Assume the abdominal crunch position. Place your hands below you or hold onto a heavy piece of furniture or exercise equipment for stabilizatioin if you need that. Straighten your legs without locking your kees. Point your toes. Kick up and down, in a controlled, steady, vertical scissor fashion. Do not let your feet go below half a foot over the floor. Do five sets of ten repetitions. One repetition is your right and left leg both kicking.
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.