An exercise apparatus for performing an abdominal exercise by a user having a lower back, legs and a trunk (T1, T2, T3) that has a longitudinal trunk axis and a trunk weight, the apparatus comprising: a frame; a seat having a seating surface; and an input arm assembly including a manually graspable mechanism; wherein the input arm assembly is interconnected by a first interconnection (48, 50) to a first resistance mechanism, the first resistance mechanism being a manually selectively adjustable fixed weight resistance mechanism; and characterized in that: the seat has a pelvic stabilization pad having a lower back engagement surface, the seating surface and the pelvic stabilization pad being mounted, adapted and arranged on the frame in a disposition relative to each other such that the user can simultaneously sit on the seating surface and engage the user's lower back against the lower back engagement surface, the input arm assembly is interconnected by a second interconnection (47, 60, 70) to a second resistance mechanism, the input arm assembly is arranged on the apparatus such that the input arm assembly is pivotable beginning from a start motionless position along a path of travel forwardly away from the pelvic stabilization pad under resistance (R1, R2) exerted by one or both of the resistance mechanisms (42, 43), the input arm assembly is arranged on the apparatus such that when the user is seated on the seating surface and the user's lower back is engaged against the lower back engagement surface, the seat and the pelvic stabilization pad position the user in a position at which the user can manually engage the manually graspable mechanism to exert a forwardly directed pushing force on the input arm assembly beginning from the start motionless position continuing along the path of travel (PT, PT2) against resistance (R1, R2) exerted by one or both of the first and second resistance mechanisms, and the second resistance mechanism is adapted to increase resistance as the degree of pivoting of the input arm assembly increases (PT, PT2) along the path of travel away from the start motionless position and away from the pelvic stabilization pad. a frame; a seat having a seating surface; and an input arm assembly including a manually graspable mechanism; wherein the input arm assembly is interconnected by a first interconnection (48, 50) to a first resistance mechanism, the first resistance mechanism being a manually selectively adjustable fixed weight resistance mechanism; and the seat has a pelvic stabilization pad having a lower back engagement surface, the seating surface and the pelvic stabilization pad being mounted, adapted and arranged on the frame in a disposition relative to each other such that the user can simultaneously sit on the seating surface and engage the user's lower back against the lower back engagement surface, the input arm assembly is interconnected by a second interconnection (47, 60, 70) to a second resistance mechanism, the input arm assembly is arranged on the apparatus such that the input arm assembly is pivotable beginning from a start motionless position along a path of travel forwardly away from the pelvic stabilization pad under resistance (R1, R2) exerted by one or both of the resistance mechanisms (42, 43), the input arm assembly is arranged on the apparatus such that when the user is seated on the seating surface and the user's lower back is engaged against the lower back engagement surface, the seat and the pelvic stabilization pad position the user in a position at which the user can manually engage the manually graspable mechanism to exert a forwardly directed pushing force on the input arm assembly beginning from the start motionless position continuing along the path of travel (PT, PT2) against resistance (R1, R2) exerted by one or both of the first and second resistance mechanisms, and the second resistance mechanism is adapted to increase resistance as the degree of pivoting of the input arm assembly increases (PT, PT2) along the path of travel away from the start motionless position and away from the pelvic stabilization pad.