Leg Curl Machine Exercise is one of the most effective hamstring exercises. The only disadvantage is that you will require a gym machine to perform it :) .br Instruction: Lie down on the machine, with your ankles under the cushion. Hold a position, where your legs are slightly bent; this will keep your femoral muscles tensed during the entire exercise. Bend your knees, stopping before your legs reach a vertical position. Pay attention, that the weights used, never rest on the holders.