For women, he said, he encourages different types of strength training, like Pilates, which focus on the core of the body, because it's a different type of strength training
However, he said, it's not for concerns about getting larger.
"It's very difficult to bulk up, so you won't see that from doing general strength training. For everybody, it's not easy to gain muscle mass -- that's a myth in itself."
Visit the ABCNews.com OnCall+ Wellness Center to get more tips on keeping your health on track.