Acute ischemic preconditioning does not influence high-intensity intermittent exercise performance

This study evaluated the acute effect of ischemic preconditioning (IPC) on a high-intensity intermittent exercise performance and physiological indicators in amateur soccer players. Thirteen players (21.5 ± 2 yrs) attended three trials separated by 3–5 days in a counterbalanced randomized cross-over design: IPC (4 × 5-min occlusion 220 mmHg/reperfusion 0 mmHg) in each thigh; SHAM (similar to the IPC protocol but “occlusion” at 20 mmHg) and control (seated during the same time of IPC). After 6-min of each trial (IPC, SHAM or control), the players performed the YoYo Intermittent Endurance Test level 2 (YoYoIE2). The distance covered in the YoYoIE2 (IPC 867 ± 205 m; SHAM 873 ± 212 m; control 921 ± 206 m) was not different among trials (p = 0.10), furthermore, lactate concentration and rate of perceived exertion did not differ (P > 0.05) among protocols. There were also no significant differences in either mean heart rate (HR) or peak HR (p > 0.05) for both IPC and SHAM compared to control. Therefore, we conclude that acute IPC does not influence high-intensity intermittent exercise performance in amateur soccer players and that rate of perceived exertion, heart rate and lactate do not differ between the intervention IPC, SHAM and control

Estudos de caso, realmente são?

Este estudo tem o objetivo de verificar se os artigos publicados no Congresso USP de Controladoria e Contabilidade, no período de 2004 a 2010, apresentam as características necessárias para enquadramento do artigo como estudo de caso. A amostra foi composta por todos os artigos publicados no período de 2004 a 2010 no Congresso USP de Controladoria e Contabilidade. Para buscar evidências foi realizada uma análise de conteúdo dos artigos, assim como a estatística descritiva dos dados e estatística inferêncial com uso do Teste t de Student e do modelo regressivo Log-linear. Os resultados demonstraram que a nota média do nível de enquadramento dos artigos às características necessárias para classificação como estudo de caso é de 1,8 pontos, dentro do total de 4 pontos. Foi encontrada diferença significativa na média de pontos dos artigos que apresentam protocolo para os demais, concluindo-se que quando há o protocolo em um estudo de caso, tem-se maior probabilidade deste estudo ser mais robusto metodologicamente. Constatou-se ainda, através da regressão log-log entre a média de pontos (variável explicada) e o passar dos anos (variável explicativa), uma pequena evolução no nível de enquadramento metodológico. Desse modo, conclui-se que apesar do aumento da preocupação metodológica com os estudos de caso por meio da publicação de artigos críticos sobre as elaborações de trabalhos já realizados, as características necessárias ainda não estão sendo supridas para estes artigos serem classificados como estudo de caso.

Análise da correlação entre o protocolo Polar Fitness Test® para predição de VO2máx e ergoespirometria

Introduction: The importance of maximal oxygen consumption ( O 2max ) measurement is justified by its inter - national acceptance as the best physiological parameter to assess the functional capacity of the cardiorespiratory system in both athletes and non-athletes who physically train in order to achieve better health. Objective: To deter - mine the agreement between the Polar Fitness Test ® protocols to estimate of O 2max and the maximal exercise test with direct gas measurement. Methods: Seventeen active males (22.5 ± 2 years) participated in the study. At rest, the Polar Fitness Test ® protocol by direct gas collection under maximum effort on treadmill and the Bruce protocol were applied. Results: Significant difference in the O 2max estimation was observed between methods. The Polar Fitness Test ® protocol underestimated O 2max a mean of 15% (CI 95% : 24;-53%) when compared to the direct protocol. The values obtained by the Polar Fitness Test ® did not correlate well with direct measurement in ergospirometer (r = 0.1). Conclusion: The Polar Fitness Test ® protocol is not valid to estimate O 2max in physically active young men.INTRODUÇÃO: A importância da mensuração do consumo máximo de oxigênio (O2máx)é justificada por sua aceitação internacional como o melhor parâmetro fisiológico para avaliar a capacidade funcional do sistema cardiorrespiratório tanto em atletas como em não atletas que treinam fisicamente com objetivo de obter melhor saúde. OBJETIVO: Verificar a concordância entre os protocolos Polar Fitness Test® para a estimativa do O2máx e o teste de esforço máximo com medida direta de gases. MÉTODOS: Dezessete homens ativos (22,5 ± dois anos) participaram. Em repouso, aplicou-se o protocolo Polar Fitness Test® e, em seguida, a coleta direta de gases sob o esforço máximo, em esteira, seguindo o protocolo de Bruce. RESULTADOS: Houve diferença significativa entre os valores médios dos métodos para estimativa do O2máx. O protocolo Polar Fitness Test® subestimou o O2máx, em média 15% (IC95%: 24; –53%) comparado com a medida direta de gases. Os valores obtidos pelo Polar Fitness Test® não tiveram boa correlação com a medida direta em ergoespirômetro (r = 0,1). CONCLUSÃO: O protocolo Polar Fitness Test® não é válido para a estimativa do O2máx em homens jovens ativos fisicamente

Low appendicular muscle mass is correlated with femoral neck bone mineral density loss in postmenopausal women

<p>Abstract</p> <p>Background</p> <p>After menopause, rapid bone mass loss occurs in response to hypoestrogenism. Several studies suggest that muscle mass and bone mineral density (BMD) are positively associated in postmenopausal women. Therefore, it may be assumed that postmenopausal low appendicular muscle mass (aMM) can increase BMD loss in a short period of time.</p> <p>Objective</p> <p>The purpose of this study was to assess relationship of aMM with femoral neck BMD in postmenopausal women.</p> <p>Methods</p> <p>Prospective, controlled clinical Trial including 64 women aged 45-70 years, who had not had their last menstruation for at least one year. Subjects were divided into two groups: low aMM (n = 32), and normal aMM (n-32). Femoral neck BMD and muscle mass were measured by DXA at baseline and after twelve months. Pairwise and independent t tests were used for data analysis.</p> <p>Results</p> <p>Baseline weight, BMI and muscle mass (total and appendicular) significantly differ between groups (p < 0.05). After twelve months, femoral neck BMD was significantly lower in the group with low aMM, whereas no significant difference was observed in the group with normal aMM (p < 0.05).</p> <p>Conclusion</p> <p>In postmenopausal women, low appendicular muscle mass is associated negatively with femoral neck BMD in a short period of time.</p

Exercise Training Attenuates Sympathetic Activity and Improves Morphometry of Splenic Arterioles in Spontaneously Hipertensive Rats

Background: Alterations in the structure of resistance vessels contribute to elevated systemic vascular resistance in hypertension and are linked to sympathetic hyperactivity and related lesions in target organs. Objective: To assess the effects of exercise training on hemodynamic and autonomic parameters, as well as splenic arteriolar damages in male Wistar Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR). Methods: Normotensive sedentary (WKYS) and trained (WKYT) rats, and hypertensive sedentary (SHRS) and trained (SHRT) rats were included in this study. After 9 weeks of experimental protocol (swimming training or sedentary control), arterial pressure (AP) and heart rate (HR) were recorded in freely moving rats. We assessed the autonomic control of the heart by sympathetic and vagal autonomic blockade. Morphometric analyses of arterioles were performed in spleen tissues. The statistical significance level was set at p < 0.05. Results: Resting bradycardia was observed in both trained groups (WKYT: 328.0 +/- 7.3 bpmSHRT: 337.0 +/- 5.2 bpm) compared with their respective sedentary groups (WKYS: 353.2 +/- 8.5 bpmSHRS: 412.1 +/- 10.4 bpmp < 0.001). Exercise training attenuated mean AP only in SHRT (125.9 +/- 6.2 mmHg) vs. SHRS (182.5 +/- 4.2 mmHg, p < 0.001). The WKYT showed a higher vagal effect (Delta HR: 79.0 +/- 2.3 bpm) compared with WKYS (Delta HR: 67.4 +/- 1.7 bpmp < 0.05). Chronic exercise decreased sympathetic effects on SHRT (Delta HR: -62.8 +/- 2.8 bpm) in comparison with SHRS (Delta HR: -99.8 +/- 9.2 bpmp = 0.005). The wall thickness of splenic arterioles in SHR was reduced by training (332.1 +/- 16.0 mu m(2) in SHRT vs. 502.7 +/- 36.3 mu m(2) in SHRSp < 0.05). Conclusions: Exercise training attenuates sympathetic activity and AP in SHR, which may be contributing to the morphological improvement of the splenic arterioles.Fundamento: Alterações na estrutura dos vasos de resistência contribuem para elevar a resistência vascular sistêmica na hipertensão, estando ligadas à hiperatividade simpática e lesões em órgãos-alvo. Objetivo: Avaliar os efeitos do treinamento físico nos parâmetros hemodinâmicos e autônomos, assim como as lesões arteriolares esplênica em ratos machos Wistar Kyoto (WKY) e espontaneamente hipertensos (SHR). Métodos: Ratos normotensos sedentários (WKYS) e treinados (WKYT), e ratos hipertensos sedentários (SHRS) e treinados (SHRT) foram incluídos neste estudo. Após nove semanas de aplicação do protocolo experimental (treinamento de natação ou controle sedentário), registraram-se a pressão arterial (PA) e a frequência cardíaca (FC) dos ratos em movimento livre. Avaliamos o controle autônomo do coração através de bloqueio autônomo simpático e vagal. Análises morfométricas das arteríolas esplênicas foram realizadas. Adotou-se o nível de significado estatístico de p < 0,05. Resultados: Observou-se bradicardia de repouso nos dois grupos treinados (WKYT: 328,0 ± 7,3 bpm; SHRT: 337,0 ± 5,2 bpm) em comparação aos seus respectivos grupos sedentários (WKYS: 353,2 ± 8,5 bpm; SHRS: 412,1 ± 10,4 bpm; p < 0,001). O treinamento físico atenuou a PA média apenas no grupo SHRT (125,9 ± 6,2 mmHg vs. 182,5 ± 4,2 mmHg no SHRS; p < 0,001). O grupo WKYT mostrou maior efeito vagal (∆FC: 79,0 ± 2,3 bpm) em comparação ao grupo WKYS (∆FC: 67,4 ± 1,7 bpm; p < 0,05). Exercício crônico diminuiu os efeitos simpáticos em SHRT (∆FC: -62.8 ± 2.8 bpm) em comparação a SHRS (∆FC: -99,8 ± 9,2 bpm; p = 0,005). A espessura da parede das arteríolas esplênicas nos SHR foi reduzida pelo treinamento (332,1 ± 16,0 µm2 nos SHRT vs. 502,7 ± 36,3 µm2 nos SHRS; p < 0,05). Conclusões: O treinamento físico atenua a atividade simpática e a PA em SHR, o que pode contribuir para melhorar a morfologia das arteríolas esplênicas.CapesCNPqFapemigUniv Fed Triangulo Mineiro UFTM, Uberaba, MG, BrazilUniv Fed Juiz de Fora UFJF, Juiz De Fora, MG, BrazilUniv Fed Sao Paulo, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Sao Paulo, SP, BrazilWeb of Scienc

Intradialytic aerobic training improves inflammatory markers in patients with chronic kidney disease: a randomized clinical trial

Abstract Aims: To investigate the effect of 12 weeks of intradialytic aerobic training on serum levels of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor alpha and functional capacity. Methods: Thirty sedentary volunteers were randomly assigned to either to exercise or control group. Exercise group were submitted to 12 weeks of aerobic training performed on a cycle ergometer for 30 minutes at intensity rated using the Borg scale (6 to 7) three times a week while control group kept the daily habits. Results: After 12 weeks only exercise group presented a significant reduction of serum levels of interleukin-1β, interleukin-6, interleukin-8, tumor necrosis factor alpha and an increase in serum levels of interleukin-10 and functional capacity. Conclusion: Twelve weeks of intradialytic aerobic training was effective in controlling inflammation and improving the functional ability of patients with chronic kidney disease

Exercise Training Attenuates Sympathetic Activity and Improves Morphometry of Splenic Arterioles in Spontaneously Hipertensive Rats

Abstract Background: Alterations in the structure of resistance vessels contribute to elevated systemic vascular resistance in hypertension and are linked to sympathetic hyperactivity and related lesions in target organs. Objective: To assess the effects of exercise training on hemodynamic and autonomic parameters, as well as splenic arteriolar damages in male Wistar Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR). Methods: Normotensive sedentary (WKYS) and trained (WKYT) rats, and hypertensive sedentary (SHRS) and trained (SHRT) rats were included in this study. After 9 weeks of experimental protocol (swimming training or sedentary control), arterial pressure (AP) and heart rate (HR) were recorded in freely moving rats. We assessed the autonomic control of the heart by sympathetic and vagal autonomic blockade. Morphometric analyses of arterioles were performed in spleen tissues. The statistical significance level was set at p < 0.05. Results: Resting bradycardia was observed in both trained groups (WKYT: 328.0 ± 7.3 bpm; SHRT: 337.0 ± 5.2 bpm) compared with their respective sedentary groups (WKYS: 353.2 ± 8.5 bpm; SHRS: 412.1 ± 10.4 bpm; p < 0.001). Exercise training attenuated mean AP only in SHRT (125.9 ± 6.2 mmHg) vs. SHRS (182.5 ± 4.2 mmHg, p < 0.001). The WKYT showed a higher vagal effect (∆HR: 79.0 ± 2.3 bpm) compared with WKYS (∆HR: 67.4 ± 1.7 bpm; p < 0.05). Chronic exercise decreased sympathetic effects on SHRT (∆HR: -62.8 ± 2.8 bpm) in comparison with SHRS (∆HR: -99.8 ± 9.2 bpm; p = 0.005). The wall thickness of splenic arterioles in SHR was reduced by training (332.1 ± 16.0 µm2 in SHRT vs. 502.7 ± 36.3 µm2 in SHRS; p < 0.05). Conclusions: Exercise training attenuates sympathetic activity and AP in SHR, which may be contributing to the morphological improvement of the splenic arterioles

Effects of Mind–Body Exercises (Tai Chi/Yoga) on Heart Rate Variability Parameters and Perceived Stress: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

Background: Heart rate variability (HRV) as an accurate, noninvasive measure of the Autonomous Nervous System (ANS) can reflect mental health (e.g., stress, depression, or anxiety). Tai Chi and Yoga (Tai Chi/Yoga), as the most widely practiced mind&#8315;body exercises, have shown positive outcomes of mental health. To date, no systematic review regarding the long-lasting effects of Tai Chi/Yoga on HRV parameters and perceived stress has been conducted. Objective: To critically evaluate the existing literature on this topic. Methods: Five electronic databases (Web of Science, PubMed, Scopus, SportDiscus and Cochrane Library) were searched from the start of the research project to July 2018. Study selection, data extraction, and study quality assessment were independently carried out by two reviewers. The potentially identified randomized controlled trials (RCT) reported the useful quantitative data that were included only for meta-analysis. Results: meta-analysis of 17 medium-to-high quality RCTs showed significantly beneficial effects on HRV parameters (normalized low-frequency, Hedge&#8217;s g = &#8722;0.39, 95% CI &#8722;0.39 to &#8722;0.56, p &lt; 0.001, I2 = 11.62%; normalized high-frequency, Hedge&#8217;s g = 0.37, 95% CI 0.22 to &#8722;0.52, p &lt; 0.001, I2 = 0%; low-frequency to high-frequency ratio, Hedge&#8217;s g = &#8722;0.58, 95% CI &#8722;0.81 to &#8722;0.35, p &lt; 0.001, I2 = 53.78%) and stress level (Hedge&#8217;s g = &#8722;0.80, 95% CI &#8722;1.17 to &#8722;0.44, p &lt; 0.001, I2 = 68.54%). Conclusions: Stress reduction may be attributed to sympathetic-vagal balance modulated by mind&#8315;body exercises. Tai Chi/Yoga could be an alternative method for stress reduction for people who live under high stress or negative emotions