Everton Crivoi do Carmo

Effects of Aerobic Exercise Training on Cardiac Renin-Angiotensin System in an Obese Zucker Rat Strain

Objective Obesity and renin angiotensin system (RAS) hyperactivity are profoundly involved in cardiovascular diseases, however aerobic exercise training (EXT) can prevent obesity and cardiac RAS activation. The study hypothesis was to investigate whether obesity and its association with EXT alter the systemic and cardiac RAS components in an obese Zucker rat strain. Methods The rats were divided into the following groups: Lean Zucker rats (LZR); lean Zucker rats plus EXT (LZR+EXT); obese Zucker rats (OZR) and obese Zucker rats plus EXT (OZR+EXT). EXT consisted of 10 weeks of 60-min swimming sessions, 5 days/week. At the end of the training protocol heart rate (HR), systolic blood pressure (SBP), cardiac hypertrophy (CH) and function, local and systemic components of RAS were evaluated. Also, systemic glucose, triglycerides, total cholesterol and its LDL and HDL fractions were measured. Results The resting HR decreased (∼12%) for both LZR+EXT and OZR+EXT. However, only the LZR+EXT reached significance (p<0.05), while a tendency was found for OZR versus OZR+EXT (p = 0.07). In addition, exercise reduced (57%) triglycerides and (61%) LDL in the OZR+EXT. The systemic angiotensin I-converting enzyme (ACE) activity did not differ regardless of obesity and EXT, however, the OZR and OZR+EXT showed (66%) and (42%), respectively, less angiotensin II (Ang II) plasma concentration when compared with LZR. Furthermore, the results showed that EXT in the OZR prevented increase in CH, cardiac ACE activity, Ang II and AT2 receptor caused by obesity. In addition, exercise augmented cardiac ACE2 in both training groups. Conclusion Despite the unchanged ACE and lower systemic Ang II levels in obesity, the cardiac RAS was increased in OZR and EXT in obese Zucker rats reduced some of the cardiac RAS components and prevented obesity-related CH. These results show that EXT prevented the heart RAS hyperactivity and cardiac maladaptive morphological alterations in obese Zucker rats.

Anabolic steroid associated to physical training induces deleterious cardiac effects.

PURPOSE Cardiac aldosterone might be involved in the deleterious effects of nandrolone decanoate (ND) on the heart. Therefore, we investigated the involvement of cardiac aldosterone, by the pharmacological block of AT1 or mineralocorticoid receptors, on cardiac hypertrophy and fibrosis. METHODS Male Wistar rats were randomized into eight groups (n = 14 per group): Control (C), nandrolone decanoate (ND), trained (T), trained ND (TND), ND + losartan (ND + L), trained ND + losartan (TND + L), ND + spironolactone (ND + S), and trained ND + spironolactone (TND + S). ND (10 mg·kg(-1)·wk(-1)) was administered during 10 wk of swimming training (five times per week). Losartan (20 mg·kg(-1)·d(-1)) and spironolactone (10 mg·kg(-1)·d(-1)) were administered in drinking water. RESULTS Cardiac hypertrophy was increased 10% by using ND and 17% by ND plus training (P < 0.05). In both groups, there was an increase in the collagen volumetric fraction (CVF) and cardiac collagen type III expression (P < 0.05). The ND treatment increased left ventricle-angiotensin-converting enzyme I activity, AT1 receptor expression, aldosterone synthase (CYP11B2), and 11-β hydroxysteroid dehydrogenase 2 (11β-HSD2) gene expression and inflammatory markers, TGFβ and osteopontin. Both losartan and spironolactone inhibited the increase of CVF and collagen type III. In addition, both treatments inhibited the increase in left ventricle-angiotensin-converting enzyme I activity, CYP11B2, 11β-HSD2, TGFβ, and osteopontin induced by the ND treatment. CONCLUSIONS We believe this is the first study to show the effects of ND on cardiac aldosterone. Our results suggest that these effects may be associated to TGFβ and osteopontin. Thus, we conclude that the cardiac aldosterone has an important role on the deleterious effects on the heart induced by ND.

Acute Effect of High-Intensity Aerobic Exercise Performed on Treadmill and Cycle Ergometer on Strength Performance

Abstract Panissa VLG, Tricoli VAA, Julio UF, Ribeiro N, de Azevedo Neto RM, Carmo EC, and Franchini E. Acute effect of high-intensity aerobic exercise performed on treadmill and cycle ergometer on strength performance. J Strength Cond Res 29(4): 1077–1082, 2015—Concurrent training (i.e., combination of endurance with strength training) may result in negative interference on strength performance. Moreover, there are indications that the magnitude of this interference is dependent on endurance exercise mode. Thus, this study aimed to verify the acute effects of previous running and cycling on strength endurance performance. After the determination of the maximum intensity reached (Imax) during treadmill running and cycle ergometer pedaling and half-squat maximum strength (1 repetition maximum [1RM]), 10 physically active men were submitted to 3 experimental conditions: control condition (S) comprised of 4 sets of maximum repetitions at 80% 1RM, intermittent running (RS), and cycling (CS) conditions (15 × 1 minute:1 minute in the Imax) followed by the strength exercise (S). Maximum number of repetitions (MNR), total session volume (TV), and vastus lateralis electromyographic signal (VLRMS) were analyzed. It was observed that MNR and TV performed in set 1 in the S condition was superior to that performed in set 1 in the RS (p < 0.001) and CS (p < 0.001) conditions; and set 2 in the S condition was superior to set 2 only in the CS for the MNR (p = 0.032) and TV (p = 0.012). For the VLRMS, there was a main effect for repetition, with higher values in the last repetition compared with the second one (p < 0.01). In conclusion, an aerobic exercise bout before strength exercise impairs the subsequent strength endurance performance. In addition, the magnitude of the interference effect was higher after the aerobic cycling exercise.

The Influence of Collective Behavior on Pacing in Endurance Competitions

A number of theoretical models have been proposed in recent years to explain pacing strategies observed in individual competitive endurance events. These have typically related to the internal regulatory processes that inform the making of decisions relating to muscular work rate. Despite a substantial body of research which has investigated the influence of collective group dynamics on individual behaviors in various animal species, this issue has not been comprehensively studied in individual athletic events. This is somewhat surprising given that athletes often directly compete in close proximity to one another, and that collective behavior has also been observed in other human environments including pedestrian interactions and financial market trading. Whilst the reasons for adopting collective behavior are not fully understood, collective behavior is thought to result from individual agents following simple local rules that result in seemingly complex large systems that act to confer some biological advantage to the collective as a whole. Although such collective behaviors may generally be beneficial, competitive endurance events are complicated by the fact that increasing levels of physiological disruption as activity progresses may compromise the ability of some individuals to continue to interact with other group members. This could result in early fatigue and relative underperformance due to suboptimal utilization of physiological resources by some athletes. Alternatively, engagement with a collective behavior may benefit all due to a reduction in the complexity of decisions to be made and a subsequent reduction in cognitive loading and mental fatigue. This paper seeks evidence for collective behavior in previously published analyses of pacing behavior and proposes mechanisms through which it could potentially be either beneficial, or detrimental to individual performance. It concludes with suggestions for future research to enhance understanding of this phenomenon.

A associação de esteroide anabolizante ao treinamento físico aeróbio leva a alterações morfológicas cardíacas e perda de função ventricular em ratos

INTRODUCAO: O esteroide anabolizante (EA) associado ao treinamento fisico induz mudanca da hipertrofia cardiaca (HC) fisiologica para patologica. Entretanto, esses trabalhos foram realizados com atletas de forca, sendo os efeitos do EA associados ao treinamento aerobio poucos conhecidos. Com isso, o objetivo do estudo foi avaliar os efeitos do treinamento aerobio e dos EA sobre a estrutura e funcao cardiaca. METODOS: Foram utilizados 28 ratos Wistar divididos em quatro grupos: sedentarios controle (SC), sedentarios anabolizante (SA), treinados controle (TC) e treinado anabolizante (TA). O EA foi administrado duas vezes por semana (10mg/kg/ semana). O treinamento fisico de natacao foi realizado durante 10 semanas, cinco sessoes semanais. Foram avaliadas a pressao arterial e frequencia cardiaca por pletismografia de cauda, funcao ventricular por ecocardiografia, diâmetro dos cardiomiocitos e fracao volume de colageno por metodos histologicos. RESULTADOS: Nao foram observadas diferencas na PA. O grupo TC apresentou reducao da frequencia cardiaca de repouso apos o periodo experimental, o que nao ocorreu no grupo TA. Foram observadas HC de 38% no grupo SA, 52% no grupo TC e de 64% no grupo TA em relacao ao grupo SC. O grupo TA apresentou diminuicao da funcao diastolica em relacao aos outros grupos. Os grupos treinados apresentaram aumentos significantes no diâmetro dos cardiomiocitos. Os grupos SA e TA apresentaram aumento na fracao volume de colageno em relacao aos grupos SC e TC. CONCLUSAO: Os resultados apresentados mostram que o treinamento fisico de natacao induz a HC, principalmente pelo aumento do colageno intersticial, o que pode levar a prejuizos da funcao diastolica.

Risco de fadiga prematura, percepção subjetiva de esforço e estratégia de prova durante uma corrida de 10 km

O objetivo do estudo foi verificar as modificacoes na estrategia de prova frente as alteracoes do risco de fadiga prematura e da percepcao subjetiva de esforco (PSE) em corredores durante uma corrida de 10 km. Participaram do estudo 55 corredores com tempo nos 10 km de 41:39 ± 3:52 min:s. A estrategia de prova e a PSE foram avaliadas a cada quilometro. O risco de fadiga prematura foi determinado pelo produto entre a PSE e a distância restante de prova e a estrategia de prova foi determinada pela curva da velocidade e distância. A ANOVA de um caminho para medidas repetidas foi utilizada para determinar as diferencas na velocidade, PSE e risco de fadiga a cada quilometro e entre a velocidade a cada quilometro e a velocidade media da prova. O coeficiente de correlacao de Pearson foi calculado entre a PSE e o risco de fadiga prematura com a velocidade. A velocidade do primeiro quilometro foi 8,1% maior do que a media (p ≤ 0,001). A velocidade diminuiu gradualmente ao longo da prova, ocorrendo um novo aumento no decimo quilometro. A PSE aumentou linearmente ao longo da prova e o risco de fadiga diminuiu significantemente apos o terceiro quilometro. Houve forte correlacao negativa entre a PSE e a velocidade desenvolvida durante a prova (r = -0,80; p = 0,006). Foi observada uma correlacao moderada negativa entre o risco de fadiga prematura e a velocidade (r = -0,57; p = 0,04). Com isso, os achados do presente estudo sugerem que a PSE parece ter importante papel sobre os ajustes da velocidade ao longo da prova, sendo que o aumento da velocidade observado no ultimo quilometro pode estar associado ao baixo risco de fadiga prematura.

O papel do esteroide anabolizante sobre a hipertrofia e força muscular em treinamentos de resistência aeróbia e de força

INTRODUCAO: Os efeitos dos esteroides anabolizantes (EA) sobre a massa muscular e forca sao controversos e dependentes do treinamento realizado e das fibras musculares recrutadas. Com isso, o objetivo deste estudo foi avaliar os efeitos da associacao de EA ao treinamento de forca ou aerobio sobre a hipertrofia e forca muscular. METODOS: Ratos Wistar (42) foram divididos em seis grupos: sedentario (SC, n = 7), sedentario anabolizante (SA, n = 7), treinado natacao controle (TNC, n = 7), treinado natacao anabolizante (TNA, n = 7), treinado forca controle (TFC, n = 7) e treinado forca anabolizante (TFA, n = 7). O EA foi administrado duas vezes por semana (10mg/kg/semana). Os protocolos de treinamento foram realizados durante 10 semanas, cinco sessoes semanais. Foram avaliadas a hipertrofia dos musculos soleo, plantar e gastrocnemio (massa muscular corrigida pelo comprimento da tibia), a proteina total muscular (Bradford) e a forca muscular em patas traseiras (testes de resistencia a inclinacao). RESULTADOS: Nao foram observadas diferencas significantes na hipertrofia do musculo soleo. Os grupos TFC e TFA apresentaram, respectivamente, hipertrofia de 18% e 31% no musculo plantar comparado ao grupo SC. A hipertrofia foi 13% maior no grupo TFA em relacao ao grupo TFC. Resultados semelhantes foram encontrados no musculo gastrocnemio. Os grupos TFC e TFA apresentaram significantes aumentos na quantidade total de proteina nos musculos plantares, sendo essa mais pronunciada no grupo TFA e positivamente correlaciona a hipertrofia muscular. Observamos aumento de forca nas patas traseiras nos grupos TCF e TAF. CONCLUSAO: A administracao de EA ou sua associacao ao treinamento aerobio nao aumenta a massa muscular e forca. Porem, a associacao ao treinamento de forca leva a maior hipertrofia muscular em fibras glicoliticas. Portanto, o tipo de treinamento fisico, recrutamento muscular e caracteristicas das fibras musculares, parecem ter importante impacto sobre as respostas anabolicas induzidas pelo EA

Effects of resisted sprint training on sprinting ability and change of direction speed in professional soccer players

ABSTRACT Resisted sprint training consists of performing overloaded sprints, which may produce greater effects than traditional sprint training. We compared a resisted sprint training with overload control versus an unresisted sprint training program on performance in soccer players. Eighteen elite athletes were randomly assigned to resisted (RST) or unresisted sprint training protocol (UR). Before and after a 6-week training period, sprinting ability, change of direction speed (COD), vertical jumps (SJ and CMJ), mean power (MP) and mean propulsive power (MPP) at distinct loads were assessed. Both groups improved sprinting ability at all distances evaluated (5m: UR = 8%, RST = 7%; 10m: UR = 5%, RST = 5%; 15m: UR = 4%, RST = 4%; 20m: UR = 3%, RST = 3%; 25m: UR = 2%, RST = 3%;), COD (UR = 6%; RST = 6%), SJ (UR = 15%; RST = 13%) and CMJ (UR = 15%; RST = 15%). Additionally, both groups increased MP and MPP at all loads evaluated. The between-group magnitude-based inference analysis demonstrated comparable improvement (“trivial” effect) in all variables tested. Finally, our findings support the effectiveness of a short-term training program involving squat jump exercise plus sprinting exercises to improve the performance of soccer players.

Previous participation in FIFA World-Cup: the key to success?

This qualitative-descriptive investigation examining the influence exerted by experienced soccer-players on the ranking obtained from the four best-ranked by their teams in the last four FIFA World Cups (WC). They were divided into experienced-players (at least one WC participation [+1WC]) or non-experienced players (no previous participation [1WC]). Thereafter, they were classified according to their contribution in each of the playoff matches in a given WC: STARTER (started all matches); START/SUBST (started at least one match); SUBST/BENCH (did not start any matches, but replaced a player in at least one match); and BENCH (did not participate in matches). The sample was composed of 33.7% experienced and 66.3% non-experienced players. The number of players +1WC in finalist teams was significantly higher than in the non-finalist teams (p<0.05). In addition, when compared with the non-finalist teams, the finalists presented significantly higher number of players STARTER with +1WC (p<0.05). Possibly, the selection of experienced players to participate in WC may be an effective strategy to achieve better competitive performance.

O treinamento físico aeróbio corrige a rarefação capilar e as alterações nas proporções dos tipos de fibra muscular esquelética em ratos espontaneamente hipertensos

Aerobic exercise training (ET) has been established as an important non-pharmacological treatment of hypertension, since it decreases blood pressure. Studies show that the skeletal muscle abnormalities in hypertension are directly associated with capillary rarefaction, higher percentage of fast-twitch fibers (type II) with glycolytic metabolism predominance and increased muscular fatigue. However, little is known about these parameters in hypertension induced by ET. We hypothesized that ET corrects capillary rarefaction, potentially contributing to the restoration of the proportion of muscle fiber types and metabolic proprieties. Twelve-week old Spontaneously Hypertensive Rats (SHR, n=14) and Wistar Kyoto rats (WKY, n=14) were randomly assigned into 4 groups: SHR, trained SHR (SHR-T), WKY and trained WKY (WKY-T). As expected, ten weeks of ET was effective in reducing blood pressure in SHR-T group. In addition, we analyzed the main markers of ET. Resting bradycardia, increase of exercise tolerance, peak oxygen uptake and citrate synthase enzyme activity in trained groups (WKY-T and SHR-T) showed that the aerobic condition was achieved. ET also corrected the skeletal muscle capillary rarefaction in SHR-T. In parallel, we observed reduction in percentage of type IIA and IIX fibers and simultaneous augmented percentage of type I fibers induced by ET in hypertension. These data suggest that ET prevented changes in soleus fiber type composition in SHR, since angiogenesis and oxidative enzyme activity increased are important adaptations of ET, acting in the maintenance of muscle oxidative metabolism and fiber profile.