Asanas are but one of eight limbs of yoga as laid out

By the word “yoga”, most people think of asanas. They think of classes that stretch the body, increase physical flexibility, help people to lose weight and get into overall better physical condition. But there's more to yoga than this “asana” thing. Asanas are but one of eight limbs of yoga as laid out by Patanjali, author of “The Yoga Sutras”. So yes, they play a part in the yoga whole, but they are certainly not the whole.
If your goal is increased flexibility, weight loss and better physical condition, you may be getting what you are looking for from your asana class, but if you are looking to end personal suffering, and ways to move towards Living Unbound, then your yoga asana class will do no good.

The body and the mind are not two separate things. If the mind is polluted, so will the body be. The body is a reflection of the mind. So trying to perfect the shape of the body does very little if we are filling the mind with garbage. It is not reasonable to expect that if you can learn to control the body you will then automatically be able to control the mind, and the mind is the source of all suffering. We must work from the root of the problem upwards, we must work on the atoms before we work on that which they create. To go the other way is a lost cause.

Traditionally, asanas were done so that the body could be comfortable when sitting for pranayama (breathing exercises) and meditation which are two of the other eight limbs of yoga. The Sanskrit word “asana” even means “seat”. It has been well known for centuries that the core practice of “yoga” is meditation, not asanas. The reason for this is because the practice of meditation is what will liberate us from the suffering of this world, asanas alone will not. It is good to keep the body healthy and in good repair as it is the vessel through which the Divine in us is manifesting, but just keeping the body in good repair is not going to take us all the way to liberation, to enlightenment; to Living Unbound. To liberate ourselves from suffering we must work on the root of the problem, which is misidentification, thinking (and believing the thought) that we are something that we are not. We are not our bodies. We are not our thoughts. We are not our beliefs, our ideas or our personalities. We are pure consciousness manifesting as form. Doing yoga postures alone as spiritual practice is not going to help to break the mind’s habit of misidentifying with an external “reality”.

What yoga postures WILL do is help to create a more purified vessel making it easier to access the Divine within. They will help us to correct physical energy blockages creating open channels for the smooth flow of prana (life force) coursing through our nervous systems and they will allow us greater comfort in our physical lives. We are not our bodies (consciousness does not vanish upon the death of the physical body) but the human nervous system IS the vehicle used to access the divinity within all of us. So it is important to treat this body like the temple it is and to keep it in good repair. Without this body we would not have the opportunity to realize our selves as Divine.!! Jai Adiyogi ~ Jai Mahadev!!