The Garden Web, View Points and Ask-the-Trainer websites all offer a variety of reviews on the Total Gym Ultra system. These three resources, provide a comprehensive overview and a good understanding about the Total Gym.
According to Ask the Trainer, the Total Gym system uses the athlete's body weight as resistance for the workout. Since the athlete uses his body weight for resistance, he receives an intense, abs workout in addition to the workout that he has specifically selected. An example of this would be performing a rowing exercise. According to Ask the Trainer, while performing the rowing exercise, the abs get an added workout due to the design of the equipment.