SUMMARY: Intermittent fasting and concurrent training have been performed frequently to decrease body mass. The aim was to analyze the effects of concurrent training (CT) and intermittent fasting (IF) on cardiac remodeling. In total, 39 adult male Wistar rats were used, divided into four groups: control (C [n = 12]), fasting control (FC [n = 11]), training (T [n = 8]) and fasting training (FT [n = 8]). The CT protocol was composed of 12 sessions, with 30 minutes of aerobic training (AT) in the liquid medium at an intensity of 80 % of the anaerobic threshold, followed by resistance training (RT) with 4 series of 10 aquatic jumps at an corresponding to 50 % of body weight. The IF period was established at 12/12 hours, starting at 9 p.m. and ending at 9 a.m. Echocardiographic analyzes were performed before and after the intervention and, at the end of the experiment, samples of the cardiac tissue were collected to perform the histological analyses. Data analysis was performed using the Shapiro-Wilk tests, Analysis of Variance - ANOVA with Tukey's post-test, and Kruskal- Wallis with Dunn's post-test. All procedures assumed an error of 5 % (p<0.05). Neither group showed alterations in the functional (min. p= 0.12 - max. p= 0.83) and structural parameters of the heart (min. p=0.31 - max. p=0.83). A decrease was observed in the area of cardiomyocytes in the T (p=0.001) and FT groups (p=0.001). The CT and IF did not alter the functional and structural parameters of the heart, but did cause a decrease in the area of the cardiomyocytes.

RESUMEN: El ayuno intermitente y el entrenamiento concurrente se han realizado frecuentemente para disminuir la masa corporal. El objetivo fue analizar los efectos del entrenamiento concurrente (EC) y el ayuno intermitente (AI) sobre el remodelado cardíaco. En total, se utilizaron 39 ratas Wistar macho adultas, divididas en cuatro grupos: control (C [n = 12]), control en ayunas (AC [n = 11]), entrenamiento (E [n = 8]) y ayuno, entrenamiento [n = 8]). El protocolo de EC estuvo compuesto de 12 sesiones, con 30 minutos de entrenamiento aeróbico (EA) en el medio líquido a una intensidad del 80 % del umbral anaeróbico, seguido de entrenamiento de resistencia (ER) con 4 series de 10 saltos acuáticos correspondiente al 50 % del peso corporal. El período de AI se estableció a las 12/12 horas, a partir de las 21:00 horas. finalizando a las 9 a.m. Se realizaron análisis ecocardiográficos antes y después de la intervención y, al finalizar el experimento, se reco- lectaron muestras del tejido cardíaco para realizar los análisis histológicos. El análisis de los datos se realizó mediante las pruebas de Shapiro-Wilk, Análisis de Varianza - ANOVA con pos test de Tukey y Kruskal-Wallis con postest de Dunn. Todos los procedimientos asumieron un error del 5 % (p <0,05). No se observaron alteraciones funcionales de los grupos (mín. P = 0,12 - máx. P = 0,83) y estructurales del corazón (mín. P = 0,31 - máx. P = 0,83). Se observó una disminución en el área de cardiomiocitos en los grupos E (p = 0,001) y EA (p = 0,001). La EC y la AI no alteraron los parámetros funcionales y estructurales del corazón, pero sí provocaron una disminución del área de los cardiomiocitos.

Abstract Aim: This study aimed to evaluate the effect of High-Intensity Interval Training (HIIT) on the skeletal muscle of Spontaneously Hypertensive Rats (SHR). Method: In total, 20 male rats, SHR, 12 months old, were used, distributed into 2 groups: Control Group (C) and Training Group (HIIT). The training lasted approximately 50 minutes/day, 5 days/week, for 8 weeks. Systolic blood pressure (BP) was measured at the beginning and end of the study. Analysis: The medial gastrocnemius muscle was used to measure the smallest fiber diameter, after which the Shapiro-Wilk normality test was performed, followed by the Mann Whitney test to compare the medians and interquartile intervals (IQI) of the muscle fibers and Student t-test for performance. For analysis of BP, Analysis of Variance - ANOVA was used, followed by Tukey's post-test. All procedures adopted a significance value of 5% (p < 0.05). Results: The median values for the variable “smallest diameter” of muscle fibers were 29.48 (IQI: 9.96) µm in the C group and 33.45 (IQI: 9.44) µm in the HIIT group (p < 0.05). Also, the performance was increased in the trained animal group and blood pressure values decreased significantly at the end of the experiment (p < 0.05). Conclusion: The HIIT intensity promoted an increase in the median values of the muscle fibers and performance. Finally, a significant decrease was observed in blood pressure variation values.

SUMMARY: The consumption of industrialized foods and beverages contributes to the increase in body weight and manifestation of diverse illnesses. Among these industrialized products, soft drinks can be mentioned, which when consumed in large quantities can contribute to weight gain and the emergence of chronic non-communicable diseases such as hypertension, diabetes, and obesity. In terms of performance, several training protocols have been used, among which concurrent training is presented as a tool that can aid in the control of body weight and muscle development. Thus, the identification of dietary factors, as well as the use of appropriate training methods, can be essential factors in the increase in physical performance. To study the effects of concurrent training on the skeletal muscles of animals submitted to soft drink consumption. In the present study, 32 male rats were used, of the Wistar breed, in the post-weaning biological phase (30 days). The animals performed a concurrent training protocol. Forty-eight hours after the final training session, the animals were submitted to a surgical procedure to remove samples of gastrocnemius muscle. After preparation of the histological slides, the muscle fibers of the different groups of animals were measured. The median values for the minimum diameter of muscle fibers presented the following values: Control (C): 35.78, Control Soft Drinks (CSD): 36.93, Training (T): 39.12, and Training Soft Drinks (TSD): 37.82. The CSD and TSD groups demonstrated the greatest increase in body mass in relation to the C and T groups. In addition, the groups that performed the concurrent training presented a higher mean of the smallest fiber diameter. It was concluded that the ingestion of soft drinks had a negative effect on the muscular hypertrophy of animals submitted to a concurrent training protocol.

RESUMEN: El consumo de alimentos y bebidas industrializadas contribuyen al aumento de peso corporal y manifestación de diversas enfermedades. Entre estos alimentos, se encuentran las bebidas refrescantes, que al ser consumidas en grandes proporciones, pueden contribuir al aumento de peso y a la aparición de enfermedades crónicas, tales como la hipertensión, diabetes y obesidad. En cuanto al desempeño, diversos protocolos han sido utilizados, entre estos, el entrenamiento concurrente que puede ser una forma de ayuda en el control de peso corporal y el desarrollo muscular. Siendo así, la identificación de los factores alimentarios, como también la utilización de los métodos correctos de entrenamiento, pueden ser esenciales en el aumento del desempeño físico. El objetivo del estudio fue investigar los efectos del entrenamiento concurrente en la musculatura esquelética de animales sometidos al consumo de bebidas refrescantes. En la presente investigación fueran utilizadas 32 ratas Wistar. Los animales fueran sometidos a un protocolo de entrenamiento concurrente. Después de 48 horas de la última sesión de entrenamiento, los animales fueran sometidos a un proceso quirúrgico para la remoción de muestras de tejido muscular. Los valores de la media del diámetro de las fibras musculares fueron: Control (C): 35,78; Control y Bebida Refrescante (CBR): 36,93; Entrenamiento (ET): 39,12; y Entrenamiento y Bebida Refrescante (EBR): 37,82. Se observó que los grupos CBR y EBR presentaron mayor aumento de masa corporal en comparación con C y T. Además, los grupos que realizaran el entrenamiento concurrente obtuvieron una mayor media en el diámetro de las fibras. Es posible concluir que el consumo de bebidas refrescantes tiene una influencia negativa en la hipertrofia muscular de animales sometidos a un protocolo de entrenamiento concurrente.

SUMMARY The objective of the present study was to analyze the effects of four different training models, two aerobic and two anaerobic models, in relation to muscular hypertrophy, by means of morphometric analysis of the muscle cells of the soleus muscle and the extensor digitorum longus muscle (EDL). The animals were divided into five groups, control (C), aerobic training in swimming (ATS), resistance training in water (RTW), aerobic training on a treadmill (ATT), and resistance training in climbing (RTC). The aerobic training was performed at 70 % of the anaerobic threshold for 30 minutes, while the RTW was composed of 3 series of 10 jumps, and the RTC 4 series of climbs, both at 80 % of the maximum load. All training protocols were performed for a total period of 4 weeks, 3 times per week. The diameters of the muscle cells were measured by means of histological slides of the EDL and soleus muscles. For the EDL muscle, there was no difference between the ATS and ATT aerobic training models (p = 0.20). However, the RTW presented greater hypertrophy when compared to the RTC (p <0.01). Regarding the soleus muscle, the ATS was responsible for generating greater hypertrophy than the ATT (p <0.01). In addition, the RTC was more efficient at producing hypertrophy than the RTW (p <0.01). In this way, it was concluded that exercise adaptation was according to exercise type, aerobic or anaerobic, and not to the modality used.

RESUMEN El objetivo del estudio fue analizar los efectos de cuatro diferentes modelos de entrenamiento, dos aeróbicos y dos anaeróbicos en la hipertrofia muscular en ratas, a través del análisis morfométrico de las células musculares de los músculos sóleo y extensor largo de los dedos (ELD). Los animales fueran divididos en cinco grupos: control (C), entrenamiento aeróbico en natación (TAN), entrenamiento resistido en medio acuático (TRA), entrenamiento resistido en escalada (TRE) y entrenamiento aeróbico en estera rodante (TRE). Los entrenamientos aeróbicos fueron realizados a 70 % del umbral anaeróbico, durante 30 minutos, en cuanto los TRA fueron realizados por 3 series de 10 saltos y el TRE, 4 series de escaladas, ambos a la intensidad de 80 % de la carga máxima. Todos los protocolos de entrenamientos fueron realizados tres veces a la semana por un período de 4 semanas. Fueron demarcados los diámetros de las células musculares de los músculos ELD y sóleo por medio de láminas histológicas. En el músculo ELD no se pudo observar diferencia entre los modelos de entrenamiento aeróbico TAN y TAE (p=0,20). Además, el TRA demostró mayor hipertrofia comparado al TRE (p<0,01). Con relación al músculo sóleo, el TAN fue responsable de generar mayor hipertrofia respecto al TRA (p<0,01). De este modo es posible concluir que la adaptación depende del tipo de ejercicio, aeróbico o anaeróbico, y no en función de la modalidad utilizada.

To analyze the effects of concurrent training (CT) on the muscle fibers of Wistar rats submitted to standard and hypercaloric diets. In total, 40 rats were used, divided into 4 groups: Sedentary Group (GS); Exercise Group (GE), Obese Sedentary Group (OS) and Obese Exercise Group (OE). The animals performed a CT protocol consisting of: muscle strength training and aerobic training, carried out 3 times a week for 45 days. The smallest diameter of muscle fibers (MDF) was analyzed to evaluate muscle hypertrophy. It was observed that the OE group presented a significant decrease in MDF, compared to the OS group (OE=77.41 µm vs. OS=98.58 µm). In addition, the animals that performed CT demonstrated muscle hypertrophy (GE=74.39 µm vs. GS=72.13 µm). In conclusion, the CT with a standard diet promoted an increase in MDF while CT with a hypercaloric diet resulted in a decrease.

El objetivo de este trabajo fue analizar el efecto del entrenamiento concurrente (EC) en las fibras musculares de ratas Wistar sometidas a dietas normal e hipercalórica. Fueron utilizadas 40 ratas Wistar, distribuidas en cuatro grupos de animales: grupo sedentario (GS); grupo ejercicio (GE); grupo obeso sedentario (OS) y grupo obeso ejercicio (OE). Los animales realizaron el protocolo del EC compuesto por entrenamiento de fuerza y aeróbico, tres veces en la semana y por 45 días. La media del menor diámetro (MMD) de las fibras musculares fue medida para verificar la hipertrofia muscular. Fue observado que el grupo OE presentó una significante diminución del MMD comparado al grupo OS (OE=77.41 µm vs. OS=98.58 µm). Además, los animales que fueron sometidos al protocolo del EC demostraron hipertrofia muscular (GE=74.39 µm vs. GS=72.13 µm). Se puede concluir que el protocolo del EC con dieta normal tiene como resultado un aumento del MMD, mientras que el EC con dieta hipercalórica tiene como resultado la diminución del MMD.