Ashtanga yoga is a physically demanding form of yoga founded by Pattabhi Jois in early 1900s young adolescent males with physical strength and untamed minds (1).In a typical practice, it consists of a set routine sequence of asanas (postures) - which begins with sun salutations, follow by the standing sequence, primary - intermediate- advanced series and finally the closing sequence. Also a key part of practice which differentiates this type of yoga from the other forms is the practice of "vinyasas" - which essentially is series of lifting and jumping push ups when transitioning between postures, creating excess heat to remove ama (toxins) which makes this suitable for those looking for an aerobic, physical strenuous workouts. David Swenson, a well respected ashtanga yoga master demonstrates it beautifully in his video sequences.

Power Yoga is founded by Larry Schultz, an early student of Jois' is often regarded as the pioneer of power yoga that is popularized in the West (2). It might sometimes be referred as "Rocket yoga" as well. This form of yoga, as the name suggests is extremely physically demanding with heavy emphasis on the more vigorous asanas and the warrior sequences throughout the practice. A good demonstration video is performed by another well respected teacher - Rodney Yee.

Hatha Yoga is a system of yoga introduced by Yogi Swatmarama, a yogic sage in the 15th century in India (3). It can be considered an all round form of yoga routine - it focus on all the different aspects of yoga without placing too much emphasize on just postures. It encourages the building of physical strength and stamina via sun salutations, meditative practice also encourages development of concentration and sometimes teachers give discourses/stories of how to bring yoga out of the classroom/yoga mat into everyday living. Generally regarded as a gentle form of yoga, suitable for beginners and all levels alike. A typical slow flowing, gentle yet strong yoga class are best demonstrated by a video of these two guys (really cute as well lol) from New Zealand.

Iyengar Yoga is created by B.K.S. Iyengar, is a form of Hatha Yoga known for its use of props, such as belts, blocks, and blankets, as aids in performing postures. The props enable students to perform the postures correctly, minimising the risk of injury or strain, and making the postures accessible to both young and old. The development of strength, mobility, and stability are emphasized through the postures (4). The practice can be considered static and focus alot of correct alignment, core strength and flexibility. Postures are typically held for 10-20 minutes each. It is also considered as a complement yoga form to ashtanga yoga and Iyengar is great for those recovering from injuries, great for beginners to master asanas and those wanting to focus on flexibility.

Sivananda Yoga is a non propietary form of hatha yoga derived following the teachings of Swami Sivananda (5). This form of yoga is considered gentle and the emphasis is on full yogic breathing coupled with series of basic sequence - pranayama and frequent relaxation is involved. Chanting is often involved through the class as well and in between postures. Suitable for beginners and those looking for destress, mental relaxation and to learn more about yogic breathing techniques. A video demonstrating what a Sivanada class might look like.

Yin yoga was founded by Master Paulie Zink, who taught Paul Grilley. It's primary focus are on passive asanas that stimulates the parasympathetic nervous systems and connective joint tissues, which are involved in the unconscious regulation of internal organs- "rest and digest" activities. The yin yoga class consists of a routine 26 passive postures which are hold for as long as possible - usually 5 - 30 mins each (6).  The teachings of Paul Grilley incorporate ideas related to traditional Chinese medicine and Qiqong. Yin yoga can be incredibly restorative and are suitable for those seeking a completely restorative class, especially when you have not much physical energy but still wanting a way to de-stress and yoga at the end of day. A good video of Paul explaining the theory behind Yin yoga.

Anusara Yoga is a modern school of hatha yoga founded by John Friend in 1997 (7). Friend derives this school of yoga from Iyengar but re-incorporating elements of Hindu spirituality in it. A typical lesson involves an opening "lecture" by the instructor which discusses yoga and aspects of Hindu philosophy, followed by short chanting and then with a sequence of postures which focus on the alignment of energies, in particular "heart opening" postures. Lesson close with chanting. Suitable for people interested in philosophy behind yoga and perhaps those wanting to experiment and adventure the newer schools of yoga. A good demonstration of a complete Anusara yoga class - pay attention to opening and the postures are all focused on opening the heart chakras.

Jivamukti is derived from the Sanskrit word jivanmuktih, wherein jiva is the individual living being, and mukti – likemoksa – is liberation from the cycle of death and rebirth. Jivamukti classes are generally 90 minutes in length (8). Each class centers on a theme, based on a globally-set "focus of the month", which is explored through "dharma talks", Sanskrit chanting, reflections on the modern relevance of yoga scripture, music, asanas, pranayama and meditation. The largest portion of the class consists of vinyasa where the teacher guides the practitioner through a vigorous sequence of poses that is synchronized with steady breathing. Poses include inversions, such as headstand and shoulderstand. During the vinyasa phase the teacher assists practitioners with hands-on adjustments. The class concludes with a period of deep relaxation and meditation.

Insight yoga is what I would call a "middle path" yoga (9), inspired by Buddhist philosophies of incorporating both yin and yang asanas in the practice, with classes typically finishing off with extended periods of meditation to encourage the development of inner awareness.  Sarah Powers, a well respected yoga master discusses meditation and emphasizes that yoga is only a tool/stepping stone in helping yogis to attain proficiency in meditation and does not treat yoga as a pure physical exercise regime.