What is the difference between mobility and flexibility?

Somewhere in the last decade, "mobility" moved from physiotherapy clinics to every gym timetable, and "flexibility" started to sound slightly old-fashioned, like leg warmers. They are often used as if they meant the same thing. They do not quite, and the difference is worth knowing because it changes what you practise.

The simple version

The clearest way to think about it comes from a distinction physiotherapists use all the time: passive versus active range of motion. Medical News Today, explaining the clinical terms, describes passive range of motion as how far a joint moves when someone or something else is moving it, such as a therapist or a machine, and active range of motion as how far a person can move the joint themselves.

In fitness language, the two words roughly map onto that:

• Flexibility is closer to the passive end: how far a muscle and joint can be lengthened, often with help. Think of a partner lifting your leg, or sinking into a stretch with gravity doing the work.
• Mobility is closer to the active end: how far you can move a joint under your own control, and how well. Think of lifting your own leg as far as it will go and holding it there.

Coaches and writers do not all use the words in exactly the same way, so treat these as working definitions rather than official ones.

A test you can try

Stand next to a wall for balance.

1. Lift one knee and then straighten that leg out in front of you as far as you can, using only your own muscles. Note how far it goes.
2. Now hold the back of the same thigh with your hands, or loop a strap round your foot, and gently help it a little further.

The gap between the two is the gap between your mobility and your flexibility in that movement. Almost everyone can be helped further than they can move on their own.

Why the distinction matters

Everyday movement is mostly active. Reaching up to a top shelf, crouching to tie a child's shoe, turning to look behind you on a bike, stepping over a gate on a walk: you are moving your own joints, often while balancing and carrying something. Being able to be stretched far does not automatically mean you can use that range with control.

That is why many coaches now pair stretching with movement: they want you to be able to own the range, not just visit it. It is also why someone very flexible can still feel unsteady in a deep lunge, and why someone who cannot touch their toes might move beautifully around a tennis court.

What practising each looks like

Flexibility work tends to be slower and more passive:

• Holding a stretch, breathing and letting the muscle relax.
• Using a strap, a wall or the floor to support you.
• Positions from yoga or stretching classes.

Mobility work tends to be active and moving:

• Controlled leg swings, arm circles and hip circles.
• Deep squats and lunges you move in and out of slowly.
• Holding a position with your own strength, for example lifting your leg and keeping it there.
• Moving through a full range with a light weight.

Both have a place, and many sessions mix them. If you want to work on one specific reach, our page on touching your toes is a good example of both at once. The question of when to stretch is covered in stretching before or after exercise.

Keep it in proportion

Neither is a test you pass or fail, and nobody needs to do the splits to live a full, active life. What most people want is to move through their day, their sports and their holidays with ease. Variety does a lot of that work: walking, swimming, dancing, playing with kids, climbing stairs and the occasional yoga class all ask your joints to move in different directions.