Exercise Myth 05:
"Strength training will bulk me up."

Short answer: Wrong! Longer answer below—still Wrong!
This myth has achieved urban legend stature. It's primarily a female fitness myth, and has probably prevented more women from achieving a well-balanced exercise program than any other wrong-headed belief. Strength training should be an integral part of any fitness program. We're not talking about bulking out, but rather strengthening muscles throughout your body with practical resistance exercise.

The Good News (unless you want to be a bodybuilder)
It's a scientific fact—most women can't build big muscles. For a very simple reason. Male or female, every individual's potential to build bulky muscles is predetermined primarily by genetics and hormones—and women have 10 to 30 times less of the specifically required hormones than men do.

There's no down-side to sensible strength training
Strength training twice a week will help protect you from injury, tone your muscles, help prevent osteoporosis, and burn excess body fat even when you're resting. The vast majority of the population who strength train—men and women—will merely add strength, tone, coordination, a leaner look and better health.