Glucose homeostasis in type 1 diabetic rats after acute physical activity

Physical activity is considered an extremely effective therapy in cases of type 1 diabetes (DM-1), as it promotes glucose uptake independent of insulin action. However, there are few studies on the effect of a single session of exercise on glucose uptake in DM-1 (i.e., in the absence of insulin). Therefore, the purpose of this study was to assess the effect of a single exercise session on glucose homeostasis in DM-1 rats. For this purpose, 30 male rats were divided into three groups: sedentary control (SC), sedentary diabetic (SD), and exercise diabetic (ED). DM was induced by administration of alloxan and identified by the value of fasting glucose. The physical activity consisted of a single swimming session at the anaerobic threshold intensity for diabetic rats (3.5% body weight overload) for 30 min. The oral glucose tolerance test (OGTT) was performed immediately after the physical activity. The animals were sacrificed 48 hr after the OGTT, and samples were taken from the blood, liver, gastrocnemius, and mesenteric and subcutaneous adipose tissue. We observed that DM caused significant reduction in body weight. A single session of physical activity did not modify the response to the OGTT or glucose. However, it resulted in increased HDL cholesterol and hepatic glycogen content. These results suggest that, despite not having an effect on glucose homeostasis, acute physical activity performed at anaerobic threshold intensity leads to beneficial changes in the context of type 1 diabetes.

Energy expenditure during multiple sets of leg press and bench press

The purpose of this study was to quantify energy expenditure (EE) during multiple sets of leg press (LP) and bench press (BP) exercises in 10 males with at least 1 yr of resistance training (RT). The subjects underwent two sessions to determine 1 repetition maximum (1RM) on the BP and LP and one protocol consisting of a warm up and 4 sets for 10 repetitions at 70% 1RM with a 3-min rest period between sets for each exercise. Energy expenditure was calculated as the sum of oxygen uptake (aerobic component), EPOC, and lactate production (anaerobic component). There were no significant differences in EE between exercises for sets 1 to 4 and the total energy expended. However, statistical analysis revealed a significant difference (P<0.05) between exercises in RT economy (BP, 0.0206 ± 0.0044 kcal·kg-1 vs. LP, 0.0051 ± 0.0015 kcal·kg-1). Within exercise comparison showed set 4 was significantly different from sets 1 and 3 for BP, and for LP a significant difference was found between set 4 and sets 1, 2 and 3. Our results point to an increase in EE during multiple sets at 70% 1RM and show that in spite of the difference in muscle mass involved and total work done during each type of exercise, EE was not different due to greater economy during the LP.

Validation of the lactate minimum test as a specific aerobic evaluation protocol for table tennis players

The purpose of this study was to validate the lactate minimum test as a specific aerobic evaluation protocol for table tennis players. Using the frequency of 72 balls·min-1 for 90 sec, an exercise-induced metabolic acidosis was determined in 8 male table tennis players. The evaluation protocol began with a frequency of 40 balls·min-1 followed by an increase of 8 balls·min-1 every 3 min until exhaustion. The mean values that corresponded to the subjects' lactate minimum (Lacmin) were equal to 53.1 ± 1.5 balls·min-1 [adjusted for the time test (Lacmin_time)] and 51.6 ± 1.6 balls·min-1 [adjusted for the frequency of balls (Lacmin_Freq)], which resulted in a high correlation between the two forms of adjustment (r = 0.96 and (P = 0.01). The mean maximum lactate steady state (MLSS) was 52.6 ± 1.6 balls·min-1. Pearson's correlations between Lacmin_time vs. MLSS and Lacmin_freq vs. MLSS were statistically significant (P = 0.03 and r = 0.86, P = 0.03 and r = 0.85, respectively). These findings indicate that the Lacmin test predicts MLSS. Therefore, it is an excellent method to obtain the athletes' anaerobic threshold. Also, there is the advantage that it can be performed in 1 day in the game area. However, the Lacmin value does not depend on the Lacpeak value.

Respostas endócrinas, metabólicas, cardíacas e hematológicas de eqüinos submetidos ao exercício intenso e à administração de cafeína, aminofilina e clembuterol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metabolismo oxidativo e cardíaco de equinos submetidos a exercício de baixa intensidade antes e após suplementação com antioxidante

The present study aimed to evaluate cardiac and lipoperoxidation markers in horses subjected to low intensity and long duration (TLD) exercise test, before and after vitamin E supplementation. For this purpose, 10 horses were used, subjecting them to the first TLD with a workload based on individual maximal oxygen uptake (VO2max). Then, horses received vitamin E (dl-alpha-tocopherol) during 59 days at a daily oral dose of 1,000IU, and thereafter they performed a second TLD with the same protocol as the first. Blood samples were collected to determine plasma malondialdehyde (MDA) as an index of lipoperoxidation, serum cardiac troponin I (cTnI) and creatine kinase MB isoenzyme (CK-MB) as cardiac markers. As a result of the exercise, there was no significant increase in MDA or cTnI, but serum CK-MB increased suggesting myocardial stress. The supplementation was able to minimize reactive oxygen species production, as evidenced by lower concentrations of MDA at all times evaluated, but it didn't cause protective effect on the myocardium. It was concluded that the low intensity and long duration exercise promoted light myocardial stress in horses and vitamin E supplementation reduced lipoperoxidation.

Comparison of maximal lactate steady state with V2, V4, individual anaerobic threshold and lactate minimum speed in horses

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da suplementação com vitamina E sobre os metabolismos oxidativo e cardíaco em equinos submetidos a exercício de alta intensidade

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Protocolos de natação em modelos experimentais com ratos

Exercise physiology has attempted to reproduce the experimental exercise in the laboratory using mainly rats. The swimming exercise has emerged as one of the leading research in these type ergometers. Thus, this research consisted of a literature review addressing the key issues which involve the exercise of swimming in the model rats. Training of aerobic and anaerobic swimming, evaluation models and models of periodization were the topics suggested in this research. In several studies, models of aerobic and anaerobic training have been proposed with the aim of studying their effect on normal and abnormal physiological parameters. However, earlier studies lacked methods of analysis aiming to determine the exercise intensity in the animal model. For this reason, in the last decade, assessment models have been adapted for humans to animals, especially rats. The maximal lactate steady state (MLSS) and lactate minimum (LM) are among the various techniques used to measure the amount of effort produced by swimming exercise in rats. Thereafter, based on biochemical parameters such as lactate, swimming exercise in rats has become the highest-rated, ie, using as reference the anaerobic threshold (AT). In another aspect, an entirely new line of research has tried to understand and promising swimming training in a periodized and its effects on some biochemical parameters. But this is an area little researched so far. Thus, the experimental model of swimming has proved an important resource of exercise physiology. From this model, it becomes possible to study the exercise, especially swimming, in more accurate, based on invasive and incisive analysis of the rat

Effects of high and low volume of strength training on muscle strength, muscle volume and lipid profile in postmenopausal women

Changes in lipid profile are considered a risk factor for cardiovascular disease (CVD), especially in postmenopausal woman who have been associated with age-related loss of muscle mass. The beneficial role of aerobic exercise in the prevention of CVD has been well documented. However, the effect of strength training has not been established. The purpose of this study was to determine the changes of lipoprotein levels after 12 weeks of different volumes of strength training and its correlation with strength and muscle volume in postmenopausal women. The participants were randomized into three groups: low volume (LVST; n = 12, 1 set) and high volume of strength training (HVST; n = 11, 3 sets), or control group (n = 12). Training groups performed 12 weeks of supervised strength exercises, 15 maximum repetitions, five times a week, 20 minutes for LVST and 40 minutes for HVST for each training session. Measurements included body composition, strength and muscle volume, as well as blood analysis (glucose, total cholesterol, triglycerides, low-density lipoprotein, and high-density lipoprotein) pre- and post-training. The HVST and LVST improved the one-repetition maximum knee extension strength (p < 0.001), maximal dynamic strength (p < 0.001), and muscle volume (p = 0.048). Post-training triglyceride was lower in HVST when compared to LVST and the control group (p = 0.047). Even though they present the same neuromuscular and morphological adaptations in postmenopausal women, the HVST is more effective than LVST in improving the lipid profile of postmenopausal woman, and can be considered as an ideal program of intervention to reverse changes in lipid metabolism commonly found in this group. Copyright (C) 2014, The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd. All rights reserved.

Ischaemia modified albumin in horses exercised at different intensities in treadmill

Ischaemia modified albumin (IMA) is considered a biomarker of myocardial ischaemia in humans in contrast to other biomarkers released when cardiac necrosis occurs. Little is known about release conditions of IMA in exercise and this is the first report in equine species. For this purpose, ten clinically healthy untrained horses were submitted to a high intensity test (HIT) followed by a low intensity test (LIT) seven days later. Blood samples were taken before, during and immediately after exercise, and 15 min and 30 min thereafter. Serum IMA, lactate and albumin, and plasma malondialdehyde (MDA) were determined. There were no significant changes in IMA concentration in any of the exercise tests. There was also a negative correlation between IMA and albumin levels in both tests, and between IMA and lactate levels in LIT, suggesting possible assay interferences. It was concluded that HIT and LIT did not promote significant changes in IMA concentration in horses under these conditions.

Short-term creatine supplementation decreases reactive oxygen species content with no changes in expression and activity of antioxidant enzymes in skeletal muscle

The effect of short-term creatine (Cr) supplementation upon content of skeletal muscle-derived-reactive oxygen species (ROS) was investigated. Wistar rats were supplemented with Cr (5 g/kg BW) or vehicle, by gavage, for 6 days. Soleus and extensor digitorum longus (EDL) muscles were removed and incubated for evaluation of ROS content using Amplex-UltraRed reagent. The analysis of expression and activity of antioxidant enzymes (superoxide dismutase 1 and 2, catalase and glutathione peroxidase) were performed. Direct scavenger action of Cr on superoxide radical and hydrogen peroxide was also investigated. Short-term Cr supplementation attenuated ROS content in both soleus and EDL muscles (by 41 and 33.7%, respectively). Cr supplementation did not change expression and activity of antioxidant enzymes. Basal TBARS content was not altered by Cr supplementation. In cell-free experiments, Cr showed a scavenger effect on superoxide radical in concentrations of 20 and 40 mM, but not on hydrogen peroxide. These results indicate that Cr supplementation decreases ROS content in skeletal muscle possibly due to a direct action of Cr molecule on superoxide radical.

Evolution of form and function: morphophysiological relationships and locomotor performance in tropidurine lizards

Locomotor capacity is often considered an excellent measure of whole animal performance because it requires the integrated functioning of many morphological, physiological (and biochemical) traits. However, because studies tend to focus on either structural or functional suits of traits, we know little on whether and how morphological and physiological traits coevolve to produce adequate locomotor capacities. Hence, we investigate the evolutionary relationships between morphological and physiological parameters related to exercise physiology, using tropidurine lizards as a model. We employ a phylogenetic principal component analysis (PCA) to identify variable clusters (factors) related to morphology, energetic metabolism and muscle metabolism, and then analyze the relationships between these clusters and measures of locomotor performance, using two models (star and hierarchical phylogenies). Our data indicate that sprint performance is enhanced by simultaneous evolutionary tendencies affecting relative limb and tail size and physiological traits. Specifically, the high absolute sprint speeds exhibited by tropidurines from the sand dunes are explained by longer limbs, feet and tails and an increased proportion of glycolytic fibers in the leg muscle, contrasting with their lower capacity for overall oxidative metabolism [principal component (PC1)]. However, when sprint speeds are corrected for body size, performance correlates with a cluster (PC3) composed by moderate loads for activity metabolic rate and body size. The simultaneous measurement of morphological and physiological parameters is a powerful tool for exploring patterns of coadaptation and proposing morphophysiological associations that are not directly predictable from theory. This approach may trigger novel directions for investigating the evolution of form and function, particularly in the context of organismal performance.

Freisetzung von frei zirkulierender DNA unter einer Fahrradergometrie bei Straßenradfahrern

Ziel dieser Studie war es zu untersuchen, ob die unter Belastung vorliegenden Anstiege plasmatischer zellfreier DNA über den Mechanismus der NETose zu erklären sind. Zudem sollte die Assoziation von zellfreier DNA und leistungsphysiologischen Parametern geklärt werden. Anhand eines Stufenprotokolls wurden Straßenradfahrer belastet und durch Blutuntersuchungen auf DNA, MPO, Elastase sowie Leistungsphysiologie untersucht. Anhand der Ergebnisse kann die Herkunft der DNA aus NETs nicht bewiesen werden. Die Neutrophilen Granulozyten zeigen eine Degranulationsreaktion, die aber nicht parallel mit den DNA-Anstiegen verläuft. Leitsungsphysiologisch war auffällig, dass die absolute Leistung mit der DNA korreliert sowie Parameter des Herzkreislaufsystems ebenfalls ähnliche ansteigen wie die DNA im Blut.

From Gibbons to Gymnasts: A Look at the Biomechanics and Neurophysiology of Brachiation in Gibbons and its Human Rediscovery

This conference paper serves to examine the evolutionary linkages of a brachiating ancestor in humans, the biomechanical and neurophysiology of modern day brachiators, and the human rediscovery of this form of locomotion. Brachiation is arguably one of the most metabolically effective modes of travel by any organism and can be observed most meritoriously in Gibbons. The purpose of the research conducted for this paper was to encourage further exploration of the neurophysiological similarities and differences between humans and non-human primates. The hope is that in spurring more interest and research in this area, further possibilities for rehabilitating brain injury will be developed, or even theories on how to better train our athletes, using the biomechanics and neurophysiology of brachiation as a guide.

La Fisiología del Ejercicio como una especialización dentro del campo de la Educación Física: Un análisis desde el propio contexto institucional

El propósito de este trabajo es analizar la existencia de una aparente contradicción entre las ideas y creencias que guían la actividad académica de nuestra institución, el Departamento de Educación Física de la Facultad de Humanidades y Ciencias de la Educación de la Universidad Nacional de La Plata, y la implementación de la "Especialización en Fisiología del Ejercicio", como carrera de especialización de posgrado en el campo de la Educación Física