Abstract: An apparatus for exercising the abdominal and other muscles associated with full flexure of the lower and middle spine made up of four main components: (1) an inclined base, (2) a collapsible platform, (3) pivotally connected support members which elevate the collapsible platform above the base and allow the platform to transform from a resting state to a collapsed state, and (4) a resistance mechanism preventing the collapse of the platform and associated support members and resisting appropriately placed forces exerted by the lower back against the platform. The platform is defined by three sections, a head-end section, a middle section, and a leg-end section, attached in such a manner that the head-end section and leg-end section can collapse about the middle section throughout a range of positions wherein end-positions are defined by a resting state and a collapsed state.