Abstract: This apparatus is for the development of the abdominal muscles through their ranges of motion including that known as elongation. The objective of the apparatus is to build muscle power and endurance, not only when the abdominal muscles are mostly contracted, but also when the abdominal muscles are mostly elongated.The apparatus includes an outward arch which fits under the upper lumbar and lower thoracic spine. One slope of the arch provides the user's pelvis and lumbar spine with consistent support. The rest of the arch provides the user's remaining spine to be supported when resting, but to be free to arch beyond the amount of arch that occurs in normal standing posture. This exercise is made functional by a knee retainer that holds down on the knees which, in turn, holds down on the pelvis, thereby creating maintainable contact between the pelvis/low-lumbar area and the slope of the arch.