An exercise apparatus that lies flat on the floor having a back rest rises up when supported by two springs. The lower part of the back and buttocks lie horizontal while the upper part of the back is inclined at an angle to the horizontal. When not in use, the upper back rest folds down flat so that...http://www.google.ca/patents/US7803097?utm_source=gb-gplus-sharePatent US7803097 - Exercise apparatus for strengthening abdominal muscles
