Being “double jointed” is far more common than most people think. Depending on age, sex, and ethnicity, anywhere from 2% to over 60% of people have some degree of joint hypermobility, which is the medical term for what’s colloquially called being double jointed. In adults specifically, prevalence ranges from about 5% in the United States to as high as 43% in certain West African populations. So while it might feel like an unusual party trick, hypermobility is not particularly rare at all.
What “Double Jointed” Actually Means
Nobody actually has double the number of joints. The term describes joints that can move beyond the normal range of motion along their natural axis. Your elbow, for example, normally straightens to about 180 degrees. If yours extends noticeably past that point, that’s hypermobility in action.
The joints most commonly affected are the elbows, wrists, fingers, and knees. Some people are hypermobile in just one joint (a thumb that bends all the way back, for instance), while others have looseness throughout their body. Doctors distinguish between localized hypermobility in a single joint, peripheral hypermobility mostly in the hands and feet, and generalized hypermobility affecting joints across the body.
How Common It Is by Age, Sex, and Ethnicity
Joint hypermobility is extremely common in young children. Studies have found it in 8% to 39% of schoolchildren, with some research reporting rates as high as 64.6% in preschoolers. This makes sense: children’s connective tissues are naturally more elastic, and flexibility tends to decrease with age as collagen stiffens.
Girls and women are significantly more likely to be hypermobile than boys and men. In one study of non-Caucasian populations, 58% of women showed the hypermobile phenotype compared to 29% of men in the same group. People of African and Asian descent also tend to have higher rates than Caucasian populations. In adults, the numbers range widely depending on where you look: roughly 5% in U.S. studies, 25% to 38% in Iraqi populations, and 43% among the Noruba tribe in Nigeria.
These huge differences across populations explain why you’ll sometimes see wildly different answers to the question of how rare hypermobility is. The short answer: it depends heavily on who’s being measured.
How Doctors Measure Hypermobility
The standard clinical tool is the Beighton score, a simple 9-point scale. You earn one point for each of the following you can do:
- Bend forward and place your hands flat on the floor with straight knees
- Straighten each elbow past neutral (one point per elbow)
- Straighten each knee past neutral (one point per knee)
- Bend each pinky finger back beyond 90 degrees (one point per finger)
- Bend each thumb back to touch your forearm (one point per thumb)
A score of 4 or more generally indicates generalized joint hypermobility. On its own, a high Beighton score isn’t a diagnosis of anything. It simply confirms that your joints move farther than average.
When Flexibility Becomes a Problem
For most hypermobile people, extra flexibility causes no symptoms whatsoever. It’s considered asymptomatic joint hypermobility, and it’s perfectly benign. You might be great at yoga or gymnastics and never think twice about it.
For a smaller subset, though, that extra range of motion comes with joint pain, muscle soreness, frequent sprains, and even dislocations. When hypermobility causes these kinds of musculoskeletal symptoms but doesn’t meet the criteria for a genetic condition, it’s classified as a hypermobility spectrum disorder. The most common symptom is pain in the joints and muscles, and some people also experience fatigue, digestive issues, and recurring ligament injuries.
The Difference Between Hypermobility and Ehlers-Danlos Syndrome
Hypermobile Ehlers-Danlos syndrome (hEDS) is a more specific and less common condition that involves generalized joint hypermobility alongside skin involvement, a family history of the condition, and problems across multiple body systems. It’s caused by disruptions in how the body produces or processes collagen, the protein that gives structure and strength to connective tissues like skin, tendons, and ligaments. Several genes involved in building or folding collagen molecules have been linked to various forms of Ehlers-Danlos syndrome.
The distinction matters because someone with asymptomatic hypermobility in their thumbs is in a very different situation from someone with hEDS who experiences chronic pain, frequent dislocations, and skin fragility. A 2017 international classification created stricter diagnostic criteria to separate hEDS from the broader category of hypermobility spectrum disorders, and those guidelines are currently being updated for expected publication in late 2026.
Why Some People Are More Flexible
Joint flexibility is determined by the structure and composition of your connective tissues, particularly collagen. Collagen fibers act like the cables holding a bridge together. If those cables are a bit stretchier or more loosely woven than average, the joints they support will have a wider range of motion. The shape of your joint surfaces and the depth of your joint sockets also play a role.
This is largely genetic. If one or both of your parents are hypermobile, you’re more likely to be as well. In cases involving Ehlers-Danlos syndrome, specific gene variants disrupt the production or assembly of collagen molecules, weakening connective tissues throughout the body. But for the majority of hypermobile people, the flexibility is simply a normal variation in how their bodies are built, not a sign of disease.
Living With Hypermobile Joints
If your flexible joints don’t cause pain or injuries, there’s nothing you need to do about them. Many hypermobile people find their flexibility is an advantage in activities that reward range of motion, like dance, swimming, or playing certain musical instruments.
If you do experience joint pain, frequent sprains, or a sense that your joints are “giving way,” strengthening the muscles around your most vulnerable joints is the most effective strategy. Strong muscles compensate for loose ligaments by stabilizing the joint during movement. Low-impact exercises like swimming and cycling tend to build that support without stressing the joints further. Avoiding repetitive hyperextension of already-loose joints can also help prevent the cumulative wear that leads to pain over time.