It can bend, it can twist, it can suck, it can cup. The tongue is an essential, often playful part of human anatomy. Many of us grew up believing the assertion that the tongue is the strongest muscle in the body. But is it really?
The short answer is no. But the explanation is not as straightforward as you’d think. We asked a few tongue experts (yes they do exist) why the myth has been so easy to swallow.
Maureen Stone, of the University of Maryland School of Dentistry, speculates that the myth of the tongue’s strength arose from its amazing stamina even in precision tasks like eating and speaking. “When’s the last time your tongue was tired?” she asks. “If you don’t have any disorders, the answer is probably never.” Stone says the tongue’s tenacity springs from the way it is built—with lots of similar bits of muscle that can each perform the same task. “It doesn’t fatigue,” she says, “because there’s a lot of redundancy in the muscle architecture. You simply activate different muscle fibers and get the same result.”
Stephen Tasko, a speech scientist at Western Michigan University, says that the question of whether the tongue is the strongest muscle in the body is itself misinformed. The soft patty of flesh we call the tongue is not just one muscle, it’s a conglomeration of eight separate muscles. Unlike other muscles, such as the bicep, tongue muscles don’t develop around a supporting bone. Rather, they intertwine to create a flexible matrix, forming what is called a muscular hydrostat; this structure is similar to an octopus’s tentacles or an elephant’s trunk.
Four muscles in the matrix, called the extrinsic muscles, anchor the tongue to structures in the head and neck. One muscle holds on to the base of the skull, another connects to a bone in the throat, there is a muscle that grabs on to the lower jaw and another wrapped around the palate. These propel the tongue from side to side, front to back and up and down.
The rest of the muscles make up the tongue’s body. They’re what give it the ability to contort into endless arrays of shapes and postures. They allow it to lengthen, shorten, curl, flatten and round, and they provide shape to assist in speaking, eating and swallowing.
Because the tongue is all muscle and no bone, it is very supple, boasting a huge range of motion and shape while preserving its volume. “It’s kind of like a water balloon,” says Tasko. “If you deform it in one place, it’s going to pop out in other spots.” Tasko believes the myth of extraordinary strength has persisted because of the tongue’s tireless flexibility. "We all know that you can do all kinds of gymnastics with your tongue,” he says, “because it always seems to be going, and it's highly agile.” He adds: “I think maybe those are construed as having something to do with strength."
By sticking a pliable air-filled bulb into a subject’s mouth, scientists can measure the maximal pressure the tongue can exert on an object. This device, called an Iowa oral performance instrument, is placed on the tongue and subjects are asked to push it toward the roofs of their mouths as hard as they can. Scientists also use this bulb to measure endurance, or how long the tongue can hold a certain posture. Such measurements have given the lie to the myth, because you’re not really measuring muscles but muscle systems. But what, then, is the strongest muscle system in the body? The answer turns out to be complicated and depends on how muscular strength is defined—but no matter, the tongue doesn’t win under any criteria.
There are lots of ways to measure strength. One is brute force, in which case biggest is best. All skeletal muscles are bundles of many individual fibers that contain small force generating structures called sarcomeres. “Generally speaking, more muscle tissue means a larger total number of sarcomeres, which means greater maximum force generation,” Tasko says. That means the largest muscles—the quadriceps on the front of your thighs and the gluteus maximus on your rear—produce the most force.
Muscle size and raw force aren’t everything though. Muscles work by pulling on bones, which act as levers that convert muscular contractions (small but powerful movements) into large motions—think: curling a dumbbell. Your bicep pulls on the bones in your forearm to lift the dumbbell. Because your forearm is long and the bicep pulls on it right near the elbow, says Khalil Iskarous, a linguist at the University of Southern California, the bicep has to pull with a lot of force to move your hand up to your shoulder. Your jawbone, in contrast, is a much shorter lever. Because of this, the masseter, the main muscle in your jaw, is also a contender for strongest muscle in the body.
Or maybe it’s not about force at all, but rather about overall work done in the course of a lifetime. By that measure, the hardest working muscle in your body is the one that’s pump-pump-pumping 24/7 to keep your blood flowing round and round, including to all the other muscles: your heart.
The tongue may not be as strong as the glutes, jaw or heart but strengthening it may still be useful. Tasko says there is some evidence suggesting that strengthening exercises may benefit people who have trouble swallowing, such as those recovering from stroke. Some speculate that strengthening the tongue may even improve speaking abilities or help treat speech pathologies. Tasko warns, however, that these assertions are controversial and need further testing.
But one thing’s certain: the tongue is definitely not the strongest muscle in the body. Maybe people continue to believe in its power simply because the tongue is weird; it’s literally inside your face, and people like superlatives. “People want to attach some kind of ‘est’ to it,” Iskarous says. “‘Strongest’ or this or that—and that’s maybe what stuck.”