The idea that the mind is separate from the body is an old concept, though, in today's world I have seen it attacked by materialists, as well as those who are religious.
Regardless if the mind and body are separate, I think the idea that they are separate can be useful.
I've been an athlete for roughly ten years. When I was young my training and conditioning were filled with stress. I knew the conditioning was going to hurt me. It was a requirement if I wanted to get stronger.
When I was about 20 I began reading a lot of hippy/new age books. In one of them they spoke of Buddhist monks who could run inhuman distances. They would run at night, focusing on a single star until they fell into a trance. When they came out of it, they would be at their destination. This was appealing to me because, at that time, I was routinely woken up by unpleasant men and told to go run a 5k. I tried the trick of staring up at a star and falling into a trance. It didn't work for me, but the idea was planted in my mind.
Fast forward to me at 23. I began practicing lucid dreaming techniques. One of these was to lay in my bed, completely still. When a person does this, several things happen. The first, is that the body begins itching. The trick, is to let the itch, itch, and continue not moving and just relax. If you can do this, the next step is to allow your body to begin breathing by itself, without your input.
The body then begins to fall into sleep paralysis. The arms and legs go numb, or feel as if they are sinking into the bed. The feeling of my body breathing without me and losing feeling, all while I was completely conscious flipped a switch in my head. Since then I rarely view the feelings of my body as my feelings. To me they are wholly separate, which makes it much easier to get in those final sets of pushups, or relax and act intelligently while I'm being strangled.
I suggest everyone at least try putting their body into sleep paralysis while they are conscious, as it is a novel feeling. Simply lay down, and don't move for the next 20-30 minutes. Having complete darkness helps.
This post is already too long.