No, they are there for support but concussive forces or overwork can still cause splints to a horse that is predisposed to it. They are mainly to help support the tendons when working in surfaces that are hard going, athough it is not unheard of for horses to still pull or strain their legs whilst wearing them if the work is too hard for them or they hit a sudden boggy/soft spot. Concussion will jar the bones ect whether they have bandage on or not.
hope that makes sense and helps
Dawn