Without practicing YAMA and NIYAMA, PRANAYAMA and ASANA are of no use.
Yoga is not practice, not exercise, it is not a technique. The science of yoga is, quite simply, the science of being in perfect alignment, in absolute harmony, in complete sync with the existence.
Yoga is for connecting the mind with the body.
To be for joyful and peaceful within yourself every moment of your life.
Yoga means union or to merge, while asana means a physical posture. Those postures that allow one to achieve union with ones higher nature are referred to as Yogasanas, one of the eight limbs of yoga.
Pranayama is the regulation of breath through certain techniques and exercise. With pranayama, the proper flow of life energy will happen. With proper pranayama procedures, one can supercharge the whole body.