rehab · beginner

Banded Clamshells

A side-lying hip external rotation exercise using a resistance band above the knees. Targets the gluteus medius and deep hip external rotators that control frontal plane knee mechanics during running.

  1. 01Lie on your side with knees bent at 45 degrees, a resistance band looped above your knees.
  2. 02Stack your hips directly on top of each other — do not roll backward.
  3. 03Keep your feet together and heels touching throughout.
  4. 04Open your top knee toward the ceiling by rotating at the hip, like a clamshell opening.
  5. 05Squeeze the glute at the top of the movement and hold for 1-2 seconds.
  6. 06Lower slowly and with control — do not let the band snap your knee closed.
  7. 07Keep your core engaged and pelvis stable throughout.
Why it matters

The gluteus medius is the primary frontal plane stabiliser of the pelvis during single-leg stance in running. When it is weak, the pelvis drops on the opposite side (Trendelenburg sign), causing the knee to collapse inward (dynamic valgus). This single biomechanical fault is linked to IT band syndrome, runner's knee, patellar tendinopathy, and shin splints. Clamshells are the entry-level exercise for rebuilding this critical stabiliser.