Kundalini
By definition kundalini is the energy that lies dormant at the base of the spine until it is activated by way of yoga practice, and channeled upward through the chakras in the process of spiritual perfection.
Kundalini in sanskrit means coiled up, coiled serpent or divine cosmic force. When activated, it is said that this serpent power rises up from the muladhara chakra (root chakra) through the sushumna nadi (central channel), activating each chakra that it touches until it reaches the sashrara chakra (crown chakra). After the kundilini has been activated, divine powers are said to be activated. It is however encouraged that one not become too attached to these powers, as they can become an obstacle to true enlightenment.
It is important when working on such a deep energetic level, that one works with a highly qualified teacher to avoid frying the central nervous system, and so that one doesn’t loose sight of the spirit in the practice.
Yoga seeks to unite ones energies, not to overload. Everything in yoga practice must work together for the kundilini to work positively. The body must be strong, the mind clear, and the heart pure.