation was greater in the runners (p = 0.0090). Plasma zinc concentration and immune markers remained constant during the study. Plasma zinc concentration correlated with total leucocyte counts in the athletes at T6 (r = -0.72, p < 0.05) and with Pokeweed mitogen stimulation in the nonathletes at T6 (r = -0.92, p < 0.05). Therefore, athletes are unlikely to benefit from zinc supplementation during periods of moderately increased training volume.

Effect of the passive recovery period on the lactate minimum speed in sprinters and endurance runners

The objective of this study was to verify the effect of the passive recovery time following a supramaximal sprint exercise and the incremental exercise test on the lactate minimum speed (LMS). Thirteen sprinters and 12 endurance runners performed the following tests: 1) a maximal 500 m sprint followed by a passive recovery to determine the time to reach the peak blood lactate concentration; 2) after the maximal 500 m sprint, the athletes rested eight mins, and then performed 6 x 800 m incremental test, in order to determine the speed corresponding to the lower blood lactate concentration (LMS1) and; 3) identical procedures of the LMS1, differing only in the passive rest time, that was performed in accordance with the time to peak lactate (LMS2). The time (min) to reach the peak blood lactate concentration was significantly higher in the sprinters (12.76+/-2.83) than in the endurance runners (10.25+/-3.01). There was no significant difference between LMS1 and LMS2, for both endurance (285.7+/-19.9; 283.9+/-17.8 m/min; r= 0.96) and sprint runners (238.0+/-14.1; 239.4+/-13.9 m/min; r= 0.93), respectively. We can conclude that the LMS is not influenced by a passive recovery period longer than eight mins (adjusted according with the time to peak blood lactate), although blood lactate concentration may differ at this speed. The predominant type of training (aerobic or anaerobic) of the athletes does not seem to influence the phenomenon previously described.

Doppler echocardiography in athletes from different sports

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Anaerobic running capacity determined from the critical velocity model is not significantly associated with maximal accumulated oxygen deficit in army runners

Purpose: The aim of this study was to verify whether there is an association between anaerobic running capacity (ARC) values, estimated from two-parameter models, and maximal accumulated oxygen deficit (MAOD) in army runners. Methods: Eleven, trained, middle distance runners who are members of the armed forces were recruited for the study (20 ± 1 years). They performed a critical velocity test (CV) for ARC estimation using three mathematical models and an MAOD test, both tests were applied on a motorized treadmill. Results: The MAOD was 61.6 ± 5.2 mL/kg (4.1 ± 0.3 L). The ARC values were 240.4 ± 18.6 m from the linear velocity-inverse time model, 254.0 ± 13.0 m from the linear distance-time model, and 275.2 ± 9.1 m from the hyperbolic time-velocity relationship (nonlinear 2-parameter model), whereas critical velocity values were 3.91 ± 0.07 m/s, 3.86 ± 0.08 m/s and 3.80 ± 0.09 m/s, respectively. There were differences (P < 0.05) for both the ARC and the CV values when compared between velocity-inverse time linear and nonlinear 2-parameter mathematical models. The different values of ARC did not significantly correlate with MAOD. Conclusion: In conclusion, estimated ARC did not correlate with MAOD, and should not be considered as an anaerobic measure of capacity for treadmill running. © 2013 Elsevier Masson SAS. All rights reserved.

Comparison of pro-atrial natriuretic peptide and atrial remodeling in marathon versus non-marathon runners

Long-term endurance sports are associated with atrial remodeling and an increased risk for atrial fibrillation (AF) and atrial flutter. Pro-atrial natriuretic peptide (pro-ANP) is a marker of atrial wall tension and elevated in patients with AF. The aim of this study was to test the hypothesis that atrial remodeling would be perpetuated by repetitive episodes of atrial stretching during strenuous competitions, reflected by elevated levels of pro-ANP. A cross-sectional study was performed on nonelite runners scheduled to participate in the 2010 Grand Prix of Bern, a 10-mile race. Four hundred ninety-two marathon and nonmarathon runners applied for participation, 70 were randomly selected, and 56 entered the final analysis. Subjects were stratified according to former marathon participations: a control group (nonmarathon runners, n = 22), group 1 (1 to 4 marathons, n = 16), and group 2 (≥5 marathons, n = 18). Results were adjusted for age, training years, and average weekly endurance training hours. The mean age was 42 ± 7 years. Compared to the control group, marathon runners in groups 1 and 2 had larger left atria (25 ± 6 vs 30 ± 6 vs 34 ± 7 ml/m(2), p = 0.002) and larger right atria (27 ± 7 vs 31 ± 8 vs 35 ± 5 ml/m(2), p = 0.024). Pro-ANP levels at baseline were higher in marathon runners (1.04 ± 0.38 vs 1.42 ± 0.74 vs 1.67 ± 0.69 nmol/L, p = 0.006). Pro-ANP increased significantly in all groups after the race. In multiple linear regression analysis, marathon participation was an independent predictor of left atrial (β = 0.427, p <0.001) and right atrial (β = 0.395, p = 0.006) remodeling. In conclusion, marathon running was associated with progressive left and right atrial remodeling, possibly induced by repetitive episodes of atrial stretching. The altered left and right atrial substrate may facilitate atrial arrhythmias.

Long-term cardiac remodeling and arrhythmias in nonelite marathon runners

Long-term endurance sports are associated with atrial remodeling and atrial arrhythmias. More importantly, high-level endurance training may promote right ventricular (RV) dysfunction and complex ventricular arrhythmias. We investigated the long-term consequences of marathon running on cardiac remodeling as a potential substrate for arrhythmias with a focus on the right heart. We invited runners of the 2010 Grand Prix of Bern, a 10-mile race. Of 873 marathon and nonmarathon runners who applied, 122 (61 women) entered the final analysis. Subjects were stratified according to former marathon participations: control group (nonmarathon runners, n = 34), group 1 (1 marathon to 5 marathons, mean 2.7, n = 46), and group 2 (≥6 marathons, mean 12.8, n = 42). Mean age was 42 ± 7 years. Results were adjusted for gender, age, and lifetime training hours. Right and left atrial sizes increased with marathon participations. In group 2, right and left atrial enlargements were present in 60% and 74% of athletes, respectively. RV and left ventricular (LV) dimensions showed no differences among groups, and RV or LV dilatation was present in only 2.4% or 4.3% of marathon runners, respectively. In multiple linear regression analysis, marathon participation was an independent predictor of right and left atrial sizes but had no effect on RV and LV dimensions and function. Atrial and ventricular ectopic complexes during 24-hour Holter monitoring were low and equally distributed among groups. In conclusion, in nonelite athletes, marathon running was not associated with RV enlargement, dysfunction, or ventricular ectopy. Marathon running promoted biatrial remodeling.

Behavioral risk profile of marathon runners

Although long distance running clearly has benefits--as witnessed by its popularity--it also has risks of injury and death. Little is known, however, about the prevalence of potentially dangerous training habits in long distance runners, although anecdotal information suggests that many runners have erroneous beliefs about risks and benefits of marathon running. We conducted a cross-sectional survey to estimate the prevalence of 19 potentially dangerous training habits (risky behaviors) among marathon runners. A 66-item self-administered questionnaire was mailed to a stratified random sample of runners who finished of the 1992 Houston-Tenneco Marathon and were 21-71 years of age. Responses were obtained from 508 runners (83%) with approximately equal representation in four age-gender groups: men $<$40 years, men $\ge$40 years, women $<$40 years, and women $\ge$40 years.^ Prevalences of risky behaviors were high. 50% or more ran in dangerously hot and humid conditions, did not cool down or stretch after running, did not wear proper running gear, or ran when injured or ill; 25-49% did not warm up, ran on dangerous surfaces, did not drink sufficient water during training, increased weekly mileage too quickly, and ran during lightning storms; 10-24% ran daily, ran in areas with high pollution, ran in the same direction as traffic, did hard runs frequently, ran more than 60 miles per week, or ran against the advice of a physician.^ Positive associations were found between the practice of risky behaviors and self-reported prevalence of musculoskeletal injuries, heat-related injuries, noncompliance with recommendations for preventive health examinations, and noncompliance with positive health habits.^ These results indicate that many marathon runners engage in training habits that may increase risk of substantial injury or illness. Further studies are needed to explore the association of risky training behaviors on the incidence of injuries, and to determine reasons for noncompliance with recommendations from sports medicine specialists. ^

Continuous glucose monitoring in diabetic long distance runners

Marathon running is growing in popularity, and many diabetic patients are participating in various marathon races all over the world each year. This study aimed to investigate the prevalence and extent of glycemic excursions (hypo- and hyperglycemic) during a marathon run in patients with well-controlled diabetes mellitus using a continuous glucose monitoring system (CGMS). Five subjects with type 1 and one patient with type 2 diabetes mellitus were monitored with the Medtronic MiniMed CGMS during the 2002 Vienna City Marathon (n = 3) or the Fernwarme run (n = 3) long distance runs of 42.19/15.8 km. All six patients finished their course. The CGSM system was well tolerated in all patients over an average duration of 34 +/- 4.0 hours and it did not limit the patients' activities. The mean running time for the Vienna city marathon was 257 +/- 8 min (247 to 274 min) and for the Fernwarme run 134 +/- 118 min (113 to 150 min). A total of 1470 blood glucose measurements (mean 245 readings per subject) were performed. During and after the marathons frequent hypo and hyperglycemic episodes with and without clinical symptoms were measured. Our data confirm that the CGMS may help to identify asymptomatic hypoglycemia or hyperglycemia during and after a long distance run. The system may also be helpful to improve our understanding about the individual changes of glucose during and after a marathon and may protect hypoglycemic or hyperglycemic periods in future races.

Runners during Houston International Women's Year

General note: Title and date provided by Bettye Lane.

A Computer Model of Drafting Effects on Collective Behavior in Elite 10,000 m Runners

Purpose Drafting in cycling influences collective behaviour of pelotons. Whilst evidence for collective behaviour in competitive running events exists, it is not clear if this results from energetic savings conferred by drafting. This study modelled the effects of drafting on behavior in elite 10,000 m runners. Methods Using performance data from a men’s elite 10,000 m track running event, computer simulations were constructed using Netlogo 5.1 to test the effects of three different drafting quantities on collective behaviour: no drafting, drafting to 3m behind with up to ~8% energy savings (a realistic running draft); and drafting up to 3m behind with up to 38% energy savings (a realistic cycling draft). Three measures of collective behaviour were analysed in each condition; mean speed, mean group stretch (distance between first and last placed runner), and Runner Convergence Ratio (RCR) which represents the degree of drafting benefit obtained by the follower in a pair of coupled runners. Results Mean speeds were 6.32±0.28m.s-1, 5.57±0.18 m.s-1, and 5.51±0.13 m.s-1 in the cycling draft, runner draft, and no draft conditions respectively (all P<0.001). RCR was lower in the cycling draft condition, but did not differ between the other two. Mean stretch did not differ between conditions. Conclusions Collective behaviours observed in running events cannot be fully explained through energetic savings conferred by realistic drafting benefits. They may therefore result from other, possibly psychological, processes. The benefits or otherwise of engaging in such behavior are, as yet, unclear.

Extreme sports as a facilitator of ecocentricity and positive life changes

Extreme sports and extreme sports participants have been most commonly explored from a negative perspective, for example the 'need to take unnecessary risks'. This study reports on findings that indicate a more positive experience. A phenomenological method was used via unstructured interviews with 15 extreme sports participants and other first hand accounts. The extreme sports included B.A.S.E. jumping, big wave surfing, extreme skiing, waterfall kayaking, extreme mountaineering and solo rope-free climbing. Results indicate that participating in activities that involve a real chance of death, fear and the realisation that nature in its extreme is far greater and more powerful than humanity triggers positive life changes, and an eco-centric standpoint.

Extreme Sports: A positive transformation in courage and humility

Extreme sports and extreme sports participants have been most commonly explored from a negative perspective, for example the “need to take unnecessary risks.” This study explored what can be learned from extreme sports about courage and humility - two positive psychology constructs. A phenomenological method was used via unstructured interviews with 15 extreme sports participants and other first hand accounts. The extreme sports included B.A.S.E. jumping, big wave surfing, extreme skiing, waterfall kayaking, extreme mountaineering and solo rope-free climbing. Results indicate that humility and courage can be deliberately sought out by participating in activities that involve a real chance of death, fear and the realisation that nature in its extreme is far greater and more powerful than humanity.