Side-lying Clamshell

Side-lying Clamshell is a strength – resistance exercise exercise involving Gluteus medius, Hip external rotators. Use these steps to learn the movement and work with your coach to choose a suitable level.

Last updated: 2026-10-31 · DynPerformance

Primary muscles: Gluteus medius, Hip external rotators
Secondary muscles: Gluteus maximus, Lateral abdominal wall
Exercise type: Strength – resistance exercise

Exercise technique

Side-lying position
Support your head and stack your hips.
Knee angle
Bend both knees and keep your feet together.
Pelvis
Stabilize your top hip without letting it roll backward.
Open
Lift your top knee while keeping your heels together.
Pause
Stop before your pelvis begins to rotate.
Close
Slowly bring your top knee toward the lower knee.
Switch
Turn to the other side while preserving body alignment.

Key technique points

Keep your heels together.
Do not roll the top hip backward.
Do not twist your lower back to open the knee.
Keep your shoulders stacked.
Choose a small, controlled range.
Do not knock your knees together as you close.

Common mistakes

Rolling backward

The knee opening comes from torso rotation instead of hip rotation.

Separating the feet

This loses the fixed heel connection of the clamshell.

Twisting the lower back

This reduces pelvic stability.

Opening too far

The torso moves once you exceed your control limit.

Throwing the shoulder backward

Upper-body movement rotates the hips too.

Closing quickly

This removes the external rotators’ control of the return.

Frequently asked questions