Which muscle on the side of the hip is commonly targeted by clamshell exercises?

The muscle on the side of the hip commonly targeted by clamshell exercises is the gluteus medius.

The gluteus medius is a broad, fan-shaped muscle on the outer surface of the pelvis. It connects the ilium to the upper part of the femur and helps abduct the hip, meaning it moves the leg away from the body's midline. Its fibers also assist with hip rotation and help keep the pelvis level when one leg is supporting the body.

During a clamshell, a person lies on their side with the knees bent and lifts the upper knee while keeping the feet together. This movement emphasizes hip abduction and external rotation, so the gluteus medius is a principal target. The gluteus maximus, gluteus minimus, and deep hip rotators can also contribute, depending on technique and range of motion.

A common mix-up is assuming that every glute exercise primarily trains the gluteus maximus, the large muscle responsible for much of the buttocks' size and hip-extension power. Clamshells are especially associated with the gluteus medius because of their role in lateral hip stability and pelvic control.