INTRODUCTION: The effects of the anabolic steroids (AS) on muscle mass and strength are controversial and dependent on the training protocol performed and the muscle fibers recruited. Thus, the aim of this study was to evaluate the AS effects combined with strength training or aerobic exercise training on muscle hypertrophy and strength. METHODS: Wistar rats (42) were divided into six groups: sedentary control (SC, n = 7), steroid sedentary (SS, n = 7), swimming training control (STC, n = 7), swimming training steroid (STS, n = 7), strength training control (SRC, n = 7) and strength training steroid (SRS, n = 7). AS was administered twice a week (10mg/kg/week). The training protocols were performed for 10 weeks, 5 sessions per week. Soleus, gastrocnemius and plantar hypertrophy (muscle mass corrected for tibia length), total muscle protein (Bradford) and muscle strength in hind limb (resistance to twist) were assessed. RESULTS: No significant differences were observed in soleus muscle hypertrophy. SRC and SRS groups showed hypertrophy of 18% and 31% in plantar muscles compared to the SC group. Hypertrophy was 13% higher in SRS than SRC group. Similar results were found in gastrocnemius muscle. SRC and SRS groups showed significant increases in the protein total amount in the plantar muscles, it was more pronounced in SRS group and positively correlated to muscle hypertrophy. The strength was increase in SRC and SRS groups. CONCLUSION: AS administration or its association to aerobic training does not increase muscle mass and strength. However, its association to strength training leads to muscle hypertrophy in glycolytic fibers. Therefore, the physical training protocol, muscle recruitment and muscle fibers characteristics, appear to have significant impact on anabolic responses induced by AS
hypertrophy; skeletal muscle; physical training; rats
