ACSM Personal Trainer Certification Practice Exam

What is the primary action of the gluteus medius at the hip joint?

1. Flexion

2. Abduction

3. Extension

4. Medial rotation

The correct answer is: Abduction

The primary action of the gluteus medius at the hip joint is abduction. This muscle is located on the lateral aspect of the pelvis and plays a crucial role in stabilizing the pelvis during activities such as walking or running. When the gluteus medius contracts, it pulls the thigh away from the midline of the body, which is the definition of abduction. Additionally, the gluteus medius is important for maintaining pelvic stability when standing on one leg. This action prevents the pelvis from tilting downward on the opposite side, which is especially critical for effective movement biomechanics and injury prevention. While the gluteus medius can also assist in other movements such as medial rotation and flexion, its primary and most significant role is in abduction.