Ligament laxity is a condition in which the tough, fibrous bands connecting bones at a joint are looser than normal, allowing a greater range of motion than the joint was designed to handle. It can be inherited, acquired through injury, or influenced by hormones, and it ranges from a harmless party trick to a source of chronic pain, instability, and fatigue. The term sometimes gets used interchangeably with “joint hypermobility,” but laxity specifically describes the mechanical looseness of the ligament tissue itself, while hypermobility describes the resulting excess movement at the joint.
What Ligaments Do and What Goes Wrong
Ligaments are dense cords of connective tissue made primarily of collagen. Their job is to hold bones together at joints, limiting movement to a safe range and distributing mechanical loads across the joint surfaces. When ligaments are appropriately taut, they act like guide wires that keep the joint tracking smoothly under stress. At the molecular level, collagen fibers elongate and stiffen under load, which is part of what makes ligaments resilient during sudden movements. Research using advanced imaging has shown that at higher strain rates, collagen molecules shift how they distribute force internally, contributing to the tissue’s ability to resist sudden jolts.1Scientific Reports. Nano-scale mechanisms explain the stiffening and strengthening of ligament tissue with increasing strain rate
When a ligament is lax, this built-in restraint system is compromised. The joint can move beyond its intended range, which shifts how forces are distributed through the cartilage and bone. Over time, this altered loading pattern can damage the joint surface and the surrounding structures, setting the stage for a cascade of symptoms that extend well beyond simple looseness.
Genetic and Heritable Causes
The most common cause of widespread ligament laxity is genetic. Collagen is the structural protein that gives ligaments their tensile strength, and variations in the genes that encode collagen or the proteins that help organize it can produce ligaments that are stretchier than average. This is why ligament laxity often runs in families and tends to affect multiple joints at once rather than just one.
The most well-known genetic conditions associated with ligament laxity fall under the umbrella of Ehlers-Danlos syndrome, a group of connective tissue disorders. The latest classification recognizes 13 subtypes, all characterized by varying degrees of skin, ligament, joint, and blood vessel abnormalities.2PubMed Central. Differences in manifestations of Marfan syndrome, Ehlers-Danlos syndrome, and Loeys-Dietz syndrome The hypermobile subtype is the most common and primarily manifests as joint hypermobility, while rarer subtypes involve fragile blood vessels or severely stretchy skin. Researchers have identified specific gene variants that contribute, including splice-site mutations in the TNXB gene, which encodes a protein called tenascin-X that helps organize collagen fibers in connective tissue. When tenascin-X production is reduced, the extracellular matrix that supports ligaments becomes less structured.3PubMed Central. A TNXB splice donor site variant as a cause of hypermobility type Ehlers-Danlos syndrome in patients with congenital adrenal hyperplasia
Not everyone with genetically lax ligaments meets the criteria for a named syndrome. In 2017, an international consortium updated the classification system to distinguish between hypermobile Ehlers-Danlos syndrome and a broader category called hypermobility spectrum disorders, which captures people who have symptomatic joint hypermobility but don’t meet the full diagnostic criteria for EDS.4PubMed. Hypermobile Ehlers-Danlos Syndrome and Hypermobility Spectrum Disorders This distinction matters because it acknowledges that you can have clinically meaningful ligament laxity without having a textbook connective tissue disorder.
How Hormones Affect Ligament Tension
Ligament laxity isn’t always fixed. Hormones can temporarily loosen ligaments, and this is most obvious in two contexts: the menstrual cycle and pregnancy.
Estrogen and progesterone receptors are present in ligament tissue, and fluctuations in these hormones appear to influence how taut ligaments are. A systematic review of 13 clinical trials found that the anterior cruciate ligament in the knee becomes measurably more lax during certain phases of the menstrual cycle, with the greatest looseness occurring around the pre-ovulatory phase when estrogen peaks.5PubMed Central. Anterior cruciate ligament laxity related to the menstrual cycle: an updated systematic review of the literature Individual studies have confirmed that both peak estrogen and peak progesterone levels correspond with increased ACL laxity compared to baseline.6PubMed Central. Hormonal changes throughout the menstrual cycle and increased anterior cruciate ligament laxity in females This hormonal effect is one reason researchers have investigated whether certain phases of the cycle carry a higher risk of ligament injuries, though translating lab-measured laxity into real-world injury risk has proven complicated.
During pregnancy, the hormone relaxin plays a more dramatic role. Relaxin is specifically designed to loosen pelvic ligaments and joints, making space for delivery.7PubMed. Circulating levels of relaxin are normal in pregnant women with pelvic pain Its effects aren’t confined to the pelvis, though. Many pregnant people notice increased looseness in their knees, ankles, and feet, which is why shoe size sometimes changes during pregnancy. This hormone-driven laxity is generally temporary and resolves in the months after delivery, though some people report lasting changes.
Acquired Laxity From Injury
You don’t need a genetic predisposition to develop ligament laxity. A single bad sprain can permanently stretch or tear ligament fibers, and the repaired tissue is often less taut than the original. This is especially well-documented in the ankle. When the lateral ankle ligaments are disrupted by a sprain, the resulting mechanical instability makes the joint vulnerable to repeat injury. A systematic review of ankle instability research found that chronic ankle instability produced the largest effects on inversion laxity, with the joint becoming substantially looser in the direction of the original injury.8PubMed Central. Mechanical Joint Laxity Associated With Chronic Ankle Instability: A Systematic Review The same pattern applies to other joints: a torn ACL, even after surgical reconstruction, often leaves the knee with slightly more play than it had before injury.
Repetitive microtrauma can also gradually stretch ligaments over time. Occupations or sports that involve repeated end-range loading of a joint, such as gymnastics, swimming, or manual labor involving overhead reaching, can slowly increase laxity without a single dramatic injury event. The distinction between “naturally flexible” and “lax from overuse” can be difficult to draw in people who have spent years in these activities.
How Laxity Changes With Age
Children are, on the whole, much more flexible than adults, and a significant portion of childhood joint hypermobility resolves naturally. A longitudinal study tracking children over two years found that the proportion meeting criteria for generalized joint hypermobility dropped sharply, from about one in four to roughly one in sixteen by the final measurement. The decrease was driven primarily by reduced range of motion at the elbows and knees rather than changes in finger or hamstring flexibility.9PubMed Central. Age- and sex-related changes in children with and without generalized joint hypermobility: a two-year follow-up study
This age-related tightening means that a bendy eight-year-old is not necessarily destined for lifelong laxity. However, children whose hypermobility is accompanied by pain, frequent subluxations, or delayed motor milestones may be showing signs of an underlying connective tissue disorder that won’t simply be outgrown. A systematic review of prevalence data found that hypermobility rates in children and adolescents varied widely depending on the measurement tool and population studied, ranging from roughly 9% to 36%.10PubMed Central. Hypermobility prevalence, measurements, and outcomes in childhood, adolescence, and emerging adulthood: a systematic review That wide range reflects both real population differences and inconsistencies in how hypermobility is defined and measured.
Joint Symptoms and Instability
The most obvious symptom of ligament laxity is joints that move farther than expected. You might be able to bend your thumb to your forearm, hyperextend your elbows or knees, or touch your palms flat to the floor with straight legs. When laxity is mild and painless, it’s often just an interesting quirk. When it’s more pronounced, the excess movement becomes a problem.
Unstable joints are vulnerable to subluxations, partial dislocations where the joint briefly slips out of alignment and then returns. These can happen during ordinary activities: reaching for a jar on a high shelf, rolling over in bed, or carrying a bag of groceries. Recurrent subluxations cause local inflammation and pain, and over time they can damage cartilage and other soft tissues. People with significant laxity often describe a feeling of joints “giving way” or of constantly having to brace themselves against their own flexibility.
Laxity is also associated with a range of musculoskeletal findings beyond simple looseness. Clinical evaluations often reveal flat feet, knock knees, spinal curvatures like scoliosis or exaggerated lumbar lordosis, and kneecaps that tend to drift out of their groove.11The American Journal of Medicine. What Is Ligament Laxity? Causes and Symptoms – Section: Clinical Evaluation These aren’t separate conditions so much as downstream consequences of connective tissue that doesn’t hold structures in their intended alignment.
Impaired Proprioception
One of the less intuitive effects of ligament laxity is reduced proprioception, the body’s sense of where its joints are positioned in space. Ligaments contain mechanoreceptors that send position and tension information to the brain, and when ligaments are lax, those signals become less precise. A study comparing hypermobile and non-hypermobile individuals found that the hypermobile group had significantly greater errors in joint position sense tests at both the elbow and the knee.12PubMed Central. The effects of joint hypermobility on strength, proprioception, and functional performance
This matters because proprioception is what lets you catch yourself when you stumble, adjust your grip when you’re carrying something heavy, or land safely after a jump. When it’s impaired, you’re more reliant on visual cues and conscious effort to maintain coordination, which increases both injury risk and the mental fatigue of everyday movement. People with lax ligaments often describe feeling clumsy or uncoordinated, and impaired proprioception is a significant part of why.
Symptoms Beyond the Joints
Ligament laxity, especially when it stems from a connective tissue disorder, often produces symptoms that seem to have nothing to do with joints. Connective tissue is everywhere in the body, and when it’s structurally different, the effects can be widespread.
Gastrointestinal problems are among the most commonly reported. An increasing body of research has identified a cluster of conditions that frequently travel together: hypermobility spectrum disorders, postural orthostatic tachycardia syndrome (a form of autonomic dysfunction that causes rapid heart rate upon standing), and mast cell activation syndrome (an immune condition involving inappropriate release of inflammatory chemicals).13PubMed Central. The Suggested Relationships Between Common GI Symptoms and Joint Hypermobility, POTS, and MCAS People in this cluster often experience nausea, bloating, acid reflux, and altered bowel habits. The exact mechanisms linking these conditions are still being worked out, but the connective tissue lining the gut and the autonomic nerves that control digestion both appear to be involved.
Other extra-articular symptoms reported in people with generalized laxity include easy bruising, varicose veins, thin or stretchy skin, and pelvic organ prolapse.11The American Journal of Medicine. What Is Ligament Laxity? Causes and Symptoms – Section: Clinical Evaluation Fatigue is also extremely common and often more disabling than the joint symptoms themselves. When every movement requires extra muscular effort to compensate for loose ligaments, and when sleep is disrupted by pain or positional discomfort, chronic exhaustion is an almost inevitable result.
How Laxity Is Measured
The standard screening tool for generalized joint hypermobility is the Beighton Score, a nine-point system that tests five specific maneuvers: bending the little finger back past 90 degrees, bending the thumb to the forearm, hyperextending the elbows, hyperextending the knees, and touching the palms flat to the floor with straight legs. A score above a certain threshold (typically 5 out of 9 for adults) is considered positive for generalized hypermobility.
The Beighton Score is quick and easy to administer, which is why it became the go-to tool. But it has real limitations. A comprehensive review found that the score predominantly tests upper-limb joints and ignores many major joints entirely, including the shoulders, hips, and spine. It consistently failed to identify hypermobility in joints outside its scoring system, meaning someone with very lax shoulders and hips but normal fingers and elbows could score as “not hypermobile.”14PubMed Central. The Beighton Score as a measure of generalised joint hypermobility The review concluded that clinicians shouldn’t rely on the Beighton Score alone to rule out generalized hypermobility and should use their own clinical judgment alongside it.
For localized laxity resulting from injury, assessment typically involves stress tests specific to the affected joint: anterior drawer tests for the ankle or knee, valgus and varus stress tests for the elbow, and so on. Imaging with MRI can reveal the structural damage underlying the laxity, but the clinical exam remains the primary diagnostic method.
Who Is Most Affected
Joint hypermobility is not evenly distributed across populations. Most studies find it’s more common in women than in men, though one systematic review noted that the gender difference wasn’t always consistent in children, with some studies showing higher rates in boys within certain age ranges.10PubMed Central. Hypermobility prevalence, measurements, and outcomes in childhood, adolescence, and emerging adulthood: a systematic review A study of military service members found that women had a higher incidence of joint hypermobility syndrome than men, and that white service members had higher rates than Black service members or those of other racial backgrounds.15PubMed Central. Incidence of joint hypermobility syndrome in a military population: impact of gender and race
Ethnicity also plays a role in baseline flexibility norms. Populations in parts of Asia and Africa have been found to have higher average joint mobility than European populations, which complicates the use of a single numerical cutoff to define “hypermobility” globally. A Beighton Score of 5 might be unremarkable in one population and quite unusual in another. This is one reason prevalence estimates vary so widely across studies.
Long-Term Consequences for Joint Health
Ligament laxity, whether genetic or acquired, is a risk factor for osteoarthritis. When a joint isn’t adequately stabilized, the cartilage and underlying bone are subjected to abnormal loading patterns. Instead of forces being distributed evenly across the joint surface, they concentrate in areas that weren’t built to handle them, leading to accelerated wear.16PubMed Central. Ligament Injury, Reconstruction and Osteoarthritis This is why a ligament-injured knee, even after surgical repair, carries a substantially elevated risk of developing arthritis in the following decades.17PubMed Central. Joint instability and osteoarthritis
For people with generalized laxity, this risk applies to multiple joints simultaneously. It’s not uncommon for someone with hypermobility to develop osteoarthritis in their knees, hips, and hands while still relatively young. The paradox of hypermobility-related arthritis is that these are often people who appear exceptionally flexible and “healthy” from the outside, which can lead to delayed diagnosis and dismissal of their pain.
Management Approaches
There’s no way to tighten a genetically lax ligament. The collagen is structurally different, and no medication or supplement changes that. Management instead focuses on building the muscular strength and neuromuscular control needed to compensate for the lack of passive stability.
Therapeutic exercise is the best-supported intervention. A scoping review of physical therapy for people with generalized hypermobility spectrum disorder and hypermobile Ehlers-Danlos syndrome found that exercise programs and motor function training were effective at reducing symptoms.18PubMed. Physical therapy interventions in generalized hypermobility spectrum disorder and hypermobile Ehlers-Danlos syndrome: a scoping review The emphasis is on controlled strengthening rather than stretching. People with ligament laxity already have excessive range of motion; what they need is the muscular endurance to maintain joint alignment through that range. Proprioceptive training, exercises that challenge balance and joint position awareness, is also a key component.
Beyond exercise, management often involves bracing or taping for specific unstable joints, pacing activities to avoid overloading vulnerable joints, and addressing associated conditions like dysautonomia or gastrointestinal problems. For acquired laxity from a torn ligament, surgical reconstruction may be appropriate, though even successful surgery typically restores something close to, rather than identical to, the original stability.
Laxity in Athletes and Performers
The relationship between ligament laxity and athletic performance is complicated. In some activities, extra flexibility is an outright advantage. Dancers, gymnasts, and swimmers often self-select for hypermobility because their sports reward extreme range of motion. But that same laxity increases vulnerability. A five-year follow-up study of ballet dancers found that those with joint hypermobility syndrome appeared to face a greater risk of injury or prolonged recovery from injury, with potential implications for career longevity.19Rheumatology. Injury and joint hypermobility syndrome in ballet dancers—a 5-year follow-up
Recognition of joint hypermobility goes back much further than modern sports medicine. Hippocrates described families with shoulder instability in the fourth century BC and even noted medical interventions to improve function for javelin throwers and archers. Similar observations have been documented throughout history in contortionists and musicians.20PubMed Central. International Perspectives on Joint Hypermobility: A Synthesis of Current Science to Guide Clinical and Research Directions – Section: HISTORICAL PERSPECTIVES OF JOINT HYPERMOBILITY The condition wasn’t formally defined as a medical syndrome until the 1960s, but humans have been grappling with its practical consequences for millennia.
The Psychological Toll of Chronic Laxity
Living with ligament laxity, especially the symptomatic kind, takes a psychological toll that often gets overlooked. One of the more specific psychological consequences is kinesiophobia, a fear of movement driven by the expectation that movement will cause pain or injury. A study of patients with joint hypermobility syndrome found that kinesiophobia was prevalent in the group and that it was strongly correlated with the overall severity of fatigue, even though it didn’t correlate with pain intensity.21PubMed Central. Evaluation of kinesiophobia and its correlations with pain and fatigue in joint hypermobility syndrome/Ehlers-Danlos syndrome hypermobility type In other words, it’s not that people in more pain are more afraid to move; rather, the experience of having unreliable joints creates a generalized avoidance of physical activity that feeds directly into fatigue.
This creates a vicious cycle. Avoiding movement leads to muscle deconditioning, which makes the joints even less stable, which makes movement feel even more risky. Breaking this cycle is one of the central challenges of managing symptomatic laxity, and it’s why psychological support and graded exercise programs are so important alongside purely physical interventions. The condition is also frequently dismissed or minimized by clinicians who equate flexibility with health, which adds frustration and isolation to the experience of chronic symptoms.