4.29 Pranayama-parayanah, constantly practising control of the vital forces-i.e. they practise a form of pranayama called Kumbhaka (stopping the breath either inside or outside) ['Three sorts of motion of Pranayama (control of the vital forces) are, one by which we draw the breath in, another by which we throw it out, and the third action is when the breath is held in the lungs or stopped from entering the lungs.'-C.W., Vol.I, 1962, p. 267. 
Thus, there are two kinds of Kumbhaka-internal and external.]-; prana-apana-gati ruddhva, by stopping the movements of the outgoing and the incoming breaths-the outgoing of breath (exhalation) through the mouth and the nostrils is the movement of the Prana; as opposed to that, the movement of Apana is the going down (of breath) (inhalation); these constitute the prana-apana-gati, movements of Prana and Apana; by stopping these; some juhvati, offer as a sacrifice; pranam, the outgoing breath, which is the function of Prana; apane, in the incoming breath, which is the function of Apana-i.e. they practised a form of pranayama called Puraka ('filling in'); while tatha apare, still others; offer apanam, the incoming breath; prane, in the outgoing breath, i.e. they practise a form of pranayama called Recaka ('emptying out'). [Constantly practising control of the vital, forces, they perform Kumbhaka after Recaka and Puraka.]