Christian prayer is embodied prayer. In C.S. Lewis' Screwtape Letters we discovered an experienced devil giving lessons to a young temptor. At one point, the veteran orders his young charge to encourage his 'client,' a budding Christian, to envision prayer as something very 'interior' and 'mystical,' having little to do with posture or the position of the body. He wants the poor Christian to think that whether he stands, slouches, sits, or kneels is irrelevant to the quality of his communication with God. This, of course, is the Cartesian voice, the belief that our bodies and souls are independent and have little to do with each other.
But then consider the view of William James. In his Principles of Psychology, James writes that it is not so much sadness that makes us cry as crying that makes us feel sad. The body in a significant sense precedes the mind.
The same dynamic occurs when we pray. It is not so much keen feelings of devotion that force us to our knees as kneeling that gives rise to keen feelings of devotion.
If you're having difficulty in prayer today, try kneeling, or bowing, or making some sort of reverent gesture. The body often leads the mind into a deeper spiritual space. - Fr Robert Barron