An exerciser includes two rails pivotally attached to a base, two handles pivotally attached to the base, two foot supports having one end pivotally coupled to the handles and the other end slidably engaged with the rail, and a tilting device may tilt the rails relative to the base to different angular positions in order to adjust the moving strokes of the foot supports. A bolt may be rotatably attached to the base and threaded with a follower, and a motor coupled to the bolt for rotating the bolt relative to the base, and for adjusting the follower along the bolt, and the follower is coupled to the rails for tilt the rails relative to the base to different angular positions.