^ Burd, Nicholas A.; Yang, Yifan; Moore, Daniel R.; Tang, Jason E.; Tarnopolsky, Mark A.; Phillips, Stuart M. (2012). "Greater stimulation of myofibrillar protein synthesis with ingestion of whey protein isolate v. Micellar casein at rest and after resistance exercise in elderly men". British Journal of Nutrition. 108 (6): 958–62. doi:10.1017/S0007114511006271. PMID 22289570.
The origins of yoga have been speculated to date back to pre-Vedic Indian traditions; it is mentioned in the Rigveda,[note 1] but most likely developed around the sixth and fifth centuries BCE, in ancient India's ascetic and śramaṇa movements.[note 2] The chronology of earliest texts describing yoga-practices is unclear, varyingly credited to Upanishads. The Yoga Sutras of Patanjali date from the first half of the 1st millennium CE, but only gained prominence in the West in the 20th century. Hatha yoga texts emerged sometimes between the 9th and 11th century with origins in tantra.