Hips · 30–60 seconds of controlled repetitions per side

The clamshell, for the side of the hip

A small movement aimed at a muscle that keeps your pelvis level every time you take a step.

Gluteus medius sits on the outside of the hip and does an unglamorous job: it stops the pelvis dropping every time you stand on one leg, which is most of walking. The clamshell isolates it in side-lying, where the bigger muscles cannot easily take over.

How to do it

1. 1

   Lie on your side with your knees bent to roughly forty-five degrees

   Hips stacked, one directly above the other. Head supported on your lower arm or a cushion.

2. 2

   Keep your feet together and lift the top knee

   Open the knee like the hinge of a clam. The movement is small — this is not about how far the knee travels.

3. 3

   Lower with control and repeat

   You should feel it on the outside of the top hip. If you feel it in the front of the thigh, the leg has rotated — reset and go smaller.

Make it easier

Reduce the range to a few centimetres and slow it down. This muscle responds to being isolated, not to being pushed.

Make it harder

Pause for two seconds at the top of each repetition, or lift the whole bottom side slightly off the floor to add a stability demand.

The mistake that undoes it

Rolling the pelvis backwards to open the knee further. It makes the range look bigger and takes the load straight off the muscle you came for. Keep the hips stacked.

Sharp pain at the outside of the hip, or pain that lingers afterwards, is worth having looked at rather than working through.

Also called clamshell exercise, clam shell, side-lying hip. Drawn from the clinically authored Vinys exercise library — how the method works. General movement guidance, not medical advice.