Follow the machines directions exactly. Follow the machines directions exactly. Lie face down on a leg-curl machine and hook ONE heel under the roller pad. Your leg should be stretched out straight so that the pads rest on the back of your ankle. Grasp the handles under the bench for support. Remaining flat on the bench, curl your leg up until your hamstrings are fully contracted. Release and lower the weight slowly back to the starting position. Concentrate on using a full range of motion and do not SWING the weight up. You can point your toe to intensify the burn in your hamstrings. Repeat with other leg.