The reason why Ashtanga yoga is considered to be more effective over any other type of yoga is because it incorporates the eight limb parts, one of which being constructive breathing throughout the session.
The Ashtanga yoga series starts with Yoga Chikitsa. Yoga Chikitsa comprises of a set of 75 poses, commencing with surya namaskar or sun salutation and going through various back bends, standing and seated poses.