I have two patients in mind that I see regularly. One is 84: she climbs the stairs in her building without holding the railing, gardens every weekend, and rarely complains about her knees. The other is 45: he can no longer crouch down to pick something up without thinking twice, and his shoulders are stiff every morning. If age explained mobility, it should be the other way around.
This contrast isn't unusual — I see it constantly in clinic. And it's taught me something I repeat often: age is almost never the real explanation for a stiff joint.
What age doesn't explain
It's true that cartilage changes over time — a natural, well-documented process affecting much of the population past a certain age, with or without osteoarthritis. But this structural change isn't directly proportional to how much discomfort someone feels. Many people show visible wear on imaging without significant stiffness, while others, younger, have very limited mobility with no particular abnormality. Age sets a context — it doesn't dictate the outcome.
What actually makes the difference
What I observe, year after year, is that the variable that matters most isn't the number of years, but how regularly a joint is mobilised. A joint that moves through varied ranges, regularly, keeps its flexibility far longer than a young joint immobilised by lifestyle — prolonged sitting, sedentary habits, the same movements repeated endlessly. This is exactly what we saw in our September series on mechanical load: it's not the joint's age that matters, it's what you do with it day to day.
Osteoarthritis isn't a life sentence
Osteoarthritis affects millions of people in France today, and it's the most common joint condition. But having osteoarthritis doesn't mean being condemned to immobility — many people live actively with it, when mobility is maintained. What I want to challenge here isn't the existence of osteoarthritis, but the idea that it, or age in general, alone explains the stiffness someone feels.
If you feel your joints are stiffer than those of people older than you, that's probably not an anomaly — it's a signal. In the next article, we'll look at an often-overlooked factor: the real role of weather in joint pain, and why it's not quite what most people believe.
— Physical Therapist, founder of Reprogrammer Boutique