While yoga has increasingly gained popularity and acceptance in Western culture, it’s certainly not new. Yoga dates back thousands of years ago to the Hindu culture. At its core, it is based on a series of poses which seek to align one’s mind (spirit) and body.
Contemporary yoga still maintains this goal, and of course there are others that use yoga purely as a form of exercise. Its various poses can increase strength and certainly work to increase flexibility (including spinal flexibility, an important benefit).
What’s more, even Western science is finding yoga useful for stress relief, which has an impact on various diseases and other maladies.