People go to prayer in many ways. Some fold their hands, some lift their arms, some are on their knees while others may sit or stand. Of course, God is available 24/7 and many pray in the night while they are in bed having a restless night. So I realize any prayer posture is basically acceptable as long as it is meant to put the focus on God's superiority. But in considering Jesus coming again, and "every knee shall bow", does that posture have more significance to God? Is our prayer posture meant to be a physical reminder to ourselves how we are suppose to humble ourselves before Him in prayer (and not just ask what we want done but to always remember to add "may Your will be done?") Do you suppose that He listens more intently when we ask from our knees or prostrate?
It is all about the attitude of the heart. If you kneel for recognition it is wrong. If your kneeling reminds you you are humble in the presence of a Holy God, will not your heart be right for approaching the throne? Listen to the Lord, He will impress on you how He wishes for you to approach Him each time. You approach a friend casually (as you go throughout the day) and you approach a King with bowing or kneeling...even prostrate...God should be both to you. Your dearest friend and most honored Master, King of Kings and Lord of Lords.