Those who lift weights are likely to be familiar with this exercise and its benefits. Besides strengthening and helping to maintain your back in good working order, reverse back extension will make your back feel really good.
Because theres no need to strap or support your legs, you dont need any special gym equipment to do it, like you need in regular back extensions. You only need some kind of elevated surface to lie on your stomach, which allows your legs to hang free, or nearly free. With a little imagination, a place like that can be improvised in almost every environment.
While the exercise itself is about as safe as exercise can ever be, the setup for it can be dangerous. Make sure the platform where you do it is stable and can handle your weight, and doesnt accidentally collapse underneath you. Always when in doubt, find sturdier place.
The actual performance of the exercise is simple. After you have positioned yourself properly, arch your back and lift your legs slowly parallel to your body, then lower.
Here is a very good and complete description with pictures.
http://www.bodybuilding.com/fun/henkin16.htm (youll have to scroll down a little to find the reverse hyperextension.)
Like in all exercises, there are no absolute rights or wrongs. You must find the groove that feels good and doesnt hurt.
Do it for few sets every other day or so, and be prepared to say youre welcome when your lower back thanks you for it.
