Bwwwaaaaaaaahhhhaaa. Men parading their greased up man-asses in public should never be accepted as a sport in polite society, although you could make a case for it being a bit more sporting back in the day when bodybuilders were expected to be lifters also. It is more a pageant, if anything.
It you wanted to class the strength sports by athletic ability, the order would be somewhat like this:
Strongman, Olympic Lifting, Powerlifting. Highland games might be shoe horned in there somewhere.