Gaining somatic awareness of your neutral alignment of spine and pelvis is essential in Pilates practice, and I would say, essential if you want to understand when and where your body is in balance (or not). Somatic awareness of yourself is understanding your body from your own internal perspective as opposed to someone else looking at it from an outside view. Gaining somatic knowledge is vital for anyone looking to improve their own health and well-being as your own deep knowledge of yourself allows you to make good choices for yourself.
So how does apparatus help in becoming more aware of your body from an internal perspective? Let's start with the best and most readily available piece of apparatus available anywhere – the floor. There is a reason why Pilates and somatic movement spends so much time on the floor to begin with as it gives you so much feedback on where your spine and pelvis is in space. You can physically tune in to and feel where your body is touching the floor. You can feel the whole way along your spine, from the back of your head down to your pelvis and even down the backs of your legs if you're lying with your legs long.
When you transition to another position where your spine isn't touching the floor, for example on your hands and knees, you have to develop a deeper internal awareness of where your spine is in space as you don't have the kinetic feedback of your back touching the floor.
Therabands are a great tool for helping you feel engagement of muscles that you may otherwise find hard to switch on, such as the muscles in and around your shoulders and scapula. Tying a band around your thighs can help you feel engagement of your deep hip rotator muscles or smaller glute muscles. These are the ones you want to be finding and activating in so many Pilates moves to help balance the work that other larger muscles can be over-enthusiastic in doing.
Finding good muscular engagement that might otherwise be hard to access is one of the functions of the straps and footbar/plate of the Pilates reformer. It's such a wonderful piece of equipment for targeting and activating every muscle in the body, giving you the ability to increase your somatic awareness and improve your function.
What about other apparatus? Small hand weights, Pilates circles, small balls, rolled up towels, cushions, foam rollers and walls. There are so many things to play with and ignite your imagination to increase your somatic awareness.