What makes a legal javelin throw?

A legal javelin throw requires that the athlete hold the javelin by its grip and release it with a single motion, ensuring that the tip of the javelin strikes the ground first within the designated sector. The throw must occur from within a marked throwing area, and the athlete must not step outside the boundary lines during or after the throw. Additionally, the javelin must land in the sector marked by a 29-degree angle from the throwing point. Failing to meet these criteria results in the throw being deemed invalid.