My friend asked me, “Neel, I have only 4 limbs. How can I do Ashtanga Yoga? That involves 8 limbs!” Question is most appropriate.
Anga means limb. So, Ashtanga yoga is an Eightfold practice, no doubt. Now, who decides these 8 limbs? Traditionally, they are mentioned in the Yoga Sutras of Patanjali as Yama, Niyama, etc. Some other branches of Yoga practice have more than eight limbs, sometimes they have fewer.
Is it not obvious that each set of limbs will take you somewhere? e.g. if you follow the ones mentioned in the Patanjali’s sutras, they will land you in Samadhi state. They will not land you up the President’s seat!
What I am proposing in Adhiyoga is: first decide where you want to go. It is possible that you may change your want later. But, you must keep your want stable for certain time. Otherwise, you will go nowhere. Once you decide where you want to go, then form the limbs that are necessary to go there. If you can make them to be 8, then call that Ashtanga Adhiyoga! Or, if you want call it, Ashtanga Nicole, if your name is Nicole. etc.
In short, you have to decide where you want to go, and which and how many limbs you need. If you have only 4 limbs, try to use them most efficiently!