HomeWorkoutsGlutes

Clamshells

Lie on your side and open the top knee like a shell. Physiotherapists give this one out constantly, because weak side glutes are behind a lot of knee pain.

Level Beginner
Equipment None
Sets and reps 3 sets x 15-20 each side
Works on Side glutes

How to do it

  1. Lie on your side with knees bent and stacked, heels in line with your back.
  2. Rest your head on your lower arm and keep the hips stacked.
  3. Keeping the feet touching, open the top knee upward.
  4. Lower slowly. Finish the set, then turn over and do the other side.

Common mistakes

  • × Rolling the top hip backwards to open wider - the hips stay stacked.
  • × Letting the feet come apart.
  • × Going fast - it is a small slow movement.
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One thing that matters

Put your top hand on the side of your hip. If you feel it working there, you are doing it right.

How much

Sets and reps for Clamshells

Where you are Aim for
Just starting 3 sets x 12 each side
The standard 3 sets x 15-20 each side
Once it is easy 3 sets x 25 each side, 3 second hold
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Breathing

Out as the knee opens, in as it closes. Small movement, steady breath.

Too hard, or too easy?

Where this sits

Questions

Clamshells, answered

Why are clamshells used in physiotherapy so often?

They isolate the gluteus medius with almost no load on the spine or knees, which makes them safe to prescribe to almost anyone. The same reason makes them a good beginner exercise at home.

Should my hips roll back?

No, and that is the main mistake. Stack your hips exactly on top of each other and keep them there. If the top hip rolls backwards, the movement becomes much easier and stops working the target.

I feel nothing. Am I doing it wrong?

Probably rolling the hip back, or moving too fast. Put your free hand on the side of your hip - you should feel the muscle under it tighten on every rep.

One exercise is never the whole story

Which day to do Clamshells, how many sets, and what to pair it with - the AI builds the whole plan. Your first one is free.

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Glutes

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This is general information, not medical advice

Everything on this page is worked out from a formula or from published averages. It has never met you, and it cannot see your blood pressure, your medication or an old injury.

Talk to a doctor before you start if you are pregnant or breastfeeding, have a heart condition, diabetes or high blood pressure, take regular medication, have or have had an eating disorder, are recovering from injury or surgery, or are under 18. Stop and get advice if any exercise causes pain, dizziness or chest discomfort.

More about where these numbers come from is on the about page.