One of Joseph Pilates' fundamental concepts in his approach to fitness was "flow". I take that to mean working with energy, generating relaxed energy, moving that energy in a directed way throughout the body and ultimately interacting with that energy in what could be called the dance of felt movement.
The word "felt" is important, because we so often don't feel what we do, what and how we move, and our experience is cut off before it gets started.
One thing I found in Pilates that I recognized from my training in Kung Fu was this flowing movement. In Kung Fu flowing energy is used to generate and direct power out from the body's center, called the "Tan Tien" in Chinese. In Pilates the center is called the "Core" and the core is referred to as the Hara in Yoga. Whatever we call it, it is the same idea and it is given the same importance.
It can be seen from the outside, evidenced by very efficient movement, no wasted motion, precise placement of each body part, no "held" positions or blocked breathing patterns. A Pilates practitioner (or Kung Fu or Yoga practitioner) at a certain level of training will move effortlessly, as if the movement is totally natural and requires no thought. On the reformer it is like being part of the machine, on the mat it is like gravity is suspended, when practicing Kung Fu and in athletics it appears in an obvious control over the actions of the opponent - and you can see in it overwhelming speed, accuracy and power.
Inside it is a more subtle experience. There is a quiet calm, a feeling centered in the Core, the Hara, the Tan Tien. The muscles are active, energized, working at optimum efficiency. The is a sense of equanimity throughout the physical self and there is an emotional component here as well. It's a feeling of wakeful awareness, with a whole-body experience of breath. Breathing happens all through the space of movement, all through the body. Whole-body breathing, whole body release of tension, whole body movement.
All this is happening now and there is little need for physical/mental effort right now - not when you move. Moving is easy, moving is what we're built for, it just needs to be discovered and embraced.
That was the genius of Joseph Pilates - his passion for movement. He understood and shared with us our birthright of physicality, the inherent Joy we contain. That feeling is just waiting for us to take it up. So please do that, please be aware of how important this is to all of us. Find your core, find ease in movement, in your life.