how can i work on my core and upper body with no workout equipment most of the time?

i dont have anywork out equipment at my house, but i do get to go in the weight rom at school at least 3 times a week in the mornig for 35 minutes, wat can i do at home to get a flat stomach, then build up to a six pack, oh yea, i do have a treadmil at my house and a 10 pound dunbell

Read more ...