“… When you are tired of standing it is good that instead of sitting down comfortably you alternate the prayer so that it is sometimes said standing, sometimes kneeling and sometimes even sitting. When we don’t have the strength God provides for us whether we stand or kneel or set; even when we lie in bed we can pray. However if you have the physical ability the devil doesn’t joke around and he immediately brings on negligence,muddling of the mind and sleep. Many strugglers even get used to saying the prayer while walking in order to fight all the negligence and sleep.”
(Abbot Haralambos, on the ‘Jesus Prayer’)