Lie down on flat bench so that your hips are on the edge. You can hold on to the bottom of the bench with your hands around where your hips are. With bended knees, lower your feet to the floor and then bring your legs up, 90 degrees, until your knees are over your hips. For a harder exercise, do this with straight legs. Do five sets of ten repetitions. This is a good lower abdominal muscle exercise, and works slightly different muscle fibers than other lower abdominal exercises.
Disclaimer: None of the above information can be taken as a substitute for advice from a medical professional such as a physician.
My third book, Pocket Guide to Fitness, is available on www.louizapatsis.com, http://www.authorhouse.com, www.bn.com and http://www.amazon.com. If you look up my name on those Web sites, you will find my other books The Boy in a Wheelchair and Life, Work and Play: Poems and Short Stories.