Clamshell exercise for hips and lower back: how to do it

The clamshell is a small floor exercise for the muscles at the side of your hips. Many people who sit most of the day do not use these muscles much, and a short strengthening exercise is an easy way to include them in a routine. It takes about 45 seconds.

It will not fix back pain on its own. Guidance on back pain generally recommends staying active and moving regularly, and gentle strengthening can be part of that.

General information, not medical advice. Move gently and stop if anything hurts.

How to do it

Lie on your side with your knees bent and heels together.
Keep your feet touching and lift your top knee like a clamshell, without rolling your pelvis back.
Lower slowly. Finish all reps, then switch sides.

Dose: 10 slow repetitions per side.

Tip: Place a hand on your hip to feel that your pelvis stays still.

Common mistakes

Rolling your pelvis backward as you lift. Only the knee should move.
Lifting too high. A small, controlled range is enough.
Letting the knee drop quickly. Lower it slowly.
Holding your breath or pushing into pain.

Easier options

Lift the knee only a little.
Do 5 repetitions per side instead of 10.
Rest your head on a pillow or your lower arm.

This matches the Clamshell exercise in the Mo app.

When to stop and see a professional

Stop and speak to a doctor or physiotherapist if you notice:

numbness, tingling or weakness in a leg or foot
pain that shoots down a leg
pain that started after an accident, fall or other injury
problems controlling your bladder or bowels (seek emergency care)
pain that keeps getting worse, wakes you at night, or comes with fever or unexplained weight loss

If the movement causes sharp pain, stop and try the lying knee rock guide instead, or ask a professional.

Do this with Mo, a 5-minute guided routine app

Mo the sloth guides short daily posture, neck and back exercises, with gentle reminders and a pain check-in. Learn more about Mo.

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