What does flexion refer to in terms of joint movement?

Flexion refers to the movement that decreases the angle between two body parts, typically involving bending at a joint. This action becomes apparent when one limb approaches another, such as when bending the elbow or knee. During flexion, the muscle contractions draw the two segments closer together, causing a reduction in the angle formed at the joint.

For instance, when you bend your arm at the elbow, the angle between the forearm and the upper arm decreases, which is a clear demonstration of flexion. In contrast, straightening the limb represents extension, lengthening involves further distance between body parts, and twisting describes rotational movement, all of which do not align with the definition of flexion. Understanding flexion is crucial in various medical and fitness contexts, as it plays a significant role in movement mechanics and rehabilitation practices.