Hatha yoga postures come in numerous forms. For a beginner, states the historian of religion Mircea Eliade, these "asanas" are uncomfortable, typically difficult, cause the body shakes and typically unbearable to hold for extended periods of time. However, with repetition and persistence, as the muscle tone improves, the effort reduces and posture improves. According to the Hatha yoga texts, each posture becomes perfect when the "effort disappears", one no longer thinks about the posture and one's body position, breathes normally per "pranayama", and is able to dwell in one's meditation ("anantasamapattibhyam"). The "asanas" discussed in different Hatha yoga texts vary significantly. Unlike
Karma karma theories is the concept of reincarnation or the cycle of rebirths ("saṃsāra"). Rebirth is a fundamental concept of Hinduism, Buddhism, Jainism and Sikhism. The concept has been intensely debated in ancient literature of India; with different schools of Indian religions considering the relevance of rebirth as either essential, or secondary, or unnecessary fiction. Karma is a basic concept, rebirth is a derivative concept, so suggests Creel; Karma is a fact, asserts Yamunacharya, while reincarnation is a hypothesis; in contrast, Hiriyanna suggests rebirth is a necessary corollary of karma. Rebirth, or "saṃsāra", is the concept that all life forms go