Having strong knees is very important to help prevent injuries and to improve daily activities. As with any other strengthen program, a person will be able to perform the exercise without having to spend hours a day performing numerous exercises. Only a few exercise will have to me performed as the knee basically only moves forward and backwards and only those two motions will need to be strengthened.
Start by laying on your back and putting a rolled up towel of pillow under the knees. With the towel under the knees, push the knees down into the towel as hard as you can. Hold this position for 3-5 seconds then relax. Repeat the exercises so that 10 repetitions are performed with each leg every other day. This exercise will strength the quadriceps muscles or the muscles that straighten the knee.
To strengthen the back of the knee or the hamstrings, a person will start same as the exercises above but will pull the heel down into the bed or floor and just lift the knee slightly off the pillow or towel roll. Again, this position will be held for 3-5 seconds with 10 repetitions performed with each leg every other day.
These two exercises will set the base for strengthening the knees, and as a person progresses he/she can move to more advance exercises.