Abstract: An abdominal exercise device is disclosed which comprises a base support member assembly upon which the user sits, a vertical resistance and restorative force member assembly mounted on the base support member assembly, and an arm support member. The arm support member positions the body of the user in an upright position. The invented exercise device permits the user to train and strengthen the major and minor muscles of the upper and lower back, to train the frontal portion of the midsection, the abdominals, the obliques to avoid spinal compression and to maintain decompression of the spinal vertebrae.