Let’s look at lowering to the ground as a yoga transition and that knees, chest, chin is an alternative to chaturanga
Firstly what is the purpose of the pose? What are we trying to achieve here?
I don’t teach chaturanga to up dog as a transition anymore and rarely teach chaturanga at all but if the purpose is to lower to the ground then why not simply do and say that? When we look at chaturanga dandasana, the aim is to retain that flat plank like shape and descend whereas knees, chest, chin (ashtanga namaskara) requires a bend in the back to descend- so why is this confusingly used as a substitute?
Two different poses, requiring different form and often lost amongst the speed of a group class. If we stood these two poses up, it would be like offering a standing back bend as an alternative to tadasana, mountain pose.
We attach a lot of importance to poses and claims about their benefits that are not always biomechanically accurate, for example, ‘strength building’, so revert back to what is the aim- to simply lower down? To just do chaturanga for the sake of it, because this is what we are conditioned to expect to do in class, or is the aim to work in some back bends? If back bends are the aim, what’s our alternative to knees, chest, chin for those who don’t have that much extension available? How about a cow pose then lie down- does this achieve the aim?
So what should our alternative to chaturanga look like to retain characteristics of the original? How is that best described? Are we perpetuating complexity when the purpose of the pose is actually simply? How about simply lie down, come down on to your tummy or knees down, lie down? Whatever the alternatives and instruction it is definitely time to retire both poses as a substitute or alternative for each other when they both have different demands and requirements.