The Ashtanga Primary Series is called Yoga Chikitsa, meaning yoga therapy, because of the cleansing and toning effect it has on both body and mind. On a physical level the asanas (poses) of the Primary Series build strength and flexibility in the body, loosening tight muscles and realigning and detoxifying the body and nervous system. The series begins with forward bends, then twists and hip openers with a vinyasa between each asana.
On a mental level, through regular practice, focus, willpower, mind-body awareness and confidence are improved as we overcome the mental obstacles to our practice. On a subtle level the Primary series works therapeutically to clear obstacles in the energy channels in the body (known as Nadis).
This clearing of obstacles allows the Prana to flow more freely so the body and mind are therefore allowed to work more effectively.