Myth 1) Lifting light weights will tone your body and lifting heavy weights will bulk you up.
I’m not sure who first pioneered this idea that heavy weights will bulk you up, but it has stuck over the years and erroneously makes many people—both men and women—afraid of lifting heavy weights. While there is some truth to the idea that lifting lighter weights for more reps does a better job of increasing the muscular endurance, lighter weights will not help you “tone” better than heavy weights. In fact, because heavier weights build the strength of your muscles (and the size to a small degree—no Hulk action here), thereby helping to increase your metabolism and burn fat, lifting heavier weights with fewer reps (8 to 12 on average) and working until you’re fatigued is more effective at helping you reach your toning goals than lifting lighter weights. Not to mention that it’s more time efficient, too!