Quad Sets: The first exercise is to simply sit in a chair, and tighen your thigh muscles. Hold the contraction for at least six seconds. Repeat this six times and do at least three sets a day.
Short Arc Quads are the second set of exercises:
Hold you leg ALL the way up, with the knee straight. Then bend your knee only slightly, as shown.
Repeat this exercise 10 repetitions, and perform at least three sets a day.
Add a one pound ankle weight, or use an empty purse with a can of soup or tuna fish on the end of your ankle to add resistance.