This question is asked a lot by students who have been practicing yoga
for a while but have never come across this particular challenging style.
Yin Yoga has the same goals and objectives as any other school of yoga; however, it directs the stimulation normally created in the asana portion of the practice deeper than the superficial or muscular tissues (which we are calling the yang tissues). Yin Yoga targets the connective tissues, such as the ligaments, bones, and even the joints of the body that normally are not exercised very much in a more active style of asana practice.
Suitable for almost all levels of students, Yin Yoga is a perfect complement to the dynamic and muscular (yang) styles of yoga that emphasize internal heat, and the lengthening and contracting of our muscles. Yin Yoga generally targets the connective tissues of the hips, pelvis, and lower spine.
While initially this style of yoga can seem quite boring, passive, or soft, yin practice can be quite challenging due to the long duration of the poses. We can remain in the postures anywhere from one to twenty minutes! Yin and yang tissues respond quite differently to being exercised. You need to experience this to really know what Yin Yoga is all about. After you have experienced it, even just once, you will realize that you have been doing only half of the asana practice.
Please note: Yin Yoga is not restorative yoga. Like all yoga practices, if the tissues you are targeting for exercise are damaged in some way, please give yourself a chance to heal before resuming your regular practice.