Body Composition and Aerobic Performance Changes After 8 Weeks of Exposure to Normobaric Intermittent Hypoxia / Cambios en la Composición Corporal y el Rendimiento Aeróbico Después de 8 Semanas de Exposición a Hipoxia Normobárica Intermitente

SUMMARY: To take advantage of altitude, "intermittent hypoxia" methods have been developed that involve shorter exposures to hypoxia. In general, systemic hypoxia can be produced in two ways: (1) by lowering barometric pressure (BP, hypobaric hypoxia) or (2) by reducing the amount of oxygen in inspired air (FiO2) through oxygen filtration or nitrogen dilution (normobaric hypoxia). The objective of this analysis was to observe changes in body composition and aerobic performance after 8 weeks of intermittent hypoxia exposure at rest. A total of 20 male volunteers between the ages of 18-26 participated in the study. Participants were randomly divided into 2 groups (Control Group and Intermittent Hypoxia Group). The Intermittent Hypoxia Group completed the process by being exposed to intermittent hypoxia for 8 weeks. Each intermittent hypoxia session was planned as 3 days a week and for 1 hour. After 8 weeks of experimental process, statistically significant differences were found for lean mass, android lean mass, gynoid lean mass, the relative skeletal muscle mass index, peak lactate, 1mmol lactate threshold, 4mmol lactate threshold, and MaxVo2 variables (p<0,05). After 8 weeks of intermittent hypoxia exposure, an increase in maximal oxygen consumption capacity was observed. The increase in lean mass, especially in the gynoid and android regions, can be explained by the increase in fat burning activities due to oxygen utilization capacity. Almost every study reviewed in the literature used different intermittent hypoxia exposure protocols and different simulated altitudes. The method discussed in this study may be beneficial on the body composition and oxygen utilization capacity of sedentary individuals.

Para aprovechar la altitud, se han desarrollado métodos de «hipoxia intermitente» que implican exposiciones más cortas a la hipoxia. En general, la hipoxia sistémica se puede producir de dos maneras: (1) reduciendo la presión barométrica (PA, hipoxia hipobárica) o (2) reduciendo la cantidad de oxígeno en el aire inspirado (FiO2) mediante filtración de oxígeno o dilución de nitrógeno (hipoxia normobárica). El objetivo de este análisis fue observar cambios en la composición corporal y el rendimiento aeróbico después de 8 semanas de exposición intermitente a hipoxia en reposo. Participaron en el estudio un total de 20 voluntarios varones de entre 18 y 26 años. Los participantes se dividieron aleatoriamente en 2 grupos (grupo control y grupo hipoxia intermitente). El grupo de hipoxia intermitente completó el proceso al estar expuesto a hipoxia intermitente durante 8 semanas. Cada sesión de hipoxia intermitente se planificó 3 días a la semana y durante 1 hora. Después de 8 semanas de proceso experimental, se encontraron diferencias estadísticamente significativas para la masa magra, la masa magra androide, la masa magra ginoide, el índice de masa muscular esquelético relativo, el pico de lactato, el umbral de lactato de 1 mmol, el umbral de lactato de 4 mmol y las variables MaxVo2 (p< 0,05). Después de 8 semanas de exposición intermitente a hipoxia, se observó un aumento en la capacidad máxima de consumo de oxígeno. El aumento de la masa magra, especialmente en las regiones ginoidea y androide, puede explicarse por el aumento de las actividades de quema de grasa debido a la capacidad de utilización de oxígeno. Casi todos los estudios revisados en la literatura utilizaron diferentes protocolos de exposición intermitente a la hipoxia y diferentes altitudes simuladas. El método analizado en este estudio puede ser beneficioso para la composición corporal y la capacidad de utilización de oxígeno de personas sedentarias.

Associação entre prática de atividade física e aptidão cardiorrespiratória em adolescentes / Association between physical activity practice and physical fitness in school adolescents

O objetivo do estudo foi verificar a associação entre diferentes volumes de atividade física moderada e/ou vigorosa durante o lazer e a aptidão cardiorrespiratória (ACR) adequada em adolescentes de ambos os sexos. A atividade física moderada (AFM), vigorosa (AFV ) ou moderada-vigorosa (AFMV) de lazer foi avaliada por meio de questionário e a ACR foi medida com o teste de vai-e-vem de 20m. Foram utilizados modelos de Regressão Poisson para análises. As AFM, AFV ou AFMV no lazer foram categorizadas de acordo com três limiares de atividade física no lazer (150, 300 e 420 min/sem). Foram consideras para as análises de associação as AFM, AFV e AFMV, de acordo com o compêndio de atividade físicas para adolescentes. A prática de AFMV no lazer por pelo menos 420 min/sem obteve a maior probabilidade de ACR adequada (RP = 2,03; IC95%: 1,18 ­ 3,51). Na mesma direção, a prática de AFV por pelo menos 150 min/sem também foi estatisticamente significativa (RP = 1,72; IC95%: 1,07 ­ 2,80). Os resultados indicaram uma associação positiva entre prática de atividade física no lazer e ACR, independentemente da intensidade e limiar de tempo, enfatizando que a participação em ambas as intensidades de atividade física no lazer estão associadas aos níveis adequados de aptidão cardiorrespiratória.

The aim of this study was to verify the association between different volumes of moderate and/or vigor-ous physical activity during leisure time and adequate cardiorespiratory fitness in adolescents of both sexes. Leisure-time moderate and/or vigorous physical activity (MPA, VPA, and MVPA) was assessed by means of a questionnaire and cardiorespiratory fitness was measured with the 20m back-and-forth test. Poisson regression models were used for analyses where moderate and/or vigorous physical activity in leisure time, it was categorized according to three thresholds of leisure-time physical activity (150, 300 and 420 min/week). The following factors were considered for the association analyses: MPA, VFA, and MVPA, according to the compendium of physical activity for adolescents. Leisure time MVPA for at least 420 min/week had the highest probability of adequate cardiorespiratory fitness (PR = 2.03; 95%CI: 1.18 ­ 3.51). In the same direction, the practice of VFA for at least 150 min/week was also statistically significant (PR = 1.72; 95%CI: 1.07 ­ 2.80). The results indicated a positive association between leisure time physical activity and cardiorespiratory fitness, regardless of intensity and time threshold, emphasizing that participation in both modalities of leisure time physical activity can provide substantial benefits for cardiorespiratory fitness.

Moderate-intensity continuous training reduces triglyceridemia and improves oxygen consumption in dyslipidemic apoCIII transgenic mice

This study aimed to investigate metabolism modulation and dyslipidemia in genetic dyslipidemic mice through physical exercise. Thirty-four male C57Bl/6 mice aged 15 months were divided into non-transgenic (NTG) and transgenic overexpressing apoCIII (CIII) groups. After treadmill adaptation, the trained groups (NTG Ex and CIII Ex) underwent an effort test to determine running performance and assess oxygen consumption (V̇O2), before and after the training protocol. The exercised groups went through an 8-week moderate-intensity continuous training (MICT) program, consisting of 40 min of treadmill running at 60% of the peak velocity achieved in the test, three times per week. At the end of the training, animals were euthanized, and tissue samples were collected for ex vivo analysis. ApoCIII overexpression led to hypertriglyceridemia (P<0.0001) and higher concentrations of total plasma cholesterol (P<0.05), low-density lipoprotein (LDL) cholesterol (P<0.01), and very low-density lipoprotein (VLDL) cholesterol (P<0.0001) in the animals. Furthermore, the transgenic mice exhibited increased adipose mass (P<0.05) and higher V̇O2peak compared to their NTG controls (P<0.0001). Following the exercise protocol, MICT decreased triglyceridemia and cholesterol levels in dyslipidemic animals (P<0.05), and reduced adipocyte size (P<0.05), increased muscular glycogen (P<0.001), and improved V̇O2 in all trained animals (P<0.0001). These findings contribute to our understanding of the effects of moderate and continuous exercise training, a feasible non-pharmacological intervention, on the metabolic profile of genetically dyslipidemic subjects.

The bioprotective role of irradiated hibiscus against harmful effects of using repeatedly frying edible oil / O papel bioprotetor do hibisco irradiado contra os efeitos nocivos do uso de óleo comestível para fritar

Abstract Repeatedly frying process of dietary edible oil has a potential role in the generation of free radicals. Therefore, questions have always been raised as to whether, there is an efficient and economical method to reduce the harmful effects of repeated use of frying edible oil. Since hibiscus has been stated to have a wide variety of therapeutic effects, it was important to investigate its properties against harmful effects of free radicals. The current study aspires to find out whether irradiated powder of hibiscus has a protective role against adverse effects of repeated use of frying edible oil. Thirty-five adult male albino rats were equally assigned into five groups. First group"G1" was fed with normal diet as control group, meanwhile, group"G2" the diet mixed with fresh oil, "G3" diet mixed with repeatedly frying oil only, "G4" diet mixed with frying oil treated with hibiscus and "G5" diet mixed with frying oil treated with irradiated hibiscus. Feeding duration was six weeks. Fatty acid analyses of oil as well as peroxide values were determined. Blood and liver samples were collected for biochemical analyses as well as histological study. Repeatedly heated cooked oil has significant increases in peroxide value, acid value, free fatty acid and both conjugated diene and triene compared with repeatedly frying oil treated with hibiscus. Also there are significant increases in cholesterol and triglyceride and impaired in liver functions in "G3"compared with others. In addition, relative to the hibiscus groups, there is a substantial reduction in oxygen consumption in "G3". Both hibiscus as well as irradiated hibiscus attract attention in order to play a vital and economical role against harmful effects of frequent use of frying edible oil on some biological functions but, irradiated hibiscus was more effective.

Resumo O processo de fritura repetida de óleo comestível da dieta tem papel potencial na geração de radicais livres que podem ter efeitos prejudiciais em algumas funções biológicas. Portanto, sempre se questionou se existe uma maneira eficiente e econômica de prevenir ou pelo menos reduzir os efeitos nocivos do uso repetido de óleo comestível para fritar. Como o hibisco tem ampla variedade de efeitos terapêuticos, foi importante investigar suas propriedades como agente antioxidante contra os efeitos nocivos dos radicais livres. O presente estudo pretende descobrir se o pó irradiado de hibisco tem papel protetor contra os efeitos adversos do uso repetido de óleo comestível para fritar. Trinta e cinco ratos albinos machos adultos foram divididos igualmente em cinco grupos. O primeiro grupo "G1" foi alimentado com dieta normal como grupo controle, enquanto o grupo "G2" dieta misturada com óleo fresco, dieta "G3" misturada com óleo de fritura repetida, dieta "G4" misturada com óleo de fritura tratada com hibisco e dieta "G5" misturada com óleo de fritura tratada com hibisco irradiado. A duração da alimentação foi de seis semanas. Foram determinadas as análises de ácidos graxos de óleo, bem como os valores de peróxidos. Amostras de sangue e fígado foram coletadas para análises bioquímicas e estudo histológico. O óleo cozido repetidamente aquecido tem aumentos significativos no valor de peróxido, valor de ácido, ácido graxo livre e dieno e trieno conjugados em comparação com óleo de fritura repetidamente tratado com hibisco. Também há aumentos significativos no colesterol e triglicérides e comprometimento das funções hepáticas no "G3" em comparação com outros. Além disso, em relação aos grupos de hibiscos, há uma redução substancial no consumo de oxigênio no "G3". Tanto o hibisco como o hibisco irradiado chamam atenção por desempenhar papel vital e econômico contra os efeitos nocivos do uso frequente de óleo comestível para fritar em algumas funções biológicas, mas o hibisco irradiado foi mais eficaz.

The bioprotective role of irradiated hibiscus against harmful effects of using repeatedly frying edible oil

Abstract Repeatedly frying process of dietary edible oil has a potential role in the generation of free radicals. Therefore, questions have always been raised as to whether, there is an efficient and economical method to reduce the harmful effects of repeated use of frying edible oil. Since hibiscus has been stated to have a wide variety of therapeutic effects, it was important to investigate its properties against harmful effects of free radicals. The current study aspires to find out whether irradiated powder of hibiscus has a protective role against adverse effects of repeated use of frying edible oil. Thirty-five adult male albino rats were equally assigned into five groups. First groupG1 was fed with normal diet as control group, meanwhile, groupG2 the diet mixed with fresh oil, G3 diet mixed with repeatedly frying oil only, G4 diet mixed with frying oil treated with hibiscus and G5 diet mixed with frying oil treated with irradiated hibiscus. Feeding duration was six weeks. Fatty acid analyses of oil as well as peroxide values were determined. Blood and liver samples were collected for biochemical analyses as well as histological study. Repeatedly heated cooked oil has significant increases in peroxide value, acid value, free fatty acid and both conjugated diene and triene compared with repeatedly frying oil treated with hibiscus. Also there are significant increases in cholesterol and triglyceride and impaired in liver functions in G3compared with others. In addition, relative to the hibiscus groups, there is a substantial reduction in oxygen consumption in G3. Both hibiscus as well as irradiated hibiscus attract attention in order to play a vital and economical role against harmful effects of frequent use of frying edible oil on some biological functions but, irradiated hibiscus was more effective.

Resumo O processo de fritura repetida de óleo comestível da dieta tem papel potencial na geração de radicais livres que podem ter efeitos prejudiciais em algumas funções biológicas. Portanto, sempre se questionou se existe uma maneira eficiente e econômica de prevenir ou pelo menos reduzir os efeitos nocivos do uso repetido de óleo comestível para fritar. Como o hibisco tem ampla variedade de efeitos terapêuticos, foi importante investigar suas propriedades como agente antioxidante contra os efeitos nocivos dos radicais livres. O presente estudo pretende descobrir se o pó irradiado de hibisco tem papel protetor contra os efeitos adversos do uso repetido de óleo comestível para fritar. Trinta e cinco ratos albinos machos adultos foram divididos igualmente em cinco grupos. O primeiro grupo G1 foi alimentado com dieta normal como grupo controle, enquanto o grupo G2 dieta misturada com óleo fresco, dieta G3 misturada com óleo de fritura repetida, dieta G4 misturada com óleo de fritura tratada com hibisco e dieta G5 misturada com óleo de fritura tratada com hibisco irradiado. A duração da alimentação foi de seis semanas. Foram determinadas as análises de ácidos graxos de óleo, bem como os valores de peróxidos. Amostras de sangue e fígado foram coletadas para análises bioquímicas e estudo histológico. O óleo cozido repetidamente aquecido tem aumentos significativos no valor de peróxido, valor de ácido, ácido graxo livre e dieno e trieno conjugados em comparação com óleo de fritura repetidamente tratado com hibisco. Também há aumentos significativos no colesterol e triglicérides e comprometimento das funções hepáticas no G3 em comparação com outros. Além disso, em relação aos grupos de hibiscos, há uma redução substancial no consumo de oxigênio no G3. Tanto o hibisco como o hibisco irradiado chamam atenção por desempenhar papel vital e econômico contra os efeitos nocivos do uso frequente de óleo comestível para fritar em algumas funções biológicas, mas o hibisco irradiado foi mais eficaz.

Valores cardiorrespiratorios de árbitros de fútbol profesional de Pichincha

Introducción: La capacidad de resistencia física es uno de los indicadores del rendimiento profesional en el fútbol, no estando exceptos los profesionales del arbitraje, los cuales requieren entrenamientos especializados en función de sus aptitudes físicas; por lo cual, es útil conocer sus desempeños. Objetivo: determinar los parámetros reales de aptitud cardiorrespiratoria al esfuerzo máximo progresivo, de árbitros de fútbol de Pichincha. Métodos: se estudia a 25 árbitros hombres seleccionados intencionalmente, de la asociación de árbitros de fútbol profesional de Pichincha. Luego de un reconocimiento de salud previo, de realizó una prueba de esfuerzo progresivo sobre una banda sinfín, con un lector de consumo de oxígeno. Los árbitros tienen una experiencia media de 11 años, entrenan 3-4 días a la semana, y arbitran partidos oficiales 1-2 veces por semana. Resultados: el valor medio global de consumo máximo de oxígeno (VO2máx.) relativo de los árbitros evaluados en el presente estudio es: (= 52.00 ml·kg-1·min-1, similar al obtenido en otros estudios internacionales sobre la valoración de la capacidad física en árbitros, que describen unos valores relativos de vo2máx de 46-51 ml·kg-1·min-1 para hombres. Conclusiones: las competencias profesionales del arbitraje ecuatoriano son similares en la capacidad de resistencia que sus homólogos extranjeros. Se sugiere una implementación de contenidos del entrenamiento basados en mejorar la aptitud cardiorrespiratoria en el arbitraje, así como su control sistemático.

Introduction: Physical endurance capacity is one of the indicators of professional performance in soccer, not excepting referee professionals, who require specialized training based on their physical capabilities; Therefore, it is useful to know their performances. Objective: Determine the real parameters of cardiorespiratory fitness at maximum progressive effort, of soccer referees from Pichincha. Methods: 25 male referees intentionally selected from the Pichincha professional soccer referee association are studied. After a previous health examination, a progressive stress test was performed on a treadmill, with an oxygen consumption reader. Referees have an average experience of 11 years, train 3-4 days a week, and referee official matches 1-2 times a week. Results: The overall average value of relative maximum oxygen consumption (VO2max) of the referees evaluated in the present study is: (= 52.00 ml·kg-1·min-1, similar to that obtained in other international studies on the capacity physics assessment in referees, who describe relative vo2max values of 46-51 ml·kg-1·min-1 for men. Conclusions: the professional skills of Ecuadorian arbitration are similar in resistance capacity to their foreign counterparts. An implementation of training content based on improving cardiorespiratory fitness in refereeing, as well as its systematic control, is suggested.

Predição do Consumo de Oxigênio de Pico em Pacientes Cardiopatas com Base no Desempenho no Teste Timed Up and Go / Prediction of Peak Oxygen Consumption in Patients with Heart Disease Based on Performance on the Timed Up and Go Test

Resumo Fundamento A utilização do teste timed up and go (TUG) na avaliação da aptidão cardiorrespiratória em cardiopatas não está bem definida na literatura. Objetivos Testar a associação entre o TUG e o consumo de oxigênio de pico (VO2pico), construir uma equação com base no TUG para prever o VO2pico e determinar um ponto de corte para estimar um VO2pico ≥ 20 mL.kg−1.min−1. Métodos Estudo transversal com 201 indivíduos portadores de doença arterial coronariana ou insuficiência cardíaca, com idade entre 36 e 92 anos, submetidos ao TUG e ao teste cardiopulmonar de exercício. Foram realizadas análises de correlação, curva ROC, regressão linear múltipla e Bland-Altman. Um p < 0,05 foi adotado como significante. Resultados A média de idade da amostra total foi 67 ± 13 anos, e 70% dos participantes eram do sexo masculino. A média de VO2pico foi de 17 ± 6 mL.kg−1.min−1 e a média de desempenho no TUG foi de 7 ± 2,5 segundos. A correlação entre o VO2pico e o TUG foi r = −0,54 (p < 0,001) e R2 de 0,30. Foi desenvolvida a equação com base no TUG: V O 2 pico = 33 , 553 + ( − 0 , 149 ∗ idade ) + ( − 0 , 738 ∗ T U G ) + ( − 2 , 870 ∗ sexo ); sendo atribuído o valor 0 ao sexo masculino e 1 ao sexo feminino (R ajustado: 0,41; R2 ajustado: 0,40). O VO2pico estimado pela equação foi 18,81 ± 3,2 mL.kg−1.min−1 e o determinado pelo teste cardiopulmonar de exercício foi 18,18 ± 5,9 mL.kg−1.min−1 (p > 0,05). O melhor ponto de corte para o VO2pico ≥ 20 mL.kg−1.min−1 foi de ≤ 5,47 segundos (área sob a curva: 0,80; intervalo de confiança de 95%: 0,74 a 0,86). Conclusões O TUG e o VO2pico apresentaram associação significativa. A equação preditiva do VO2pico foi desenvolvida e validada internamente com bom desempenho. O ponto de corte no TUG para prever um VO2pico ≥ 20 mL.kg−1.min−1 foi ≤ 5,47 segundos.

Abstract Background The use of the timed up and go (TUG) test to assess cardiorespiratory fitness in patients with heart disease has not been well defined in the literature. Objectives Test the association between TUG and peak oxygen consumption (VO2peak), construct an equation based on TUG to predict VO2peak, and determine a cutoff point to estimate VO2peak ≥ 20 mL/kg/min. Methods This cross-sectional study included 201 patients with coronary artery disease or heart failure, between 36 and 92 years of age, who underwent TUG and cardiopulmonary exercise test. Correlation, ROC curve, multiple linear regression, and Bland-Altman analyses were performed. The significance level was set at p < 0.05. Results The mean age of the total sample was 67 ± 13 years, and 70% of participants were male. The mean VO2peak was 17 ± 6 mL/kg/min, and the mean TUG time was 7 ± 2.5 seconds. The correlation between VO2peak and TUG was r = −0.54 (p < 0.001), and R2 was 0.30. The following equation was developed based on TUG: V O 2 peak = 33.553 + ( − 0.149 × age ) + ( − 0.738 × TUG ) + ( − 2.870 × sex ); a value of 0 was assigned to the male sex and 1 to the female sex (adjusted R: 0.41; adjusted R2: 0.40). The VO2peak estimated by the equation was 18.81 ± 3.2 mL/kg/min, and the VO2peak determined by cardiopulmonary exercise test was 18.18 ± 5.9 mL/kg/min (p > 0.05). The best cutoff point in the TUG for VO2peak ≥ 20 mL/kg/min was ≤ 5.47 seconds (area under the curve: 0.80; 95% confidence interval: 0.74 to 0.86). Conclusions TUG and VO2peak showed a significant association. A prediction equation for VO2peak was developed and validated internally with good performance. The cutoff point in the TUG to predict VO2peak ≥ 20 mL/kg/min was ≤ 5.47 seconds.

Lack of change in the respiratory quotient during oxygen supply dependence in endotoxemic shock: a subanalysis of an experimental controlled study / Ausência de alteração no quociente respiratório durante a dependência do suprimento de oxigênio no choque endotoxêmico: subanálise de um estudo experimental controlado

ABSTRACT Objective: To evaluate if the reductions in systemic and renal oxygen consumption are associated with the development of evidence of anaerobic metabolism. Methods: This is a subanalysis of a previously published study. In anesthetized and mechanically ventilated sheep, we measured the respiratory quotient by indirect calorimetry and its systemic, renal, and intestinal surrogates (the ratios of the venous-arterial carbon dioxide pressure and content difference to the arterial-venous oxygen content difference. The Endotoxemic Shock Group (n = 12) was measured at baseline, after 60 minutes of endotoxemic shock, and after 60 and 120 minutes of fluid and norepinephrine resuscitation, and the values were compared with those of a Control Group (n = 12) without interventions. Results: Endotoxemic shock decreased systemic and renal oxygen consumption (6.3 [5.6 - 6.6] versus 7.4 [6.3 - 8.5] mL/minute/kg and 3.7 [3.3 - 4.5] versus 5.4 [4.6 - 9.4] mL/minute/100g; p < 0.05 for both). After 120 minutes of resuscitation, systemic oxygen consumption was normalized, but renal oxygen consumption remained decreased (6.3 [5.9 - 8.2] versus 7.1 [6.1 - 8.6] mL/minute/100g; p = not significance and 3.8 [1.9 - 4.8] versus 5.7 [4.5 - 7.1]; p < 0.05). The respiratory quotient and the systemic, renal and intestinal ratios of the venous-arterial carbon dioxide pressure and content difference to the arterial-venous oxygen content difference did not change throughout the experiments. Conclusion: In this experimental model of septic shock, oxygen supply dependence was not associated with increases in the respiratory quotient or its surrogates. Putative explanations for these findings are the absence of anaerobic metabolism or the poor sensitivity of these variables in detecting this condition.

RESUMO Objetivo: Avaliar se as reduções do consumo de oxigênio sistêmico e renal estão associadas ao desenvolvimento de evidências de metabolismo anaeróbico. Métodos: Esta é uma subanálise de estudo já publicado. Em ovinos anestesiados e ventilados mecanicamente, medimos o quociente respiratório por calorimetria indireta e seus substitutos sistêmicos, renais e intestinais (as razões entre a diferença de pressão venoarterial do teor de dióxido de carbono e a diferença arteriovenosa do teor de oxigênio). O Grupo Choque Endotoxêmico (n = 12) foi medido inicialmente, após 60 minutos do choque endotoxêmico e após 60 e 120 minutos da ressuscitação com fluidos e norepinefrina, e os valores foram comparados com os do Grupo Controle (n = 12) sem intervenções. Resultados: O choque endotoxêmico diminuiu o consumo de oxigênio sistêmico e renal (6,3 [5,6 - 6,6] versus 7,4 [6,3 - 8,5] mL/minuto/kg e 3,7 [3,3 - 4,5] versus 5,4 [4,6 - 9,4] mL/minuto/100g; p < 0,05 para ambos). Após 120 minutos de ressuscitação, o consumo sistêmico de oxigênio foi normalizado, mas o consumo renal de oxigênio permaneceu reduzido (6,3 [5,9 - 8,2] versus 7,1 [6,1 - 8,6] mL/minuto/100g; p = NS e 3,8 [1,9 - 4,8] versus 5,7 [4,5 - 7,1]; p < 0,05). O quociente respiratório e as razões sistêmica, renal e intestinal entre a diferença na pressão venoarterial do teor de dióxido de carbono e a diferença arteriovenosa do teor de oxigênio não se alteraram ao longo dos experimentos. Conclusão: Nesse modelo experimental de choque séptico, a dependência do suprimento de oxigênio não foi associada a aumentos no quociente respiratório ou em seus substitutos. As explicações possíveis para esses achados são a ausência de metabolismo anaeróbico ou a baixa sensibilidade dessas variáveis na detecção dessa condição.

Factors Associated with Low Back Pain in Coffee Pickers from Chinchiná and Palestina (Colombia)

Objective. The objective of the study was to determine the prevalence of low back pain and associated risk factors among coffee pickers. Methods. The participants completed a survey and underwent tests to determine flexibility and V̇O2max. Results. Among 98 coffee pickers with an average age of 44.7 (±13.7), 58.2% had experienced low back pain. The average duration and intensity of low back pain in the patients were 6.0 ± 6.5 years and 47.1 ± 21.0 mm/100 mm respectively. The average values of body fat and V̇O2max were 13.2 ± 2.8% y 32.5 ± 8.6 ml.kg-1.min-1 respectively. Regression analysis showed that for a higher V̇O2max value decreased the probability of experiencing low back pain, while a higher body fat content increased the probability of suffering from low back pain. Conclusions. There is a high prevalence of low back pain among coffee pickers from Chinchiná and Palestina. Higher body fat content increases the likelihood of experiencing lumbar pain, while elevated levels of V̇O2max decrease it.

Objetivo. El estudio tuvo como objetivo determinar la prevalencia del dolor lumbar y los factores de riesgo asociados entre los recolectores de café. Métodos. Los participantes respondieron a una encuesta y se sometieron a pruebas para determinar la flexibilidad y el V̇O2max. Resultados. Entre 98 recolectores de café de 44,7 años (±13,7), el 58,2% había experimentado dolor lumbar. La duración e intensidad promedio del dolor lumbar en los pacientes fue de 6,0 ± 6,5 años y 47,1 ± 21,0 mm/100 mm, respectivamente. Los valores promedio de grasa corporal y V̇O2max fueron 13.2 ± 2.8% y 32.5 ± 8.6 ml.kg-1.min-1 respectivamente. El análisis de regresión demostró que para un valor alto de V̇O2max la probabilidad de padecer dolor lumbar es menor mientras que para un valor alto de contenido de grasa corporal la probabilidad de sufrir dolor lumbar es mayor. Conclusiones. Existe una alta prevalencia de dolor lumbar entre los recolectores de café de Chinchiná y Palestina. Un mayor contenido de grasa corporal incrementa la probabilidad de padecer lumbalgia, mientras que niveles elevados de V̇O2max la disminuye.

Objetivo. O estudo teve como objetivo determinar a prevalência da dor lombar e fatores de risco associados entre os catadores de café. Métodos. Os participantes responderam a uma enquete e foram submetidos a testes para determinar flexibilidade e V̇O2max. Resultados. Entre 98 catadores de café com 44,7 anos (±13,7), 58,2% apresentavam dor lombar. A duração média e intensidade da dor lombar nos pacientes foi de 6,0 ± 6,5 anos e 47,1 ± 21,0 mm/100 mm, respectivamente. Os valores médios de gordura corporal e V̇O2max foram 13,2 ± 2,8% e 32,5 ± 8,6 ml.kg-1.min-1 respectivamente. A análise de regressão amostrou que para um alto valor de V̇O2max a probabilidade de sofrer lombalgia é menor enquanto que para um alto índice de gordura corporal a probabilidade de sofrer lombalgia é maior. Conclusões. Tem uma alta prevalência da dor lombar entre os catadores de café de Chinchiná e Palestina. Um valor mais alto de V̇O2max diminui a probabilidade de sofrer lombalgia, enquanto um valor alto de gordura corporal a aumenta.

La prueba cardiopulmonar de ejercicio contribuye a determinar con precisión el riesgo en pacientes con hipertensión pulmonar de bajo riesgo / Cardiopulmonary Exercise Testing Contributes to Accurate Risk Assessment in Patients with Low-risk Pulmonary Hypertension

RESUMEN Introducción : Las guías europeas de hipertensión arterial pulmonar (HAP) estratifican el riesgo valiéndose de características clínicas y estudios complementarios entre los cuales está la prueba cardiopulmonar de ejercicio (PCPE), de la cual toma en cuenta 3 parámetros: el consumo de O2 (VO2) pico, su porcentaje respecto del predicho y la pendiente ventilación minuto/ producción de dióxido de carbono (VE/VCO2). Sin embargo, ninguno de los modelos que validaron esta forma de estratificar el riesgo incluyeron la PCPE entre sus variables. Objetivos : Determinar qué proporción de pacientes con HAP del grupo I considerados de bajo riesgo y que caminan >440 metros en la prueba de caminata de 6 minutos (PC6M) tienen en la PCPE parámetros considerados de riesgo moderado o alto. Material y métodos : Se incluyeron pacientes >18 años con diagnóstico de HAP del grupo I considerados de bajo riesgo con una PC6M >400 metros a los que se les realizó una PCPE en la que se registró el VO2 pico, su porcentaje respecto del VO2 predicho y la pendiente VE/VCO2. Se determinó qué proporción de pacientes presentaban estos parámetros en un estrato de riesgo mayor a bajo riesgo (VO2 pico <15 ml/kg/min, su porcentaje respecto del predicho <65% y la pendiente VE/VCO2 >36). Resultados : Se incluyeron 18 pacientes. A pesar de ser pacientes de bajo riesgo y con buena clase funcional todos presentaron un VO2 pico menor al 85% del predicho, lo cual determina un deterioro al menos leve de la capacidad funcional. Un único paciente (6%) presentó los tres parámetros evaluados en bajo riesgo, 8 pacientes (44%) tuvieron al menos un parámetro alterado, 7 pacientes (39%) presentaron 2 parámetros alterados y en 2 pacientes (11%) todos los parámetros estuvieron alterados. Los parámetros que más frecuentemente se vieron alterados fueron el porcentaje respecto del VO2 predicho y la pendiente VE/VCO2, en el 67% de los casos. Solo 4 pacientes presentaron un VO2 pico <15 ml/k/m. Ningún paciente presentó valores de VO2 pico o porcentaje respecto del predicho en la categoría de alto riesgo. Sin embargo, 6 pacientes (33%) presentaron una pendiente VE/VCO2 considerada de alto riesgo. Conclusión : El 94% de los pacientes considerados de bajo riesgo presentaron al menos una variable en la PCPE que no corresponde a un perfil de riesgo bajo. La pendiente VE/VCO2 y el porcentaje de VO2 pico respecto del predicho fueron las variables más frecuentemente alteradas. La pendiente VE/VCO2 fue la única que mostró valores considerados de alto riesgo. La PCPE podría tener un lugar en la estratificación de precisión de pacientes de bajo riesgo. El valor de este hallazgo deberá ser evaluado en estudios prospectivos, al tiempo que genera las bases para el planteo de hipótesis respecto de la estratificación de riesgo y la intensidad del tratamiento en pacientes que aparentan estar en bajo riesgo.

ABSTRACT Background : European guidelines for pulmonary arterial hypertension (PAH) stratify the risk using clinical characteristics and complementary studies, including the cardiopulmonary exercise test (CPET). This takes into account 3 parameters: peak O2 consumption (peak VO2), its percentage with respect to the predicted VO2, and the minute ventilation/carbon dioxide production (VE/VCO2) slope. However, none of the models that validated this way of stratifying risk included PCPE among their variables. Objectives : To determine what proportion of patients with group I PAH considered to be at low risk and who walk >440 meters in the 6-minute walk test (6MWT) have parameters considered to be of moderate or high risk in the PCPE. Methods : Patients >18 years of age, diagnosed with group I PAH at low risk of events, who walked >440 meters in the 6MWT and had NT-proBNP value <300 pg/dL were included. A CPET was performed in which the peak VO2, its percentage with respect to the predicted VO2, and the VE/VCO2 slope were recorded. It was determined what proportion of patients presented these parameters in a higher than low risk stratum (peak VO2 consumption ≤15 ml/min/Kg, its percentage with respect to the predicted VO2 ≤65% and the VE/VCO2 slope ≥36). Results : Eighteen patients were included. Despite being low-risk patients with a good functional class, all patients presented a peak VO2 less than 85% of predicted, which determines a deterioration of functional capacity. A single patient (6%) presented the three parameters evaluated at low risk, 8 patients (44%) had at least one altered parameter, 7 patients (39%) presented 2 altered parameters and in 2 patients (11%) all parameters were altered. The parameters that were most frequently altered were the percentage of predicted peak VO2 and the VE/VCO2 slope in 67% of the cases. Only 4 patients presented a peak VO2 <15 ml/kg/m. No patient presented peak VO2 values or percentage of predicted VO2 in the high-risk category. However, 6 patients (33%) presented a high-risk VE/VCO2 slope. Conclusion : Majority (92%) of the patients considered low risk and who walk more than 440 meters in 6 minutes presented at least one altered variable in the CPET. The VE/VCO2 slope and the percentage of predicted peak VO2 consumption were the most frequently altered variables. The VE/VCO2 slope was the only one that showed values considered high risk. CPET could have a place in the precision stratification of low-risk patients. The value of this finding should be evaluated in prospective studies.

Importancia del VO2máx y la capacidad de recuperación de los futbolistas

El consumo máximo de oxígeno se considera un indicador directamente relacionado con la resistencia aeróbica, por lo que dicha capacidad se hace determinante en el rendimiento del futbolista. Conocer los criterios teóricos nacionales que sustentaron la importancia del VO2máx en la capacidad de recuperación en el fútbol constituyó un paso previo hacia conformar estrategias prospectivas de intervención directa para la toma de decisiones. En tal sentido, se planteó como objetivo de la investigación determinar, por consulta de especialistas, los criterios existentes de la importancia del VO2máx en la capacidad de recuperación de los futbolistas. La investigación fue descriptiva-correlacional de orientación exploratoria; se encuestaron a 13 especialistas que emitieron criterios sobre cinco indicadores. La importancia de la resistencia aeróbica en el entrenamiento del fútbol obtuvo un puntaje de (X4.62) y en relación al resto de las capacidades físicas aplicadas al fútbol un (X3.23); la importancia del VO2máx en el proceso de dirección un (X4.46); la correlación entre VO2máx y la recuperación un (X4.54) y la necesidad de perfeccionar la resistencia aeróbica en el fútbol ecuatoriano un (X4). El índice de concordancia entre especialistas obtuvo un nivel aceptable (w=0.527). Todos los indicadores de análisis obtuvieron una cualificación entre alta y muy alta, por lo que la investigación resaltó la importancia teórica brindada por los especialistas sobre el consumo máximo de oxígeno como indicador directamente relacionado con la resistencia aeróbica y el vínculo entre este y la capacidad de recuperación de los futbolistas.

SÍNTESE O consumo máximo de oxigênio é considerado um indicador diretamente relacionado à resistência aeróbica, tornando esta capacidade um fator determinante no desempenho de um jogador de futebol. Conhecer os critérios teóricos nacionais que sustentavam a importância do VO2max na capacidade de recuperação no futebol foi um passo anterior para a formação de estratégias prospectivas de intervenção direta para a tomada de decisões. Neste sentido, o objetivo da pesquisa foi determinar, consultando especialistas, os critérios existentes sobre a importância do VO2max na capacidade de recuperação dos jogadores de futebol. A pesquisa foi descritivo-correlacional com uma orientação exploratória; 13 especialistas foram pesquisados e deram critérios sobre cinco indicadores. A importância da resistência aeróbica no treinamento de futebol obteve uma pontuação de (X4,62) e em relação ao resto das capacidades físicas aplicadas ao futebol a (X3,23); a importância do VO2max no processo de gerenciamento a (X4,46); a correlação entre VO2max e recuperação a (X4,54) e a necessidade de aperfeiçoar a resistência aeróbica no futebol equatoriano a (X4). O índice de concordância entre especialistas obteve um nível aceitável (w=0,527). Todos os indicadores de análise obtiveram uma qualificação entre alto e muito alto, portanto a pesquisa destacou a importância teórica dada pelos especialistas sobre o consumo máximo de oxigênio como um indicador diretamente relacionado à resistência aeróbica e a ligação entre esta e a capacidade de recuperação dos jogadores de futebol.

The maximum oxygen consumption is considered an indicator directly related to aerobic endurance, so this capacity becomes decisive in the performance of the soccer player. Knowing the national theoretical criteria that supported the importance of VO2max in the recovery capacity in soccer was a previous step towards shaping prospective strategies of direct intervention for decision making. In this sense, the objective of the research was to determine, by consulting specialists, the existing criteria of the importance of VO2max in the recovery capacity of soccer players. The research was descriptive-correlational with an exploratory orientation; 13 specialists were surveyed who issued criteria on five indicators. The importance of aerobic endurance in soccer training obtained a score of (X 4.62) and in relation to the rest of the physical capacities applied to soccer a (X3.23); the importance of VO2max in the direction process a X 4.46); the correlation between VO2max and recovery a (X 4.54) and the need to improve aerobic endurance in Ecuadorian soccer a (X 4). The concordance index between specialists obtained an acceptable level (w=0.527). All the analysis indicators obtained a qualification between high and very high, so the research highlighted the theoretical importance provided by specialists on maximum oxygen consumption as an indicator directly related to aerobic endurance and the link between this and the ability to recovery of footballers.

Determination of oxygen consumption in water by continuous flow injection analysis using potassium permanganate / 预防医学

Objective@#To establish a continuous flow injection analysis with potassium permanganate for determination of oxygen consumption in water.@*Methods@#The water samples and acid potassium permanganate working solutions were mixed using the continuous flow bubble spacing, and subjected to online heating reaction at 97 ℃. The peak height of the electrical signal of potassium permanganate was measured at the maximum absorption wavelength of 520 nm, and the standard substance, sulfuric acid concentration and potassium permanganate concentration were optimized according to the peak height of the electrical signal. The standard curve was plotted to measure the limit of detection, the limit of quantification, and spiked recovery rate of the method. The CODMn concentration was determined in 40 drinking water samples using acid potassium permanganate titration and continuous flow injection analysis using potassium permanganate, and the determination results of the two methods were compared with paired t-test.@*Results@#Glucose was selected as the standard substance, and the mixture of 17.5% sulfuric acid and 3.2 mmol/L potassium permanganate was selected as the working solution. CODMn had a good linear relationship at concentrations of 0 to 6.00 mg/L, with a correlation coefficient of 0.999 and higher, a detection limit of 0.013 mg/L and a quantitation limit of 0.043 mg/L, respectively. The spiked recovery rates were 90.00% to 105.00% in 40 drinking water samples, with relative standard deviations of 0.12% to 1.36%. The determination results of two permanganate index standard substances were all within the range of standard values. The relative errors of CODMn concentration were 1.55% to 9.26% between the continuous flow injection analysis using potassium permanganate and acid potassium permanganate titration, and there was no significant difference (t=2.023, P=0.185). @*Conclusion@#The established continuous flow injection analysis with potassium permanganate is feasible for batch determination of oxygen consumption in water.

The effect of high-intensity interval training on post-exercise oxygen consumption: a meta-analysis / Efecto del entrenamiento de intervalos de alta intensidad sobre el consumo de oxígeno después delejercicio: metaanálisis / Efeito do treinamento intervalado de alta intensidade sobre o consumo de oxigênio depois do exercício: metanálise

ABSTRACT Introduction: The objective of this study was to present a systematic review and meta-analysis to compare total excess post-exercise oxygen consumption (EPOC) for two training intervention models in healthy individuals, and the secondary objective was to understand whether oxygen consumption after exercise could really promote a meaningful help. Design: To design a meta-analysis review to compare two training intervention models (experimental: high-intensity interval training; and control: continuous moderate-intensity) and their effects on total EPOC in healthy individuals. Participants: Seventeen studies were considered to be of good methodological quality and with a low risk of bias. Methods: Literature searches were performed using the electronic databases with no restriction on year of publication. The keywords used were obtained by consulting Mesh Terms (PubMed) and DeCS (BIREME Health Science Descriptors). Results: The present study findings showed a tendency (random-effects model: 0.87, 95%-CI [0.35,1.38], I2=73%, p<0.01) to increase EPOC when measured following high-intensity interval training. Conclusions: Our study focused on the analysis of high- and moderate-intensity oxygen uptake results following exercise. Despite the growing popularity of high-intensity interval training, we found that the acute and chronic benefits remain limited. We understand that the lack of a standard protocol and standard training variables provides limited consensus to determine the magnitude of the EPOC. We suggest that longitudinal experimental studies may provide more robust conclusions. Another confounding factor in the studies investigated was the magnitude (time in minutes) of VO2 measurements when assessing EPOC. Measurement times ranged from 60 min to 720 min. Longitudinal studies and controlled experimental designs would facilitate more precise measurements and correct subject numbers would provide accurate effect sizes. Systematic reviewb of Level II studies.

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RESUMO Introdução: O objetivo deste estudo foi apresentar uma revisão sistemática e metanálise para comparar os efeitos de dois modelos de intervenção de treinamento sobre o consumo excessivo de oxigênio pós-exercício (EPOC) em indivíduos saudáveis em treinamento, e o objetivo secundário foi entender se o consumo de oxigênio depois de exercício realmente pode proporcionar ajuda substancial. Objetivo: Elaborar uma revisão de metanálise para comparar um modelo de treinamento de duas intervenções (experimental: treinamento intervalado de alta intensidade, e controle: contínuo de intensidade moderada) e o efeito sobre o EPOC total em indivíduos saudáveis. Participantes: Os 17 estudos foram considerados de boa qualidade metodológica e baixo risco de viés. Métodos: As buscas bibliográficas foram realizadas nos bancos de dados eletrônicos sem restrição de ano de publicação. Os descritores usados foram obtidos em MeSH (PubMed) e DeCS (Descritores em Ciências da Saúde da BIREME). Resultados: Os achados do presente estudo mostraram uma tendência (modelo de efeitos aleatórios: 0,87, IC 95% [0,35;1,38], I ² = 73%, p < 0,01) de aumento do EPOC quando as medidas foram realizadas depois de treinamento intervalado de alta intensidade. Conclusões: Nosso estudo concentrou-se na análise dos resultados de alta e moderada intensidade no consumo de oxigênio depois do exercício. Apesar da crescente popularidade do treinamento intervalado de alta intensidade, descobrimos que os benefícios agudos e crônicos permanecem limitados. Entendemos que a falta de um protocolo e variáveis padronizadas de treinamento fornecem consenso limitado para determinar a magnitude do EPOC. Sugerimos que estudos experimentais longitudinais podem fornecer conclusões mais robustas. Outro fator de confusão nos estudos investigados foi a magnitude (tempo em minutos) das medidas do VO2na avaliação do EPOC. Os tempos de medição variaram de 60 a 720 min. Estudos longitudinais e projetos experimentais controlados facilitariam medições mais precisas e números corretos de indivíduos forneceriam tamanhos de efeito precisos. Nível de evidência II; Revisão sistemáticabde Estudos.

The relationship between lower limb stiffness and running economy in child soccer players / La relación entre la rigidez de los miembros inferiores y la economía de carrera en jugadores de fútbol infantil / A relação entre rigidez dos membros inferiores e economia de corrida em jogadores de futebol infantil

ABSTRACT Introduction Lower limb stiffness has been shown to be associated with running economy (RE) in adults, but this relationship in children remains unclear. Objectives The purpose of this study was to investigate the relationship between lower limb stiffness, RE, and repeated-sprint ability in child soccer players. Methods Twenty-eight male child soccer players (mean age 11.8 ± 0.9 years) participated in the study. RE was determined by measuring the steady-state oxygen uptake (ml/min/kg) at submaximal running speeds of 8 and 9 km/h. Vertical and leg stiffness were calculated from the flight and contact time data obtained during two submaximal running tests. Additionally, vertical stiffness was measured during the maximal and submaximal hopping tests. All participants performed the repeated sprint test consisting of 10 × 20-m all-out sprints interspersed with 20-s active recovery. Results During both submaximal running tests, vertical (r= -0.505 to -0.472) and leg stiffness (r= -0.484 to -0.459) were significantly correlated with RE (p< 0.05). Maximal (r= -0.450) and submaximal hopping stiffness (r= -0.404) were significantly correlated with RE at 8 km/h (p< 0.05). Maximal hopping stiffness was significantly correlated with the best sprint time (r= -0.439) and mean sprint time (r= -0.496) (p< 0.05). Vertical (r= -0.592 to -0.433) and leg stiffness (r= -0.612 to -0.429) at 8 and 9 km/h and submaximal hopping stiffness (r= -0.394) were significantly correlated with the fatigue index (p< 0.05). Conclusions Current findings indicate that the lower limb stiffness may be an important determinant of both RE and repeated-sprint ability in child soccer players. Level of Evidence II; Diagnostic Studies - Investigating a Diagnostic Test.

RESUMEN Introducción Se ha demostrado que la rigidez de los miembros inferiores está relacionada con la economía de carrera (RE) en los adultos, sin embargo esta relación no es muy clara cuando se trata de niños. Objetivos El objetivo de este estudio fue investigar la relación entre la rigidez de los miembros inferiores, la RE y la capacidad de sprints repetidos en jugadores de fútbol infantil. Métodos Veintiocho jugadores de fútbol infantil de sexo masculino (edad media de 11,8 ± 0,9 años) participaron en el estudio. La determinación de la RE se produjo midiendo el consumo de oxígeno en estado estacionario (ml/min/kg) a velocidades de carrera submáximas de 8 km/h y 9 km/h. El cálculo de la rigidez vertical y de la rigidez de las piernas se basó en los datos de tiempo de vuelo y de contacto obtenidos durante dos tests submáximos de carrera. Además, se midió la rigidez vertical durante los tests submáximos y máximos de salto (hop test). Todos los participantes realizaron el test de sprints repetidos, que consistía en diez repeticiones de sprints a velocidad máxima de 20 m intercalados por una recuperación activa de 20 s. Resultados Durante ambos tests submáximos de carrera, la rigidez vertical (r= -0,505 a -0,472) y la rigidez de las piernas (r= -0,484 a -0,459) se correlacionaron significativamente con la RE (p<0,05). La rigidez de salto máximo (r= -0,450) y la rigidez de salto submáximo (r= -0,404) demostraron una correlación significativa con la RE a 8 km/h (p<0,05). La rigidez de salto máximo se asoció sustancialmente con un mejor tiempo de sprint (r= -0,439) y con el tiempo medio de sprint (r= -0,496) (p< 0,05). La rigidez vertical (r= -0,592 a -0,433), la rigidez de las piernas (r= -0,612 a -0,429) a 8 km/h y 9 km/h y la rigidez de salto submáximo (r= -0,394) se correlacionaron significativamente con el índice de fatiga (p< 0,05). Conclusiones Los hallazgos actuales indican que la rigidez de los miembros inferiores puede ser un determinante clave tanto de RE como de la capacidad de sprints repetidos en jugadores de fútbol infantil. Nivel de evidencia II: Estudios diagnósticos - Investigación de una prueba diagnóstica.

RESUMO Introdução A rigidez dos membros inferiores demonstrou estar associada à economia de corrida (RE) em adultos, porém essa relação não é muito clara quando se trata de crianças. Objetivos O objetivo deste estudo foi investigar a relação entre a rigidez dos membros inferiores, a RE e a capacidade de sprints repetidos em jogadores de futebol infantil. Métodos Vinte e oito jogadores do sexo masculino de futebol infantil (idade média de 11,8 ± 0,9 anos) participaram do estudo. A determinação da RE ocorreu por meio da medição do consumo de oxigênio em estado estacionário (ml/min/kg) a velocidades submáximas de corrida de 8 km/h e 9 km/h. O cálculo da rigidez vertical e da rigidez das pernas baseou-se nos dados de tempo de voo e tempo de contato obtidos durante dois testes submáximos de corrida. Além disso, mediu-se a rigidez vertical durante os testes máximo e submáximo de salto ( hop test ). Todos os participantes realizaram o teste de sprints repetidos que consistiu em dez repetições de sprints em velocidade máxima de 20 m intercalados por recuperação ativa de 20 s. Resultados Durante ambos os testes submáximos de corrida, a rigidez vertical (r= -0,505 a -0,472) e a rigidez das pernas (r= -0,484 a -0,459) estavam significativamente correlacionadas à RE (p<0,05). A rigidez de salto máximo (r= -0,450) e a de salto submáximo (r= -0,404) demonstraram uma correlação significativa com RE em 8 km/h (p<0,05). A rigidez de salto máximo estava associada, de forma substancial, ao melhor tempo de sprint (r= -0,439) e ao tempo médio de sprint (r= -0,496) (p< 0,05). A rigidez vertical (r= -0,592 a -0,433), a rigidez das pernas (r= -0,612 a -0,429) em 8 km/h e 9 km/h e a rigidez de salto submáximo (r= -0,394) estavam expressivamente correlacionadas ao índice de fadiga (p< 0,05). Conclusões Os achados atuais indicam que a rigidez dos membros inferiores pode ser um determinante fundamental tanto de RE quanto de capacidade de sprints repetidos em jogadores de futebol infantil. Nível de evidência II: Estudos diagnósticos - Investigando um teste diagnóstico.

Cholic and deoxycholic acids induce mitochondrial dysfunction, impaired biogenesis and autophagic flux in skeletal muscle cells

BACKGROUND: Skeletal muscle is sensitive to bile acids (BA) because it expresses the TGR5 receptor for BA. Cholic (CA) and deoxycholic (DCA) acids induce a sarcopenia-like phenotype through TGR5-dependent mechanisms. Besides, a mouse model of cholestasis-induced sarcopenia was characterised by increased levels of serum BA and muscle weakness, alterations that are dependent on TGR5 expression. Mitochondrial alterations, such as decreased mitochondrial potential and oxygen consumption rate (OCR), increased mitochondrial reactive oxygen species (mtROS) and unbalanced biogenesis and mitophagy, have not been studied in BA-induced sarcopenia.METHODS: We evaluated the effects of DCA and CA on mitochondrial alterations in C2C12 myotubes and a mouse model of cholestasis-induced sarcopenia. We measured mitochondrial mass by TOM20 levels and mitochondrial DNA; ultrastructural alterations by transmission electronic microscopy; mitochondrial biogenesis by PGC-1α plasmid reporter activity and protein levels by western blot analysis; mitophagy by the co-localisation of the MitoTracker and LysoTracker fluorescent probes; mitochondrial potential by detecting the TMRE probe signal; protein levels of OXPHOS complexes and LC3B by western blot analysis; OCR by Seahorse measures; and mtROS by MitoSOX probe signals. RESULTS: DCA and CA caused a reduction in mitochondrial mass and decreased mitochondrial biogenesis. Interestingly, DCA and CA increased LC3II/LC3I ratio and decreased autophagic flux concordant with raised mitophagosome-like structures. In addition, DCA and CA decreased mitochondrial potential and reduced protein levels in OXPHOS complexes I and II. The results also demonstrated that DCA and CA decreased basal, ATP-linked, FCCP-induced maximal respiration and spare OCR. DCA and CA also reduced the number of cristae. In addition, DCA and CA increased the mtROS. In mice with cholestasis-induced sarcopenia, TOM20, OXPHOS complexes I, II and III, and OCR were diminished. Interestingly, the OCR and OXPHOS complexes were correlated with muscle strength and bile acid levels. CONCLUSION: Our results showed that DCA and CA decreased mitochondrial mass, possibly by reducing mitochondrial biogenesis, which affects mitochondrial function, thereby altering potential OCR and mtROS generation. Some mitochondrial alterations were also observed in a mouse model of cholestasis-induced sarcopenia characterised by increased levels of BA, such as DCA and CA.

Effect of 12-week rehearsal on cardiorespiratory fitness and body composition in Brazilian samba dancers

ABSTRACT Objective To investigate the effect of 12 weeks of rehearsals on cardiorespiratory parameters and body composition in Brazilian samba dancers belonging to a first-league samba school. Methods Twenty-six women were divided into a Samba Group (n=13) and a Control Group (n=13). Cardiorespiratory parameters (cardiopulmonary exercise test) and body composition (skinfold assessment) were assessed before and after the 12 weeks of rehearsals. The Samba Group rehearsed three times per week for 30-60 minutes, and the Control Group participated in no physical activity. A comparison test was performed within and between groups, with p<0.05 indicating statistical significance. Results Compared with the Control Group, the Samba Group showed a significant increase in maximal oxygen uptake (19%), oxygen pulse (13%), and lean body mass (3%) and a decrease in body fat percentage (11%) and fat mass (12%). Conclusion Twelve weeks of samba dance rehearsals improved the cardiorespiratory and body composition parameters in women dancers compared with the Control Group. These findings suggest that dancing samba regularly can increase physical activity levels and positively affect the health parameters of samba dancers.

Physiological responses during walking in men and women with intermittent claudication

ABSTRACT Objective Peak oxygen consumption (VO2peak), anaerobic threshold, walking economy, and cardiovascular responses during walking are used to guide and monitor walking training in patients with peripheral artery disease and intermittent claudication. Women with peripheral artery disease and intermittent claudication present greater impairments than men, and evaluating training markers according to sex for decisions regarding walking prescription in this population is important. This study aimed to compare VO2peak, walking economy, anaerobic threshold, and cardiovascular responses during walking in men and women with peripheral artery disease and intermittent claudication. Methods Forty patients (20 men and 20 women with similar baseline characteristics) underwent a cardiopulmonary treadmill test (3.2km/h and 2% increase in slope every 2 minutes until maximal leg pain). The VO2 and rate-pressure product were assessed. Data from men and women were compared using t-tests. Results There were no significant differences between men and women (VO2peak: 15.0±4.8 versus 13.9±2.9mL∙kg-1∙min-1, p=0.38; walking economy: 9.6±2.7 versus 8.4±1.6mL∙kg-1∙min-1, p=0.09; anaerobic threshold: 10.5±3.2 versus 10.5±2.2mL∙kg-1∙min-1, p=0.98; rate pressure product at 1st stage: 13,465± 2,910 versus 14,445±4,379bpm∙mmHg, p=0.41; and rate pressure product at anaerobic threshold:13,673±3,100 versus 16,390±5,870bpm∙mmHg, p=0.08 and rate pressure product at peak exercise: 21,253±6,141 versus 21,923±7,414bpm∙mmHg, p=0.76, respectively). Conclusion Men and women with peripheral artery disease and similar baseline characteristics presented similar responses to walking, suggesting that decisions regarding walking prescription and monitoring can be made regardless of sex in this specific population.

Cambios enzimáticos durante el entrenamiento anaeróbico láctico y su influencia en la capacidad aeróbica / Enzymatic changes during lactic anaerobic training and their influence on aerobic capacity

Introducción: El entrenamiento deportivo es un proceso que requiere una planificación orientada a la adaptación del cuerpo a las cargas internas versus cargas externas; de allí, surge la necesidad de conocer el comportamiento de algunas enzimas musculoesqueléticas a través del control bioquímico y fisiológico del entrenamiento en el atletismo de medio fondo. Objetivo: Analizar los cambios enzimáticos de la creatinfosfoquinasa y la lactodeshidrogenasa durante el entrenamiento anaeróbico láctico y su influencia en la capacidad aeróbica en atletas de medio fondo. Método: Se utilizó el método descriptivo comparativo con una muestra de 20 sujetos aleatorizados en dos grupos: experimental y control; el análisis se realizó bajo el modelo estadístico Anova descriptiva, pruebas T y diseño de medidas repetidas con un intervalo del 95 por ciento de confianza (p<0,05). Resultados: En las variables creatinfosfoquinasa y lactodeshidrogenasa inicial y final no hubo variaciones significativas intergrupos; se observaron diferencias en la creatinfosfoquinasa en varianza (p=0,022) del orden del 97,8 por ciento; que en promedio (p=0,088) representó los niveles alcanzados del 91,2 por ciento. En las medidas repetidas no se presentaron cambios estadísticamente significativos intergrupos. Para la variable del VO2máx se aplicó la prueba T para comparar los estados inicial y final en cada grupo y hubo diferencias en ambos grupos (control p=0,002; experimental p=0,000). Conclusiones: No hubo cambios enzimáticos importantes durante los entrenamientos anaeróbico láctico y aeróbico, a su vez, el entrenamiento anaeróbico láctico si tuvo influencia en la capacidad aeróbica(AU)

Introduction: Sports training is a process that requires a planning oriented to the adaptation of the body to internal loads versus external loads; from there, arises the need to know the behavior of some musculoskeletal enzymes through the biochemical and physiological control of training in middle-distance athletics. Objective: To analyze the enzymatic changes of creatine phosphokinase and lactodehydrogenase during lactic anaerobic training and their influence on aerobic capacity in middle-distance athletes. Methods: The descriptive comparative method was used with a sample of 20 subjects randomized in two groups: experimental and control; the analysis was performed under the descriptive Anova statistical model, T-tests and repeated measures design with a 95 percent confidence interval (p<0.05). Results: In the initial and final creatine phosphokinase and lactodehydrogenase variables, there were no significant intergroup variations; differences were observed in creatine phosphokinase regarding variance or standard deviation (p=0.022) in the order of 97.8 percent; which in average (p=0.088) represented the levels reached of 91.2 percent. In the repeated measures, there were no statistically significant intergroup changes. For the VO2max variable, the T-test was applied to compare the initial and final states in each group and there were differences in both groups (control p=0.002; experimental p=0.000). Conclusions: There were no important enzymatic changes during lactic anaerobic and aerobic training, and lactic anaerobic training had an influence on aerobic capacity(AU)