Yoga is a Mind Body Practice that Creates Receptivity; Yoga Prepares the Body for Meditation by Harnessing in the mind
Receptivity is the allowing of life to happen without reaction. Yoga does this through creating specific geometric shapes with the body that help stimulate the energetic flow through it and align the mind to the receptive center of the body. The stimulated energy flow pressurizes to the center of the body which allows for it to flow effortlessly through the body and up into the head causing 'enlightenment' or a feeling of goodness.
Another way of looking at the science of yoga is by understanding that mind exists throughout the body. Throughout the day the mind draws on and stores information, both negative and positive. Yoga assists the individual to reach more blissful states of being by “wringing out the mind” through specific stretching which releases pent up negative energies (positive energies flow).
There are many different types of yoga which can balance the mind to the body in order to bring good health and longevity to the individual. Yoga also has the power to eliminate illness from the body through its practice which re-establishes and strengthens the alignments between the body and mind.
Just like meditation, yoga can work in a two-part segment of active and then non-active engagement (i.e.: Hatha Yoga). Here the individual will experience an active movement and then enter into non-activity (rest/ receptivity) which brings the two components (dark and light) of your being together in harmony. Harmony is always a balance between these two forces - the active male force and the receptive female force (energies personified).
Etymology of the word "yoga" stems from yoke. A yoke is worn by a bull to till the farmers field and bring yields. Yoga works in the very same way. Yoga yokes in the mind and causes it to align, tilling the fields of the body, in order to bring the yields (energy). These energetic yields move through the head to allow higher knowledge to permeate the individual. Eventually, over time, mind will completely transcend its busyness within the confinements of matter.