What type of movement does "flexion" usually result in?

Flexion is a type of movement that typically decreases the angle between two body parts, bringing them closer together. It often involves bending a joint, such as the elbow or knee, which results in the body parts moving toward each other. This can be visualized when discussing movements like bending the arm or leg, where the forearm moves closer to the upper arm, or the calf moves closer to the thigh.

In the context of the options provided, movement towards the center aligns with the principle of flexion, as it effectively describes how flexion draws parts of the body closer, rather than extending or spreading them apart. Other movements such as extension, which involves increasing the angle between body parts and moving them further away from each other, don't align with the definition of flexion. Similarly, spreading limbs or upward stretching does not characterize the action of flexion, as they imply an increase in distance rather than a decrease.