You will definitly overtrain malic, its not just your muscles that need to heal its you CNS(central nervous system). You dont r need to be lifting more than once a day unless youre training for something specific such as Pro bodybuilding and you need to remember these guys are on tons of gear. You can lift and run in the same day, but i wouldnt suggest training more than once per day, it doesnt really have any benifits. Rest is just as, if not more important that the training itself.