Voluntary Efforts and Involuntary Effects in an Āsana Practice

4. Thus, with these two aspects there can be a lot of variables.
For example, using or not using the breath in Āsana
practice can be either a voluntary or involuntary aspect.
Thus, if you are not used to using the breath in an Āsana
and its quality is affected involuntarily, then we must apply
a voluntary action to improve or sustain the quality of the breath.
Or, if we are used to using the breath, the way we use it
can become fixed and unchanging – an involuntary effect.

Āsana Mudrā & Prāṇāyāma
– Collected Viniyoga of Practice Planning Principles

Āsana Mudrā & Prāṇāyāma
– Collected Practice Planning and Practice Theory Questions