ACSM Personal Trainer Certification Practice Exam

Which muscles are primarily involved in lateral rotation of the hip?

1. Gluteus maximus and obturator

2. Iliopsoas and gluteus medius

3. Quadriceps and hamstrings

4. Gastrocnemius and soleus

The correct answer is: Gluteus maximus and obturator

Lateral rotation of the hip primarily involves the gluteus maximus and the deep external rotators of the hip. The gluteus maximus is a large muscle that plays a significant role in the movement and stabilization of the hip joint, especially during activities that require power and strength. It helps to extend and laterally rotate the hip. Additionally, the obturator muscles (namely the obturator internus and externus, and other deep external rotators) are also key players in this action. They assist in the lateral rotation by anchoring the femur against the acetabulum and allowing for the outward turning of the leg. The other options include muscles that do not primarily function in lateral rotation. The iliopsoas and gluteus medius are more involved in hip flexion and abduction, respectively. The quadriceps are primarily responsible for knee extension, while the hamstrings primarily assist in knee flexion and hip extension. The gastrocnemius and soleus are two muscles of the calf that are primarily involved in plantar flexion at the ankle, making them unrelated to hip rotation.