Place a bench or platform behind the smith bar. With the bar at upper chest height, position the bar on the back of the shoulders and grasp it on the sides. Extend one leg back and place top of foot on bench. The other front should be flat on the floor under your shoulder and hip. Do not place your knee in front of your toes. Disengage the bar and start squats with one leg in a normal position and one on the bench or platform.
Lower the body by flexing the knee and hip of the front leg until the knee of the rear leg is almost in contact with floor, so that the front knee is at 90 degrees and the back knee is almost at 90 degrees. Return to the original standing position. Do four sets of ten repetitions, and repeat with the other leg in the front.
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.