So, after more than 3 decades of dutifully doing daily sit-ups and crunches (standards, bicycles, with and without weights, etc.)a recent trip to the physio, due to lower back pain, has left me feeling right mardy as I've been told to stop these immediately as they're likely to be the cause of the problem.

Sadly most of my old 1970s PE teachers are probably no longer around for me to litigate ( ) . Recommendations for the best (none apparatus requiring),alternative exercises, that I could perform on the kitchen floor, etc. would be much appreciated.