Vinyasa means that poses will flow from one to another in conjunction with the breath. Ashtanga Vinyasa Yoga is a dynamic form of yoga which promotes strength, flexibility, endurance and clarity of mind. Power Yoga is a general term used in the west to describe a vigorous, fitness-based approach to Vinyasa-style yoga.
The main difference of this style of Yoga to other styles is the focus on vinyasa, literally the intelligent putting together of things but taken in this style of asana practice as a variant of suryanamaskara practised between asana. The practice is a defined set of postures always done in the same order, which are combined with specific breathing patterns (ujjayi breathing). The purpose of vinyasa is to create heat in the body, which leads to purification of the body through increased circulation and sweating. It also improves flexibility, which allows the student to practice advanced asanas with reduced risk of injury. Other components of Yoga include bandhas (internal locks) and drishti (gaze), common to all forms of Hatha yoga asana.
The sequence begins with Sun-Salutations and standing poses, which is also called the "opening sequence," then the student moves to either the Primary, Intermediate, Advanced A, B, C, or D, depending on his or her skill level, and closes with a set of inversions called the "finishing sequence." Ashtanga Yoga is traditionally taught in Mysore style (supervised self practice). Each student moves through the practice at his or her own pace and level.