You don’t have to lift the heaviest weights to build bigger muscles. But you do have to do enough reps to exhaust your muscles.
Many gym-goers believe they have to pump iron with heavy weights to get the biggest muscle gain. But a new study at McMaster University shows you can build just as much muscle using lighter weights, as long as you reach muscle fatigue. That means keep going until you can’t lift anymore. This is especially good news for the elderly, people with arthritis and weight lifting novices. Start with a weight that you can lift 12 to 15 times before fatiguing. Repeat each exercise until you can no longer do another while still maintaining proper form.