In Sanskrit, the word "Sankara" is described as a physical manifestation of tension in the body (knots). However, it is defined as "Defilement of the Mind".
The Yogis understood that there was a direct connection between the way one thinks & the tension generated in one's body & mind. It implies that one's thinking is related to one's physical, psychological & spiritual state.
At it's core, the "Sankara" is the karmic pattern that connects one to behaviors that rob the individual of life force. Certain behavioral patterns create fissures or leaks within one's bio-energy field & this is opens a door for "Energetic Leaking" to take place. This ultimately results in a state of low energy, which reflects out in one's mood, actions, thoughts & appearance.
The Yogis tell us, our spirit is part of the eternal energy source of creation. It is continuously generating "creative force" or just plainly, energy.
Through the Ashtanga (8 Limbs of Yoga) one begins the process of sealing these "Energetic Leaks". When these leaks are sealed, the individual can amass tremendous amounts of "creative force" or energy which allows them to attune to "higher" states of consciousness in which negative emotions cannot exist.
The Yogis tell us, our true normal or natural state, is Bliss.