Iyengar yoga and Ashtanga yoga share the same root principles but differ in style and purpose. Ashtanga yoga is an ancient system of yoga handed down to Pattabhi Jois in 1927. Pattabhi Jois promoted a flowing style of yoga geared toward internal cleansing. Iyengar yoga is a therapeutic style of yoga introduced by B.K.S. Iyengar in 1966 in the publication "Light on Yoga."
Ashtanga yoga uses a vinyasa or flowing style of yoga that connects one breath to each movement. For example, you inhale as you raise your arms overhead, then exhale as you come into a forward fold. Ashtanga yogis perform the same postures in a preset sequence. There are six total sequences of poses that ascend in difficulty from primary to intermediate and advanced.
Iyengar yoga uses different techniques, sequences and timing. Instead of practicing a preset series, sequences vary and poses last longer to achieve different effects. Iyengar teachers create different approaches for individual students, employing proprs such as blankets, blocks and belts to modify poses for students depending on their ability level.
Practitioners of Ashtanga yoga seek to cleanse the body internally. Each sequence of poses is intended to build bodily heat, improve circulation and remove toxins via sweat. Philosophically, Ashtanga includes eight parts, or “eight limbs”: the yamas, niyamas, postures, breath control, sense control, concentration, meditation and absorption into the universal. Yamas are moral rules or restraints, such as nonviolence, and niyamas are beneficial practices for self-purification and study.
Iyengar yoga applies the eight limbs of Ashtanga yoga. However, the focus of Iyengar yoga is more therapeutic. Iyengar yoga possibly relieves aches and pains through correct alignment and pose modifications. Experienced Iyengar instructors assist students suffering from serious medical problems. To deeply absorb the healing effects of postures, Iyengar yogis hold poses for longer periods of time.