This knee exercise should be used twice a day, 20 times each time, to strengthen the femoral muscles. 1. Sit with your legs straight on the floor, bed or sleeper chair, bend your feet toward yourself and press your knees down toward the floor to tense the femoral muscles, maintain this position, count from 1 to 5, and then relax completely. Shi Dongping, Department of Spine Surgery, China-Japan Friendship Hospital 2. Repeat as above, keeping the knee straight, raise the foot from the floor about 2-3 inches and count to 5. 3. Repeat as above, placing a rolled towel under the knee, with the knee straight, and counting to 5. This is the only exercise that allows the lower knee to be supported. (Never put the hair and under the knee while sleeping, this will be comfortable but will increase the possibility of deformity) 4. Take a sitting position, place the knee on the edge of the bed, straighten the knee completely and hold it, count to 5. After becoming proficient in these exercises, add weight to the foot in small amounts, using microwave mittens or socks tied together and hanging from the ankle, so that the most adapted starting weight, any increase in weight must be be gradual.