How to do the Clamshell
The clamshell is an accessible side-lying accessory exercise. Its value comes from pelvic control, not from opening the knee as far as possible.
How to do it
- 1
Lie on your side
Stack shoulders and hips with the knees comfortably bent.
- 2
Keep the feet together
Brace gently and keep the top hip from rolling back.
- 3
Open the top knee
Use a small range that does not move the pelvis.
- 4
Lower slowly
Return with control and keep tension between repetitions.
Common mistakes and fixes
Rolling backward
Fix: Reduce the range and imagine the top hip staying forward.
Rushing repetitions
Fix: Pause briefly at the top and lower for two seconds.
Using a band too soon
Fix: Master bodyweight control before adding resistance.
Programming starting point
Use 2–3 sets of 12–20 per side. Add a light loop only when the pelvis remains still.
Frequently asked questions
Is the clamshell beginner-friendly?
Yes. Begin with light or no resistance and prioritize a stable, pain-free range.
How many clamshell reps should I do?
Use 2–3 sets of 12–20 per side. Add a light loop only when the pelvis remains still.
Sources
- Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults — American College of Sports Medicine / PubMed (accessed August 2026)