Upvote:0
I don't know that its necessary, but its for the purpose of noticing the body sensations as they occur naturally. Moving would create a sensation and possibly the desire to create or cease a particular sensation. If you find difficulty in staying still maybe try mindfulness walking, and/or observances of daily activities
Upvote:0
I've read, say that it's good to sit completely still during practise. Does the same implay to body scan?
Yes. Ideally.
If it is difficult you can take the liberty to move. But staying still:
Upvote:1
I think there are things to learn by not moving but i doubt it is essential since it is nowhere mentioned in the Sutta afaik.