Abstract: An exercising device of an overall length relating to the length of an exercising person lying prone thereon and of a width relating to the width of an exercising person. The device has a first section having a concave portion for accommodating the back of the exercising person, a second mid section having a convex portion of an overall height greater than the first section for accommodating the body portion of an exercising person between the gluteus maximus and the lower back portion of an exercising period and a third section having a convex portion of an overall height greater than the second section for accommodating the rear knee portion of an exercising person, the second section being spaced from the third section by a concave portion for supporting the gluteus maximus of an exerciser.