Background Exercise training regulates the expression of miRs in diabetes. We investigated the effects of metformin alone or in combination with high-intensity interval training (HIIT) and moderate continuous training (MCT) on miR-133a expression in skeletal muscles of diabetic rats. Sprague-Dawley rats were randomly allocated into nine groups (n = 10 per group): control group (CG), control group + MCT group (CMTG), control group + HIIT group (CHTG), diabetic control group (CDG), diabetic + metformin group (DMG), diabetic + HIIT group (DHTG), diabetic + MCT group (DMTG), diabetic + metformin and MCT group (DMMTG), diabetic + metformin and HIIT group (DMHTG). Type 2 diabetes mellitus was induced in Sprague-Dawley rats and exercise protocols were performed for eight weeks. MiR-133a was extracted from skeletal muscles and their expression profile was determined by real-time reverse-transcription polymerase chain reaction (RT-PCR). Results The expression of miR-133a was increased in skeletal muscles of sedentary diabetic rats (CDG) in comparison to treated (CMTG,CHTG,DMG, DMTG) and healthy controls (CG). Treatment with either HIIT and MCT reduced miR-133a expression, but the combination of HIIT and MCT caused to a further reduction of miR-133a expression in diabetic rats. Conclusion The increased expression of MiR-133a in skeletal muscles of rats can be attenuated by metformin and / or HIIT and MCT. This presents an intervention target that could be used in preventing, treating, and/or delaying diabetes.