Complex sentence: The athletics meeting forms the backbone of the modern Summer Olympics, and other leading international meetings include the IAAF World Championships and World Indoor Championships, and athletes with a physical disability compete at the Summer Paralympics and the IPC Athletics World Championships.
Split into simpler sentences: The athletics meeting forms the backbone of the modern Summer Olympics, and other leading international meetings include the IAAF World Championships and World Indoor Championships. Athletes with a physical disability compete at the Summer Paralympics and the IPC Athletics World Championships.