Abstract: A device for exercising the abdominal muscles which facilitates movement of the lower torso against a resistive force and in a complex arc which conforms to the normal forward arc of rotation of the spine comprising: a rigid shaft slidably disposed within a housing; arcuate thigh supports for maintaining the housing stationary with respect to a person's thighs; a handle generally transverse to and attached to a first shaft end; an elastic band positioned intermediate the ends of the shaft and for connecting the housing to a second shaft end so as to generate a resistive restoring force by pressing on the handle so as to displace the shaft relative to the housing in a direction from the first shaft end to the second shaft end, thereby executing a downstroke; a pivot positioned intermediate the ends of the shaft and for pivoting the upper portion of the shaft away from the torso as a downstroke is executed; a stop member for limiting displacement of the shaft with respect to the housing as the shaft moves in a