Try it! One Arm Lift
Lay on your belly with your legs wide apart. Put one hand under your shoulder and the other hand on your butt. Squeeze the muscles in your arm and the muscles surrounding your arm (in chest, armpit, back).
Press with your arm to get your upper body up and than lift your hips up towards the sky. Keep your back straight and your abs contracted. Reverse the movement and get back to the starting position.
Do 5 reps on each arm.
Source: BodyRock.tv
Trying to exercise more despite finals. This was really hard, but I did it!