Clamshell
How to Do a Clamshell
Lie on your side on an exercise mat with your legs stacked and knees bent at 45 degrees.
Rest your head comfortably on your bottom arm and place a mini-band above your knees (optional).
Brace your core muscles and stack your hips directly over one another perpendicular to the floor.
Keeping your feet pressed together, rotate your top knee upward as high as possible.
Hold the peak open clamshell position for one second, squeezing your outer glute.
Lower your top knee back down under control until it meets your bottom knee.
Complete all repetitions on one side before flipping over to the opposite side.
Form Check & Technique
DO THIS (Technique Tips)
- Keep feet pressed together.
- Keep hips stacked straight up.
- Squeeze outer glute at peak open position.
AVOID THIS (Common Mistakes)
- Rolling Hips Backward — Fix: keep hips stacked vertically throughout.
- Separating the Feet — Fix: keep soles of feet pressed together.
- Rushing reps — Fix: hold a 1-second squeeze at peak knee open.
About Clamshell
The clamshell is a highly effective exercise designed to target and strengthen the gluteus medius. Executing the clamshell with proper technique optimizes muscle recruitment while keeping joint stress minimal. Learn how to perform the clamshell safely, avoid common form mistakes, and integrate it into your workout routine.
Clamshell Muscles Worked
The clamshell isolates hip external rotation and abduction from a side-lying position.
- Keeping feet glued together forces the top gluteus medius and deep hip rotators to open the knees.
Sets & Reps Guidance
Technique / Learning
Technique: 2 sets of 15 bodyweight reps per leg.
Strength Focus
Strength accessory: 3 sets of 12–15 reps per leg with a heavy mini-band.
Muscle Growth (Hypertrophy)
Hypertrophy: 3–4 sets of 15–20 reps per leg with band.
General training baseline. Need.fit automatically adjusts exact sets, reps, and working weight based on your individual fitness level, recovery, and progress over time.
Exercise Variations & Alternatives
Fire Hydrant
Quadruped hip abduction.
Lateral Band Walk
Standing lateral resistance walk.
Hip Airplane
Standing bodyweight hip rotation.
Hip Thrust
Learn proper hip thrust form, muscles worked, bench and foot setup, top-position cues, common mistakes, progressions, variations, and practical sets and reps.
Barbell Bench Press
Learn proper barbell bench press form, muscles worked, grip and bar-path cues, common mistakes, and practical sets and reps for strength or muscle.
Dumbbell Bench Press
Learn dumbbell bench press form, muscles worked, setup, range-of-motion cues, common mistakes, and practical sets and reps for controlled chest training.
Targeting Deep Hip External Rotators
In addition to the gluteus medius, clamshells target deep hip stabilizers like the piriformis and obturator internus, which keep the femoral head centered in the hip socket.
Physical Therapy and Rehab Foundations
Clamshells are widely prescribed in physical therapy to treat IT band syndrome, patellofemoral pain, and gluteal amnesia.
Programming Clamshells
Perform 3 sets of 15–20 reps per leg as a glute activation drill or hip physical therapy exercise.
Sources & References
- [1]
- [2]