Abdominal exercise apparatus comprising a flexible and resilient board of a length extending from one end near the head portion of a user to an opposing end removed therefrom. The board is constructed to be normally flat in configuration and is bondable into an upwardly curved configuration by upward...http://www.google.ca/patents/US5100130?utm_source=gb-gplus-sharePatent US5100130 - Abdominal exercise device
