Strain is a type of Injury. Strain is related to Effort. Trouble is a type of Effort. Trouble is related to Penalty. 
Rope is related to Thick. Thick is a synonym of Close. 
Injury <--IsA-- Strain <--RelatedTo--> Effort <--IsA-- Trouble <--RelatedTo--> Penalty 
Rope <--RelatedTo--> Thick <--Synonym--> Close 