ACSM Personal Trainer Certification Practice Exam

Which term is used to describe the action of moving a limb around its long axis?

1. Rotation

2. Protraction

3. Flexion

4. Extension

The correct answer is: Rotation

The term that accurately describes the action of moving a limb around its long axis is rotation. This movement involves the pivoting of a bone around its own axis, which can occur in various joints, notably the shoulder and hip joints. For instance, when you rotate your arm or leg, you are causing the limb to turn in either an inward or outward direction along its long axis, which is characterized as rotation. In contrast, protraction refers to the movement of a part of the body forward along the transverse plane, such as when the shoulders move forward. Flexion is the action of decreasing the angle between body parts, such as bending the elbow. Extension is the opposite of flexion and involves increasing the angle between body parts, such as straightening the elbow. Each of these movements has a distinct definition and context that help differentiate them from rotation.