Pilates works in several different ways. Let's begin with the basics - the pelvic floor, which is the hammock of muscles which stop your internal organs from dropping out between your legs. If you imagine your abdomen, the centre of your body , as being like a cardboard box, the diaphragm being the top of the box, the deep tummy muscles (transversus abdominus, and the obliques) as being the front and sides, the back muscles, (stabilisers multifidus, and the erector spinae) as the back of the box, then the base of the box is the pelvic floor.