I think swimming is the only safe exercise to avoid negative externalities from the bit you're supposed to be strengthening.

Unless your back spasms and you drown.

That's considered very unsafe in medical circles.

Sorry not to be of more help.

I saw an article today headlined 'the revolutionary new plank that everyone is doing this week/nanosecond' or something like that. The very opposite of clickbait, so I remain none the wiser.

Take care, Bev.