Yoga Sūtra Chapter Two verse 49

तस्मिन् सति श्वासप्रश्वास्योर्गतिविच्छेदः प्राणायामः ॥४९॥

tasmin-sati-śvāsa-praśvāsayoḥ gati-vicchedaḥ prāṇāyāmaḥ ||49||

Being in this,
dividing the motion of the exhalation and the inhalation
is extending the breath.

tasmin - in thissati - beingśvāsa - breathing or aspiration; hissing, snorting, panting; affection of the breath, hard breathing, asthmapraśvāsā - breathing in, inhaling; breath, respiration;gati - going, moving, gait, deportment, motion in generalviccheda - cutting asunder, cleaving, piercing, breaking, dividing, separation; interruption, discontinuance, cessation; caesura, pause in a verseprāṇāyāma - extending the breath

Commentaries and Reflections

Commentary by T Krishnamacharya:

Commentary by TKV Desikachar:

Prāṇāyāma leads to this. Pratyāhāra,
to see without the senses distracting or pulling the mind,
and Dhāraṇā –
To see without the mind losing itself,
because of colouring or expectations.
Dhyānam arises out of this.”

Commentary by S Ramaswami:

“The idea here is to use Kumbhaka.
Thus there must be long inhalation, long exhalation.

In this Sutra, one learns that one must attain Āsana Siddhi.
This means taking one Āsana and perfecting it to use as a base for the practice of Prānāyāma.”

Commentary by Paul Harvey: