When someone takes a header, it means they fall headfirst or dive suddenly. To describe the opposite of this action, we could use the antonyms stand up or rise. These words signify lifting oneself instead of falling. Another antonym could be sit down or settle, indicating a controlled and deliberate motion. To further express a lack of suddenness, we could use the antonyms slow or gradual to describe the opposite action to taking a header. Overall, antonyms for takes a header would focus on motions that are deliberate and controlled, as opposed to the sudden and uncontrolled motion of falling headfirst.