We've been working on training folks to pray more at church and cell groups. Some of us have sore backs sometimes from getting "mature" saints back up off their knees. Once down they often can't get up. So we've got the question of position worked out.
And we're having some exercise sessions, starting with sitting and standing from a chair without pushing with arms.
Dr. Cho in Korea (million member church) likes to pray hours on his knees, actually must do that to be able to lead that church, but has cut it from 5 hours every morning to 2 hours due to aged knees. As I age I understand the need to move around with very rare seating sessions. Each person should simply find a position that will let you do some serious prayer. I really like a video of his that explains what we Americans need to adopt at
https://www.youtube.com/watch?v=cpAUjNmuRzg&feature=youtu.be
I prefer standing (stand praying Mk 11:25) with open Bible, using scriptures to talk covenant talk with the Father. My pattern of prayer comes from studying Jesus' prayers, to stand before God confident of what I say, and that he answers back through that very word being spoken. From that also comes many precious sermons and Bible lessons to share later.