An elongate member having a fixed end is passed through a plurality of grippers that impart tension in the elongate member and prevent the tension from being released. At least one gripper is movable while at least one other can be fixed. The movable gripper travels along the elongate member toward the fixed end then reverses direction, grips the elongate member, and carries the elongate member away from the fixed end, thereby creating tension in the elongate member. At least one gripper prevents the tension from being released. In some embodiments, the elongate member passes through a rotatable shaft with a lumen. The shaft can be in communication with a crank, whereby operation of the crank rotates the shaft.