Kundalini Yoga is a school of yoga that is influenced by Shaktism and Tantra. It derives its name through the focus on awakening kundalini energy through a regular practice of meditation, pranayama, chanting mantras and yoga asanas. Technically, Kundalini energy is explained as being sparked during yogic breathing when prana and apana blend at the 3rd chakra (navel) at which point it initially drops down to the 1st and 2nd chakras before traveling up to the spine to the higher centers of the brain to activate the golden cord - the connection between the pituitary and pineal glands - and penetrate the 7 chakras. The Sanskrit adjective kundalin means "circular, annular".
Kundalini is the term for "a spiritual energy or life force located at the base of the spine", conceptualized as a coiled-up serpent. The practice of Kundalini yoga is supposed to arouse the sleeping Kundalini Shakti from its coiled base through the 6 chakras, and penetrate the 7th chakra, or crown. This energy is said to travel along the left, right and central, or sushumna nadi - the main channels of pranic energy in the body.
The practice of kriyas and meditation in Kundalini Yoga are designed to raise complete body awareness to prepare the body, nervous system, and mind to handle the energy of Kundalini rising. Majority of the physical postures focus on the navel activity, the activity of the spine, and selective pressurization of body points and meridians. Breath work and the application of aid to release, direct and control the flow of Kundalini energy from the lower centers to the higher energetic centers.
Along with the many kriyas, meditation and practices of Kundalini Yoga, a simple breathing technique of alternate nostril breathing (left nostril, right nostril) is taught as a method to cleanse the nadis, or subtle channels and pathways, to help awaken Kundalini energy.