Alignment can be defined as the optimal relationship between the bones of the body and its musculature that maximizes physical efficiency and ease of movement. In yoga, the purpose of proper alignment is to prevent injury and reduce strain on muscles and ligaments. (Learn more in Naturally Healing Common Ailments Through Asanas.)
'The Plumb Line'
Understanding the concept of a plumb line is effective for determining proper alignment. The plumb line can be visualized as a line running from the crown of the head through the mid-line of the body straight down into the feet. When visualizing the plumb line, it is helpful to look at the body from the side. This imaginary line runs down the ear lobe, through the shoulder joint, the chest, the greater trochanter, and continues down slightly anterior to both the knee and ankle joints.
There are several styles of yoga, such as Iyengar yoga and certain kinds of yoga therapy, that focus primarily on the physical mechanics of asana. Though these particular styles focus on alignment, there is a difference between the aesthetic choices of performing asana and body mechanics.
Alignment for Tadasana
To truly understand proper alignment, we must experience it ourselves. An easy way to do this is while in tadasana, or mountain pose. To start, come to the front of your mat and stand with your feet parallel to one another. Starting at your ankle joint, check to see that your knees are directly over your ankles. You will want to keep a micro bend in your knees to avoid locking them. Your kneecap is actually slightly in front of your knee joint, so it’s okay if there appears to be slightly more of a bend then you think necessary.
Once your knees are aligned, move your attention up into your pelvis. It’s helpful to imagine your pelvis as a bowl that has been filled to the brim with water. Your goal is to keep any of the water from spilling out of either the front or the back. For most of us that means dropping our tailbone down toward the floor while pulling slightly up on the pubic bone. The pelvis should be stacked directly over the knees and ankle joints.
Moving up to the torso, drop the front ribs and release the shoulder blades down your back. The chest should feel buoyant here and the torso stacked over the hips. Next, the ear lobes line up with the outside edges of the shoulders. The chin drops down and softly back toward the neck so that the head can move effortlessly from side to side. Check your profile in a full length mirror to make sure everything stacks up properly. Initially, this may feel strange, but that's okay as long as you are pain free. It may take a while for your muscles to condition themselves to holding proper alignment, especially if you are used to hunching over at a desk or computer. (Learn about Relieving Muscle Pain and Tension With Breath.)
Maximizing All Asanas
Over time, practicing good postural alignment will make holding asanas easier and prevent injuries in the future. While every body is different, proper alignment will provide you with the maximum support and least amount of physical strain. It will also increase overall health and vitality.