Many people find that to take a walk will encourage them to pray as they walk but attention to the actual process of walking can be a prayer in itself.
We seldom give attention to this process and yet it involves the whole of the body. To ponder the activity of walking can lead to a sense of wonder at the complexity and (usually!) efficiency of the body God has given us.
In a large room or hall, or in a garden, invite members of the group to walk very slowly indeed around the outside of the room or garden, being aware of very deliberately lifting the leg... moving the leg forward... placing the heel, then the toe on the ground... being aware of the shift of weight in the whole body... and so on.
After a while ask people to pause and read aloud psalm 139. 12-16:
For you have created my inward parts; you knit me together in my mother's womb
I will praise you for you are to be feared; fearful are your acts and wonderful your works.
You knew my soul and my bones were not hidden from you; when I was formed in secret and woven in the depths of the earth
Your eyes saw my limbs when they were yet imperfect; and in your book were all my members written;
Day by day they were fashioned; and not one was late in growing.
Ponder this for a little while. A theme may now be introduced and people may choose to walk as slowly as their sense of balance will allow (still very slowly indeed, but at their own pace) while pondering a given theme or one of their own, e.g.:
I am on my journey to God...
I am one of the shepherds travelling to Bethlehem...
I am one of the wise men following the star...
I am accompanying Jesus as he goes into the desert for his forty days in the wilderness - or as he leaves the desert to begin his ministry...