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]
Overtraining occurs when a bodybuilder has trained to the point where his workload exceeds his recovery capacity. There are many reasons why overtraining occurs, including lack of adequate nutrition, lack of recovery time between workouts, insufficient sleep, and training at a high intensity for too long (a lack of splitting apart workouts). Training at a high intensity too frequently also stimulates the central nervous system (CNS) and can result in a hyperadrenergic state that interferes with sleep patterns. To avoid overtraining, intense frequent training must be met with at least an equal amount of purposeful recovery. Timely provision of carbohydrates, proteins, and various micronutrients such as vitamins, minerals, phytochemicals, even nutritional supplements are acutely critical. A mental disorder, informally called “bigorexia” (by analogy with anorexia), may account for overtraining in some individuals. Sufferers feel as if they are never big enough or muscular enough, which forces them to overtrain in order to try and reach their goal physique.
Onesicritus also mentions his colleague Calanus trying to meet them, who is initially denied audience, but later invited because he was sent by a "king curious of wisdom and philosophy". Onesicritus and Calanus learn that the yogins consider the best doctrine of life as "rid the spirit of not only pain, but also pleasure", that "man trains the body for toil in order that his opinions may be strengthened", that "there is no shame in life on frugal fare", and that "the best place to inhabit is one with scantiest equipment or outfit". These principles are significant to the history of spiritual side of yoga. These may reflect the ancient roots of "undisturbed calmness" and "mindfulness through balance" in later works of Hindu Patanjali and Buddhist Buddhaghosa respectively, states Charles Rockwell Lanman; as well as the principle of Aparigraha (non-possessiveness, non-craving, simple living) and asceticism discussed in later Hinduism and Jainism.
The first known appearance of the word "yoga", with the same meaning as the modern term, is in the Katha Upanishad, probably composed between the fifth and third century BCE, where it is defined as the steady control of the senses, which along with cessation of mental activity, leading to a supreme state.[note 13] Katha Upanishad integrates the monism of early Upanishads with concepts of samkhya and yoga. It defines various levels of existence according to their proximity to the innermost being Ātman. Yoga is therefore seen as a process of interiorization or ascent of consciousness. It is the earliest literary work that highlights the fundamentals of yoga. White states:
In the modern bodybuilding industry, the term "professional" generally means a bodybuilder who has won qualifying competitions as an amateur and has earned a "pro card" from their respective organization. Professionals earn the right to compete in competitions that include monetary prizes. A pro card also prohibits the athlete from competing in federations other than the one from which they have received the pro card. Depending on the level of success, these bodybuilders may receive monetary compensation from sponsors, much like athletes in other sports.
The early practice of Jain yoga seems to have been divided into several types, including meditation (dhyāna), abandonment of the body (kāyotsarga), contemplation (anuprekṣā), and reflection (bhāvanā). Some of the earliest sources for Jain yoga are the Uttarādhyayana-sūtra, the Āvaśyaka-sūtra, the Sthananga Sutra (c. 2nd century BCE). Later works include Kundakunda's Vārassa-aṇuvekkhā (“Twelve Contemplations”, c. 1st century BCE to 1st century CE), Haribhadra's Yogadṛṣṭisamuccya (8th century) and the Yogaśāstra of Hemachandra (12th century). Later forms of Jain yoga adopted Hindu influences, such as ideas from Patanjali's yoga and later Tantric yoga (in the works of Haribhadra and Hemachandra respectively). The Jains also developed a progressive path to liberation through yogic praxis, outlining several levels of virtue called gunasthanas.
The Maitrayaniya Upanishad, likely composed in a later century than Katha and Shvetashvatara Upanishads but before Patanjali's Yoga Sutra, mentions sixfold yoga method – breath control (pranayama), introspective withdrawal of senses (pratyahara), meditation (dhyana), mind concentration (dharana), philosophical inquiry/creative reasoning (tarka), and absorption/intense spiritual union (samadhi).
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".
The spiritual sense of the word yoga first arises in Epic Sanskrit, in the second half of the 1st millennium BCE, and is associated with the philosophical system presented in the Yoga Sutras of Patanjali, with the chief aim of "uniting" the human spirit with the Divine. The term kriyāyoga has a technical meaning in the Yoga Sutras (2.1), designating the "practical" aspects of the philosophy, i.e. the "union with the supreme" due to performance of duties in everyday life.