The Science of Yoga

Graceful. Common name for styles with interconnected poses.
    HATHA. Ancestral. The forerunner of all postural yoga, from medieval India. Modern forms tend to be gentle.
    IYENGAR. Precise and popular. Focuses on alignment and holding poses. Uses blocks, straps, and blankets to improve positioning and avoid injury. Trains instructors for at least two years, versus weeks for many styles.
    KRIPALU. Introspective. Puts emphasis on slowly introducing more challenging poses and holding them longer. Stresses awareness.
    KUNDALINI. Intense. Focuses on breathing, chanting, and meditating more than postures. Seeks to awaken kundalini energy at base of spine.
    POWER. Ashtanga on steroids. Many variations.
    SIVANANDA. Thorough. Promotes lifestyle of moderate poses, breathing, relaxation, vegetarian diet, and cheerful attitude.
    VINIYOGA. Gentle. Puts emphasis on Sun Salutations as warm-ups for more vigorous stretching.
    VINYASA. Fluid. Links body movements with breath in a continuous flow. A yoga ballet.
    YOGAFIT. Athletic. Targets gyms and health clubs. Mixes poses with sit-ups, push-ups, and other exercises.

Styles of Yoga
    ANUSARA. Lighthearted. Puts emphasis on alignment of limbsand upbeat philosophy. Uses props to ease postures.
    ASHTANGA. Serious. Features linked poses that flow together, as in Sun Salutation. Ties breath to postural flow. Physically demanding.
    BIKRAM. Hot and sweaty. Heats practice room to loosen joints and muscles. Features twenty-six poses and two breathing exercises. Challenging.
    FLOW. Graceful. Common name for styles with interconnected poses.
    HATHA. Ancestral. The forerunner of all postural yoga, from medieval India. Modern forms tend to be gentle.
    IYENGAR. Precise and popular. Focuses on alignment and holding poses. Uses blocks, straps, and blankets to improve positioning and avoid injury. Trains instructors for at least two years, versus weeks for many styles.
    KRIPALU. Introspective. Puts emphasis on slowly introducing more challenging poses and holding them longer. Stresses awareness.
    KUNDALINI. Intense. Focuses on breathing, chanting, and meditating more than postures. Seeks to awaken kundalini energy at base of spine.
    POWER. Ashtanga on steroids. Many variations.
    SIVANANDA. Thorough. Promotes lifestyle of moderate poses, breathing, relaxation, vegetarian diet, and cheerful attitude.
    VINIYOGA. Gentle. Puts emphasis on Sun Salutations as warm-ups for more vigorous stretching.
    VINYASA. Fluid. Links body movements with breath in a continuous flow. A yoga ballet.
    YOGAFIT. Athletic. Targets gyms and health clubs. Mixes poses with sit-ups, push-ups, and other exercises.

Chronology
    BCE
c. 2500
Clay seals of the Indus Valley civilization show figuresin poses that some scholars consider the earliest known precursors of yoga. The feet of the sitting figures are tucked beneath the torso, near the genitals. The depicted individuals are seen as seeking inner heat for magic power.
438
Athens dedicates the Parthenon.
    CE
c. 400
Patanjali writes Yoga Sutras , a series of aphorisms on enlightenment. It describes the value of sitting comfortably for meditation but says nothing of body twists and rearrangements despite its regular citation as a founding document of postural yoga.
c. 600
Tantra emerges in India and begins to spread through Asia. It worships female deities, roots its ceremonies in human sexuality, seeks supernatural powers for material gain, and cloaks its rites in secrecy.
c. 950
Erotic sculptures of the Lakshmana temple at Khajuraho in central India depict orgies, echoing Tantric themes.
c. 1200
Gorakhnath, a Hindu ascetic of western India, fuses traditions of Tantra and body discipline into Hatha yoga. The goal is to speed enlightenment.
1288
Marco Polo visits India.
c. 1400
Swatmarama writes Hatha Yoga Pradipika , an early text thatsurvives to modern times. It describes fifteen postures and many techniques of physiologic arousal.
1588
A Tantric text details a magic rite meant to let a man seduce a woman against her will.
c. 1650
The Yoni Tantra advises yogis to revere the female sex organ and engage in vigorous intercourse. Suggested candidates include sisters, actresses, and prostitutes.
1687
Newton posits universal gravitation and three laws of motion.
c. 1700
The Gheranda Samhita , a Hatha text, describes thirty-two postures and many techniques of physiologic arousal.
1772
Calcutta becomes the capital of British India.
1837
A wandering yogi undergoes live burial at the court of