Hydraulics is a great core workout that requires no weights at all. All you need is your own body! Firstget down in the plank position show with your face towards the ground as if in a pushup position. Then retract your arms so your elbows and forearms are resting on the ground. Your bottom should be slightly elevated during exercise. Make sure your elbows and hands are going down into the same spot as you raise your body and arms from elbows to hands.
