Why Does Flexibility Change With Age?

Many people notice, at some point, that certain movements don't come as easily as they used to. That general pattern is well documented in research. What's less often discussed — and worth being honest about — is how much it varies from person to person, and how much of it staying active can actually change.

What's Happening in the Tissue

A 2026 narrative review of the mechanisms behind joint range of motion points to the connective tissue around joints, rather than muscle length itself, as the main structural factor in how much a joint can move. That review also notes that tissue can hold less water with age, which affects how tissue behaves under stretch, and that part of what's measured as “tightness” reflects the nervous system's stretch tolerance — not solely a fixed, fully mechanical property of the tissue.

The Decline Isn't Uniform

A large study analyzing roughly 6,000 flexibility assessments across a wide age range found a clear, statistically significant decline in mobility with age — but a joint-specific one, not a uniform one. Shoulder mobility, for example, declined considerably more than knee or elbow mobility across the age groups studied; the researchers speculated this may be because extreme ranges of motion at the shoulder are rarely used in daily life, leaving that joint more vulnerable to decline. That same research found that only about half to three-fifths of the variability in flexibility was explained by age itself. The remainder is harder to pin down: the researchers suggested less active lifestyles over time could plausibly play a role, but they didn't directly measure participants' activity levels — they noted that gap as a limitation of the study, not a tested finding.

It's Genuinely Individual

How much any one person's flexibility changes, and how quickly, varies substantially. One study of adults aged 55–86 found that age and physical activity level together explained only about 9–10% of the variation in hip flexibility measured across participants — meaning most of the difference between individuals wasn't explained by either factor in that particular sample. That's a useful reminder that broad patterns don't predict any one person's experience especially well.

Does Staying Active Help? The Evidence Is Real but Tentative

This is the part worth being most careful about. Some research does support a benefit: one 2024 systematic review and meta-analysis found long-term static stretching improved range of motion and stretch tolerance in older adults specifically, and a separate 2025 meta-analysis found resistance training improved joint flexibility with a moderate-to-large effect, with age not significantly changing that effect. Both of those reviews, however, flagged real limitations in the underlying studies — the resistance-training review noted that none of the included studies were rated low risk of bias, and both called for more research.

At the same time, the individual-variation study mentioned above found that physical activity level was not a statistically significant predictor of flexibility in that particular sample, even though age was. That's a genuine tension in the evidence, not a settled answer, and it's worth holding both findings rather than picking the more encouraging one.

The Bottom Line

Flexibility does tend to decline with age on average, driven mainly by changes in connective tissue and how much a person moves through a full range of motion — not an inevitable, uniform deterioration that happens the same way to everyone. Individual variation is substantial, and while staying active appears to help for many people, the evidence for exactly how much, and for whom, is still being worked out.