Head is related to Live. Live requires Breath. 
Stumble is a synonym of Trip. one thing you do when you Running is Trip. Running is related to Course. Course is related to Obstacle. 
Head <--RelatedTo--> Live --HasPrerequisite--> Breath 
Stumble <--Synonym--> Trip <--HasSubevent-- Running <--RelatedTo--> Course <--RelatedTo--> Obstacle 