The main reason we do asanas or postures in yoga is so we can sit longer in meditation. When our mind and body is stressed our whole body tightens up. When this happens our mind becomes more tense. Through yoga postures we begin to relax tense muscles and release the tension within. As a result the mind becomes more relaxed. We think more clearly and can see things for what they really are. The end result is we are able to sit in meditation for a longer period of time and connect to higher states of being.