have been doing weights for about eighteen months at a small gym that doesn't have every bit of equipment. I like the Smith machine and free weights. I want to train with weights twice per week and want to know how i should split these days ie should I do upper/lower or a whole body circuit type thing. I want to tone my midriff and backside in particular and also improve my running distance. I have been told not to increase my muscle mass so I become too heavy to run, but I do want to be fitter and more toned. If I do weights twice per week and three cardio would that be good?