^ For instance, Kamalashila (2003), p. 4, states that Buddhist meditation "includes any method of meditation that has Enlightenment as its ultimate aim." Likewise, Bodhi (1999) writes: "To arrive at the experiential realization of the truths it is necessary to take up the practice of meditation.... At the climax of such contemplation the mental eye … shifts its focus to the unconditioned state, Nibbana...." A similar although in some ways slightly broader definition is provided by Fischer-Schreiber et al. (1991), p. 142: "Meditation – general term for a multitude of religious practices, often quite different in method, but all having the same goal: to bring the consciousness of the practitioner to a state in which he can come to an experience of 'awakening,' 'liberation,' 'enlightenment.'" Kamalashila (2003) further allows that some Buddhist meditations are "of a more preparatory nature" (p. 4).
According to Crangle, some researchers have favoured a linear theory, which attempts "to interpret the origin and early development of Indian contemplative practices as a sequential growth from an Aryan genesis",[53][note 4] just like traditional Hinduism regards the Vedas to be the ultimate source of all spiritual knowledge.[55][note 5] Thomas McEvilley favors a composite model where pre-Aryan yoga prototype existed in the pre-Vedic period and its refinement began in the Vedic period.[58]
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.[24] 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.[25]
An article by Muscle & Fitness magazine, "Overtrain for Big Gains", claimed that overtraining for a brief period can be beneficial. Overtraining can be used advantageously, as when a bodybuilder is purposely overtrained for a brief period of time to super compensate during a regeneration phase. These are known as "shock micro-cycles" and were a key training technique used by Soviet athletes.[54]

The earliest extant systematic account of yoga and a bridge from the earlier Vedic uses of the term is found in the Hindu Katha Upanisad (Ku), a scripture dating from about the third century BCE[…] [I]t describes the hierarchy of mind-body constituents—the senses, mind, intellect, etc.—that comprise the foundational categories of Sāmkhya philosophy, whose metaphysical system grounds the yoga of the Yogasutras, Bhagavad Gita, and other texts and schools (Ku3.10–11; 6.7–8).[101]
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.