Knee pain, what to do: start with your hips and ankles.

You get up after a long meeting and there's that knee pain. Going downstairs at night, you hold the banister. Your Saturday run is on hold.

Usually there's been no knock. I see it a lot in people who go from desk to weekend run. Diagnosis is your doctor's job; meanwhile, you can strengthen what keeps the knee in place.

Where you feel it

The ache builds slowly, usually at the front, around the kneecap.

• When you bend it. Squatting down, getting up from a low chair, getting into the car.
• On the stairs. Going up, and often more coming down.
• After a run. Especially on tarmac or cambered roads.

The mirror test. Stand on one leg in front of a mirror and bend the knee halfway. If it drifts inwards, your hip and ankle aren't keeping it in line.

Why your knee pays for the rest

Your knee mostly just bends and straightens. It sits between two freer joints, hip and ankle, and when either works badly, the knee takes the load. Like a hosepipe trodden on further back: the water stops at the nozzle.

Above, the hip. On one leg, with every step and stair, the muscles at the side of your bottom keep your pelvis level and your knee in line. Weak ones let the knee drop inwards, overloading one side of the joint.

Below, the ankle. If it doesn't bend forward enough, the knee looks for room by moving inwards. A stiff ankle tends to wear the knee out sooner.

In between, the thigh. Going downstairs or sitting down, your quads brake your weight: the stronger they are, the better they spread the load. Extra weight, shoes and surfaces count too, and a small misalignment repeated for years can become wear and tear by fifty or sixty.

Knee pain: what should you do?

For a few weeks, drop whatever sets it off and strengthen hips, thighs and ankles, always pain-free. Stopping completely is a common mistake: the muscles protecting the knee get weaker.

No impact, for now. Jumping, running downhill, deep squats with weight. In the gym, reverse lunges are kinder than forward ones; on the leg press, never lock your knees.

Start still. Back to the wall, feet slightly forward: slide down only as far as is pain-free and hold a few seconds, at two or three heights. A muscle pushing without moving produces plenty of force and protects the joint.

Work the side of your hip. At the gym, the abductor machine. At home, a similar move with a band just above your knees: knees slightly bent and pain-free, push them apart and back slowly. Sets of fifteen reps or more, in your two weekly strength sessions. Stronger hip muscles often ease pain at the front of the knee.

Thighs, with a straight leg. On the floor, one knee bent, the other leg straight: lift it a hand's width, hold, lower slowly. Your quads work and the knee stays straight.

Free up your ankle. Foot five fingers' width from the wall: bring your knee forward to touch it, heel down. If you can't, rock in and out five times over your second toe and five over your little toe. And foam roll your calf daily.

Tonight, a mirror and a wall are all you need. If the stairs don't feel easier within a few weeks, get it looked at.