An exercise apparatus includes a housing, a pair of pivoting foot treadles and a pair of reciprocating bellows that support the foot treadles. A sealed air system including a conduit interconnects the bellows and is operable for reciprocating transfer of air from bellow to bellow. Each of the foot treadles is pivotably movable between upper and lower positions, and has a resting position between the upper and lower positions. The resting position of the foot treadles defines a resting position of the bellows while the upper and lower positions of the foot treadles respectively define elongated and compressed positions of the bellows. In use, the elongated and compressed positions of the bellows are each no more than 5 degrees off the center resting position thereby reducing stress on the bellows.