Round dumbbells are standard in gyms because they work well and last a long time.The round shape of their heads allows them to be used in so many different workout types, like lunges, rows or bicep curls.Round dumbbells are common in professional gyms and serious home gyms.They come in various weights, so that with each new stage of training you can continue to raise the training load.During heavy exercises, the rubber-coated or cast iron dumbbells will protect not only themselves but also the floor.