Just what is cross training ???????

SV17GT

I do sit-ups,pull-ups,weights,and I walk a lot. I try to give it 2 hrs a day not counting the walk. I started at 270 lbs and I'm down to 190 lbs now, but thin isn't really my goal. I'm not looking to be the incredable hulk either. Just wondering if this could give me a happy medium ??