Yoga as exercise is a physical activity consisting largely of asanas, often connected by flowing sequences called vinyasas, sometimes accompanied by the breathing exercises of pranayama, and usually ending with a period of relaxation or meditation. It is often known simply as yoga, despite the existence of multiple older traditions of yoga within Hinduism where asanas played little or no part, some dating back to the Yoga Sutras, and despite the fact that in no tradition was the practice of asanas central.
As the number of service sector jobs has risen in developed countries, more and more jobs have become sedentary, presenting a different array of health problems than those associated with manufacturing and the primary sector. Contemporary problems, such as the growing rate of obesity and issues relating to stress and overwork in many countries, have further complicated the interaction between work and health.
According to Pāṇini, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau ("to concentrate"). In the context of the Yoga Sutras of Patanjali, the root yuj samādhau (to concentrate) is considered by traditional commentators as the correct etymology. In accordance with Pāṇini, Vyasa who wrote the first commentary on the Yoga Sutras, states that yoga means samādhi (concentration).
In contrast to strongman or powerlifting competitions, where physical strength is paramount, or to Olympic weightlifting, where the main point is equally split between strength and technique, bodybuilding competitions typically emphasize condition, size, and symmetry. Different organizations emphasize particular aspects of competition, and sometimes have different categories in which to compete.
Weight training aims to build muscle by prompting two different types of hypertrophy: sarcoplasmic and myofibrillar. Sarcoplasmic hypertrophy leads to larger muscles and so is favored by bodybuilders more than myofibrillar hypertrophy, which builds athletic strength. Sarcoplasmic hypertrophy is triggered by increasing repetitions, whereas myofibrillar hypertrophy is triggered by lifting heavier weight. In either case, there is an increase in both size and strength of the muscles (compared to what happens if that same individual does not lift weights at all), however, the emphasis is different.
Due to the growing concerns of the high cost, health consequences, and illegal nature of some steroids, many organizations have formed in response and have deemed themselves "natural" bodybuilding competitions. In addition to the concerns noted, many promoters of bodybuilding have sought to shed the "freakish" perception that the general public has of bodybuilding and have successfully introduced a more mainstream audience to the sport of bodybuilding by including competitors whose physiques appear much more attainable and realistic.
The Rigveda, however, does not describe yoga, and there is little evidence as to what the practices were. Early references to practices that later became part of yoga, are made in Brihadaranyaka Upanishad, the earliest Hindu Upanishad. For example, the practice of pranayama (consciously regulating breath) is mentioned in hymn 1.5.23 of Brihadaranyaka Upanishad (c. 900 BCE), and the practice of pratyahara (concentrating all of one's senses on self) is mentioned in hymn 8.15 of Chandogya Upanishad (c. 800–700 BCE).[note 8] The Jaiminiya Upanishad Brahmana teaches mantra repetition and control of the breath.