Exercise is related to Step. Step is a type of Support. Support is the opposite of Opposition. 
Practitioner is a type of Professional. Professional is related to Doctor. Doctor is related to Professor. Professor is the opposite of Student. 
Exercise <--RelatedTo--> Step --IsA--> Support <--Antonym--> Opposition 
Practitioner --IsA--> Professional <--RelatedTo--> Doctor <--RelatedTo--> Professor <--Antonym--> Student 