Yoga may have pre-Vedic elements. Some state yoga originated in the Indus Valley Civilization. Marshall, Eliade and other scholars note that the Pashupati seal discovered in an Indus Valley Civilization site depicts a figure in a position resembling an asana used for meditation, Mulabandhasana. This interpretation is considered speculative and uncertain by more recent analysis of Srinivasan and may be a case of projecting "later practices into archeological findings".
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The Rigveda, however, does not describe yoga, and there is little evidence as to what the practices were. Early references to practices that later became part of yoga, are made in Brihadaranyaka Upanishad, the earliest Hindu Upanishad. For example, the practice of pranayama (consciously regulating breath) is mentioned in hymn 1.5.23 of Brihadaranyaka Upanishad (c. 900 BCE), and the practice of pratyahara (concentrating all of one's senses on self) is mentioned in hymn 8.15 of Chandogya Upanishad (c. 800–700 BCE).[note 8] The Jaiminiya Upanishad Brahmana teaches mantra repetition and control of the breath.
The practice of awakening the coiled energy in the body is sometimes specifically called Kundalini yoga. It is based on Indian theories of the subtle body and uses various pranayamas (breath techniques) and mudras (bodily techniques) to awaken the energy known as kundalini (the coiled one) or shakti. In various Shaiva and Shakta traditions of yoga and tantra, yogic techniques or yuktis are used to unite kundalini-shakti, the divine conscious force or energy, with Shiva, universal consciousness. A common way of teaching this method is to awaken the kundalini residing at the lowest chakra and to guide it through the central channel to unite with the absolute consciousness at the highest chakra (in the top of the head).
^ James Mallinson, "Sāktism and Hathayoga," 6 March 2012. PDF file Archived 16 June 2013 at the Wayback Machine [accessed 10 June 2012] pp. 20–21 "The Buddha himself is said to have tried both pressing his tongue to the back of his mouth, in a manner similar to that of the hathayogic khecarīmudrā, and ukkutikappadhāna, a squatting posture which may be related to hathayogic techniques such as mahāmudrā, mahābandha, mahāvedha, mūlabandha, and vajrāsana in which pressure is put on the perineum with the heel, in order to force upwards the breath or Kundalinī."
Equipment required? No. You don't need any equipment because you'll rely on your own body weight for resistance. But you'll probably want to use a yoga mat to keep you from sliding around in standing poses, and to cushion you while in seated and lying positions. Other, optional equipment includes a yoga ball for balance, a yoga block or two, and straps to help you reach for your feet or link your hands behind your back.