Philosophy is mainly linked to existential questions, abstract concepts and metaphysical issues. However, many philosophers (maybe all of them) mentioned, studied and conceptualized the body. Some did it in an attempt to understand the cause behind the being just like the pre-Socratic did by studying nature, the physis; others focused more on the human body.
The body as a philosophical concept is underrated and it deserves our attention to comprehend life, energy and fitness! While the latter is never linked to philosophy, philosophers talked about it in between the lines.
In a round up of this subject, the principal problematic that always emerges about the body is its relation to the mind that you can check in my posts:
I will not mention in this post the many benefits of yoga that can be found a click away if you Google it. I am more interested to point out the specificities of yoga as a Body without Organs or BwO as I would refer to all along this post.
The BwO is a complex concept of the french philosopher Gilles Deleuze (1925-1995), one of the most compelling and intriguing philosophers:
The BwO refers to the deeper reality underlying some well-formed whole, constructed from fully parts. At the same time the BwO may also describe a relationship to one’s literal body, for example: in yoga (Deleuze gives the example of anorexia). To say it differently, the BwO is when the body stops working as an organism and starts to take on a certain perspective on reality, far from the normal behaviour of a human towards his or her body.
Deleuze began using the term in The logic of sense (1969), while discussing the experiences of playwright Antonio Artaud. Later the term BwO would expand in meaning and become one of the major concepts of Capitalism and Schizophrenia (in its 2 volumes written with Félix Guattari: Anti-Oedipus  and A thousand plateaus ). The BwO is an exploration of depths by rejecting the surface completely and returning to the body. Furthermore, Deleuze describes an undifferentiated unhierarchical realm that lies deeper than the world of appearances as it is told in mythologies. This underlying realm is an idea found in the yogic tradition saying that the Absolute lies deeper than the Veil of Maya or the illusionary appearances of what we see in our daily world. The daily world is the Veil of Maya (Matrix I, the movie, explores this idea). Deleuze explains the BwO by the image of the Dogon egg (or the Genesis of the cosmos) as a container of the germs of things that starts to develop within the egg:
Let’s go back to yoga and see how the the BwO of the yogic’s body is a Dogon egg where emotions, ideas, capacities, creativity, wisdom etc… start to develop and extend through inhuman postures (it hurts just by looking at them!) as shown in the pictures bellow:
Then, energy flows, body brain and mind are freed (the 3 are the same entity). This becoming is like any kind of birth: it takes time, it is violent and painful, it is the Nietzsche’s “becoming who you are”; at the end it is joyful! Therefore, yoga is a BwO experience leading towards new becomings, such as the Genesis of the cosmos!