Structure of abdomen exerciser

DETAILED DESCRIPTION According to one aspect of the present invention, the abdomen exerciser comprises two three-end links respectively pivoted to two curved supports on a mainframe at opposite sides to hold two leg presses, two sets of weights, and a back cushion.
The sets of weights automatically turn the three-end links on the curved supports in lifting the back cushion from a horizontal position to a vertical position as the player bends the trunk upwards, or give a pressure to the player's back as the player lies down.
According to another aspect of the present invention, either leg press can be turned into the operative position for hanging the respective leg in raising the player's center of gravity, or the non-operative position for permitting the respective leg to be hung on pairs of cross bars on a front frame of the mainframe.
According to still another aspect of the present invention, two handlebars are respectively made on the three-end links for holding with the hands during exercising.
According to still another aspect of the present invention, the mainframe can be alternatively arranged to hold the seat cushion a sloping position or a horizontal position.