Kundalini means "coiled like a serpent" in Sanskrit. Kundalini energy refers to the coiled up energy that lies at the base of the spine. When released, this energy moves from the base of the spine through the seven chakras (or energy centers) in the spine. Specific meditation and breathing techniques were used to tap the kundalini energy, and these practices were known as Laya yoga. This school of yoga was founded by Sage Gorakshnatha, a sage from Nepal.
The ancient practice of Laya yoga was secret, and finds mention in classical Indian texts such as the Upanishads (which date back to 500 B.C.E.). The secrecy of these practices was challenged and it was eventually taught publicly to the West in 1969 by Yogi Bajan.
Kundalini yoga is a combination of specific kriyas and meditation aimed at raising the kundalini energy. The practices also help prepare the practitioner physically and spiritually for the intensity of this energy. Each kundalini class begins with a chant and is followed up by a warmup for the spine. The main part of the class is the kriyas, which combine postures and breathing techniques and end with a meditation and chant.