Test Your Muscle IQ!

By Monica Gomez

Muscle Confusion^™, Muscle Burns Fat^®, "the more lean muscle you have, the more fat you burn," lean muscle, ripped muscle, etc.—muscle is a word you come across often here at Beachbody. We know that the lean and ripped varieties are highly coveted. But what do you know about this body tissue consisting of long cells that contract when stimulated and produce motion?

True or False?

1. False: The second largest muscle in the human body is the gluteus maximus. Actually, it's the largest muscle in the human body. The gluteus maximus is also the largest of the three gluteal muscles: gluteus maximus, gluteus medius, and gluteus minimus. The gluteus maximus acts to extend the thigh. The gluteus medius acts to abduct and medially rotate the thigh. And the gluteus minimus acts to abduct the thigh. Basically, they're essential for standing, running, and walking—you know, small stuff. It's safe to say that they're pretty important, so don't forget to do those lunges and squats!
2. False: Your heart muscle is likely to shrink if it's weak and can't squeeze as hard. Your heart may enlarge, or dilate, to compensate for being unable to pump out the normal amount of blood. And it could enlarge to the point that it fails to function normally. Each day, the average heart beats (expands and contracts) 100,000 times and pumps about 2,000 gallons of blood. According to the Mayo Clinic, heart disease is the number one killer of men and women—worldwide! In the U.S., heart disease is responsible for nearly 40 percent of all deaths; that's more than all forms of cancer combined. To stay heart healthy, the American Heart Association recommends getting 30 minutes of exercise on most days of the week—even simple exercise like a brisk walk or gardening can contribute to heart health.
3. True: Disuse atrophy can be reversed. Unless it's extremely severe, disuse atrophy can be reversed. There are two types of muscle atrophy: disuse atrophy and neurogenic atrophy (neurogenic atrophy is the most severe type of muscle atrophy, occurring when there is an injury to or a disease of a nerve; ALS or Lou Gehrig's disease and polio are examples of diseases affecting the nerves that control muscles). Disuse atrophy results from lack of exercise (hmmm . . . Push Play, anyone?)—it can be reversed with vigorous exercise or better nutrition. Those vulnerable to this type of muscle atrophy include people with sedentary jobs, medical conditions that restrict movement, or decreased activity levels.
4. True: Strabismus is an eye muscle condition in which one or both eyes may turn in, out, up, or down. More commonly known as cross-eye or walleye, eyes may turn in (esotropia), out (exotropia), up (hypertropia), or down (hypotropia). Strabismus is caused by a weak eye muscle or a weak signal from the nerve that controls the eye muscle. Other causes of strabismus include bleeding in the brain, brain tumors, nervous system disorders, diabetes, high blood pressure, myasthenia gravis, thyroid disease, and severe vision loss.
5. False: Chewing is performed by the coordinated function of 15 muscles. You use eight muscles, four on each side of your head, to enjoy those delicious and healthy (right?!) meals. The four muscles are the masseter, lateral pterygoid, medial pterygoid, and temporalis. Based on its weight, the masseter muscle is the strongest muscle in the human body. Together with the temporalis and a few other smaller muscles, most people can generate at least 150 pounds of force between their teeth. Ouch! Sorry, bruxism sufferers—the masseter is an accomplice in your teeth grinding.