Endurance represents how far a character can push themselves physically before they give out. Any type of distance sport such as running, swimming, cycling or climbing will clearly be limited or enhanced by Endurance. It also measures the character's ability to control their body in situations requiring stamina, such as holding one's breath, continue to function in extreme weather, or to overcome pain.
While representing stamina, Endurance also encompasses a character's fortitude and health; characters with little Endurance will be more prone to illness and will recover from injury more slowly, while character with high Endurance will shrug off wounds that might stop a lesser person.