Hips don’t lie; if they’re weak, you’ll have a saggy stomach and be at risk for injuries. In this video, contributing fitness editor Tracy Anderson shows you four moves that will firm them up and give you a stronger, flatter belly. Do these six days a week, paired with 30 to 60 minutes of cardio.

Looking for tips on picking the freshest and ripest avocados? This Cooking Light video has the top 6 things you need to know about this delicious and nutritious fruit.

When you ask a doctor a question, you expect an answer backed by the latest science. But the reality is, the field of medicine is always advancing, and “there’s too much knowledge for any one physician to master,” says Renée Fox, PhD, professor emerita at the University of Pennsylvania, who studies the sociology of medical research, education and ethics. As a result, certain popular beliefs that seem to make sense persist long after they’ve been challenged by studies. So we asked a range of experts, “What health myths drive you nuts?” Here, they bust five vexing misconceptions.RELATED: 15 Diseases Doctors Often Get WrongMYTH: “Rest is best for back pain.”THE ORIGINSIn years past, doctors tended to assume the worst—that back pain was a sign of a serious injury—and thought the way to heal was to stay off your feet. Today we know that most soreness stems from the muscles, ligaments and joints. Yet “many ER and primary care doctors still default to ‘rest’ out of uncertainty or a fear of liability,” says Robert Eastlack, MD, codirector of the San Diego Spine Fellowship at the Scripps Clinic for Orthopedic Surgery. SCIENCE SAYSThe vast majority of back problems— from lumbar sprains to slipped disks—benefit from activity, according to 2007 guidelines from the American College of Physicians. Studies have shown that bed rest actually makes pain worse and last longer. “The key is to keep moving,” says Dr. Eastlack—to stretch out tight muscle fibers and prevent your joints from stiffening. He suggests starting with gentle daily exercise, like walking or swimming. Then gradually work your way up to more vigorous activities, like running, yoga or spin, as you become able to tolerate them. If the pain worsens or hasn’t improved significantly in four to six weeks, get it checked out by your doctor.RELATED: 15 Natural Back Pain RemediesMYTH: “Hormone replacement therapy causes cancer.”THE ORIGINSDocs can be skittish about prescribing estrogen to ease symptoms of menopause, such as hot flashes and night sweats. But they’re probably clinging to outdated findings from a 2002 NIH Womens Health Initiative study that linked hormone replacement therapy (HRT) to a slightly elevated risk of breast cancer—even though more recent research has demonstrated that that risk is not associated with how HRT is formulated and prescribed today.SCIENCE SAYSSeveral large studies have shown that taking estrogen is safe, says Mary Jane Minkin, MD, clinical professor of obstetrics, gynecology and reproductive sciences at Yale School of Medicine: “It really makes me crazy when doctors tell patients they’ll suffer terrible consequences from hormone therapy.” Typically it’s needed for only two to three years to treat menopausal symptoms, she adds. There are women who cant take estrogen (say, because of a history of breast cancer or blood clots). For them there’s another option to ease hot flashes: Brisdelle, a very low-dose antidepressant…