Recently, kettlebells have become increasingly popular around the world, but, in fact, they are a traditional Russian strength training tool that has been around for over a hundred years. They have been deemed a great tool for fitness and to build strength, but they are also a great tool to burn calories and get in shape fast. In addition, kettlebells help improve flexibility and overall stability. They have become popular because of their unique design compared to standard dumbbells and other weights. Their shape allows for easy transition between exercises; you can go from doing a clean to a squat to a press to a windmill without any difficulty.