One of the most effective ways to overload muscles for strength or muscle building purposes is to increase range of motion. There is only so much range of motion one can accomplish with a row or press, not the case with dumbbell variations! Dumbbells can help you improve cardiovascular fitness, burn calories, build muscle or increase muscular endurance for sports. Change up your strength workout with Sunny Health & Fitness 14" Threaded Chrome Dumbbell Bar.