An elliptical exercise apparatus includes two cranks disposed rotatably on
a frame and rotatable about a common crank axis, two rails each disposed
fixedly on the frame and having a non-circular guide slot, two extension
links connected respectively, radially, and slidably to the cranks and
mounted with rollers disposed respectively and movably within the guide
slots, two connector members disposed on the frame and reciprocatable
along a longitudinal direction of the frame, and two foot links each
having a first end connected pivotally to the corresponding extension
link and a second end connected pivotally to the corresponding connector
member. When the rollers move along the rails, the extension links are
extendable and retractable relative to the cranks, respectively.