What is the action of increasing the angle at a joint known as?

The action of increasing the angle at a joint is known as extension. This movement occurs when the bones at a joint move away from each other, effectively increasing the angle between them. For example, when you straighten your arm or leg, you are performing an extension at the elbow or knee joint, respectively.

In contrast, flexion refers to decreasing the angle at a joint, while abduction and adduction describe movements that involve the limbs moving away from or towards the midline of the body, respectively. Understanding these terms is essential for any personal fitness trainer, as they form the foundational vocabulary used in describing movement patterns in exercise and physical activities.