Back in the 1950s, the Royal Canadian Air Force commissioned Dr Bill Orban to come up with a simple exercise programme that their staff could use without any equipment. It became very popular with the general public too, and was probably the precursor to many of the exercise programmes that are available today. You’ll need to get a copy of the book to find out more detail. As with all home fitness and exercise plans, make sure that you go carefully and don’t hurt yourself. If you want some more specific advice about how to do sit-ups safely, have a look at the video that we did here.