Fitness is related to Quality. Credibility is a type of Quality. 
Automobile is related to Car. Car can be Slow. Slow is related to Speed. Speed is a type of Pace. 
Fitness <--RelatedTo--> Quality <--IsA-- Credibility 
Automobile <--RelatedTo--> Car --HasProperty--> Slow <--RelatedTo--> Speed --IsA--> Pace 