There are a few ways to prepare your body for meditation. Meditation works best when you can keep your body relatively motionless and your back relatively straight. Here’s why:
When you’re constantly acting and reacting in response to thoughts and outside stimulation, you don’t have a chance to get to know how your mind works. By sitting still, you have a mirror that shows you just how slippery and elusive your mind can be.
Keeping still gives you a tremendous edge when you’re working on developing your concentration. Imagine a heart surgeon or a concert pianist who can’t quiet her body while plying her craft. The fewer physical distractions you have, the easier it becomes to follow your breath, practice your mantra, or whatever your meditation happens to be.
By aligning the spine and opening the channels that run through the center of the body, upright sitting encourages an unimpeded circulation of energy, which, in turn, contributes to wakefulness on all levels — physical, mental, and spiritual. Besides, it’s a lot easier to sit still for extended periods of time when your vertebrae are stacked like a pile of bricks, one on top of the other.
Otherwise, over time, gravity has this irritating habit of pulling your body down toward the ground — and in the process, causing the aches and pains so typical of a body at war with the forces of nature. So the most comfortable way to sit in the long run is straight, which puts you in harmony with nature.
A word of caution, however: These sitting instructions aren’t intended to turn your body into a stone. The point is to set your intention to sit still and notice what happens. The Buddha liked to use the metaphor of a stringed instrument like a sitar or guitar — if the strings are too loose, you can’t play it, and if they’re too tight, they’ll break.
If you’re too rigid with yourself, you’ll just end up miserable — but if you keep shifting your body this way and that, you’ll never get your mind concentrated and quiet enough to reap the benefits of meditation.