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”, just like traditional Hinduism regards the Vedas to be the ultimate source of all spiritual knowledge.
Ascetic practices (tapas), concentration and bodily postures used by Vedic priests to conduct yajna (sacrifice), might have been precursors to yoga.
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.