No surprise here--the six-pack is a hot topic. It's a phrase searched for more than 1.2 million times a month on Google alone. But there's more to your midsection than its six sexy segments. In fact, that washboard is actually made of one muscle, the rectus abdominis, which gets its "separations" from dense connective tissue called fascia. The muscles on the sides of your torso are also considered part of the abdominals: Your external and internal obliques help you bend your torso from side to side and rotate your upper body left and right. If all of this is news to you, read on for 11 more essential facts about your abs that you probably don't know.
Print It: The Greatest Abs Workout Ever
If you perform ab exercises daily in the pursuit of a perfect belly, you could be overtaxing your muscles. "A lot of people go overboard," says Jim White, RD, ACSM, owner of Jim White Fitness & Nutrition Studios in Virginia Beach, VA. "They'll do abs 7 days a week and won't allow for any rest. That just damages the muscles." He recommends focusing on abs three or four times a week.
It's also important to mix things up: New research published in the Journal of Strength and Conditioning Research shows that doing a routine of core-strengthening exercises alone won't slim your waistline. When volunteers did seven moves 5 days a week, they had stronger ab muscles but they didn't lose fat or inches. To reveal chiseled abs, you need to train all your major muscle groups, do cardio, and follow a healthy diet.
Related: Get Rock Solid Abs!
If your abs are the star of the show, think of your lower back as the supporting cast. When it comes to waist circumference, your lower back factors into that figure just as much as belly fat does, says White. "By tightening your lower back, your waist will look slimmer." Also, a strong lower back makes it possible for you to complete intense ab-focused workouts with less risk of injury. "You can't be one-sided," says White. "It's the same problem we see in athletes who overdevelop their quads and end up with hamstring injuries." If you neglect your back, not only will you have a more difficult time completing ab exercises in the first place, but you'll also have a better chance of injuring yourself and having to put off ab-targeted moves completely while you recover. In other words, if you want that six-pack, your lower back better be in shape. (Search: Lower-back exercises)
Exercise infomercials love to lure in buyers with the promise of six-pack abs. But a 2001 study sponsored by the American Council on Exercise (ACE) found that the most effective ab-targeted moves can actually be done at home with minimal equipment. Researchers tested the amount of muscle activity required of participants while they performed 13 basic ab exercises. The bicycle crunch, the captain's chair, and the stability ball crunch were named the best moves, requiring 148, 112, and 39% more muscle activity, respectively, than the traditional crunch. And if you want an obliques-targeted move, incorporate the reverse crunch into your workout. It's 140% more effective at hitting the sides of your torso than the traditional crunch.
The same ACE-sponsored study determined the least effective ab-targeted exercises. The exercise tubing pull and the Ab Rocker machine were at the bottom of the list, requiring 8 and 79% less muscle activity, respectively, than the traditional crunch.
Showing off a six-pack on film is an everyday occurrence now. (Is there a Ryan Reynolds movie in which he doesn't find an opportunity to disrobe?) But the first Hollywood ab shot caused a sensation. When Clark Gable took off his button-down and bared his belly in the 1934 film It Happened One Night, it's said that undershirt sales plummeted.
See More Hollywood Ab Shots: Secrets to a Celebrity Six-Pack
There are two types of fat: subcutaneous and visceral. Subcutaneous fat is the most common--it resides all over the body, just below the skin--but visceral fat resides deep within the torso and wraps itself around your heart, liver, and other major organs. While subcutaneous fat is easy to see in the mirror (it's the stuff you can pinch), visceral fat is difficult to detect without a CT scan or a MRI. In fact, it's possible to look relatively thin and still have too much visceral fat. Find out why this is a problem on the next slide.
Visceral fat is not only harder to detect, but also more dangerous than subcutaneous fat. It's more likely to produce substances that can damage your heart and blood vessels and could interfere with your body's ability to use insulin. What's more, large amounts of belly fat can increase your risk of serious health problems like high blood pressure, stroke, type 2 diabetes, metabolic syndrome, sleep apnea, certain types of cancer, and heart disease. A study published in Circulation: Journal of the American Heart Association even found that visceral fat has a greater impact on the cardiovascular health of older women than does obesity. Visceral fat could also have an effect on mental health: A Kaiser Permanente study comparing people with different levels of fat found that participants who had the most belly fat were 145% more likely to develop dementia than participants with the least amount of belly fat. (Related: 6 Happiest Ways to Beat Belly Fat)
Free Guide! Eat to Beat Belly Fat
Because underweight women are known to have increased risk of osteoporosis, it was assumed that the heavier you are, the healthier your bones. But the results of a recent study presented at the Annual Meeting of the Radiological Society of North America suggest otherwise: Researchers found that visceral fat is associated with reduced bone-mineral density in obese women. (Subcutaneous fat did not demonstrate such a link.)
Related: Build Strong Bones with Yoga
A Spanish study published in the journal Diabetes Care found that eating a diet rich in monounsaturated fatty acids (MUFAs) can actually help prevent weight gain in your belly--more specifically, the accumulation of visceral fat. Foods like avocados, nuts, and olive oil are high in MUFAs, which are also known to help lower LDL (bad) cholesterol.
A study conducted by the U.S. Army found that strong abdominal muscles are linked to injury prevention. Researchers tracked 120 soldiers during a year of field training and found that those who were able to perform the most situps (73 situps in 2 minutes) during their initial standard army fitness test were 5 times less likely to suffer lower-body injuries (including lower-back injury) than the men who completed fewer than 50 situps. What's more, top performance in other areas of the fitness test--like pushups and the 2-mile run--offered no such injury protection, suggesting that a strong core plays a larger role in injury prevention than other muscle groups do.
How fit are you? One-Minute Fitness Tests