There are few studies that associate indicators of aerobic capacity and the substrates produced by the muscular metabolism in rats. The aim of the present study was to analyze the effects of physical training in different intensities on the aerobic capacity and lactate production by the isolated soleus muscle of Wistar rats (90 days) that had the aerobic/anaerobic metabolic transition determined by the Maximal Lactate Steady State Test (MLSS). Subsequently, the rats were trained 40 minutes/day, 5 days/week, in the speed equivalent to MLSS (MT) or 5% above it (AT), for 8 weeks. Rats maintained sedentary (S) were used as controls. At the end, all rats were sacrificed for analysis of lactate production by the isolated soleus muscle. The main results were: in the beginning of the experiment, in most of the rats the MLSS was obtained in the speed of 25m/min, to the concentration of 4.38+0.22mmol/L of blood lactate. At the end of the experiment, most of the rats trained at the MLSS intensity presented MLSS in the speed of 25m/min, to the concentration of 3.10+0.27 mmol/L of blood lactate. Most of the animals trained above-MLSS had MLSS in the speed of 25m/min, to the concentration of 3.36+0.62 mmol/L of blood lactate. Sedentary rats showed MLSS in the speed of 20m/min to the concentration of blood lactate of 4.83+0.67mmol/L. The lactate production (μmol/g.h): S 4.31+0.58, MT 4.71+0.39, AT 3.83+0.62 was lower in the ST group., It can be concluded from the results of the present study that the aerobic training prevented the deterioration of the aerobic conditioning imposed by the age advance, and that physical training above the MLSS reduced muscle lactate production.
anaerobic threshold; glycogen; physical exercise
