FACT: Unless you’re taking in substances that alter your hormone profile (anabolic steroids), it is highly unlikely that you will gain large amounts of muscle, Bosse says. Doing a high number of reps (20+) using light weights and stopping each set well before the point of muscular failure certainly helps improve fitness and burn calories, but it’s not the best way to get a lean, toned body. What is? Integrate periods of heavier training (six to 10 reps) with some sets taken to muscular failure. The ability to build muscle is very different for men and women and should not be confused, Bosse says.