An exercise machine applicable for strengthening users abdominal muscles is described. The machine can include a track frame and a support frame adjustably coupled to the track frame. The track frame can include parallel rails to provide gliding support for movement along the parallel rails. Two sliding assembly may be movably mounted on separate pairs of the parallel rails respectively. Each sliding assembly may be configurable to move together or separately along the parallel rails. Two seat pads may be adjustably secured to the two sliding assembly respectively. Each seat pad may be rotationally adjustable to change angular relationship between the seat pad's longitudinal direction and movement direction along the parallel rails.