The yoga transmitted from great master B.K.S. Iyengar is based on the precise alignment of the postures, to the aim to catch up a sense of inner and external balance.
The real alignment means that the inner mind catches up every cell and fiber of the external body.
The posture gradually maintained for a longer time, and, through the respiration, the perfect position is caught up.
Iyengar is famous for the perfection of its executions and in order to have invented supports, straps to help the students to execute the postures correctly.
For more info: B.K.S. Iyengar