India gave Yoga to the world. The West has appropriated Yoga and made it an industry. Yet there is no doubt that the physical practices of yoga have many benefits such as better breathing, increased strength and flexibility/suppleness, good posture and muscular-skeletal alignment. They also effect change in the nervous system, so that you can do physical practices to stimulate or calm the nervous system and the mind/body. Breathing (connected to movement) is both the most fundamental and most subtle part of the practice that can create profound shifts in the body’s nervous system.
For a summary of the health benefits of yoga and meditation please see this article (PDF) from US based www.yogahealthfoundation.org. 10 reasons to practice yoga
Given these different effects and the variety of human dispositions, there are many different ways of practicing physically, hence the explosion of different ‘brands’ of yoga. Arguably from a traditionalist persepctive, the purpose of physical practices is to prepare the body for sitting in meditation. Most certainly energy is needed for meditation, it is no good if you feel sleepy or your energy is stagnant. So moving the body to stimulate energy or release tension is always good before sitting meditation.
There are many health benefits to meditation (also applicable to physical/asana pratice) such as better sleep, stress relief, sense of being more in touch with oneself, clarity of thinking – to name but a few easily observable changes.
In classical yoga, meditation is a tool and a spiritual path to purify the mind, that is, free the mind of fears, prejudice, negativity, in fact all conditioned reactions. The Yogis say that most of our thoughts and responses to the world are based on pre-exisiting memories and habitual responses (family/personal history/social conditioning), thus they are not ‘fresh’ and clear responses to being in the moment. Of course some of these responses serve us well, others do not.
Meditation, like all subjective experience, is very hard to describe in words. You just have to experience it.
There are many different approaches to meditation, many different techniques, so it is important to find one that works for you. For more information about meditation generally, what it is and isn’t, go to the online article called ‘The Real Meaning of Meditiation’ in Yoga International (June 2014).