If you’re determined to build strong muscles in your arms, set the lighter weights aside and focus on using heavier weights, whether that means in dumbbell or barbell form. As for how many repetitions you should perform, keep the number down. Your goal should be to lift more weights for fewer repetitions, rather than less weight for more repetitions. Many body builders focus on “training to failure,” which means you lift until you can no longer complete a full repetition.
Of course, it’s important to take caution when using this method. Avoid making drastic changes to the amount of weight you’re lifting, such as from 20 pounds to 40 pounds. Take your time; otherwise, you could be putting yourself at risk of injury.