they are trained for stand up and ground techniques. A great boxer has them extremely overmatched in standup and the mma guy only has a marginal advantage when it goes to the ground. Now i know this might come off as me saying any good boxer can go into the octagon and wreck shop. Thats not what i'm saying. It would take a certain type of boxer (i'd have trouble finding you one today in any boxing weight class) to pull this off.