In my research there is a consistent Xi Sui Jing Shaolin form, that is a gentle form, usually sitting positions, if the story about Da Mo is correct, his goal being to find a way to strenghten the body and cultivate spirit at the same time, I think this form matches that goal.
I’ve seen Jeffrey teach similar methods (perhaps some the same?),
and I personally think they may be harmful to the lungs if the practice is forced.
It is not unlike the problems I had with excessive iron shirt breath packing in the 80’s –
it can stress the organs and blood vessels. I got red spots of vessels bursting on my skin.
There are ways to do it very gradually and gently,but take time and training will.
michael