On reviewing the poem I've noticed a few things:-
"if you can FORCE your heart" - one of the names is a unit of Force
"Except the WILL which says" - one name is a familiar term for Will
"worth of DISTANCE run" - one name is a Distance
"Don't GIVE way to hating - one name is a synonym of Give
"Or walk with KINGS - obvious two names
Of course this could be me reading too much into it:-)