The nautilus instinct rotary torso is a great machine to use as a way of properly working the upper body and core muscles this machine has the awesome lock n load feature that nautilus have created in order to make weight selection easy and quick so that users can concentrate more on the actual exercises this machine forces users to work in a kneeling position so that the exercise can be carried out safely and ensuring the back isn t overworked comfort is a massive feature on this machine wit