"Bandhas protect and project, that is what they are for. They protect the alignment of your spine and project your energy where you want it to go."
~Guru Prem Singh Khalsa, author of Divine Alignment
Opening the Flow of Kundalini Energy
The bandhas, or body locks, direct the prana and apana, the generative and eliminating energies, during the practice of Kundalini Yoga. The blending of these two energies opens the flow of energy into the central energy channel along the spine, the sushmuna, which gently awakens the kundalini energy in a controlled manner. With continuing, deepening practice of the bandhas, the body systems are cleansed, restored, and refined through this circulation of kundalini energy.
Creating Hydraulic Pressure
The primary function of the bandhas, or body locks, is to create inner strength to hold open the sushmuna and at the same time, to create a hydraulic pressure to encourage energy to move feely within that channel. The sushmuna is a spiritual channel, but its physical counterpart is the spine. It is of primary importance to maintain the integrity and alignment of the spine so that this channel can remain open. Bandhas are not just strong measures used occasionally to create an energy surge, but are also subtle internal contractions that can be consistently applied to hold the spine in correct alignment.
Correct Alignment and Release of Tension
Through using one or more of the bandhas we can consciously construct an internal framework that creates and supports the correct alignment of the spine in any posture we attempt. With a correctly bandhed internal framework, our postural alignment uses only the most appropriate muscles to hold the position and this allows us to release unnecessary tension in the rest of the body.
These techniques consolidate the effects of a Kundalini Yoga practice and direct prana within the physical and energetic pathways to promote healing, energizing, and strengthening of the whole human being.
[From Divine Alignment by GuruPrem Singh, and The Aquarian Teacher: KRI Teacher Training Textbook Level One]