Upper legs

Clamshell

Lying on your side with your knees bent, you open your top knee like a clamshell: simple, effective glute activation.

Also known as: clamshells, clam exercise

Level: Intermediate
Equipment: Bodyweight
Type: Compound

Movement

Muscles worked

Clamshell muscle map: abductors, glute medius and glutes highlighted on the front and back of the body

How to do it

Lie on your side with your knees bent to about 45 degrees and your feet together.
Rest your head on your arm and keep your hips stacked.
Open your top knee without separating your feet or rolling your hips back.
Close slowly and repeat.

Form cues

Your pelvis stays still.
Open only as far as your hips stay stacked.
With a band, place it just above your knees.

Common mistakes

Rolling your hips back to open wider: the movement comes from your back.
Rushing: the glute medius needs control.
Separating your feet: keep them together.

Sets and reps

2-3 sets of 15-20 reps per side, as a warm-up or at the end of a session.

Variations

Same movement, different equipment. Pick based on what you have and what you want from clamshells.

Banded clamshell
A band around your knees adds resistance.
Loop Band · Beginner
How to do it
1. Lie on your side with hips and knees bent to roughly 45 degrees, feet stacked.
2. Place a loop band around both legs above the knees.
3. Keep the feet pressed together and the pelvis stable — do not roll back as you move.
4. Open the top knee upward against the band, like a clamshell opening, until you feel the glute fire.
5. Pause briefly at the top, then lower under control to the start.
6. Complete all reps on one side, then switch.
Primary
Glute Medius
Secondary
Glutes
Clamshell hold
Hold your knee open for a few seconds.
Bodyweight · Intermediate
How to do it
1. Lie on one side with the hips and knees bent about 45 and 90 degrees, heels together and knees stacked.
2. Stack the shoulders and hips vertically and brace the trunk so the pelvis cannot roll backwards.
3. Open the upper knee as far as it goes without the pelvis rotating, keeping the heels touching.
4. Hold that open position for the prescribed time, breathing normally.
5. Lower the knee under control and repeat on the other side.
Primary
Abductors, Glute Medius
Secondary
Glutes

Alternatives

Other exercises from the Nuvana library for the same muscle.

FAQ

What are clamshells good for?

To activate and strengthen the glute medius; common in warm-ups and knee and hip rehab.

With or without a band?

Start without one; once 20 reps feel easy, add a light band.

Will it grow my glutes?

Not much; it's more for activation. Growth needs loaded exercises.

What muscles do clamshells work?

They mainly work the abductors and the glute medius, with help from the glutes.

Train with Nuvana

Add clamshells to your next workout

Log your sets and weights, and see how each muscle progresses in the app.