http://pokemondb.net/pokedex/cofagrigus Here is Cofagrigus's page.
As we can see, Cofagrigus's best stat lies in his Defense, while his worst stat is his speed.
So to abuse Cofagrigus's inner strength, you could try out a relaxed Cofagrigus alongide a Trick Room Team, where the speed loss is just an advantage to "damage" and "sweep", although his purpose is to stall.
Hope I helped :)
