Abstract: An exercise apparatus resistance unit includes flex members to bend to provide a resistance, a first end piece, a second end piece provided another end of the flex members to secure the flex members to rotate and translate within the body according to a bending motion of the flex members, a main pulley, and auxiliary pulleys rotatably provided on the first end piece. The resistance unit may provide a variable resistance.

Abstract: A tubular structural member that provides adjustable directional resistance to a device. When orientated in a certain manner with respect to the direction of use, the tubular structural member will provide a different stiffness to the device it is affixed. The tubular structural member may be integrated with these devices so that these devices can have adjustable resistance and stiffness.