This research is about training on the lumbar abdominal fitness machine to collect patent and related literature. Based on the different parts of the strength training to collate and analyze to classify their advantages and defects. This research has combine with waist and abdominal muscle strength training of the new design direction. This research use the way of motion generation to find three -position synthesis of a four-bar mechanism. Create to waist/abdomen muscle trainer 3D model by CAD software (SolidWorks). And check that is no conflicts between linkages. The last, CAE software (ANSYS 11.0) could be used for analyzing stresses distributed in different modes. These are ways confirmed the strength and security of waist/abdomen muscle trainer.