Yogasanas are specialised postures of the body often imitating many of  the animal postures. Large number of Ásanas exist. The same ásana is often named differently and performed in various modes by different schools in our  country and abroad. All these are permutations and combinations of the two basic types of Ásanás.

Type 1 : Dynamic type of Ásanás  of the Hatha yoga
Type  2:  Relaxing type of Ásanás performed on the principles laid down by Patanjali in his Yoga aphorisms. 

The first school utilizes speed, repetitions, maintenance with strength (Isometric)  and often jerks in the mode of performance.

Relaxation, slow breathing  and calming the mind which form the triplet of Yoga featured in the Patanjali Yoga lore is adopted in the later years of man (above say 18 years) where the normal growth of the physical  frame  would  be  almost  complete. 

It  is  here  that  energy channelisation,  and  conservation  processes  are  harnessed  and the  overshoots  and  imbalance  of  the  bodily  functions  are  controlled. The real contribution of Yoga to modern world is found at this  level. It is this system that we have described in this chapter.