I’ve been in a few parishes that have even tried to help with the question. Unfortunately, far too many of the efforts focus on practice and practicalities. Not enough of them focus on the inner logic of worship.
Spiritual practice is not just about the mind or the soul. We are not “Tinkerbell” trapped in bodies.
We are body, mind, and soul — an inextricable unity. What we do with our bodies is reflected in our souls. What our souls motivate us to do is enacted by the way in which we use our bodies.
So, do you kneel, sit, or stand? Many of the answers are imbedded in seasons of celebration and reflection. We stand during Easter, the saved, resurrected, and hoped for image of God. During Lent we kneel, aware of our created nature. During other times of the year we sit, beings mindful of our need for rest and trust.
The genius of worship is that it calls on us to act like the people that we are: neither masters of the universe, nor its cast offs. We are the beloved children of God, transparent in body, mind, and spirit to the one who made us.