from Wendy Doniger's review of Mark Singleton's YOGA BODY: The origins of modern posture practice:
The word "yoga" occurs in this text [The Rig Veda], but only in the primary sense of "yoking" horses to chariots or draft animals to ploughs or wagons (the Sanskrit and English words are cognate, as is the English "junction"); and then, secondarily, designating the effort of "yoking" oneself to do physical labor.
Many contemporary yoga practitioners cite this text [Patanjali's Yoga-Sutra] as the basis of their praxis. But Patanjali says nothing about the "postures" other than remarking that the adept should sit in a manner that is relaxed and conducive to meditation and breath control. On the contrary, he speaks of cultivating "aversion to one's own body".
One yogic text composed some time between the thirteenth and eighteenth centuries, the Hatha-yoga-pradipika ("Illumination of the Yoga of Force"), describes fifteen yogic postures. It also describes the Tantric technique of raising the coiled serpent power (the Kundalini) up the spine, through the series of chakras (centres of force), to the brain, and a related technique whereby the adept draws fluids (such as the secretions of his female partner in the Tantric sexual ritual) up through his penis (the vajroli process).
Bodybuilding became a religion that resacralized the body, and the British proselytized for this muscular Christianity just as the missionaries did for their evangelical Christianity. In Indian schools, the gymnastics instructor was usually a brutal and ignorant retired non-commissioned British officer, more often a sepoy, an Indian who served in the British Army. In an ironic twist, Indian nationalists were able to use this colonial technique, designed to build soldiers to master the inferior races in the Empire, to train their own people to combat and resist the Europeans. Even when they took poses from Hatha Yoga, they renamed them, and interpreted them in the language of modern gymnastics.
There is an ancient Indian yoga, but it is not the source of most of what people do in yoga classes today. That same history, however, also demonstrates that there are more historical bases for contemporary postural yoga than Singleton allows. The Europeans did not invent it wholesale. But they changed it enormously. They changed it from an embarrassment to an occasion for cultural pride, and from a tradition that encouraged the cultivation of "aversion to one's own body" to another, also rooted in ancient India, that aimed at the perfection of the body. The modern Indian and American yogis didn't take their methods from European physical culture; they took them back from physical culture. What Mark Singleton does prove ... is that yoga is a rich, multi-cultural, constantly changing inter-disciplinary construction, far from the pure line that its adherents often claim for it.