Yoga (/ˈjoʊɡə/; Sanskrit: योग; pronunciation) is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India. Yoga is one of the six orthodox schools of Hindu philosophical traditions. There is a broad variety of yoga schools, practices, and goals in Hinduism, Buddhism, and Jainism. The term "yoga" in the Western world often denotes a modern form of Hatha yoga, consisting largely of the postures called asanas.
According to Geoffrey Samuel, our "best evidence to date" suggests that yogic practices "developed in the same ascetic circles as the early śramaṇa movements (Buddhists, Jainas and Ajivikas), probably in around the sixth and fifth centuries BCE." This occurred during what is called the ‘Second Urbanisation’ period. According to Mallinson and Singleton, these traditions were the first to use psychophysical techniques, mainly known as dhyana and tapas. but later described as yoga, to strive for the goal of liberation (moksha, nirvana) from samsara (the round of rebirth).
Intensive weight training causes micro-tears to the muscles being trained; this is generally known as microtrauma. These micro-tears in the muscle contribute to the soreness felt after exercise, called delayed onset muscle soreness (DOMS). It is the repair of these micro-traumas that results in muscle growth. Normally, this soreness becomes most apparent a day or two after a workout. However, as muscles become adapted to the exercises, soreness tends to decrease.
Core: Yes. There are yoga poses to target just about every core muscle. Want to tighten those love handles? Then prop yourself up on one arm and do a side plank. To really burn out the middle of your abs, you can do boat pose, in which you balance on your "sit bones" (the bony prominences at the base of your pelvic bones) and hold your legs up in the air.