Today, when I stood in my living room, practicing this Qigong, I made an insight.
While doing the motion called Diagonal knock, I realised that I had to use the same amount of energy and focus pulling back my hand, besides aligning my breath, as when I draw it forward. It's easy to give out - extend - but not always to take back - retrieve. This can of course also be translated into life wisdom; to not overgive, and to use the same force for keeping my energy. And, this is in fact also true for dancing ballet, modern or jazz, where we for example pull back our tendues, just as much as we push forward our feet on pointe. Motions with balance.