How does yoga transform people? And why?

Any passionate yoga teacher or student will tell you that yoga changes lives—again and again—regardless of whether they’re from a school of Bhakti Yoga (yoga of devotion) or a school of Yoga Asana (yoga postures).
Yoga, as a spiritual practice, has been around for thousands of years, while yoga as a physical practice has really only been widely practiced for the past century or so. But how does yoga transform people?
And why?
If you ask the Kundalini Yogis, they’ll tell you that when the nadis (internal energies) align, positive change is inevitable. If you ask the Ashtanga Yogis, they’ll tell you that physical practice cleanses the nerves and everything reveals itself in a natural progression.
So who is right?
The answer is simple: everyone! The real power of yoga is not in the outward form or the school of yoga (though no doubt some are more effective than others). The REAL power of yoga is that yoga itself is a system based almost exclusively on disciplined practice with just a skeleton structure of theory.
Here’s where this gets interesting…
You already know about the power of the mind, the power of thought and intention; but the challenge we face daily is that it’s infinitely more difficult to use your mind to change your mind than it is to use systematic and disciplined actions to do the same.
Whether you’re reciting the Yoga Sutras or practicing a handstand, this constant and continuous discipline is what gives such tremendous, visceral benefits; therefore, there’s no need to get caught up in the names and labels of yoga. Simply find a practice you love—and do it!
While religion is personal belief system that you may or might not subscribe to, yoga is a system of spiritual practices that is truly for everyone. So if you do your practice, whatever it is, positive change is inevitable.

Source: http://evolutionezine.com