What mobility actually means — and what changes after 40

The short answer: mobility is range of motion you can actually use — get into, control, and get out of with your own strength. It is not flexibility alone. After 40 it narrows mostly through disuse, not decree: positions you stop visiting (deep squats, floor sitting, arms overhead) quietly leave the menu. Which means most of the loss is recoverable, because the cause is behavioral.

What changes with age

Connective tissue stiffens and tolerates sudden load less graciously. Discs and joints lose some water content. Balance erodes — less from the inner ear than from losing the fast muscle power that catches a stumble. And modern life shrinks the movement diet to sitting, standing, and walking on flat ground, so everything outside that range atrophies on schedule.

What the evidence supports

Strength training through a full range of motion has been shown to improve flexibility roughly as well as stretching — while also building the strength to use it. Stretching improves range of motion too, and research suggests the gains are mostly in stretch tolerance. Balance improves with practice and with leg power work, not with caution. And walking remains genuinely underrated: regular brisk walking is associated with better joint health and function, not the joint “wear” people fear.

What to do about it

Reintroduce the positions you’ve lost, gently and daily. Sit on the floor and get up once a day, any style. Squat to something low while holding a support. Take hips and ankles through slow circles after waking. Walk enough that your shoes wear out. None of this needs a gym; all of it needs frequency.

What we don’t know

How much stretching adds on top of full-range strength work is genuinely unsettled, and pre-exercise static stretching is neither the injury shield nor the performance killer either camp claims. Do what makes movement feel better.

When to talk to a clinician

Joint pain at rest, pain that wakes you, swelling, or a joint that gives way — those are medical, not mobility, problems. Same for numbness or tingling that follows a limb. See someone before training around it.