Significance

• The third limb of classical or Ashtanga yoga is called Asana or posture. Asanas are not merely physical exercises. Instead, they train every nerve, gland, and muscle in the body, while also disciplining the mind. According to B.K.S. Iyengar's "Light on Yoga," "The yogi conquers the body by the practice of asanas and makes it a fit vehicle for the spirit." By practicing asanas the yogi develops balance, endurance, physical strength, flexibility, muscle tone, and steadiness of mind.
  
  

Considerations

• The stomach and bowels should be empty when practicing yoga. Clothing should be appropriate to the temperature of the room and should not be so tight as to restrict movement or breathing. The breath should not be held; instead it should be relaxed and natural. To avoid injury, practice only under the guidance of an experienced, intuitive teacher. You should never force your body beyond its capacity, nor should you allow a teacher to force you. Stop if you feel pain--it's a sign of an incorrect posture or physical injury. During menstruation women are often advised not to do inverted postures. Also if you are pregnant, ask your teacher for guidance and avoid any asanas, especially twisting postures, that constrict the abdomen.
  
  

Types

• There are several fundamental types of yoga postures: standing postures, balancing postures, inverted postures, back-bending and twisting postures, forward-bending, seated postures, and relaxation/reclining postures. Asanas are named for vegetation--for instance, tree pose or lotus pose. Some are named for insects, such as locust or scorpion, or for animals--fish, tortoise, frog, or the downward-facing dog pose. There are also heron, peacock, and swan poses. The heroic figures Virabhadra and Hanuman, the son of the Wind, also have poses named after them.
  
  

Benefits

• Documented medical benefit of all yoga postures include increased strength, relief of stress and anxiety, and lowered blood pressure. But each type of pose has unique benefits. Standing postures develop power and stability in the lower body and aid in digestion, circulation, mobility, balance, posture, and mental focus. Balancing postures develop poise, concentration, coordination, and control over your body. Inverted postures reverse the effects of gravity; stimulate the brain, organs and glands; and improve digestion and elimination. Back-bending postures keep the spine supple and release emotional energy. Twisting postures detoxify the glands and organs and improve circulation to the spine. Forward-bending postures soothe the nervous system and increase circulation. Seated and relaxation/reclining postures reduce fatigue, soothe the nervous system, aid in digestion and elimination, and bring focus to the mind.
  
  

Expert Insight

• Research suggests that yoga has positive benefits. The effects of yoga have been studied on low back pain, asthma, weight loss, cancer survivors, and treatment of mental disorders. According to an October 2006 study in Psycho-Oncology, breast cancer survivors who participated in a seven-week yoga program had improved their quality of life, emotional function, and physical fitness, and fewer adverse gastrointestinal symptoms. However, according to the National Institutes of Health, more studies are needed before definitive conclusions can be made about yoga's use for specific health conditions.