Maha Bandha
In Sanskrit, Maha means "great" and Bandha means "to lock," "to hold," or "to tighten," therefore this practice translates to "great lock."
This practice is an advanced Yoga practice that incorporates all three Bandha practices. It is highly advisable to be experienced with the three Bandhas separately before combining them into one practice. This is one of ten Mudra practices that are said to destroy old age and death as well as giving divine wealth.
When Mula and Jalandhara Bandhas are preformed together they act as a seal, closing off the top and bottom of Sushumana Nadi or the central Nadi located in the spine. Add Uddiyana Bandha forces the two Pranic energy currents to meet in Manipura Chakra.
When the two opposite poles of Prana meaning "life force energy" meet in Manipura Chakra, they are forced up through the Sushumana Nadi or the main energetic pathway and into Ajna Chakra. When this happens the mind reaches the seat of Shiva, known as the highest capacity of Consciousness.
Practice
Sit in a Meditative Asana or a comfortable seated position.
Preform Uddiyana Bandha combined with Jalandhara Bandha.
Preform Mula Bandha.
This is the final position.
Retain the breath for as long as comfortable without straining.
Release Mula Bandha, Uddiyana Bandha and finally Jalandhara Bandha.
The six cleansing actions are intended to be the start of a Yoga practice in order to clean, strengthen, remove toxins and improve the flow of Prana through out the practitioner.
Yoga poses help to elongate and strengthen the muscles of the body as well as to calm the mind for the deeper spiritual practices of Yoga.
Breathing exercises are a great practice to remove carbon dioxide, increase lung capacity as well as being a good preparatory practice for the deepest spiritual practice of Yoga, Meditation.
The four body locks that makes up this practice give the practitioner the ability to hold or lock Prana in certain locations of the body. These practices also allow the practitioner to release blockages that may be holding the practitioner back.
The gestures in this practice include the whole body and are intended to awaken Prana, Chakras as well as Kundalini energy within the practitioner.
Meditation is the highest spiritual practice of Yoga which is why this practice is the most difficult practice to preform, but with correct knowledge and dedication, can be the most profound practice of Yoga.