It has been said, that one could compare Ashtanga yoga to beads on a string: the postures are the beads, and the foundations (root lock, abdomen lock, drishti and ujjiyi breath) are the string that connects the all the beads together. I like this analogy, so lets explore this "string" a little more closely.
First, we have the locks, and there are three of them. In our classes we currently focus on the first two, mula bandha, or root lock and uddiyana bandha, or abdomen lock. Jalandhara bandha is the chin lock and we start to bring that in as we become more familiar with the practice. To further summarize (and I'll break these down more in depth at some later point):
Mula bandha (root lock) - a lifting of the perineum or pelvic floor. For women, think of holding a "kegel exercise". Gentlemen, you are lifting and holding the perineum which is behind the boys and in front of the anus. It is our objective to someday holding this slight contraction and lift throughout the entire practice.
Uddiyana bandha (lesser uddiyana, abdomen lock) - There are two variations of Uddiyana Bandha. One is practiced in the Hatha tradition, where you are lifting the entire abdominal cavity up in a very controlled manner in conjunction with pranyama. In the Ashtanga practice we are engaging the lower abdomen, gently drawing back the area below your belly button as if trying to touch your spice. We are also trying to hold this action throughout the entire practice.
Drishti (focus point) - is a point of gaze or focus and is meant to direct our attention to the subtle practice ("it’s what you can’t see that matters"; the breath and bandhas). We want our gaze move in the direction of the stretch, and thus our attention stays within the body and the practice rather than wandering around worrying about our pedicure, dentist appointment or work day. In conjunction with the breath, this is what helps make the practice a moving meditation. We are turning down the volume on our internal thoughts.
Ujjayi Breath (victorious breath) - a slight constriction at the back of the throat which becomes an audible breath on which to focus our attention during the practice. Why? To create a rhythm in the breath and ride it gracefully through the practice, the breath becomes a mantra to focus the mind, and this tells us the quality of our practice. So the breath becomes the mantra to facilitate the moving meditation, to focus the ear upon and gauge the quality of the practice.
Why do we do all this? To trap heat/energy in torso; the ujjayi breath is regulating heat from the top and the bandhas are preventing the release of heat and energy from below. In creating this internal furnace we burn off and purge our body of excess toxins. By engaging uddiyana bandha we encourage the exercising of internal muscles by supporting and lifting the organs and we support the lower back throughout the practice. By combining all these elements, we focus our attention on the subtle body and bring a meditative quality to our practice.
That’s quite a bit for a bunch of little "strings"! Truly, Ashtanga Yoga is about what you can't see.