An apparatus for exercising the abdominal muscles of a user includes an elongate track having first and second ends and a middle portion wherein the elongate track is positionable transverse to a user. The apparatus further includes a carriage movable along the track, wherein that carriage is biased toward the middle portion of the track, and an arm extending substantially perpendicular from the carriage. The arm has a free distal end such that application by user of an alternating torque to the free distal end of the arm urges the carriage in a corresponding reciprocating motion on the track.