I’m convinced that some asanas of the Ashtanga yoga series are very hard to learn (if at all) if one doesn’t add drills or additional exercises. An asana like karandavasana cannot be learned by only repeating it three times every day or every second day. What shall one repeat? To fold the legs into lotus pose while in pincha mayurasana is very difficult. One must find a method to learn it.
Additional stretching and strength training may speed up the learning. Perhaps these drills make possible what otherwise wouldn’t be possible.
You’ll be able to do this asana in your next life never convinced me.
Sometimes I do so many additional exercises that I forget the reason why I started doing them.
At the end of my drills I’ll add the asanas as it’s supposed to be. Regarding urdhva dhanurasana it is to lift myself up three times and to hold this pose for 5 breaths. I can try to drop back, but I’m not yet there. To bow backwards from a standing position might make sense. The body gets used again to this backwards movement also when it’s just the start of it.
Drills and performance belong together.
This reminds me of the story of a salsa dancer. She said that people think she and her partner danced all day. But they worked on steps, on arm positions, on expression. They rarely started and finished the entire choreography.
Some asanas are so demanding that one has to exercise the different skills separately: Strength, flexibility, technique.