Many people choose to forgo food from animal sources to varying degrees (e.g. flexitarianism, pescetarianism, vegetarianism, veganism) for health reasons, issues surrounding morality, or to reduce their personal impact on the environment, although some of the public assumptions about which diets have lower impacts are known to be incorrect. Raw foodism is another contemporary trend. These diets may require multivitamin supplements to meet ordinary nutritional needs.
Another text which teaches yoga with an Advaita point of view is the Yoga-Yājñavalkya. This work contains extensive teachings on ten Yamas (ethical rules) and ten Niyamas (duties), and eight asanas. It also discusses a theory of nadis and prana (vital breath), and follows this with instructions on pranayama (breath control), pratyahara (sense withdrawal), meditation on mantras, meditative visualizations and Kundalini.
Samuel states that Tantrism is a contested concept. Tantra yoga may be described, according to Samuel, as practices in 9th to 10th century Buddhist and Hindu (Saiva, Shakti) texts, which included yogic practices with elaborate deity visualizations using geometrical arrays and drawings (mandala), fierce male and particularly female deities, transgressive life stage related rituals, extensive use of chakras and mantras, and sexual techniques, all aimed to help one's health, long life and liberation.
Ascetic practices (tapas), concentration and bodily postures used by Vedic priests to conduct yajna (sacrifice), might have been precursors to yoga.[note 9] Vratya, a group of ascetics mentioned in the Atharvaveda, emphasized on bodily postures which may have evolved into yogic asanas. Early Samhitas also contain references to other group ascetics such as munis, the keśin, and vratyas. Techniques for controlling breath and vital energies are mentioned in the Brahmanas (texts of the Vedic corpus, c. 1000–800 BCE) and the Atharvaveda. Nasadiya Sukta of the Rig Veda suggests the presence of an early contemplative tradition.[note 10]
In 1989 and 2003, the Vatican issued two documents: Aspects of Christian meditation and "A Christian reflection on the New Age," that were mostly critical of eastern and New Age practices. The 2003 document was published as a 90-page handbook detailing the Vatican's position. The Vatican warned that concentration on the physical aspects of meditation "can degenerate into a cult of the body" and that equating bodily states with mysticism "could also lead to psychic disturbance and, at times, to moral deviations." Such has been compared to the early days of Christianity, when the church opposed the gnostics' belief that salvation came not through faith but through a mystical inner knowledge. The letter also says, "one can see if and how [prayer] might be enriched by meditation methods developed in other religions and cultures" but maintains the idea that "there must be some fit between the nature of [other approaches to] prayer and Christian beliefs about ultimate reality." Some[which?] fundamentalist Christian organizations consider yoga to be incompatible with their religious background, considering it a part of the New Age movement inconsistent with Christianity.
^ James Mallinson, "Sāktism and Hathayoga," 28 June 2012.
According to Pāṇini, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau ("to concentrate"). In the context of the Yoga Sutras of Patanjali, the root yuj samādhau (to concentrate) is considered by traditional commentators as the correct etymology. In accordance with Pāṇini, Vyasa who wrote the first commentary on the Yoga Sutras, states that yoga means samādhi (concentration).
Some bodybuilders use drugs such as anabolic steroids and precursor substances such as prohormones to increase muscle hypertrophy. Anabolic steroids cause hypertrophy of both types (I and II) of muscle fibers, likely caused by an increased synthesis of muscle proteins. They also provoke undesired side effects including hepatotoxicity, gynecomastia, acne, the early onset of male pattern baldness and a decline in the body's own testosterone production, which can cause testicular atrophy. Other performance-enhancing substances used by competitive bodybuilders include human growth hormone (HGH), which can cause acromegaly.
^ * Wynne states that "The Nasadiyasukta, one of the earliest and most important cosmogonic tracts in the early Brahminic literature, contains evidence suggesting it was closely related to a tradition of early Brahminic contemplation. A close reading of this text suggests that it was closely related to a tradition of early Brahminic contemplation. The poem may have been composed by contemplatives, but even if not, an argument can be made that it marks the beginning of the contemplative/meditative trend in Indian thought."
What is often referred to as Classical Yoga or Astanga Yoga (Yoga of eight limbs) is mainly the type of Yoga outlined in the highly influential Yoga Sutras of Patanjali. The origins of the Classical Yoga tradition are unclear, though early discussions of the term appear in the Upanishads. The name "Rāja yoga" (yoga of kings) originally denoted the ultimate goal of yoga, samadhi, but was popularised by Vivekananda as a common name for Ashtanga Yoga,[note 19] the eight limbs to be practised to attain samadhi, as described in the Yoga Sutras. Yoga is also considered as one of the orthodox philosophical schools (darsanas) of Hinduism (those which accept the Vedas as source of knowledge).
An influential text which teaches yoga from an Advaita perspective of nondualistic idealism is the Yoga-Vāsiṣṭha. This work uses numerous short stories and anecdotes to illustrate its main ideas. It teaches seven stages or bhumis of yogic practice. It was a major reference for medieval Advaita Vedanta yoga scholars and before the 12th century, it was one of the most popular texts on Hindu yoga.
Muscle growth is more difficult to achieve in older adults than younger adults because of biological aging, which leads to many metabolic changes detrimental to muscle growth; for instance, by diminishing growth hormone and testosterone levels. Some recent clinical studies have shown that low-dose HGH treatment for adults with HGH deficiency changes the body composition by increasing muscle mass, decreasing fat mass, increasing bone density and muscle strength, improves cardiovascular parameters, and affects the quality of life without significant side effects.[unreliable medical source?]
Later developments in the various Buddhist traditions led to new innovations in yogic practices. The Theravada school, while remaining relatively conservative, still developed new ideas on meditation and yogic phenomenology in their later works, the most influential of which is the Visuddhimagga. The Indic meditation teachings of Mahayana Buddhism can be seen in influential texts like the Yogācārabhūmi-Śāstra (compiled c. 4th century). Mahayana meditation practices also developed and adopted new yogic methods, such as the use of mantra and dharani, pure land practices which aimed at rebirth in a pure land or buddhafield, and visualization methods. Chinese Buddhism developed its own methods, such as the Chan practice of Koan introspection and Hua Tou. Likewise, Tantric Buddhism (also Mantrayana, Vajrayana) developed and adopted tantric methods, which remain the basis of the Tibetan Buddhist yogic systems, including the Six yogas of Naropa, Kalacakra, Mahamudra and Dzogchen.
There is no consensus on its chronology or specific origin other than that yoga developed in ancient India. Suggested origins are the Indus Valley Civilization (3300–1900 BCE) and pre-Vedic Eastern states of India, the Vedic period (1500–500 BCE), and the śramaṇa movement. According to Gavin Flood, continuities may exist between those various traditions: